BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//6.4.7.2//EN TZID:Europe/Paris X-WR-TIMEZONE:Europe/Paris BEGIN:VEVENT UID:1-10@lptms.universite-paris-saclay.fr DTSTART:20120109T143000Z DTEND:20120109T143000Z DTSTAMP:20130418T124829Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-florent-krzakala-2/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Florent Krzakala - IPhT \, CEA-Saclay\, salle Itzykson - 9 Jan 12 14:30 DESCRIPTION:Statistical physics approach to compressed sensing\nFlorent KRZ AKALA\, Physico-Chimie Théorique UMR CNRS Gulliver ESPCI\nCompressed sens ing is triggering a major evolution in signal acquisition that changes com pletely the way we think about experiments and measurements. It indicates that most data\, signals and images\, that are usually compressible and ha ve redundancy\, can be reconstructed from much fewer measurements than wha t was usually considered necessary\, resulting in a drastic gain of time\, cost\, and measurement precision. The idea consists in sampling a sparse signal using some random projections\, and later using computational power for its exact reconstruction\, so that only the necessary information is measured. This has been applied to many situations\, from medical imagery and one-pixel-camera to confocal microscopy\, acoustic holography or DNA m icro-array analysis in biology.\nIn this talk\, I will start by a general instruction to compressed sensing for physicists and discuss the state of the art reconstruction algorithms. Currently used reconstruction technique s are however limited to acquisition rates still higher than the true dens ity of the signal. By using a mapping to a statistical physics problem\, a nd motivated by the theory of crystal nucleation\, I will introduce a new algorithm\, and new measurement protocols\, that achieves exact reconstruc tion of the signal even at measurement rates very close to the lowest poss ible ones.\nReferences: http://arxiv.org/abs/1109.4424 http://nuit-blanche .blogspot.com/p/teaching-compressed-sensing.html http://nuit-blanche.blogs pot.com/2011/09/stunning-development-in-breaking-donoho.html LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-11@lptms.universite-paris-saclay.fr DTSTART:20120110T110000Z DTEND:20120110T110000Z DTSTAMP:20130418T124746Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-serguei-brazovski/ SUMMARY:Séminaire du LPTMS : Serguei Brazovski - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Jan 12 11:00 DESCRIPTION:Strong local and nonequilibrium events in electronic systems.\n Serguei Brazovskii (LPTMS)\nThis review seminar will report on resent join t experimental/theoretical studies of low-dimensional electronic system wi th symmetry broken states in general\, mostly electronic crystals\, notabl y charge density waves\, with extensions to superconductors. The selected observations will be related to strong\, usually topologically nontrivial\ , perturbations of the order parameter under an external impact. The patte rn may be either static\, induced by either electric field or doping or di sorder\, or dynamic\, under the optical pumping – a major recent trend i n solid state physics. Problems in temporal evolution and remnants of symm etry breaking phase transitions span subjects from high energy and cosmolo gy to condensed matter. Recent optical study [1] of a far-from-equilibrium electronic charge ordering recovered coherent aperiodic undulations of th e order parameter\, critical slowing down of the collective mode\, and evo lution of the particle-hole gap. Numerical modeling with no fitting parame ters allowed interpreting the observations\, particularly the spatio-tempo ral distortions arising from “earthquakes” - annihilation events of to pological defects in depth of the sample. Strong perturbations are also r ecovered at the microscopic scale accessed by the new STM [2]\; there are the amplitude solitons playing a role of neutral spin carriers - spinons. Their aggregation into solitonic lattices gives rise to modulated phases i n spin-polarized superconductors or Charge Density Waves. Other experiment s on nano-junctions and their modeling recover the intrinsic reconstructio n by creating arrays of electronic vortices – dislocations. [1] In colla boration with D. Mihailovic group\, Ljubljana\, Slovenia. Yusupov\, et al\ , “Coherent dynamics of macroscopic electronic order through a symmetry breaking transition”\, Nature Physics\, 2010 [2] In collaboration with C \, Brun (Paris-Nano center)\, Z.Z. Wang (LPN\, Marcoussis)\, P. Monceau (I nst. Neel\, Grenoble). " Direct observation of spinons - the single-electr on solitons - in an electronic solid " \, PRL 2012\, to appear. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-8@lptms.universite-paris-saclay.fr DTSTART:20120113T170000Z DTEND:20120113T170000Z DTSTAMP:20130418T124735Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-elia-zarinelli-2/ SUMMARY:Soutenance de thèse : Elia Zarinelli - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Jan 12 17:00 DESCRIPTION:Spin-glass models and interdisciplinary applications\nThe main subject of this thesis is the physics of spin glasses. After their introdu ction in the 70s in order to describe dilute magnetic alloys\, spin-glass models have been considered prototype models to understand the behavior of supercooled liquids. Among the systems that can be described and analyzed using the language of disordered systems\, there are problems of combinat orial optimization. In the first part of the thesis\, we consider spin-gla ss models with Kac interactions in order to investigate the supercooled ph ase of glass-forming liquids. Afterwards\, we show how some features of sp in-glass models can be described by ubiquitous results of Random Matrix Th eory in connection with Extreme Value Statistics. Finally\, from the inter action of spin-glass theory and computer science\, we put forward a new al gorithm of immediate application in Financial problems.\nLa soutenance ser a suivie d'un pot en salle 201.\nAuditorium Irène Joliot-Curie\, bâtimen t 100\, Orsay CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-12@lptms.universite-paris-saclay.fr DTSTART:20120118T143000Z DTEND:20120118T143000Z DTSTAMP:20130418T124712Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-guilia-ferrini/ SUMMARY:Séminaire "fluides quantiques" : Guilia Ferrini - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Jan 12 14:30 DESCRIPTION:Macroscopic superpositions in the presence of phase noise in a Bose Josephson junction\nGuilia Ferrini\, LKB (CNRS - Université P. et M. Curie)\nA Bose Josephson Junction is a system composed of bosons which ca n occupy two modes which can be coupled. This system models either an ultr acold bosonic gas trapped in a double-well potential\, either a gas of ult racold bosons in two different hyperfine states\, trapped in the same harm onic potential. Both configurations have been experimentally realized\, an d found interesting applications\, e.g. in high-precision interferometry [ 1]. If the system is initially prepared in a coherent state and evolves af ter suppressing the coupling of the two modes\, at short time the state un dergoes squeezing [2]\, and at larger time macroscopic superpositions of c oherent states are formed [3]. One of the most relevant sources of noise i n such a system\, together with particle losses\, is phase noise\, resulti ng from stochastic fluctuations of the energies of the two modes. We addre ss the question how the presence of phase noise affects the formation of s queezed states and macroscopic superpositions\, showing in particular how these latter display an unexpected robustness against decoherence induced by the noise considered [4].\n[1] M. Albiez et al\, Phys. Rev. Lett. 95\, 010402 (2005)\; J. Esteve et al\, Nature 455\, 1216 (2008). [2] C. Gross e t al\, Nature 464\, 1165 (2010). M. Kitagawa and M. Ueda\, Phys. Rev. A 47 \, 5138 (1993). [3] F. Piazza\, L. Pezze and A. Smerzi\, Phys. Rev. A 78\, 051601 (2008)\; G. Ferrini\, A. Minguzzi and F.W.J. Hekking\, Phys. Rev. A 78\, 023606 (2008). [4] G. Ferrini et al\, Phys. Rev. A 82\, 033621 (201 0)\; Phys. Rev. A 84\, 043628 (2011). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-13@lptms.universite-paris-saclay.fr DTSTART:20120120T110000Z DTEND:20120120T110000Z DTSTAMP:20130418T124658Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-p-ribeiro/ SUMMARY:Séminaire du LPTMS: P. Ribeiro - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 20 Jan 12 11:00 DESCRIPTION:Thermal and quantum fluctuations in superconducting nanostruct ures\nP. Ribeiro\, MPI Dresden\nI will report a study on the combined eff ect of thermal and quantum fluctuations in a zero dimensional superconduc tor. Using path integral techniques\, the expression for the partition fun ction is obtained as well as the superconducting order parameter which inc lude both types of fluctuations. These results are valid for any temperat ure and to leading order in $\\delta/\\Delta_0$ where $\\delta$ is the mea n level spacing and $\\Delta_0$ is the bulk energy gap. Divergences arisi ng at low temperatures\, previously reported in the literature\, are avoid ed by identifying and treating non-perturbatively a low-energy collective mode. In the low and high temperature limit our results agrees with those from the random phase (RPA) and the static path approximation (SPA) respe ctively. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-14@lptms.universite-paris-saclay.fr DTSTART:20120124T110000Z DTEND:20120124T110000Z DTSTAMP:20130418T124634Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-y-tourigny/ SUMMARY:Séminaire du LPTMS: Y. Tourigny - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 24 Jan 12 11:00 DESCRIPTION:The Dyson-Schmidt approach to studying diffusion in a Levy envi ronment\nYves Tourigny\, Université de Bristol\nA diffusion may be though t of as a certain limit of a corresponding random walk. When the environme nt is random\, this limit is convenient because of the variety of analytic al tools that can brought to bear on its study. This talk will be concerne d with the approach pioneered by Bouchaud\, Comtet\, Georges and Le Doussa l in 1990\, which maps the diffusion problem to a disordered supersymmetri c quantum problem. I shall review the Dyson-Schmidt method for the calcula tion of the Lyapunov exponent and of the density of states when the disord er is modelled by a Levy process. The interpretation of these self-averagi ng quantities in the context of difusion will be discussed\, and a number of new "solvable" cases will be presented. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-16@lptms.universite-paris-saclay.fr DTSTART:20120202T143000Z DTEND:20120202T143000Z DTSTAMP:20120223T144319Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Andreas Wagner - LPTMS\ , salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 2 Fév 12 14:30 DESCRIPTION:The origins of evolutionary innovations\nAndreas Wagner (Univer sity of Zurich)\nLife can be viewed as a four billion year long history of innovations. These range from dramatic macroscopic innovations like the e volution of wings or eyes\, to a myriad molecular changes that form the ba sis of macroscopic innovations. We know many examples of such innovations -- qualitatively new phenotypes that provide an advantage to their bearer --\, but we have no systematic understanding of the principles that allow organisms to innovate. Most phenotypic innovations result from changes in three classes of systems: metabolic networks\, regulatory circuits\, and p rotein or RNA molecules. I will discuss evidence that these classes of sys tems share two important features that are essential for their ability to innovate CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-17@lptms.universite-paris-saclay.fr DTSTART:20120207T110000Z DTEND:20120207T110000Z DTSTAMP:20120302T141308Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-b-altshuler/ SUMMARY:Séminaire du LPTMS: B. Altshuler - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 7 Fév 12 11:00 DESCRIPTION:Dissipative coupling and weak lasing of exciton-polariton conde nsates\nB. Altshuler\, Columbia University\, New York\nIn spite of having finite life-time exciton-polaritons in microcavities are known to condense at strong enough pumping of the reservoir. I will discuss an analytical t heory of such Bose-condensates on a set of localized one-particle states: condensation centers. To understand physics of these arrays one has to sup plement the Josephson coupling by the dissipative coupling caused by the i nterference between the bosons emitted by different centers. Combination o f these couplings with the one-site interaction between the bosons leads t o a rich nonlinear dynamics. In particular\, a new regime of radiation app ears. This regime can be called weak lasing: the centers have macroscopic occupations and radiate coherently\, but the coupling alone is sufficient for stabilization. The system can have several stable states and switch be tween them. Moreover\, the time reversal symmetry in this regime is\, as a rule\, broken. A number of existing experimental puzzles find natural int erpretation in the framework of this theory. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-23@lptms.universite-paris-saclay.fr DTSTART:20120208T140000Z DTEND:20120208T140000Z DTSTAMP:20120208T224906Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-chris-westbrook/ SUMMARY:Seminaire Fluides Quantiques : Chris Westbrook - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 8 Fév 12 14:00 DESCRIPTION:Acoustic analog of the dynamical Casimir effect in a BEC\nChris Westbrook\, LCFIO\, Palaiseau\nAlthough we often picture the quantum vacu um as containing virtual quanta whose observable effects are only indirect \, it is a remarkable prediction of quantum field theory that the vacuum c an generate real particles when boundary conditions are suddenly changed. Thus the dynamical Casimir effect results in the spontaneous generation of photon pairs in an empty cavity whose boundaries are rapidly accelerating . A recent experiment has demonstrated this effect in the microwave regime using superconducting circuits. Acoustic analogs of this effect exist as well\, and Bose Einstein condensates are attractive candidates in which to study such analogs because their low temperatures promise to reveal quant um effects. I will - describe our group's work to develop an acoustic anal og to the dynamical Casimir effect by modulating the confinement of a Bose -Einstein - condensate. We are able to observe the generation of correlate d pairs of excitations both in the phonon and particle-like regimes in a p rocess which also formally resembles parametric down conversion..\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-24@lptms.universite-paris-saclay.fr DTSTART:20120209T140000Z DTEND:20120209T140000Z DTSTAMP:20120208T120014Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lpt-lptms-thierry-bodineau/ SUMMARY:Séminaire commun LPT-LPTMS : Thierry Bodineau - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 9 Fév 12 14:00 DESCRIPTION:Corrélations à longue portée dans des systèmes hors équili bre\nThierry Bodineau\, DMA\, ENS\nLes systèmes maintenus hors équilibre ont\, en général\, des corrélations à longue portée dans l’état s tationnaire. Nous décrirons quelques exemples de dynamiques stochastiques où ce type de corrélations peut être calculé (exclusion symétrique a vec batterie\, modèle ABC) et discuterons les singularités de ces corré lations à l’approche de la transition de phase. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-18@lptms.universite-paris-saclay.fr DTSTART:20120214T110000Z DTEND:20120214T110000Z DTSTAMP:20120208T115951Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thierry-champel/ SUMMARY:Séminaire du LPTMS: Thierry Champel - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 14 Fév 12 11:00 DESCRIPTION:Quasi-local quantum mechanics for disordered 2D electron gases at high magnetic fields\nThierry Champel\, Université Joseph Fourier\nWe have developed a semicoherent-state Green's function formalism which rigor ously describes quantum mechanical motion of an electron in a perpendicula r magnetic field and a 2D disordered potential landscape beyond the semi-c lassical guiding center picture. Our general technique is connected to the deformation (Weyl) quantization theory in phase space developed in mathem atical physics. For generic 2D quadratic potentials\, we exactly solve the limit of large cyclotron frequency (yet at finite magnetic length) where Landau level mixing becomes negligible\, both for the ordinary two-dimensi onal electron gas and for graphene (relativistic dispersion). Furthermore\ , the coherent-state representation is shown to display a hierarchy of loc al energy scales ordered by powers of the magnetic length and successive s patial derivatives of the local potential\, which allows one to devise con trolled approximation schemes at finite temperature for arbitrary and poss ibly disordered potential landscapes. As an application\, we derive genera l analytical expressions for the local density of states\, which allow us to account for many puzzling features recently observed in high magnetic f ield scanning tunneling spectroscopies on semiconducting heterostructures and graphene. Our recent theoretical developments in relation with percola tive transport at high magnetic fields will also be evoked.\nRefs.: T. Cha mpel and S. Florens\, PRB 80\, 125322 (2009)\; T. Champel and S. Florens\, PRB 82\, 045421 (2010)\; M. Flöser\, S. Florens\, and T. Champel\, PRL 1 07\, 176806 (2011). CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-25@lptms.universite-paris-saclay.fr DTSTART:20120301T110000Z DTEND:20120301T110000Z DTSTAMP:20120208T120129Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-a-petkovic-2/ SUMMARY:Séminaire du LPTMS: A. Petkovic - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 1 Mar 12 11:00 DESCRIPTION:Fluctuations of the superconducting order parameter in two dime nsions\nA. Petkovic\, ENS Paris\nTransport properties of 2D superconductin g systems can be very different from those of bulk superconductors because thermal and quantum fluctuations of superconducting order parameter are m ore pronounced and play a crucial role. First we focus on influence of sup erconducting fluctuations on dynamics\, while the system is in the normal state but close to the superconducting transition. In the fluctuational re gime\, we derive Ginzburg-Landau-type action under far-from equilibrium co nditions. Then\, utilizing it\, we calculate fluctuation-induced density o f states and Maki-Thomson- and Aslamazov-Larkin-type contributions to the in-plane electrical conductivity [1\,2]. We propose experimental setup whe re our results can be tested: thin superconducting film sandwiched between a gate and a substrate\, which have different temperatures and different electrochemical potentials.\nThen\, we concentrate on transport at lower t emperatures in close-to-equilibrium conditions investigating influence of quantum fluctuations on unbinding of vortex-untivortex pairs. We determine the temperature below which quantum fluctuations dominate over thermal fl uctuations and describe the transport in this quantum regime. The crossove r from quantum to classical regime is discussed and the quantum correction to the classical current-voltage relation is determined [3].\n[1] Phys. R ev. Lett. 105\, 187003 (2010) [2] Phys. Rev. B 84\, 064510 (2011) [3] Phys . Rev. B 80\, 212504 (2009) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-26@lptms.universite-paris-saclay.fr DTSTART:20120306T110000Z DTEND:20120306T110000Z DTSTAMP:20120223T142912Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-m-colangeli-2/ SUMMARY:Séminaire du LPTMS: M. Colangeli - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 6 Mar 12 11:00 DESCRIPTION:Fluctuation-dissipation relation for chaotic non-Hamiltonian sy stems\nMatteo Colangeli\, Politecnico di Torino\nIn dissipative dynamical systems phase space volumes contract\, on average. Therefore\, the invaria nt measure on the attractor is singular with respect to the Lebesgue measu re. As noted by Ruelle\, a generic perturbation pushes the state out of th e attractor\, hence the statistical features of the perturbation and\, in particular\, of the relaxation\, cannot be understood solely in terms of t he unperturbed dynamics on the attractor. This remark seems to seriously l imit the applicability of the standard fluctuation dissipation procedure i n the statistical mechanics of nonequilibrium (dissipative) systems. Yet\, it will be shown that the singular character of the steady state does not constitute a serious limitation in the case of systems with many degrees of freedom. The reason is that one typically deals with projected dynamics \, and these are associated with regular probability distributions in the corresponding lower dimensional spaces. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-31@lptms.universite-paris-saclay.fr DTSTART:20120307T090000Z DTEND:20120307T090000Z DTSTAMP:20120302T130044Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mini-symposium-pa lm-lumat/ SUMMARY:Mini Symposium PALM-LUMAT - Auditorium du LAL\, bât. 200 - 7 Mar 12 09:00 DESCRIPTION:Physics at the X-FEL\nLouis DiMauro\, Jan Lüning\, Patrick Aud ebert\, Boris Vodungbo CATEGORIES:seminars LOCATION:Auditorium du LAL\, bât. 200\, 15 Rue Georges Clemenceau\, Orsay\ , France GEO:48.6981864;2.1817680000000337 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Auditorium du LAL\, bât. 200:g eo:48.6981864,2.1817680000000337 END:VEVENT BEGIN:VEVENT UID:1-28@lptms.universite-paris-saclay.fr DTSTART:20120308T140000Z DTEND:20120308T140000Z DTSTAMP:20120223T145725Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lpt-lptms-masaharu-isobe/ SUMMARY:Séminaire commun LPT-LPTMS : Masaharu Isobe - LPT\, Salle 114\, b ât. 210 - 8 Mar 12 14:00 DESCRIPTION:Higher Order Parameters for Establishing Transient Crystals\nMa saharu Isobe\, Nagoya Institute of Technology\nThe long slow decaying pote ntial part of the stress autocorrelation function has been called the “m olasses tail” to distinguish it from the hydrodynamic origin of the long time tail in the velocity autocorrelation functions and to emphasize its relation to highly viscous glassy state. We are investigating the molasses tail in dense hard core fluids by using extensive Event-Driven MD simulat ion through the orientational autocorrelation functions[1\, 2]. Near the f luid-solid phase transition\, there exist three regimes in the relaxation of the pair orientational autocorrelation function\, namely the kinetic\, molasses(stretched exponential)\, and diffusional power decay. The most st riking observation through the bond orientatinal order parameter is the dr amatic increase of the transient nuclei cluster size near the freezing den sity[2]. We are now improving the alternative general methods based on the autocorrelation functions of higher order parameters even for quadruplet contributions (i.e. 8 point-correlation) to establish the transient nuclei \, which are composed of a few hundred hard particles in dense liquid syst em [3].\n\n[1] M. Isobe and B. J. Alder\, Mol. Phys. 107\, 609 (2009).\n[2 ] M. Isobe and B. J. Alder\, Prog. Theor. Phys. Suppl. 184\, 437 (2010).\n [3] M. Isobe and B. J. Alder\, in preparation.\n CATEGORIES:seminars LOCATION:LPT\, Salle 114\, bât. 210\, 15 Rue Georges Clemenceau\, Orsay\, France GEO:48.6981864;2.1817680000000337 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPT\, Salle 114\, bât. 210:geo :48.6981864,2.1817680000000337 END:VEVENT BEGIN:VEVENT UID:1-27@lptms.universite-paris-saclay.fr DTSTART:20120312T143000Z DTEND:20120312T143000Z DTSTAMP:20120208T120230Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-jean-philippe-bouchaud/ SUMMARY:Séminaire de la fédération PHYSTAT SUD : Jean-Philippe Bouchaud - IPhT\, CEA-Saclay\, salle Itzykson - 12 Mar 12 14:30 DESCRIPTION:Financial applications of random matrix theory : a short review \nJean-Philippe Bouchaud\, CFM\, Paris\nWe discuss the applications of ran dom matrix theory in the context of Financial markets and econometric mode ls\, a topic about which a considerable number of papers have been devoted to in the last decade. We intended to briefly review various theoretical results\, old ones (the Marcenko-Pastur spectrum and its various generaliz ations) and newer ones (random singular value decomposition\, eigenvector dynamics) as well as some concrete applications to portfolio optimization and out-of-sample risk estimation. CATEGORIES:seminars LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-29@lptms.universite-paris-saclay.fr DTSTART:20120313T110000Z DTEND:20120313T110000Z DTSTAMP:20120223T143223Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-j-bellissard-2/ SUMMARY:Séminaire du LPTMS: J. Bellissard - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 13 Mar 12 11:00 DESCRIPTION:Séminaire du LPTMS: J. Bellissard CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-30@lptms.universite-paris-saclay.fr DTSTART:20120315T140000Z DTEND:20120315T140000Z DTSTAMP:20120302T130416Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lpt-lptms-gregory-berkolaiko/ SUMMARY:Séminaire commun LPT-LPTMS : Gregory Berkolaiko - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Mar 12 14:00 DESCRIPTION:Universality in chaotic quantum transport : the concordance bet ween random matrix and semiclassical theories\nGregory Berkolaiko\, Texas A&\;M University\nElectronic transport through chaotic quantum dots exh ibits universal\, system independent properties which are consistent with random matrix theory. The observable quantities can be expressed\, via the semiclassical approximation\, as sums over the classical scattering traje ctories. Correlations between such trajectories are organized diagrammatic ally and have been shown to yield universal answers for some observables.\ nWe develop a general combinatorial treatment of the semiclassical diagram s by casting them as unicellular maps (graphs embedded on surfaces) and re lating them to factorizations of permutations. The expansion of transport quantities in inverse channel number corresponds to a genus expansion of t he combinatorial generating function. Taking previously calculated answers (Heusler et al\, 2006) for the contribution of a given diagram\, we prove agreement between the semiclassical and random matrix approaches to momen ts of the transmission amplitudes. The proof covers all orders\, all momen ts (including nonlinear)\, and systems with or without time reversal symme try. It explains the mathematics behind the applicability of random matrix theory to chaotic quantum transport. The streamlined calculation could al so pave the way for inclusion of non-universal effects.\nBased on joint wo rk with Jack Kuipers (Regensburg) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-32@lptms.universite-paris-saclay.fr DTSTART:20120320T110000Z DTEND:20120320T110000Z DTSTAMP:20120302T130348Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-c-cammarota/ SUMMARY:Séminaire du LPTMS: C. Cammarota - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 20 Mar 12 11:00 DESCRIPTION:Exploration of glass transition by pinning particles\nChiara Ca mmarota\, IphT Saclay\nUnderstanding the physical mechanism behind glass f ormation is a lasting problem in condensed matter physics. Interestingly f rom a theoretical point of view\, there are reasons to think that the visc ous slowing down of super-cooled liquids' dynamics\, preluding glass forma tion\, is due to a new kind of thermodynamic transition\, the glass transi tion. This is conjectured to be an entropy vanishing critical point with m any peculiarities\, notably an exponential growth of relaxation time.\nI w ill first point out why assessing the mere existence of the glass transiti on in real systems is particularly difficult\; indeed this issue is still largely questioned. Then I will present an idea\, based on pinning particl es at random from an equilibrium configuration\, recently designed to solv e this problem. Furthermore\, I will show our predictions for the static a nd dynamical behaviors of glassy pinned systems\, obtained through mean fi eld computations and a non-perturbative Renormalization Group approach. I will finally discuss why the idea of pinning particles could be used to pr oduce decisive tests for the existence of the glass transition in real sys tems. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-35@lptms.universite-paris-saclay.fr DTSTART:20120321T110000Z DTEND:20120321T110000Z DTSTAMP:20130418T124609Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-y-ikhlef/ SUMMARY:Séminaire exceptionnel du LPTMS: Y. Ikhlef - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 21 Mar 12 11:00 DESCRIPTION:Finite-size left-passage probability in percolation\nYacine Ikh lef\, Université de Genève\nThe main objects of study in 2D percolation are the percolation clusters and the lattice curves surrounding them (hull s). In the scaling limit\, Conformal Field Theory (CFT) and SLE allow the determination of correlation functions of these hulls. It turns out that s ome of these functions can be computed in finite size\, opening a way to r igorous proofs of conformal invariance and universality\, and uncovering s ome less understood aspects of CFT. I will present how\, using transfer-ma trix methods (Yang-Baxter\, qKZ)\, we obtained an exact expression of the probability for a percolation hull to touch the boundary\, on a strip of f inite width L. We also relate the left-passage probability in the Fortuin- Kasteleyn cluster model to the magnetisation profile in the open XXZ chain : this is a new geometrical application of Bethe-Ansatz techniques develop ed for spin chains. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-36@lptms.universite-paris-saclay.fr DTSTART:20120327T110000Z DTEND:20120327T110000Z DTSTAMP:20120314T182929Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-a-kundu/ SUMMARY:Séminaire du LPTMS: A. Kundu - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Mar 12 11:00 DESCRIPTION:Energy conduction in lattice systems\nAnupam Kundu\, ESPCI\nThe famous phenomenological law in the context of energy conduction is the Fo urier’s law\, which relates current density with local temperature gradi ent. Many computer simulation and analytical studies\, starting from micro scopic description\, show that Fourier’s law is not satisfied in low dim ensional systems. We will discuss the validity of this law in higher dimen sional lattice system. We will also discuss about large deviation of the e nergy current in a mass-disordered harmonic chain. In the end we present a more general linear response theory in this context to obtain a Green-Kub o type formula for open system. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-33@lptms.universite-paris-saclay.fr DTSTART:20120329T140000Z DTEND:20120329T140000Z DTSTAMP:20120302T130329Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lpt-lptms-olga-dimitrova/ SUMMARY:Séminaire commun LPT-LPTMS : Olga Dimitrova - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 29 Mar 12 14:00 DESCRIPTION:Specific heat of the Gaussian random bond Ising model on a squa re lattice\nOlga Dimitrova\nThe free energy and the specific heat of the t wo-dimensional Gaussian random bond Ising model on a square lattice are fo und with high accuracy using graph expansion and analysis of continuation of the high-temperature series. At low temperatures the specific heat reve als a zero-temperature criticality described by the power law $C\\propto T ^1+\\alpha$\, with $\\alpha= 0.65(10)$\, the result confirmed independentl y by counting many-body states in finite size samples. The interpretation of the free energy in terms of droplet excitations gives the density of th e two-level states\, that follows a novel power law $\\rho(\\epsilon)\\pro pto \\epsilon^\\alpha$ at low energies. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-39@lptms.universite-paris-saclay.fr DTSTART:20120403T110000Z DTEND:20120403T120000Z DTSTAMP:20130418T124556Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-f-ricci-tersenghi/ SUMMARY:Séminaire du LPTMS: F. Ricci-Tersenghi - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 3 Avr 12 11:00 DESCRIPTION:Adding loops to mean field approximation for disordered models\ nFederico Ricci-Tersenghi\, Université Sapienza\, Rome\nIn disordered mod els\, the extension of mean-field approximations in order to include the e ffects of short loops is a challenging task\, still largely open. Recently we have developed an analytical approximation (Replica Cluster Variationa l Method) and some related algorithms\, which are able to provide a much b etter description of finite-dimensional spin glass models\, than what the Bethe approximation does. I will summarize these results.   LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-40@lptms.universite-paris-saclay.fr DTSTART:20120405T143000Z DTEND:20120405T153000Z DTSTAMP:20130418T124539Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phsytat-sud-x-viennot/ SUMMARY:Séminaire de la Fédération PHSYTAT-SUD : X. Viennot - LPTMS\, sa lle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 5 Avr 12 14:30 DESCRIPTION:The combinatorics of some exclusion model in physics\nXavier Vi ennot\, LaBRI\, Université de Bordeaux\n The PASEP (partially asymmetric exclusion process) is a toy model in the physics of dynamical processes f ar from equilibrium (particles moving in a strip) and has been extensively studied by physicists. They gave explicit expressions for the stationary probabilities of the associated Markov chain\, in relation with some ortho gonal polynomials and some quadratic algebras. More recently\, combinatori sts gave a combinatorial approach to this model. I will give an introducti on to this hot and active subject\, which is at the crossroad of physics\, probability\, algebra and combinatorics. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-41@lptms.universite-paris-saclay.fr DTSTART:20120406T110000Z DTEND:20120406T120000Z DTSTAMP:20120328T071953Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-benoit-estienne/ SUMMARY:Séminaire exceptionnel: B. Estienne - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 6 Avr 12 11:00 DESCRIPTION:D-Algebra Structure of Topological Insulators\nBenoit Estienne\ nIn the quantum Hall effect\, the density operators at different wave-vect ors generally do not commute and give rise to the Girvin MacDonald Plazman n (GMP) algebra with important consequences such as ground-state center of mass degeneracy at fractional filling fraction\, and W_{1 + \\infty} symm etry of the filled Landau levels. We show that the natural generalization of the GMP algebra to higher dimensional topological insulators involves t he concept of a D-algebra formed by using the fully anti-symmetric tensor in D-dimensions. For insulators in even dimensional space\, the D-algebra is isotropic and closes for the case of constant non-Abelian F(k) ^ F(k) . .. ^ F(k) connection (D-Berry curvature)\, and its structure factors are p roportional to the D/2-Chern number. In odd dimensions\, the algebra is no t isotropic\, contains the weak topological insulator index (layers of the topological insulator in one less dimension) and does not contain the Che rn-Simons \\theta form (F^A - 1/3 A^A^A in 3 dimensions). The possible rel ation to D-dimensional volume preserving diffeomorphisms and parallel tran sport of extended objects is also discussed.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-37@lptms.universite-paris-saclay.fr DTSTART:20120410T110000Z DTEND:20120410T110000Z DTSTAMP:20120314T183031Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-g-montambaux/ SUMMARY:Séminaire du LPTMS: G. Montambaux - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 10 Avr 12 11:00 DESCRIPTION:Manipulation de points de Dirac\, du graphène aux atomes froid s\nGilles Montambaux\, LPS\, Université Paris-Sud\nJe considère plusieur s exemples de cristaux 2D où les propriétés électroniques de basse én ergie peuvent être décrites par un hamiltonien 2 X 2 avec un spectre pr ésentant plusieurs cônes de Dirac. Ces cônes sont caractérisés par un e relation de dispersion linéaire et\, tout aussi important\, par une “ charge” topologique reliée à une phase de Berry associée à la struct ure spinorielle de la fonction d’onde. Par exemple\, le spectre du graph ène présente une paire de cônes de Dirac avec des phases de Berry oppos ées. On étudie sous quelles conditions ces cônes peuvent être manipul és\, créés ou supprimés par des modifications des paramètres de bande \, sous la condition de conservation de la charge totale.\nNous avons trou vé deux scénarios: (1) La fusion de points de Dirac avec des “charges ” opposées est une transition topologique entre une phase semi-métalli que et un isolant\, avec un spectre remarquable\, “semi-Dirac” à la t ransition : il est linéaire dans une direction et massif dans l’autre ! (2) Une paire de points de Dirac avec la même charge peut aussi fusionne r en un point unique avec une charge double\, et un spectre quadratique sa ns gap. C’est le cas dans les bicouches de graphène. Pour les deux scé narios\, on a obtenu un hamiltonien universel qui décrit continûment le couplage entre les vallées.\nRécemment\, une très belle expérience ave c des atomes ultrafroids dans un réseau optique a permis la réalisation de « graphène artificiel »\, dans lequel il est possible de déplacer et fusionner les points de Dirac et d’étudier le scénario (1) prévu théoriquement. L’évolution du spectre et la transition topologique son t révélés par les oscillations de Bloch d’un gaz de Fermions (40K). O n mesure la probabilité Landau-Zener de transition entre les deux bandes et on caractérise ainsi les points de Dirac qui relient les deux bandes. Nous avons calculé cette probabilité de transition en utilisant l’hami ltonien universel qui décrit la fusion des points de Dirac et j’expliqu erai l’accord remarquable que nous avons obtenu avec les résultats exp érimentaux.\nFinalement je discuterai d’autres scénarios de fusion de points de Dirac\, en particulier dans les bicouches de graphène sous cont rainte ou dans des gaz ultrafroids en présence de champs de jauge artific iels. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-42@lptms.universite-paris-saclay.fr DTSTART:20120411T143000Z DTEND:20120411T153000Z DTSTAMP:20120411T122136Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-d-gangardt/ SUMMARY:Séminaire Fluides Quantiques: D. Gangardt - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 11 Avr 12 14:30 DESCRIPTION:Quantum Grey Solitons in Confining Potentials - Trapped Lieb II mode\nDimitry Gangardt\, University of Birmingham\nWe define and study ho le-like excitations (the Lieb II mode) in a weakly interacting Bose liquid subject to external confinement. These excitations are obtained by semicl assical quantization of grey solitons propagating on top of a Thomas-Fermi background similarly to the uniform case. Radiation of phonons by an acce lerated gray soliton leads to a finite lifetime of these excitations. We c alculate the life-time of grey solitons and show that\, for a large number of trapped atoms\, most of the Lieb II levels can be experimentally resol ved.\nD. C. Wadkin-Snaith and D. M. Gangardt\, Phys. Rev. Lett. 108\, 0853 01 (2012) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-34@lptms.universite-paris-saclay.fr DTSTART:20120417T110000Z DTEND:20120417T110000Z DTSTAMP:20130418T124525Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-m-tamm/ SUMMARY:Séminaire du LPTMS: M. Tamm - LPTMS\, salle 201\, 2ème étage\, B ât 100\, Campus d'Orsay - 17 Avr 12 11:00 DESCRIPTION:Overlap of Brownian trajectories\nMikhail Tamm\, Physics Dept.\ , Moscow State University\nI will present our recent results on the mean n umber of common sites visited by several random walk trajectories of a giv en length starting at a given distance from each other. I will start with the formulation of the problem and show the general solution in the Laplac e space which is viable for any Markovian random walks in any geometry\; t hen proceed to consideration of the Brownian motion in two specific cases: that of several trajectories starting from a common center\, and that of two trajectories starting at a given distance. For the first case\, I will show the existence of three distinct regimes depending on the dimensional ity of space and the number of trajectories\, and construct the correspond ing morphology diagram. For the second case\, I will show that in 1D and 3 D it is possible to do the reverse Laplace transform and get the explicit expressions for the scaling functions of interest\, which turn out to be i n perfect agreement with computer simulation results.\nThe work is done in collaboration with S. Majumdar (LPTMS)\, A. Ilyina (Moscow State Universi ty)\, and D. Grebenkov (Ecole Polytechnique). CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-47@lptms.universite-paris-saclay.fr DTSTART:20120509T110000Z DTEND:20120509T110000Z DTSTAMP:20130201T114236Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-iosif-bena-2/ SUMMARY:Séminaire du LPTMS: Iosif Bena - LPTMS-batiment 100\, salle des co nseils - 9 Mai 12 11:00 DESCRIPTION:Trous noirs dans la Théorie des Cordes\nIosif Bena (IPhT Sacla y)\nString theory is a quantum theory of gravity\, and has had several ama zing successes in describing black holes. After discussing some paradoxes related to the physics of black holes\, I will explain how to construct bl ack holes in string theory\, and how to count their entropy. I will then d escribe a new paradigm in the study of black holes that recent research ap pears to support: a black hole solution gives only a thermodynamic descrip tion of the physics\, and the "microscopical" statistical description of t he physics is given by a very large number of microstate geometries\, that look the same as a black hole from far away\, but do not have a horizon. LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-45@lptms.universite-paris-saclay.fr DTSTART:20120510T143000Z DTEND:20120510T143000Z DTSTAMP:20130201T114601Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-neil-oconnel/ SUMMARY:Séminaire de la fédération phystat-sud: Neil O'Connell - IPhT\, amphi Bloch\, CEA-Saclay - 10 Mai 12 14:30 DESCRIPTION:Titre: Exactly solvable random polymers and their continuum sca ling limits\nOrateur: Neil O'Connell (Université de Warwick)\nRésumé: I will describe some recent developments on random polymer models which hav e an underlying integrable structure which makes them exactly solvable. Th e continuum scaling limits of these models are related to the KPZ equation and have some remarkable properties. Parts of this talk will be based on joint work with Ivan Corwin\, Timo Seppalainen\, Jon Warren and Nikos Zygo uras. LOCATION:IPhT\, amphi Bloch\, CEA-Saclay\, CEA - Saclay\, Saclay\, France GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, amphi Bloch\, CEA-Saclay:geo:48.7366 8,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-38@lptms.universite-paris-saclay.fr DTSTART:20120515T110000Z DTEND:20120515T110000Z DTSTAMP:20130201T114739Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-m-richard/ SUMMARY:Séminaire du LPTMS: Maxime Richard - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 15 Mai 12 11:00 DESCRIPTION:One dimensional polariton condensate in semiconductor microstru cture\nMaxime Richard\, Institut Néel\nIn semiconductor nanostructures li ke microcavities\, when the so-called exciton-photon strong coupling regim e is reached\, the proper eigenstates of the system are mixed exciton-phot on states called exciton-polaritons. This last decade\, 2-dimensional micr ocavity exciton-polaritons in the quantum degenerate regime have shown fas cinating properties e.g. polariton lasing\, Bose-Einstein condensation and superfluidity [1]. Recently\, new systems and new geometries are being de veloped in order to study the polariton physics of dimensionality D\nRecen tly\, new systems in the strong coupling regime like ZnO microwires have b een introduced [4]. We show that polaritons in these systems have unusual characteristics: they have only one spatial degree of freedom and they exh ibit low thermal decoherence thanks to a large Rabi splitting. Furthermore \, they are robust at large density and high temperature owing to the larg e exciton binding energy of ZnO. Striking differences exist also in the co ndensate phase. At cryogenic temperature and under strong pulsed optical e xcitation\, a transient polariton condensate is formed by stimulated relax ation into a state with a 97% excitonic fraction\, i.e. with a mass 15 tim es heavier than for polaritons usually encountered in planar microcavities . This feature is enabled by the combination of a large Rabi splitting (30 0 meV) and a very small inhomogeneous broadening of excitons (~1 meV).\n[1 ] L.S. Dang et al. Phys. Rev. Lett. 81 3920 (1998) \; J. Kasprzak et al.\, Nature 443\, 409 (2006) \; A. Amo et al.\, Nat. Phys. 5\, 805 (2009). [2] E. Wertz et al.\, Nat. Phys. 6\, 840-864 (2010). [3] G. Christmann et al. Appl. Phys. Lett. 93\, 051102 (2008). [4] L. Sun et al\, Phys. Rev. Lette rs 100\, 156403 (2008)\; A. Trichet et al.\, Phys. Rev. B 83\, 041302R (20 11) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-43@lptms.universite-paris-saclay.fr DTSTART:20120529T110000Z DTEND:20120529T120000Z DTSTAMP:20130418T124512Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mathias-albert/ SUMMARY:Séminaire du LPTMS: Mathias Albert - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 29 Mai 12 11:00 DESCRIPTION:Waiting times distribution of electrons flowing across mesoscop ic conductors\nMathias Albert (LPS\, Orsay)\n Electronic transport throug h mesoscopic devices is known to be stochastic due to the quantum nature o f the charge carriers. The noise power spectrum as well as the Full Counti ng Statistics (FCS) provide many important informations about the system u nder study as it has been shown during the past 20 years. However the dist ribution of waiting times (WTD) between the detection of several charge ca rriers has been recently investigated and shown to be very powerful to und erstand the short time physics and correlations between different elementa ry events [1-3] in the same spirit than the level spacing distribution in the spectral statistics of complex systems. In this talk we will use this quantity to discuss the short time correlations in a perfect one dimension al quantum channel with a quantum point contact. Although the system is ex tremely simple\, the WTD reveals quite striking transport properties that can be explained using random matrix theory in a totally unexpected contex t. Some other quantum states\, such as a train of Lorentzian pulses [4] wi ll be also considered and the relation between the WTD and the FCS also di scussed. [1] T. Brandes\, Ann. Phys. (Berlin) 17\, 477 (2008). [2] M. Al bert\, C. Flindt and M. Buttiker\, Phys. Rev. Lett. 107\, 086805 (2011). [2] M. Albert\, G. Haack\, C. Flindt and M. Buttiker\, Phys. Rev. Lett. 10 8\, 186806 (2012). [3] J. Keeling\, I. Klich\, L. S. Levitov\, Phys. Rev. Lett. 97\, 116403 (2006).\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-48@lptms.universite-paris-saclay.fr DTSTART:20120605T110000Z DTEND:20120605T110000Z DTSTAMP:20120514T103938Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marc-rabaud/ SUMMARY:Séminaire du LPTMS: Marc Rabaud - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 5 Juin 12 11:00 DESCRIPTION:Est-ce que le sillage des canards sur le lac du Mail est toujou rs à 19°?\nMarc Rabaud (FAST\, Orsay)\nTout objet se déplaçant à l'in terface de deux fluides peut générer des ondes de surface et subit alors un force de traînée. Kelvin (1887) a montré que les ondes de gravité sont confinées dans un triangle à l'arrière de l'obstacle qui a un angl e constant quelle que soit la vitesse de l'obstacle. Nous montrerons en im ages issues de simulations et d'expériences en quoi la longueur capillair e mais aussi la taille finie de l'obstacle peuvent modifier ce résultat. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-46@lptms.universite-paris-saclay.fr DTSTART:20120606T143000Z DTEND:20120606T143000Z DTSTAMP:20130418T124459Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-iosif-bena/ SUMMARY:Séminaire "Fluides Quantiques" du LPTMS : David Papoular - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Juin 12 14:30 DESCRIPTION:Cooling by heating a superfluid\nDavid Papoular (BEC Center\, T rento)\nWe consider a uniform superfluid confined in two compartments conn ected by a superleak and initially held at equal temperatures. If one of t he two compartments is heated\, a fraction of the superfluid will flow thr ough the superleak. We show that\, under certain thermodynamic conditions\ , the atoms flow from the hotter to the colder compartment\, contrary to w hat happens in the fountain effect observed in superfluid Helium. This flo w causes quantum degeneracy to increase in the colder compartment. In supe rfluid Helium\, this novel thermomechanical effect takes place in the phon on regime of very low temperatures. In dilute quantum gases\, it occurs at all temperatures below Tc. The increase in quantum degeneracy reachable t hrough the adiabatic displacement of the wall separating the two compartme nts will also be discussed. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-57@lptms.universite-paris-saclay.fr DTSTART:20120608T110000Z DTEND:20120608T121500Z DTSTAMP:20120606T054247Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-mikhail-zvonarev/ SUMMARY:Séminaire exceptionnel du LPTMS : Mikhail Zvonarev - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 8 Juin 12 11:00 DESCRIPTION:\nRelaxation of the mobile impurity injected into one-dimension al quantum liquid\nMikhail Zvonarev (LPTMS)\nI will discuss a time evoluti on of the mobile impurity injected with an arbitrary velocity into one-dim ensional quantum liquid. I will demonstrate that the impurity holds a fini te fraction of its initial momentum even after infinitely long waiting tim e and that the impurity momentum oscillates during the equilibration proce ss. To obtain these results a combination of exact (Bethe Ansatz)\, variat ional\, and numerical methods were used. I will finally overview the exper iments in the ultracold atomic gases which are related to impurity dynamic s.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-44@lptms.universite-paris-saclay.fr DTSTART:20120612T110000Z DTEND:20120612T120000Z DTSTAMP:20130418T124442Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-j-reingruber/ SUMMARY:Séminaire du LPTMS: J. Reingruber - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 12 Juin 12 11:00 DESCRIPTION:Phototransduction in rod and cone photoreceptors\nJürgen Reing ruber\, Ecole Normale Superieure\nVision is initiated with the absorption of light by rod and cone photoreceptors in the retina\, which are highly s pecialized sensory cells. Rods sustain monochrome night vision\, while con es maintain colorful day vision. Phototransduction is the process by which light is transformed into an electrical signal in photoreceptors\, a topi c that still moves at the forefront of signal transduction research. In th is talk I will first give an introduction to phototransduction in rod and cone photoreceptors. Despite of decades of intense research\, an overall b iophysical model that integrates and explains all the experimental data is still missing. For example\, it was realized already 70 years ago that ro ds are so sensitive that they can reliably detect the absorption of a sing le photon. However\, up to today it is still not fully understood what det ermines the high fidelity of a rod cell. Based on novel experimental recor dings of the background noise and single photon response in genetically mo dified mouse rods (collaboration with G. Fain (UCLA))\, I will present rec ent results obtained from a combined effort between biophysical modeling\, mathematical analysis and numerical simulations to understand the molecul ar mechanisms underlying the single photon response. Finally\, I will brie fly discuss the importance of molecular modeling to improve new optogeneti c treatments of retinal diseases caused by photoreceptor degeneration (col laboration with S. Picaud (Institut de la Vision\, Paris)). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-49@lptms.universite-paris-saclay.fr DTSTART:20120613T143000Z DTEND:20120613T153000Z DTSTAMP:20130201T114816Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-labo ratoire-j-harrisson/ SUMMARY:Séminaire du LPTMS: Jon Harrison - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 13 Juin 12 14:30 DESCRIPTION:New forms of quantum statistics on graphs\nJon Harrison\, Baylo r University\nWe consider the quantum statistics of indistinguishable part icles on a graph. In three dimensions quantum states are symmetric or anti -symmetric under exchange of pairs of identical particles\, corresponding to Bose-Einstein or Fermi-Dirac statistics respectively. Restricting the p articles totwo dimensions topologically inequivalent exchange paths corres pond to elements of the braid group instead of the symmetric group. This o pens up the possibility of Anyon statistics on a surface\, characterized b y a single free choice of an exchange phase. We consider the case when the particles are further restricted to lie on a quasi-one-dimensional networ k\; a graph. For sufficiently complex graphs new forms of statistics emerg e. Quantum statistics of indistinguishable particles on graphs may be char acterized by multiple independent free Anyon phases and discrete-valued ph ases. Possible applications of the new forms of quantum statistics include topological quantum computing\, the fractional quantum Hall effect\, supe rconductivity\, topological insulators and molecular physics. This is work with JP Keating and JM Robbins at Bristol University. Proc. R. Soc. A doi :10.1098/rspa.2010.0254 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-52@lptms.universite-paris-saclay.fr DTSTART:20120614T143000Z DTEND:20120614T153000Z DTSTAMP:20120521T075639Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phsystat-sud-matteo-marsili/ SUMMARY:Séminaire de la Fédération PHSYSTAT-SUD : Matteo Marsili - LPTMS \, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Juin 12 14:30 DESCRIPTION:Collaboration in social networks\nMatteo Marsili ( The Abdus Sa lam International Center for Theoretical Physics\, Trieste)\nThe very noti on of social network implies that linked individuals interact repeatedly w ith each other. This notion allows them not only to learn successful strat egies and adapt to them\, but also to condition their own behavior on the behavior of others\, in a strategic forward looking manner. Game theory of repeated games shows that these circumstances are conducive to the emerge nce of collaboration in simple games of two players. We investigate the ex tension of this concept to the case where players are engaged in a local c ontribution game and show that rationality and credibility of threats iden tify a class of Nash equilibria—that we call “collaborative equilibria ”—that have a precise interpretation in terms of subgraphs of the soci al network. For large network games\, the number of such equilibria is exp onentially large in the number of players. When incentives to defect are s mall\, equilibria are supported by local structures whereas when incentive s exceed a threshold they acquire a nonlocal nature\, which requires a “ critical mass” of more than a given fraction of the players to collabora te. Therefore\, when incentives are high\, an individual deviation typical ly causes the collapse of collaboration across the whole system. At the sa me time\, higher incentives to defect typically support equilibria with a higher density of collaborators. The resulting picture conforms with sever al results in sociology and in the experimental literature on game theory\ , such as the prevalence of collaboration in denser groups and in the stru ctural hubs of sparse networks.\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-51@lptms.universite-paris-saclay.fr DTSTART:20120619T110000Z DTEND:20120619T120000Z DTSTAMP:20130418T124426Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-r-santachiara-2/ SUMMARY:Séminaire du LPTMS: R. Santachiara - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 19 Juin 12 11:00 DESCRIPTION:Emerging integrable structures in Abelian and non-Abelian quant um Hall liquids\nRaoul Santachiara\, LPTMS\nI'll review the main propertie s of Laughlin incompressible quantum liquids. I will discuss in particular the low-energy edge excitations and their connection to the area-preservi ng transformations. The corresponding algebraic structures suggest that th e integrable 1D quantum model Calogero-Sutherland plays a crucial role. Re cently\, by using conformal field theory techniquesm we have shown that a similar scenario is emerging in the case of the non-Abelian quantum Hall l iquids. I will discuss the main results trying to focus only the general i deas behind this approach. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-58@lptms.universite-paris-saclay.fr DTSTART:20120620T143000Z DTEND:20120620T153000Z DTSTAMP:20120613T060121Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-du-lptms-layla-hormozi/ SUMMARY:Séminaire "Fluides quantiques" du LPTMS : Layla Hormozi - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Juin 12 14:30 DESCRIPTION:Fractional Quantum Hall Effect of Lattice Bosons Near Commensur ate Flux\nLayla Hormozi (National University of Ireland in Maynooth)\nWe s tudy interacting bosons on a lattice in a magnetic field. When the number of flux quanta per plaquette is close to a rational fraction\, the low ene rgy physics is mapped to a multi-species continuum model: bosons in the lo west Landau level where each boson is given an internal degree of freedom\ , or pseudospin. We find that the interaction potential between the bosons involves terms that do not conserve pseudospin\, corresponding to umklapp processes\, which in some cases can also be seen as BCS-type pairing term s. We argue that in experimentally realistic regimes for bosonic atoms in optical lattices with synthetic magnetic fields\, these terms are crucial for determining the nature of allowed ground states. In particular\, we sh ow numerically that certain paired wavefunctions related to the Moore-Read Pfaffian state are stabilized by these terms\, whereas certain other wave functions can be destabilized when umklapp processes become strong.\n(Onli ne pre-print: http://arxiv.org/abs/1109.3434) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-56@lptms.universite-paris-saclay.fr DTSTART:20120703T110000Z DTEND:20120703T120000Z DTSTAMP:20130418T124359Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gabriel-tellez-acosta/ SUMMARY:Séminaire du LPTMS: Gabriel Téllez Acosta - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 3 Juil 12 11:00 DESCRIPTION:Expanded Vandermonde powers\, Jack polynomials and the two-dime nsional one-component plasma\nGabriel Téllez\, Departamento de Física\, Universidad de Los Andes\, Bogotá\, Colombia\nThe two-dimensional one-com ponent plasma (2dOCP) is a system of N mobile particles of the same charge q on a surface with a neutralising background. The Boltzmann factor of th e 2dOCP at temperature T can be expressed as a Vandermonde determinant to the power Gamma = q^2/(k_B T). Recent advances in the theory of symmetric and anti-symmetric Jack polymonials provide an efficient way to expand thi s power of the Vandermonde in their monomial basis\, allowing the computat ion of several thermodynamic and structural properties of the 2dOCP for N values up to 14 and Gamma equal to 4\, 6 and 8. In this work\, we present some applications of this formalism. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-63@lptms.universite-paris-saclay.fr DTSTART:20120911T110000Z DTEND:20120911T120000Z DTSTAMP:20120723T105413Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-geoffroy-lerosey/ SUMMARY:Séminaire du LPTMS: Geoffroy Lerosey - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Sep 12 11:00 DESCRIPTION:A broadband approach to sub-diffraction far field imaging and f ocusing with metamaterials\nGeoffroy Lerosey (Institut Langevin\, ESPCI Pa risTech &\; CNRS UMR 7587)\nIn this talk I will show how the use of tim e dependent and broadband wavefields\, in conjunction with metamaterials\, permits to beat the diffraction limit from the far field for imaging or f ocusing purposes. I will introduce the idea of resonant metalens\, first d emonstrated in the microwave domain\, and explain its principles. In parti cular\, I will show how the concept of time reversal can be utilized to fo cus in this metamaterial based lens and from the far field\, onto focal sp ots much smaller than the diffraction limit. I will then prove the general ity of the approach by demonstrating its transposition to the acoustic dom ain thanks to a very simple setup: an array of soda cans. Then I will pres ent our latest theoretical and numerical results obtained using a resonant metalens made out of plasmonic nanorods in the visible part of the spectr um. I will show that this lens allows\, using polychromatic light\, to foc us light using far field time reversal onto spots as small as 1/30th of th e wavelength in the visible. Finally I will prove that our approach can al so be used in order to image from the far field and with a subwavelength r esolution and could lead to real time sub-diffraction imaging systems. \n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-61@lptms.universite-paris-saclay.fr DTSTART:20120918T110000Z DTEND:20120918T120000Z DTSTAMP:20120904T081628Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-anuradha-jagannathan/ SUMMARY:Séminaire du LPTMS: Anuradha Jagannathan - LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay - 18 Sep 12 11:00 DESCRIPTION:Introduction aux quasi-cristaux et modèles quantiques sur pava ges quasi-périodiques\nAnu Jagannathan\, Laboratoire de Physique des Soli des\, Orsay\nOn commencera par une introduction aux quasi-cristaux\, sujet s du prix Nobel de chimie de 2011\, et quelques-unes de leurs propriétés structurelles remarquables. Divers modèles ont été proposés pour déc rire les propriétés physiques de ces matériaux. Un des problèmes fonda mentaux concerne les propriétés d'un électron dans un potentiel quasi-p ériodique. On peut se demander quelle est la forme des fonctions d'onde t ypiques comparées à celles connues dans la matière condensée\, allant des fonctions d'onde étendues dans les métaux aux fonctions complètemen t localisées dans les amorphes. Une autre catégorie de problèmes concer ne les propriétés de spins dans une telle structure\, la nature de l'ét at fondamental magnétique\, et les corrélations. On introduira des modè les définis sur des pavages quasi-périodiques\, notamment le pavage de P enrose\, avec une discussion de quelques méthodes théoriques et des rés ultats qui ont été obtenus.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-68@lptms.universite-paris-saclay.fr DTSTART:20120924T100000Z DTEND:20120924T100000Z DTSTAMP:20120918T055356Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-tianyou-yi/ SUMMARY:Soutenance de thèse : Tianyou Yi - LPTMS-batiment 100\, salle des conseils - 24 Sep 12 10:00 DESCRIPTION:Modeling of dynamical vortex states in charge density waves\nTi anyou Yi\, LPTMS\nElectronic Crystals is a common form of organization in conducting solids. They take forms of Wigner crystals at hetero-junctions and nano-wires\, charge density waves (CDWs) in chain compounds\, spin den sity waves in organic conductors\, stripes in doped oxides and high-Tc sup erconductors. In the CDW ground state\, the elementary units can be readju sted by absorbing or rejecting pairs of electrons. Such a phase-slip proce ss should go via topologically nontrivial configurations: solitons and dis locations – the CDW vortices. An experimental access to those states cam e from studies of nano-fabricated mesa-junctions\, from the STM visualizat ions and from the X-ray micro-diffraction.\n Following these requests\, w e performed a program to model the stationary states and their transient d ynamic for the CDW in restricted geometries under the applied field or the passing current. A particular care had to be taken to derive a gauge inva riant and current conserving scheme for the interacting condensed and norm al charge densities. The model takes into account multiple fields in mutua l nonlinear interactions: the amplitude and the phase of the CDW complex o rder parameter\, distributions of the electric field\, the density and the current of normal carriers. We have found that vortices are formed stepwi se in the junction when the voltage across\, or the current through\, exce ed a threshold. The vortex core concentrates the voltage drop\, working as a self-tuned microscopic tunnelling junction. The studied reconstruction in junctions of the CDW is a convenient playground for modern efforts of f ield-effect transformations in strongly correlated materials with spontane ous symmetry breakings LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-59@lptms.universite-paris-saclay.fr DTSTART:20120925T110000Z DTEND:20120925T120000Z DTSTAMP:20120907T082009Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-a-bouzdin/ SUMMARY:Séminaire du LPTMS: A. Bouzdin - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 25 Sep 12 11:00 DESCRIPTION:Non-uniform (FFLO) states and quantum oscillations in supercon ductors and superfluid ultracold Fermi gases\nA. Buzdin\, Université de B ordeaux\nA long time ago\, it was predicted by Larkin and Ovchinnikov and Fulde and Ferrell that the non-uniform superconducting state (FFLO state) must appear in the magnetic field acting on the electron spins. We start with the discussion of the distinctive features of the Fulde-Ferrell-Larki n-Ovchinnikov (FFLO) non-uniform superconducting state and review recent e xperiments on the heavy fermion superconductor CeCoIn5 and layered organi c superconductors providing strong evidences in favor of FFLO phase observ ation. It is demonstrated that in 2D ( or quasi 2D) superconductors the F FLO state leads to an appearance of a very special oscillatory – like de pendence of the upper critical field versus the field orientation.\nIntere stingly\, in the superconductor-ferromagnet heterostructures the FFLO-like state may result in the formation of the Josephson junction with a sponta neous phase difference.\nThe FFLO-type instability may be also expected in ultracold Fermi gases in magneto-optical traps. In these systems it is ca used not by the Zeeman interaction but by the tuning of the population imb alance between two lowest hyperfine states of the atoms. We briefly discus s the properties of such FFLO state and analyze the role the trapping pote ntial confining the condensate.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-62@lptms.universite-paris-saclay.fr DTSTART:20121002T110000Z DTEND:20121002T120000Z DTSTAMP:20120925T080716Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sanjib-sabhapandit-2/ SUMMARY:Séminaire du LPTMS: Sanjib Sabhapandit - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 2 Oct 12 11:00 DESCRIPTION:Fluctuations and large deviations in nonequilibrium processes\n Sanjib Sabhapandit (Raman Research Institute\, Bangalore)\nI will start wi th fluctuation theorems and its connections to large deviations. I will th en describe how the large deviation function can be evaluated for the heat flow across a harmonic chain. Finally\, I will show application of the re sults to an recent experiment. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-67@lptms.universite-paris-saclay.fr DTSTART:20121004T143000Z DTEND:20121004T153000Z DTSTAMP:20120924T061102Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phsytat-sud-marcos-marcino/ SUMMARY:Séminaire de la fédération PHSYTAT SUD : Marcos Marino - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 4 Oct 12 14:30 DESCRIPTION:Matrix models and string theory\nMarcos Marino (University of G eneva)\nIn this talk I will try to provide a pedagogical overview of the i nterplay between random matrices and string theory. I will start with the "old" matrix models of non-critical strings and their applications to stat istical systems\, and explain some more recent developments on the connect ion between matrix models\, gravity\, and superstrings. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-53@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20121008 DTEND;VALUE=DATE:20121009 DTSTAMP:20120524T123059Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journees-detude-d u-laboratoire/ SUMMARY:Journées d'étude du Laboratoire - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 8 Oct 12 00:00 DESCRIPTION:Domaine de Seillac\, 41150 Seillac\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-54@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20121009 DTEND;VALUE=DATE:20121010 DTSTAMP:20120524T123134Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journees-detude-d u-laboratoire-2/ SUMMARY:Journées d’étude du Laboratoire - - 9 Oct 12 00:00 DESCRIPTION:Domaine de Seillac\, 41150 Seillac\n END:VEVENT BEGIN:VEVENT UID:1-55@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20121010 DTEND;VALUE=DATE:20121011 DTSTAMP:20120524T123157Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journees-detude-d u-laboratoire-3/ SUMMARY:Journées d’étude du Laboratoire - - 10 Oct 12 00:00 DESCRIPTION:Domaine de Seillac\, 41150 Seillac\n END:VEVENT BEGIN:VEVENT UID:1-64@lptms.universite-paris-saclay.fr DTSTART:20121016T110000Z DTEND:20121016T120000Z DTSTAMP:20121005T081846Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicolas-laflorencie/ SUMMARY:Séminaire du LPTMS: Nicolas Laflorencie - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 16 Oct 12 11:00 DESCRIPTION:The Best Enemies of Superfluid Bose Condensates\nNicolas Laflor encie\, LPT Toulouse\nLooking back at Helium-4\, it took some time to admi t that superfluidity and Bose-Einstein condensation\, while distinct pheno mena\, occur (and disappear) together. However\, apart from the particular cases of T=0 in one dimension and the finite-T BKT regime for 2D superflu ids\, we may ask if such a fact is always true. In this seminar we will ad dress this issue through the idea of the competitors or "enemies" of the s uperfluid / Bose condensate\, namely: repulsive interactions\, disorder\, and frustration. Across 2 specific examples of hard-core bosonic models in 3D\, I will discuss the possibility to achieve \n(i) a T=0 condensate-fre e superfluid state through a frustrated proximity effect\, directly releva nt for the frustrated antiferromagnet BaCuSi2O6\, and \n(ii) a finite temp erature sliding regime for randomly stacked superfluid layers\, which migh t explain some anomalies in the transport properties of the layered superc onductors LSCO. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-69@lptms.universite-paris-saclay.fr DTSTART:20121018T140000Z DTEND:20121018T150000Z DTSTAMP:20121002T093442Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lpt-lptms-sara-jabbari/ SUMMARY:Séminaire commun LPT-LPTMS: Sara Jabbari - LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay - 18 Oct 12 14:00 DESCRIPTION:Interplay of anisotropy and interactions in charged colloidal d isks \nSara JABBARI-FAROUJI\, LPTMS\n\nCharged plate-like colloidal suspen sions such as gibbsite and some clays exhibit interesting and rich phase b ehavior including liquid-crystalline and arrested gel-like states. The ani sotropic shape of such particles suggests that these materials could form liquid crystalline phases due to the competition between positional and or ientational entropy. In some cases\, however\, isotropic-nematic transitio n is hindered by formation of a gel-like viscoelastic phase. The question that arises is how the electrostatic interactions influence the liquid cry stal formation. Motivated by these experimental findings\, we have investi gated the structure and dynamics of charged disks by means of Monte-Carlo simulations. In this talk\, I will clarify the the role of anisotropic nat ure of screened electrostatic interactions on the formation of liquid-crys talline phases and arrested states. Finally\, I will compare the results o f our simulations with experiments. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-71@lptms.universite-paris-saclay.fr DTSTART:20121026T110000Z DTEND:20121026T120000Z DTSTAMP:20121003T083813Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-takahiro-sagawa/ SUMMARY:Séminaire du LPTMS: Takahiro Sagawa - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 26 Oct 12 11:00 DESCRIPTION:Information Thermodynamics in Small Systems\nTakahiro Sagawa\, Yukawa Institute for Theoretical Physics\, Kyoto University\nEver since th e proposal of "Maxwell's demon" in the nineteenth century\, the relationsh ip between thermodynamics and information has attracted numerous attention s concerning the foundation of the second law of thermodynamics [1\,2]. T he demon seems to be able to violate the second law by using the informati on about the microscopic degrees of freedom of thermodynamic systems. Due to the recent developments of the experimental technologies of manipulati ng small thermodynamic systems\, the demon has become a topic of active re searches both in terms of theory and experiment of nonequilibrium statisti cal physics. In this seminar\, I'd like to talk about our theoretical and experimental results on the foundation of the relationship between thermo dynamics and information [3-6]. Theoretically\, I will focus on the gener alizations of the second law of thermodynamics to information processing p rocesses such as measurement and feedback\, in which information contents and thermodynamic variables are treated on an equal footing. I'd also lik e to talk about our experimental result\, which has experimentally realize d a Maxwell's demon that uses the obtained information as a resource of th e free energy and the work [7].\n\nReferences:\n\n[1] "Maxwell's demon 2: Entropy\, Classical and Quantum Information\, Computing\," H. S. Leff and A. F. Rex (eds.)\, (Princeton University Press\, New Jersey\, 2003).\n[2] T. Sagawa and M. Ueda\, arXiv:1111.5769\, to appear in R. Klages\, W. Just \, C. Jarzynski (Eds.)\, "Nonequilibrium Statistical Physics of Small Syst ems: Fluctuation Relations and Beyond" (Wiley-VCH\, Weinheim\, 2012).\n[3] T. Sagawa and M. Ueda\, Phys. Rev. Lett. 100\, 080403 (2008).\n[4] T. Sag awa and M. Ueda\, Phys. Rev. Lett. 102\, 250602 (2009).\n[5] T. Sagawa and M. Ueda\, Phys. Rev. Lett. 104\, 198904 (2010).\n[6] T. Sagawa and M. Ued a\, arXiv:1206.2479\, to appear in PRL.\n[7] S. Toyabe\, T. Sagawa\, M. Ue da\, E. Muneyuki\, and M. Sano\, Nature Physics 6\, 988-992 (2010).\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-81@lptms.universite-paris-saclay.fr DTSTART:20121106T110000Z DTEND:20121106T120000Z DTSTAMP:20121012T103941Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-hiroki-ohta/ SUMMARY:Séminaire du LPTMS: Hiroki Ohta - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 6 Nov 12 11:00 DESCRIPTION:Lane formation in a lattice model for oppositely driven binary particles\nHiroki Ohta\, LPTMS\nI will introduce a two-dimensional lattice model for oppositely driven binary particles with purely repulsive intera ctions \nwhere some classes of steady states have been constructed in syst ematic ways. \nUsing such constructions\, I will discuss nonequilibrium ph ase transitions in this lattice model [1]. \nAlso\, I would like to discus s those relevance to lane formations in colloidal suspensions [2] [3].\n\n Reference:\n[1] H. Ohta\, Europhys. Lett. 99\, 40006 (2012).\n[2] J. Dzubi ella\, G. P. Hoffmann\, H. Löwen\, Phys. Rev. E 65\, 021402 (2002).\n[3] T. Vissers\, A. Wysocki\, M. Rex\, H. Löwen\, C. P. Royall\, A. Imhof\, A . van Blaaderen\, Soft Matter 7\, 2352 (2011). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-72@lptms.universite-paris-saclay.fr DTSTART:20121112T154500Z DTEND:20121112T171500Z DTSTAMP:20121003T123555Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms/ SUMMARY:Cours du LPTMS : Pierpaolo Vivo - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 12 Nov 12 15:45 DESCRIPTION:"Introduction to Random Matrix Theory"\n- Invariant vs. non inv ariant ensembles - Edwards-Jones formula for density of states - The Gauss ian ensemble: semicircle law\, method of orthogonal polynomials\, resolven t equations - The Coulomb gas method and linear statistics - Largest eigen value: Tracy-Widom law and applications LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-79@lptms.universite-paris-saclay.fr DTSTART:20121113T110000Z DTEND:20121113T120000Z DTSTAMP:20121106T141338Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jacopo-viti/ SUMMARY:Séminaire du LPTMS: Jacopo Viti - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 13 Nov 12 11:00 DESCRIPTION:Field theory approach to percolation and phase separation in tw o dimensions\nJacopo Viti\, LPTENS\nIn 1+1 dimensions it exists a special class of Quantum Field Theories\, the so-called Integrable QFT\, for which an exact S-matrix can be written and correlation functions computed with a great accuracy. I will discuss some recent applications of Integrable QF T to the study of the percolation phase transition in two dimensions. Part icular emphasis will be given to the results that have been tested numeric ally. In the final part of the talk I will describe how the same formalism can be applied to analyze the structure of the interfaces between two pur e phases. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-73@lptms.universite-paris-saclay.fr DTSTART:20121113T134500Z DTEND:20121113T151500Z DTSTAMP:20121003T123729Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-pi erpaolo-vivo/ SUMMARY:Cours du LPTMS : Pierpaolo Vivo - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 13 Nov 12 13:45 DESCRIPTION:"Introduction to Random Matrix theory"\n- Invariant vs. non inv ariant ensembles - Edwards-Jones formula for density of states - The Gauss ian ensemble: semicircle law\, method of orthogonal polynomials\, resolven t equations - The Coulomb gas method and linear statistics - Largest eigen value: Tracy-Widom law and applications LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-113@lptms.universite-paris-saclay.fr DTSTART:20121115T110000Z DTEND:20121115T110000Z DTSTAMP:20130130T133706Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-nir-gov/ SUMMARY:Physics-Biology interface seminar: Nir Gov - Amphi BLANDIN du LPS d e la Faculté des Sciences d’Orsay (Bâtiment 510) - 15 Nov 12 11:00 DESCRIPTION:Non-equilibrium physics inspired by biology: from fluctuating m embranes to active gels\nNir Gov\, (Weizmann Institute of Science)\nThe mo st ubiquitous and accessible non-equilibrium systems around us are in the form of living organisms. Motivated by pattern formation and random motion that are driven by active (out-of-equilibrium) processes in cells we inve stigate the similarities and differences between such motion and thermal r andom motion. A simple theoretical model of a kicked particle is used to e xtract analytic and numerical results which we then compare to observation s of membrane fluctuations in cells\, and fluctuations in active gels reco nstituted in-vitro. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-74@lptms.universite-paris-saclay.fr DTSTART:20121119T154500Z DTEND:20121119T171500Z DTSTAMP:20121003T123904Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-pi erpaolo-vivo-2/ SUMMARY:Cours du LPTMS : Pierpaolo Vivo - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 19 Nov 12 15:45 DESCRIPTION:"Introduction to Random Matrix Theory"\n- Invariant vs. non inv ariant ensembles - Edwards-Jones formula for density of states - The Gauss ian ensemble: semicircle law\, method of orthogonal polynomials\, resolven t equations - The Coulomb gas method and linear statistics - Largest eigen value: Tracy-Widom law and applications LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-66@lptms.universite-paris-saclay.fr DTSTART:20121120T110000Z DTEND:20121120T120000Z DTSTAMP:20121109T085010Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jerome-dubail/ SUMMARY:Séminaire du LPTMS: Jérôme Dubail - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 20 Nov 12 11:00 DESCRIPTION:Trial states for quantum Hall fluids and related sytems: an ent anglement point of view\n Jérôme Dubail\, Yale University\nA celebrated theoretical approach to the Fractional Quantum Hall Effect consists in coo king up trial wavefunctions for various filling fractions. Some specific t rial states (the ones given by field theory correlators) have particularly nice properties. Physically\, they describe exotic phases of matter\, for instance with non-abelian excitations. On the technical side\, they bear some striking resemblance with Tensor Product States. The purpose of this talk is to explain how the edge excitations and the entanglement spectrum of these states both arise naturally in that framework.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-75@lptms.universite-paris-saclay.fr DTSTART:20121120T134500Z DTEND:20121120T151500Z DTSTAMP:20121003T124020Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-pi erpaolo-vivo-3/ SUMMARY:Cours du LPTMS : Pierpaolo Vivo - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 20 Nov 12 13:45 DESCRIPTION:"Introduction to Random Matrix Theory"\n- Invariant vs. non inv ariant ensembles - Edwards-Jones formula for density of states - The Gauss ian ensemble: semicircle law\, method of orthogonal polynomials\, resolven t equations - The Coulomb gas method and linear statistics - Largest eigen value: Tracy-Widom law and applications LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-78@lptms.universite-paris-saclay.fr DTSTART:20121122T160000Z DTEND:20121122T180000Z DTSTAMP:20121112T131208Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-matthieu-barbier/ SUMMARY:Soutenance de thèse : Matthieu Barbier - IPN-batiment 100\, Audito riurm - 22 Nov 12 16:00 DESCRIPTION:De l'impermanence des formes dans les fluides granulaires : cro issance et relaxation dans les mélanges\nMatthieu Barbier\, LPTMS\nCe tra vail porte sur la dynamique de la matière granulaire dans l'état fluide\ , et sa réponse à une excitation localisée dans deux limites : une faib le perturbation suite à laquelle le système relaxe rapidement vers un é tat homogène\, ou une agitation intense qui engendre une onde de choc sem blable à un souffle d'explosion. Cette réponse est affectée par deux ca ractéristiques des fluides granulaires : les particules macroscopiques qu i les composent sont d'une part inélastiques\, de sorte que leur dynamiqu e est dissipative et ne possède pas d'état d'équilibre\, et d'autre par t polydisperses\, c'est-à-dire hétérogènes en taille et en masse. Nous isolons d'abord un effet dynamique de la polydispersité en montrant qu'i l existe un mélange optimal qui minimise le temps de relaxation du fluide vers son état asymptotique. Nous nous intéressons ensuite au cas où un e seule des espèces est perturbée par l'application d'un champ extérieu r\, et étudions l'état stationnaire hors d'équilibre ainsi établi\, da ns la limite du traceur où les autres espèces constituent un bain statio nnaire. Enfin\, nous modélisons la croissance de formes auto-similaires d ans ce bain suite à une intense libération ponctuelle d'énergie\, que n ous comparons au souffle d'une explosion dans un gaz moléculaire.\n------ ---\nThis work focuses on the dynamics of the fluid state of granular matt er\, and its response to a localized perturbation in two limiting cases : relaxation toward a homogeneous state or growth of a blast wave. This resp onse is shaped by two distinctive features of granular media: their macros copic constituent particles are both inelastic\, entailing intrinsically n on-equilibrium dynamics\, and polydisperse or heterogeneous in their mater ial properties. First\, we isolate the effects of polydispersity in the re turn of a gas to its homogeneous asymptotic state\, and evidence the exist ence of an optimal mixture for which the relaxation time is minimal. We th en restrict the perturbation to accelerating a single species with an exte rnal field in order to study the induced non-equilibrium stationary state in the tracer limit\, where other species are undisturbed by this process. Finally\, we model the self-similar shock wave generated in such a dissip ative bath by an intense yet localized release of energy\, and contrast it with blast waves in molecular gases. LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-80@lptms.universite-paris-saclay.fr DTSTART:20121127T110000Z DTEND:20121127T120000Z DTSTAMP:20121113T112632Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ezequiel-ferrero/ SUMMARY:Séminaire du LPTMS: Ezequiel Ferrero - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Nov 12 11:00 DESCRIPTION:Non-steady relaxation and critical exponents at the depinning t ransition via large scale GPU simulations\nEzequiel Ferrero\, Centro Atóm ico Bariloche - CONICET\nWe study the non-steady relaxation of a driven on e-dimensional elastic interface at the depinning transition by extensive n umerical simulations concurrently implemented on graphics processing units (GPUs). We compute the time-dependent velocity and roughness as the inter face relaxes from a given initial configuration at the thermodynamic criti cal force. We extract critical exponents from the Short Time Dynamics beha vior of the system. Above the first\, non-universal microscopic time-regi me\, we find a non-trivial long crossover towards the non-steady macroscop ic critical regime\, where it is accurate to fit. Our study may explain nu merical discrepancies (as large as 30% for the velocity exponent $\\beta$) found in the literature.\nIn addition\, if time permits\, I would like to briefly mention other implementations we have been developing for simulat ions in GPUs\, including Monte Carlo dynamics of classical spin systems an d Langevin dynamics for a $\\Phi^4$ model.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-114@lptms.universite-paris-saclay.fr DTSTART:20121129T110000Z DTEND:20121129T110000Z DTSTAMP:20130130T134100Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-emmanuel-beaurepaire/ SUMMARY:Physics-Biology interface seminar : Emmanuel Beaurepaire - Moyen Am phi\, Building 510\, Université Paris-Saclay Orsay - 29 Nov 12 11:00 DESCRIPTION:Nonlinear microscopy of developing tissues and embryos\nEmmanue l Beaurepaire (Lab. for Optics and Biosciences\, École Polytechnique/CNRS /INSERM)\nUnderstanding the dynamics at play during embryonic and tissue d evelopment requires tissue-scale measurements with subcellular resolution. Nonlinear microscopy is attractive for live studies because it provides t issue 3D imaging and provides several contrast mechanisms. Intrinsic coher ent signals such as second- and third-harmonic generation (SHG\, THG) prov ide structural information and can be used in conjunction with fluorescenc e (2PEF) imaging. SHG signals are specifically obtained from dense organiz ed structures\, whereas THG signals are obtained from optical heterogeneit ies and provide images of the tissue morphology. We will discuss these pri nciples and applications such as imaging the microstructure of intact unst ained corneas\, and reconstructing the early development of zebrafish embr yos. Finally\, we will discuss ongoing efforts to improve the capabilities of nonlinear microscopy for imaging developing tissues at advanced stages \, such as wavefront control for aberration correction\, and simultaneous excitation of multiple fluorescent proteins.\nReferences:\nSupatto et al\, Curr. Opin. Gen. Dev. 21 538 (2011).\nAptel et al\, Invest. Ophtalmol. Vi s. Sci. 51\, 2459 (2010).\nOlivier et al\, Science 339\, 967 (2010).\nZeng et al\, Biomed. Opt. Express 3\, 1898 (2012).\nMahou et al\, Nat. Methods 9 815 (2012).\n LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-70@lptms.universite-paris-saclay.fr DTSTART:20121129T140000Z DTEND:20121129T150000Z DTSTAMP:20130418T124329Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lpt-lptms-hiroki-ohta/ SUMMARY:Séminaire commun LPT-LPTMS: Hiroki Ohta - LPT\, Salle 114\, bât. 210 - 29 Nov 12 14:00 DESCRIPTION:Lane formation in a lattice model for oppositely driven binary particles\nHiroki Ohta\, LPTMS\nI will introduce a two-dimensional lattice model for oppositely driven binary particles with purely repulsive intera ctions where some classes of steady states have been constructed in system atic ways. Using such constructions\, I will discuss nonequilibrium phase transitions in this lattice model [1]. Also\, I would like to discuss thos e relevance to lane formations in colloidal suspensions [2] [3].\nReferenc e: [1] H. Ohta\, Europhys. Lett. 99\, 40006 (2012). [2] J. Dzubiella\, G. P. Hoffmann\, H. Löwen\, Phys. Rev. E 65\, 021402 (2002). [3] T. Vissers\ , A. Wysocki\, M. Rex\, H. Löwen\, C. P. Royall\, A. Imhof\, A. van Blaad eren\, Soft Matter 7\, 2352 (2011). LOCATION:LPT\, Salle 114\, bât. 210\, 15 Rue Georges Clemenceau\, Orsay\, France GEO:48.6981864;2.1817680000000337 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPT\, Salle 114\, bât. 210:geo :48.6981864,2.1817680000000337 END:VEVENT BEGIN:VEVENT UID:1-76@lptms.universite-paris-saclay.fr DTSTART:20121203T154500Z DTEND:20121203T171500Z DTSTAMP:20121126T090743Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-pi erpaolo-vivo-4/ SUMMARY:Cours du LPTMS : Pierpaolo Vivo - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 3 Déc 12 15:45 DESCRIPTION:"Introduction to Random Matrix Theory"\n- Invariant vs. non inv ariant ensembles - Edwards-Jones formula for density of states - The Gauss ian ensemble: semicircle law\, method of orthogonal polynomials\, resolven t equations - The Coulomb gas method and linear statistics - Largest eigen value: Tracy-Widom law and applications LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-65@lptms.universite-paris-saclay.fr DTSTART:20121204T110000Z DTEND:20121204T120000Z DTSTAMP:20121127T082126Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-masud-haque/ SUMMARY:Séminaire du LPTMS: Masud Haque - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 4 Déc 12 11:00 DESCRIPTION:Composite object dynamics in interacting 1D lattice systems: pr opagation\, locking\, and scattering\nMasud Haque\, MPIPKS\, Dresden\nIn o ne-dimensional lattice systems\, I will present results on the dynamics of composite objects such as repulsively bound pairs\, triplets and clusters . Highlights are: [A] a dramatic series of dynamics-suppression effects ne ar edges or geometric features\, associated with fractal structures in the energy spectrum\; [B] dynamical `scattering' protocols which display visu ally obvious differences between integrable and non-integrable systems.\nV ersions of these phenomena appear in (1) the Bose-Hubbard model\; (2) the spinless fermion model with nearest neighbor repulsion\; (3) the XXZ spin chain\; (4) the fermionic Hubbard chain. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-77@lptms.universite-paris-saclay.fr DTSTART:20121204T134500Z DTEND:20121204T151500Z DTSTAMP:20121126T090816Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-pi erpaolo-vivo-5/ SUMMARY:Cours du LPTMS : Pierpaolo Vivo - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 4 Déc 12 13:45 DESCRIPTION:"Introduction to Random Matrix Theory"\n- Invariant vs. non inv ariant ensembles - Edwards-Jones formula for density of states - The Gauss ian ensemble: semicircle law\, method of orthogonal polynomials\, resolven t equations - The Coulomb gas method and linear statistics - Largest eigen value: Tracy-Widom law and applications LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-88@lptms.universite-paris-saclay.fr DTSTART:20121206T143000Z DTEND:20121206T143000Z DTSTAMP:20121127T080236Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-phystat -sud-jean-francois-joanny/ SUMMARY:Séminaire de la fédération PHYSTAT-SUD : Jean-François Joanny - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Déc 12 14:30 DESCRIPTION:Growth and instabilities of healthy and cancerous tissues\nJean -François Joanny\, Institut Curie\, Paris\nDuring development or during t umor growth\, cells organize collectively by cell division and apoptosis i n a tissue. The aim of our work is to build up theoretical tools based on non-equilibrium statistical mechanics and continuum mechanics to describe the mechanical properties of tissues and to apply them to various biologic ally relevant situations. We first show that because of the coupling betw een cell division and the local stress\, a tissue can be considered as a v isco-elastic liquid at time scales larger than the cell division time.  W e then show recent model experiments on cell aggregates showing the effect of mechanical stress on tissue growth. Finally\, we use the hydrodynamic description to discuss the steady state structure of villis which are the protrusions of the surface of the intestine. We describe the formation of villis as a buckling instability of a polar cell monolayer. Similar insta bilities occur as well for tube-like cellular structures such as arteries. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-82@lptms.universite-paris-saclay.fr DTSTART:20121211T110000Z DTEND:20121211T120000Z DTSTAMP:20121210T102432Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thomas-salez/ SUMMARY:Séminaire du LPTMS: Thomas Salez - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 11 Déc 12 11:00 DESCRIPTION:Polymers in Flatland: Self-Similarity and Nanorheology\nThomas Salez\, ENS/ESPCI\nThe study of ultra-thin polymer nanofi lms is a rich an d productive field for applied mathematics\, fundamental physics\, physio logy and engineering. It has been enlightened by the recent results on dew etting\, nanoindentation\, electrostatic instabilities and micro-bubbles. We report here on a novel and simple technique based on capillary leveling of a thin polystyrene stepped film far above the glass transition temper ature [1]. We present as well the analytical [2] and numerical [3] tools t hat allow one to precisely understand the experimental pro files in variou s conditions. In particular\, we study the self-similar intermediate asymp totics of the solutions and we describe how they provide a direct and accu rate viscosity probe for polymer materials and viscous flows in general. F inally\, we show how those solutions can give quantitative insights on fun damental questions such as : the e ffect of confinement on the macromolecu lar mobility\, the slip condition at the substrate in hydrodynamics\, the spreading of a droplet onto a precursor fi lm [4]\, or the evolution of th e super ficial mobility through the glass transition.\n[1] McGraw\, Salez\ , Baumchen\, Raphael\, Dalnoki-Veress\, PRL 109 128303 (2012) [2] Salez\, McGraw\, Baumchen\, Dalnoki-Veress\, Raphael\, PoF in press (2012) [3] Sal ez\, McGraw\, Cormier\, Baumchen\, Dalnoki-Veress\, Raphael\, EPJE in pres s (2012) [4] Cormier\, McGraw\, Salez\, Baumchen\, Raphael\, Dalnoki-Veres s\, PRL 109 154501 (2012) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-115@lptms.universite-paris-saclay.fr DTSTART:20121213T110000Z DTEND:20121213T120000Z DTSTAMP:20130130T134335Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-massimo-vergassola/ SUMMARY:Physics-Biology interface seminar : Massimo Vergassola - Amphi BLAN DIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 13 Déc 12 11:00 DESCRIPTION:Fluctuations and response in biological sensory systems\nMassim o Vergassola (Institut Pasteur)\nThe statistics of fluctuations in biologi cal pathways and its relation to the response to environmental stimuli wil l be discussed. We shall specifically focus on bacterial chemotaxis\, wher e detailed experiments and reliable models are available. A novel non-inva sive experimental method to measure the chemotaxis response will first be presented. By using fluctuation relations\, we then relate appropriate ste ady-state correlations to the response of the system to step and ramp stim uli of arbitrary amplitudes. That provides a systematic explanation for th e observed relation between fluctuations and response and it also reconcil es the out-of-equilibrium nature of the dynamics with the apparently stand ard form of the fluctuation-dissipation relation.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-85@lptms.universite-paris-saclay.fr DTSTART:20121213T150000Z DTEND:20121213T160000Z DTSTAMP:20121204T135524Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-uzy-smilansky/ SUMMARY:Séminaire exceptionnel du LPTMS: Uzy Smilansky - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Déc 12 15:00 DESCRIPTION:Spectral Statistics of Permutation Matrices\nUzy Smilansky\, We izmann Institute of Science\, Rehovot\nI shall present some new results ob tained with Idan Oren on the spectral statistics of permutation matrices o f large order. They show curious features which can be explained using cla ssical number theory\, modified slightly to be useful for the present appl ication. Our result are consistent with the known leading order asymptotic expressions\, and add to them the next to leading order corrections.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-83@lptms.universite-paris-saclay.fr DTSTART:20121218T110000Z DTEND:20121218T120000Z DTSTAMP:20121022T055724Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-michel-raimond/ SUMMARY:Séminaire du LPTMS: Jean-Michel Raimond - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 18 Déc 12 11:00 DESCRIPTION:Mesure et contrôle quantique avec des atomes et des cavités\n Jean-Michel Raimond\, LKB ENS\nNous piégeons quelques photons micro-onde dans une cavité supraconductrice et nous les sondons avec des atomes de R ydberg circulaires. Nous réalisons ainsi une mesure quantique idéale du nombre de photons\, nous les voyons apparaître et disparaître un par un. Cette mesure « sans démolition quantique » est au cœur d'une métho de de reconstruction de l'état du champ\, qui nous permet de suivre la d écohérence rapide d'une superposition quantique mésoscopique (un état « chat de Schrödinger »)\, et d'explorer ainsi la frontière entre le quantique et le classique. Enfin\, en détectant les sauts quantiques\, n ous pouvons contrecarrer leurs effets et maintenir constant le nombre de p hotons dans la cavité dans ce qui est la première réalisation d'une ré troaction quantique.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-94@lptms.universite-paris-saclay.fr DTSTART:20130107T143000Z DTEND:20130107T160000Z DTSTAMP:20121220T084348Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-ludwik-leibler/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Ludwik Leibler - IPhT\, CEA-Saclay\, salle Itzykson - 7 Jan 13 14:30 DESCRIPTION:Vitrimers\nLudwik Leibler\, Matière Molle et Chimie\, ESPCI\, Paris\nGlass-workers shape marvelous objects without using moulds or preci se temperature control because glass is a unique material that transforms from liquid to solid in a very progressive way. Can we imagine other compo unds that offer similar opportunities? I will present the concept of solid ification by molecular-networks topology freezing and introduce vitrimers\ , organic materials that behave just like glass. Beside opening new perspe ctives in chemistry and physics of glass formation and catalytically contr olled exchange reactions\, discovery of vitrimers could profoundly affect many industries that rely on polymers and composites. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-87@lptms.universite-paris-saclay.fr DTSTART:20130108T110000Z DTEND:20130108T120000Z DTSTAMP:20121204T161453Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-j-bonart/ SUMMARY:Séminaire du LPTMS: J. Bonart - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 8 Jan 13 11:00 DESCRIPTION:Impurties in trapped one-dimensional quantum liquids\nJulius Bo nart\, LPTHE\nRecent experiments with cold atoms on impurity dynamics imme rsed in trapped 1D quantum liquids have revealed an interesting interplay between the dynamic polaronic impurity mass shift and the renormalization of the optical potential. We show that the influence of the external trap on the Bose gas leads to a steeper effective potential for the impurity. W e propose a framework in which this potential renormalization and the mass shift can be quantitatively understood by using a semi-classical theory o f density wave excitations in the Luttinger liquid. Then we present more r igorous results on the impurity dynamics which are obtained via the non eq uilibrium formalism of a quantum Brownian particle. We show that the obtai ned theoretical results reproduce well recent experimental data.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-92@lptms.universite-paris-saclay.fr DTSTART:20130109T140000Z DTEND:20130109T173000Z DTSTAMP:20121218T134736Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-hdr-al berto-rosso/ SUMMARY:Soutenance HDR : Alberto Rosso - LPTMS-batiment 100\, salle des con seils - 9 Jan 13 14:00 DESCRIPTION:La physique des extrêmes : de la diffusion anormale aux systè mes désordonnés\nAlberto Rosso\n \; LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-116@lptms.universite-paris-saclay.fr DTSTART:20130110T110000Z DTEND:20130110T120000Z DTSTAMP:20130130T134606Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jean-francois-joanny/ SUMMARY:Physics-Biology interface seminar : Jean-François Joanny - Amphi B LANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 10 J an 13 11:00 DESCRIPTION:Properties of the actin cortex and dynamics of cytokinesis\nJea n-François Joanny (Institut Curie - Paris)\nIn this talk I discuss first the properties of the actin cortical layer in contact with the plasma memb rane of a cell using the hydrodynamic theory of active gels: within this f ramework\, the cortical layer can be viewed as an active prewetting layer. \nI then discuss cytokinesis which is last stage of cell division when the two daughter cells separate. Cytokinesis proceeds by the formation of an actin contractile ring at the equator of teh cell and by contraction of th is ring. The ring formation induces tension gradients in the cortical laye r and a cortical flow. Using active gel theory\, it is shown numerically t hat cytokinesis can only be completed if the activity gradient is large en ough and that the radius of the contractile ring decreases linearly with t ime in agreement with experiments. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-89@lptms.universite-paris-saclay.fr DTSTART:20130115T110000Z DTEND:20130115T120000Z DTSTAMP:20130115T151310Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christian-hagendorf/ SUMMARY:Séminaire du LPTMS: Christian Hagendorf - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 15 Jan 13 11:00 DESCRIPTION:Spin chains with dynamical lattice supersymmetry\nChristian Hag endorf\, Université de Genève\nStarting from simple observations about t he spectrum of the spin-1/2 XXZ and XYZ Heisenberg chains at particular an isotropy I will show how to construct a representation of the N=(2\,2) sup ersymmetry algebra on the lattice. The supercharges are dynamical: they ch ange the number of sites. The construction generalises to higher spin. In particular\, it allows to identify lattice precursors of the N=(2\,2) supe rconformal minimal models. The supersymmetry allows to prove the existence of zero-energy ground states which have often rich properties related to enumerative combinatorics. I will discuss in detail the case of the Fateev -Zamolodchikov chain at spin one whose ground-state components are related to the weighted enumeration of alternating sign matrices. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-97@lptms.universite-paris-saclay.fr DTSTART:20130117T110000Z DTEND:20130117T123000Z DTSTAMP:20130122T102012Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-david-saad/ SUMMARY:Séminaire exceptionnel du LPTMS : David Saad - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 17 Jan 13 11:00 DESCRIPTION:David Saad (Aston University)\nPolymer physics for route optimi sation on the London underground\nOptimizing paths on networks is crucial for many applications\, from subway traffic to Internet communication. As global path optimization that takes account of all path-choices simultaneo usly is computationally hard\, most existing routing algorithms optimise p aths individually\, thus providing sub-optimal solutions. This work includ es two different aspects of routing. In the first [1] we employ the cavity approach to study analytically the routing of nodes on a graph of given t opology to predefined network routers and devise the corresponding distrib utive optimisation algorithm. In the second [2] we employ the physics of i nteracting polymers and disordered systems (the replica method) to analyse macroscopic properties of generic path-optimisation problems between arbi trarily selected communicating pairs\; we also derive a simple\, principle d\, generic and distributive routing algorithm capable of considering simu ltaneously all individual path choices.\nTwo types of nonlinear interactio ns are considered with different objectives: 1) alleviate traffic congesti on at both cyber and real space and provide better route planning\; and 2) save resources by powering down non-essential and redundant routers/stati ons at minimal cost. This saves energy and man-power\, and alleviates the need for investment in infrastructure. We show that routing becomes more d ifficult as the number of communicating nodes increases and exhibits inter esting physical phenomena such as ergodicity breaking. The ground state of such systems reveals non-monotonic complex behaviours in average path-len gth and algorithmic convergence\, depending on the network topology\, and densities of communicating nodes and routers.\nWe demonstrate the efficacy of the new algorithm [2] by applying it to: (i) random graphs resembling Internet overlay networks\; (ii) travel on the London underground network based on Oyster-card data\; and (iii) the global airport network. Analytic ally derived macroscopic properties give rise to insightful new routing ph enomena\, including phase transitions and scaling laws\, which facilitate better understanding of the appropriate operational regimes and their limi tations that are difficult to obtain otherwise.\n [1] C. H. Yeung\, D. Saa d\, The Competition for Shortest Paths on Sparse Graphs\, Phys. Rev. Lett .\, 108\, 208701 (2012).\n[2] C. H. Yeung\, D. Saad and K. Y. M. Wong\, Fr om the Physics of Interacting Polymers to Optimizing Routes on the London Underground\, submitted (2012).\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-84@lptms.universite-paris-saclay.fr DTSTART:20130122T110000Z DTEND:20130122T120000Z DTSTAMP:20130122T102520Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-a-de-luca/ SUMMARY:Séminaire du LPTMS: A. de Luca - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 22 Jan 13 11:00 DESCRIPTION:Insights into the many-body localization transition from the st ructure of wave functions.\nAndrea de Luca\, LPT ENS\nThe possibility of c ombining interactions and disorder in a quantum system has recently become more concrete under the name of many-body localization transition. With a combination of old and new techniques\, we explore the two sides of the t ransition from the point of view of the wave function statistics\, pointin g out analogies and differences with the usual  Anderson transition. The many-body localization seems to be characterized more by ergodicity breaki ng than by concrete localization in the Fock space. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-107@lptms.universite-paris-saclay.fr DTSTART:20130125T140000Z DTEND:20130125T153000Z DTSTAMP:20130130T150226Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-carsten-janke/ SUMMARY:Physics-Biology interface seminar : Carsten Janke - Amphi BLANDIN d u LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 25 Jan 13 14 :00 DESCRIPTION:Encoding functional information into the microtubule cytoskelet on\nCarsten Janke Institut Curie - Orsay\nOur team is interested in the fu nctions of tubulin posttranslational modifications. Tubulin\, the building block of the microtubules\, is modified by a range of very special posttr anslational modifications\, such as enzymatic generation of glutamate or g lycine side chains\, enzymatic removal and re-addition of a C-terminal tyr osine. These modifications take place once the tubulin has polymerized int o microtubules\, which suggests that they encode information important for the functional specification or the fine-tuning of specific microtubule f unctions. While the modifications have been known for a long time\, functi onal studies have remained difficult because nothing was known about the e nzymes responsible for these modifications. The recent discovery of most o f these enzymes in our team has allowed us to start functional and mechani stic studies that gave us first insights into the divergent roles of tubul in posttranslational modifications. In my presentation\, I will give an ov erview of our first results\, our ongoing projects and interests.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-86@lptms.universite-paris-saclay.fr DTSTART:20130129T110000Z DTEND:20130129T120000Z DTSTAMP:20130123T071830Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-v-bapst/ SUMMARY:Séminaire du LPTMS: V. Bapst - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 29 Jan 13 11:00 DESCRIPTION:On the Quantum Annealing of Quantum Mean-Field Models\nVictor B apst\, LPT ENS\nIn this talk I will present analytical results on the quan tum annealing of quantum mean-field models. I will first explain the conne ction between static and dynamic properties of the model using results obt ained on a toy model\, the fully-connected ferromagnetic p-spin model. For p=2 this corresponds to the quantum Curie-Weiss model which exhibits a se cond-order phase transition\, while for p>\;2 the transition is first or der. Focusing on the latter case\, I will detail the link between phase tr ansitions\, metastable states and residual excitation energy on both finit e and divergent time-scales. Then\, I will present a study of the thermody namics of a more realistic optimization problem subject to quantum fluctua tions: the quantum coloring problem on random regular graphs. Using the qu antum cavity method\, that allows to solve such models in the thermodynami c limit\, we determined the order of the quantum phase transition that occ urs when the transverse field is varied and unveiled the rich structure of the quantum spin-glass phase. In particular\, I will explain why the quan tum adiabatic algorithm would fail to solve typical instances of this prob lem efficiently because of entropy induced crossings within the quantum sp in-glass phase. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-109@lptms.universite-paris-saclay.fr DTSTART:20130204T123000Z DTEND:20130204T131500Z DTSTAMP:20130418T124232Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-kabir-ramola/ SUMMARY:Journal Club du LPTMS: Kabir Ramola - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 4 Fév 13 12:30 DESCRIPTION:Watersheds are Schramm-Loewner Evolution Curves\nKabir Ramola\, Post-Doc LPTMS\nSLE has grown in prominence over the last decade and has helped unify several aspects of critical phenomena\, percolation theory an d conformal field theory. This paper discusses an interesting real world a pplication of this somewhat technical subject.\nhttp://prl.aps.org/abstrac t/PRL/v109/i21/e218701\nE. Daryaei\, N. A. M. Arau´jo\, K. J. Schrenk\, S . Rouhani\, and H. J. Herrmann\nAbstract of the article : We show that in the continuum limit watersheds dividing drainage basins are Schramm-Loewne r evolution (SLE) curves\, being described by one single parameter κ. Sev eral numerical evaluations are applied to ascertain this. All calculations are consistent with SLEκ\, with κ=1.734±0.005\, being the only known p hysical example of an SLE with κ<\;2. This lies outside the well-known duality conjecture\, bringing up new questions regarding the existence and reversibility of dual models. Furthermore\, it constitutes a strong indic ation for conformal invariance in random landscapes and suggests that wate rsheds likely correspond to a logarithmic conformal field theory with a ce ntral charge c≈-7/2. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-93@lptms.universite-paris-saclay.fr DTSTART:20130205T110000Z DTEND:20130205T120000Z DTSTAMP:20130122T102743Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-michel-bauer/ SUMMARY:Séminaire du LPTMS: Michel Bauer - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 5 Fév 13 11:00 DESCRIPTION:Mesures non-destructives en mécanique quantique\, martingales et variables échangeables\nMichel Bauer\, IPhT Saclay\nPlus de 80 ans apr ès la découverte des lois de la mécanique quantique\, celles-ci continu ent de susciter l'étonnement. La notion de mesure\, en particulier\, rest e très mystérieuse\, et ce terme recouvre aujourd'hui des processus trè s variés. Nous décrirons des expériences récentes très simples et bel les\, qui permettent de lever légèrement un coin du voile. Après quelqu es remarques sur les mesures en mécanique quantique\, nous montrerons pou rquoi l'interprétation de ces expériences est étroitement liée à des piliers de la théorie des probabilités\, et en particulier au théorème de convergence des martingales. En conclusion\, nous montrerons que le th éorème de deFinetti sur les variables aléatoires échangeables est une piste pour expliquer la robustesse de la mesure en mécanique quantique et suggère des liens avec la notion "d'éléments de réalité".\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-122@lptms.universite-paris-saclay.fr DTSTART:20130206T170000Z DTEND:20130206T170000Z DTSTAMP:20130130T163716Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-francois-treussart/ SUMMARY:Physics-Biology interface seminar : Stefan Hell - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 6 Fév 13 17:0 0 DESCRIPTION:Nanoscopy with focused light\nStefan Hell (Max Planck Institute for Biophysical Chemistry &\; German Cancer Research Center (DKFZ))\n SPECIAL DATE &\; TIMEJoint seminar with Laboratoire Aimé Cotton hosted by François Treussart LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-110@lptms.universite-paris-saclay.fr DTSTART:20130211T123000Z DTEND:20130211T131500Z DTSTAMP:20130418T124216Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-ricardo-marino/ SUMMARY:Journal Club du LPTMS: Ricardo Marino - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Fév 13 12:30 DESCRIPTION:Temporal Effects in the Growth of Networks\nRicardo Marino\, Ph D student LPTMS\nThis article explores a very interesting model in random graphs for preferential attachment with time-decaying properties\, ideal f or problems in which "popularity" decays over time (for instance\, article citations).\nhttp://prl.aps.org/abstract/PRL/v107/i23/e238701\nMatúš Me do\, Giulio Cimini\, and Stanislao Gualdi\nAbstract of the article : We sh ow that to explain the growth of the citation network by preferential atta chment (PA)\, one has to accept that individual nodes exhibit heterogeneou s fitness values that decay with time. While previous PA-based models assu med either heterogeneity or decay in isolation\, we propose a simple analy tically treatable model that combines these two factors. Depending on the input assumptions\, the resulting degree distribution shows an exponential \, log-normal or power-law decay\, which makes the model an apt candidate for modeling a wide range of real systems. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-91@lptms.universite-paris-saclay.fr DTSTART:20130212T110000Z DTEND:20130212T120000Z DTSTAMP:20130418T124158Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-serguei-nechaev/ SUMMARY:Séminaire du LPTMS: Serguei Nechaev - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 12 Fév 13 11:00 DESCRIPTION:From elongated spanning trees to vicious random walks\nSerguei Nechaev\, LPTMS\nGiven a spanning forest on a large square lattice\, we co nsider by combinatorial methods a correlation function of k paths (k is od d) along branches of trees or\, equivalently\, k loop-erased random walks. Starting and ending points of the paths are grouped such that they form a k-leg watermelon. For large distance r between groups of starting and end ing points\, the ratio of the number of watermelon configurations to the t otal number of spanning trees behaves as r^{-\nu} \\log r with \nu = (k^2- 1)/2. Considering the spanning forest stretched along the meridian of this watermelon\, we show that the two-dimensional k-leg loop-erased watermelo n exponent \nu is converting into the scaling exponent for the reunion pro bability (at a given point) of k (1+1)-dimensional vicious walkers\, \\til de{\nu} = k^2/2. Some consequences and generalizations of this result will be also discussed. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-96@lptms.universite-paris-saclay.fr DTSTART:20130219T110000Z DTEND:20130219T120000Z DTSTAMP:20130418T124144Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-c-grenier/ SUMMARY:Séminaire du LPTMS: Charles Grenier - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 19 Fév 13 11:00 DESCRIPTION:Characterization and decoherence of minimal excitations\nCharle s Grenier\, CPhT Ecole Polytechnique\nThe recent years saw the development s of quantum optics experiments with electrons propagating along the edge channels of two-dimensional electron gases in the quantum Hall regime [1]. In this context\, the realization of single electron sources is necessary to observe analogues of the fundamental results of quantum optics\, such as the Hong-Ou-Mandel effect. In the electronic context\, these experiment s would provide unprecendented insights on the behavior of electron gases at the single-particle level [2]. In this talk\, I will present a theoreti cal study of the single electron coherence properties of two different typ es of voltage pulses [3\,4]. By combining bosonization and the Floquet sca ttering approach\, the effect of interactions on a periodic source of volt age pulses is computed exactly [5]. When such excitations are injected int o one of the channels of a system of two copropagating quantum Hall edge c hannels\, they fractionalize into pulses whose characteristics reflects th e properties of interactions. We show that the dependence of fractionaliza tion induced electron/hole pair production in the pulses amplitude contain s clear signatures of the fractionalization of the individual excitations. We propose an experimental setup combining a source of Lorentzian pulses [3] and an Hanbury Brown and Twiss interferometer to measure interaction i nduced electron/hole pair production and more generally to reconstruct sin gle electron coherence of these excitations before and after their fractio nalization. [1] Y. Ji\, et al\, Nature 422\, 415 (2003) [2] P. Degiovanni\ , et al\, Phys. Rev. B 80\, 241307(R) (2009) [3] L. Levitov\, et al\, J. M ath. Phys. 37\, 4845 (1996)\; D. A. Ivanov\, et al\, Phys. Rev. B 56\, 683 9 (1997)\; J. Keeling\, et al\, Phys. Rev. Lett. 97\, 116403 (2006) [4] J. Dubois\, et al\, preprint ArXiv:1212.3921 [5] Ch. Grenier\, et al\, ArXiv :1301.6777 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-123@lptms.universite-paris-saclay.fr DTSTART:20130221T143000Z DTEND:20130221T160000Z DTSTAMP:20130201T083055Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-aris-moustakas/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Aris Moustakas - LPTMS\ , salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 21 Fév 13 14:30 DESCRIPTION:Power optimization on a random wireless network: A statistical physics approach\nAris Moustakas (National and Capodistrian University of Athens\, Dept of Physics)\nThe efficient use of transmitted power is impor tant in modern day wireless networks. Not only is the battery life of tran smitting devices thus extended\, but also the interference caused to neigh boring transmitters is minimized. There are iterative methods to obtain th e optimal power per node in a network\, however it is known that depending on the strength of the interference\, the problem may be infeasible. Howe ver\, the properties of the optimal power vector in a random network\, as well as the convergence to it are not well understood. In this work we stu dy power optimization in a simple network with randomness. We show that th e problem can be mapped to an Anderson model and we analyze its properties \, such as the average power per transmitter\, its probability of failure\ , the tails of its power distribution and dynamics using ideas from the th eory of disordered metals.\ncafé/thé seront servis à  14h00 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-121@lptms.universite-paris-saclay.fr DTSTART:20130222T140000Z DTEND:20130222T140000Z DTSTAMP:20130131T144012Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jean-francois-allemand/ SUMMARY:Physics-Biology interface seminar : Jean-François Allemand - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 22 Fév 13 14:00 DESCRIPTION:In vitro &\; in vivo single molecule approaches to DNA repli cation \nJean-François Allemand (École normale supérieure)\nDNA replic ation is an essential step of the cell cycle. Despite many biochemical stu dies\, physical approaches can still bring new informations on some proces s of DNA replication.In vitro\, using micromanipulation tools\, we have sh own that force can trigger some DNA polymerases into an exonuclease mode w here\, instead of synthesizing DNA\, the polymerase goes backward and remo ves nucleotides. This can lead to a mechanical method for DNA sequencing.I n vivo\, in E. coli\, using single molecule fluorescence techniques we hav e quantified the real time composition of the replisome\, the machinary th at copies DNA. We observed a time variation of the composition of the repl isome with a number of DNA polymerases that varies from 2 to 3. We will se e how these fluctuations are related to the synthesis of the so called Oka zaki fragments. We will describe what happens to this scenario when the re plication is blocked under specific conditions.  LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-124@lptms.universite-paris-saclay.fr DTSTART:20130222T150000Z DTEND:20130222T170000Z DTSTAMP:20130213T144347Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-jason-sakellariou/ SUMMARY:Soutenance de thèse : Jason Sakellariou - IPN-batiment 100\, Audit oriurm - 22 Fév 13 15:00 DESCRIPTION:\nInverse inference in the asymmetric Ising model\n \nIn recen t years new experimental methods have made possible the acquisition of an overwhelming amount of data for a number of biological systems such as ass emblies of neurons\, genes and proteins. Typically\, these systems consist of a large number of interacting components and can be described by high dimensional models such as the well known Ising model from statistical phy sics. The nature of the data acquired from experiments makes necessary the  development of methods that are able to infer the parameters of the mode l and thus predict the pattern of the interactions between the components of such systems. In this thesis I have studied the particular case of the Ising model with asymmetric interactions which is arguably the most releva nt case when dealing with neural networks and could be generalized to fit to other biological systems as well. I will present a new mean-field inf erence method based on a simple application of the central limit theorem\, able to infer exactly the parameters of the asymmetric Ising model from d ata in a computationally efficient way. I will also discuss some results o f numerical simulations where the performance of our new method can be eva luated and compared with other existing methods. Finally\, I will also sho w how the method can be better adapted to the case of sparse networks wher e\, additionally\, the amount of data used in the inference is low compare d to the size of the system.\n LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-112@lptms.universite-paris-saclay.fr DTSTART:20130225T120000Z DTEND:20130225T124500Z DTSTAMP:20130418T124124Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-dario-villamaina/ SUMMARY:Journal Club du LPTMS: Dario Villamaina - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 25 Fév 13 12:00 DESCRIPTION:Dario Villamaina\, post-doc LPTMS\nI will present some recent a pplications of non-equilibrium fluctuation theory to one-dimensional diffu sive models.\nSpontaneous Symmetry Breaking at the Fluctuating Level (Phys . Rev. Lett. 107\, 180601 (2011) )\nhttp://prl.aps.org/abstract/PRL/v107/i 18/e180601\nAbstract: Phase transitions not allowed in equilibrium steady states may happen\, however\, at the fluctuating level. We observe for the first time this striking and general phenomenon measuring current fluctua tions in an isolated diffusive system. While small fluctuations result fro m the sum of weakly correlated local events\, for currents above a critica l threshold the system self-organizes into a coherent traveling wave which facilitates the current deviation by gathering energy in a localized pack et\, thus breaking translation invariance. This results in Gaussian statis tics for small fluctuations but non-Gaussian tails above the critical curr ent. Our observations\, which agree with predictions derived from hydrodyn amic fluctuation theory\, strongly suggest that rare events are genericall y associated with coherent\, self-organized patterns which enhance their p robability.\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-99@lptms.universite-paris-saclay.fr DTSTART:20130226T110000Z DTEND:20130226T120000Z DTSTAMP:20130418T124114Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kabir-ramola/ SUMMARY:Séminaire du LPTMS: Kabir Ramola - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 26 Fév 13 11:00 DESCRIPTION:Columnar Order and Ashkin-Teller Criticality in the Hard Square Lattice Gas\nKabir Ramola\, LPTMS Orsay\nThe lattice gas model of particl es with nearest and next-nearest-neighbour exclusion on a square lattice ( hard squares) undergoes a transition from a fluid phase at low density to a columnar ordered phase at high density. The high-activity series for thi s model is a singular perturbation series in powers of 1/z\, where z is th e fugacity associated with each particle. We show that the different terms of the series need to be regrouped to get a Mayer-like series for a polyd isperse system of interacting vertical rods. We also analyse the nature of the phase transition as a function of density in this system. We argue th at the critical properties of the model are that of a more general Ashkin- Teller model. We employ Monte Carlo simulations to study the correlations between various quantities in the system to get a fairly precise estimate of the position of the transition on the Ashkin-Teller critical line. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-130@lptms.universite-paris-saclay.fr DTSTART:20130307T140000Z DTEND:20130307T150000Z DTSTAMP:20130418T124104Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-david-mukamel/ SUMMARY:Séminaire du LPTMS: David Mukamel - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 7 Mar 13 14:00 DESCRIPTION:Long-Range correlations in driven\, non-equilibrium systems\nDa vid Mukamel\, Weizmann\nSystems driven out of thermal equilibrium often re ach a steady state which under generic conditions exhibits long-range corr elations. As a result these systems sometimes share some common features w ith equilibrium systems with long-range interactions\, such as the existen ce of long range-order and spontaneous symmetry breaking in one dimension\ , ensemble  inequivalence and other properties. Some models of driven sys tems will be presented\, and features resulting from the existence of long -range correlations will be discussed. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-131@lptms.universite-paris-saclay.fr DTSTART:20130318T120000Z DTEND:20130318T124500Z DTSTAMP:20130418T124053Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-pierpaolo-vivo/ SUMMARY:Journal Club du LPTMS: Pierpaolo Vivo - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Mar 13 12:00 DESCRIPTION:Pierpaolo Vivo\, CNRS researcher LPTMS\nThe statistical proper ties of the city transport in Cuernavaca (Mexico) and random matrix ensemb les\nI present the results of the two papers listed below on an interestin g real-life system\, namely the bus transportation in the Mexican city of Cuernavaca. In Cuernavaca there is no covering company responsible for org anizing the city transport. Consequently\, constraints such as a time tabl e that represents external influence on the transport do not exist. Moreov er\, each bus is the property of the driver. The drivers try to maximize t heir income and hence the number of passengers they transport. This leads to competition among the drivers and to their mutual interaction. In the p aper (1) below\, the statistics of empirical inter-arrivals of buses was f ound to conform to the spacing distribution of Gaussian Unitary Ensemble ( GUE) of random matrices. In the paper (2)\, a simple but rich model of sel f-avoiding walks with Poissonian rates is put forward to explain the empir ical data\, whose connection with GUE can be then analytically elucidated. \nReferences:\n1. M. Krbalek and P. Seba\, The statistical properties of t he city transport in Cuernavaca (Mexico) and random matrix ensembles\, J. Phys. A: Math. Gen. 33\, L229 (2000)2. J. Baik\, A. Borodin\, P. Deift and T. Suidan\, A model for the bus system in Cuernavaca (Mexico)\, J. Phys. A: Math. Gen. 39\, 8965 (2006) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-128@lptms.universite-paris-saclay.fr DTSTART:20130318T143000Z DTEND:20130318T154500Z DTSTAMP:20130301T083234Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-peter-sollich/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Peter Sollich - IPhT\, CEA-Saclay\, salle Itzykson - 18 Mar 13 14:30 DESCRIPTION:Unified study of glass and jamming rheology in soft particle s ystems\nPeter Sollich\, King's College London\nAuthors: Atsushi Ikeda\, Lu dovic Berthier\, and Peter Sollich\nAbstract: We explore numerically the s hear rheology of soft repulsive particles at large volume fraction. The in terplay between viscous dissipation and thermal motion results in multiple rheological regimes encompassing Newtonian\, shear-thinning and yield str ess regimes near the ‘colloidal’ glass transition when thermal fluctu ations are important\, crossing over to qualitatively similar regimes near the ‘jamming’ transition when dissipation dominates. In the crossover regime\, glass and jamming sectors coexist and give complex flow curves. Although glass and jamming limits are characterized by similar macroscopi c flow curves\, we show that they occur over distinct time and stress sca les and correspond to distinct microscopic dynamics. We propose a simple r heological model describing the glass to jamming crossover in the flow cu rves\, and discuss the experimental implications of our results. Time perm itting a systematic comparison of the model to data for a number of paradi gmatic experimental systems will be described. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-95@lptms.universite-paris-saclay.fr DTSTART:20130319T110000Z DTEND:20130319T120000Z DTSTAMP:20130315T113950Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-g-biroli/ SUMMARY:Séminaire du LPTMS: G. Biroli - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Mar 13 11:00 DESCRIPTION:Difference between Ergodicity\, Level Statistics and Localizati on Transitions on the Bethe Lattice\nGiulio Biroli\, IPhT Saclay\nRandom M atrix Theory was initially developed to explain the eigen-energy distribut ion of heavy nuclei. It has become clear by now that its domain of applica tion is much broader and extends to very different fields such as number t heory and quantum chaos\, just to cite a few. In particular\, it has been conjectured---and proved or verified in some special cases---that quantum ergodic (or chaotic) systems are characterized by eigen-energies statistic s in the same universality class of random matrices and by eigen-functions that are delocalized over the configuration space. On the contrary\, non- ergodic quantum systems\, such as integrable models\, are expected to disp lay a Poisson statistics of energy levels and localized wave-functions. St arting from Anderson's pioneering papers\, similar properties have also be en studied for electrons hopping in a disordered environment. Remarkably\, also in this case\, similar features of the energy-level statistics have been found. All that has lead to the conjecture that delocalization in con figuration space\, ergodicity and level statistics are intertwined propert ies. \nIn this talk we revisit the old problem of non-interacting electro ns hopping on a Bethe lattice with on-site disorder. By using numerical si mulations\, the cavity method and mapping to directed polymers in random m edia we unveil the existence of an intermediate phase in which wave-functi ons are delocalized but the energy-level statistics is Poisson. This new p hase\, in which the system is non-ergodic but delocalized\, may play an im portant role in several fields from random matrix theory to strongly inter acting quantum disordered systems\, in particular it could be related to t he non-ergodic metallic phase conjectured to exist in the context of Many- Body Localization. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-126@lptms.universite-paris-saclay.fr DTSTART:20130322T140000Z DTEND:20130322T140000Z DTSTAMP:20130418T124042Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-andrea-de-martino/ SUMMARY:Physics-Biology interface seminar : Andrea De Martino - Amphi BLAND IN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 22 Mar 1 3 14:00 DESCRIPTION:MicroRNAs: a selective channel of communication between competi ng RNAs\nAndrea De Martino (Sapienza Universita' di Roma)\nIt has recently been suggested that the competition for a finite pool of microRNAs (miRNA ) gives rise to effective interactions among their common targets (competi ng endogenous RNAs or ceRNAs) that could prove to be crucial for post-tran scriptional regulation (PTR). I shall discuss a minimal model of PTR where the emergence and the nature of such interactions can be characterized in detail at steady state. Sensitivity analysis shows that binding free ener gies and repression mechanisms are the key ingredients for the cross-talk between ceRNAs to arise. Interactions emerge in specific ranges of repress ion values\, can be symmetrical (one ceRNA influences another and vice-ver sa) or asymmetrical (one ceRNA influences another but not the reverse) and may be highly selective\, while possibly limited by noise. Finally\, I wi ll show that non-trivial correlations among ceRNAs can emerge in experimen tal readouts due to transcriptional fluctuations even in absence of miRNA- mediated cross-talk\, so that more refined analyses will be needed to iden tify signatures of cross-talk in the transcriptome. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-129@lptms.universite-paris-saclay.fr DTSTART:20130326T110000Z DTEND:20130326T120000Z DTSTAMP:20130418T124031Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-camille-aron/ SUMMARY:Séminaire du LPTMS: Camille Aron - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 26 Mar 13 11:00 DESCRIPTION:Strongly Correlated Electrons Driven by an Electric Field\nCami lle Aron\, Rutgers University\nStrongly correlated many-body systems drive n out of equilibrium are attracting a lot of interest\, motivated by new experimental realizations in non-linear transport in devices\, heterostru ctures and cold atoms. Theoretically\, the challenge is to understand the  interplay between the strong correlation and the finite drive. In this  talk\, I will focus on the Hubbard model driven by a constant electric fi eld. First\, I will introduce some theoretical tools to address the non-e quilibrium steady states\, bypassing the transient dynamics. At the dynam ical mean-field level\, I will describe how the lattice problem can be se lf-consistently mapped to a multi-lead Anderson impurity model. Afterward s\, I will discuss the fate of Mott physics in the non-linear regime by d etailing two key far-from-equilibrium phenomena: \n- the dimensional cros sover towards a lower dimensional equilibrium system\;- the dielectric bre akdown of the Mott insulator.\nReferences: C. Aron\, G. Kotliar\, C. Webe r\, PRL 108\, 086401 (2012)  C. Aron\, PRB 86\, 085127 (2012) C. Aon\, C . Weber\, G. Kotliar\, arXiv:1210.4926 (2012) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-90@lptms.universite-paris-saclay.fr DTSTART:20130402T110000Z DTEND:20130402T120000Z DTSTAMP:20130418T124021Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-chase-broedersz/ SUMMARY:Séminaire du LPTMS: Chase Broedersz - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 2 Avr 13 11:00 DESCRIPTION:Actively stressed marginal networks\nChase Broedersz\, Princeto n University\nThe mechanical properties of cells are regulated in part by internal stresses generated actively by molecular motors in the cytoskelet on. Experiments on reconstituted intracellular F-actin networks with myosi n motors show that such active contractility dramatically affects network elasticity. There is also experimental evidence that cytoskeletal networks in living cells may be unstable or only marginally stable in the absence of motor activity. We study the impact of active stresses on the mechanics of disordered\, marginally stable networks using a simple model for netwo rks of fibers with linear bending and stretching elasticity. Motor activit y controls the elasticity in an anomalous fashion close to the point of ma rginal stability by coupling to critical network fluctuations. In addition \, such motor stresses can stabilize initially floppy networks\, extending the range of critical behavior to a broad regime of network connectivitie s below the marginal point. Away from this regime\, or at high stress\, mo tors give rise to a linear increase in stiffness with stress. The remarkab le mechanical response of these actively stressed networks is captured by a simple\, constitutive scaling relation\, which highlights the important role of nonaffine strain fluctuations as a susceptibility to motor stress. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-135@lptms.universite-paris-saclay.fr DTSTART:20130404T143000Z DTEND:20130404T160000Z DTSTAMP:20130319T103956Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-tomohiro-sasamoto/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Tomohiro Sasamoto - LPT MS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 4 Avr 13 14:30 DESCRIPTION:Fluctuations in the 1D Kardar-Parisi-Zhang equation and discret e analogues\nTomohiro SASAMOTO (Chiba University\, Japan)\n \nThe Kardar- Parisi-Zhang (KPZ) equation is a non-linear stochastic partial differenti al equation which describes surface growth phenomena. Recently its one-di mensional version has attracted much attention because of several excitin g experimental and theoretical developments [1]. \nIn this talk we discus s the replica analysis of the KPZ equation and its discrete analogues. St arting from the basics of the KPZ equation and the replica analysis\, we explain how one can utilize it for the analysis of the KPZ equation [2]\, where are the tricky parts\, and how they are regularized in discrete mod els like q-TASEP [3]. \n References:\n[1] K.A. Takeuchi\, M. Sano\, T. S asamoto and H. Spohn\, Growing interfaces uncover universal fluctuations b ehind scale invariance\, Sci. Rep. 1 (2011) 34.\n[2] T. Imamura and T. Sa samoto\, Exact solution for the stationary KPZ equation\, Phys. Rev. Let t. 108 (2012) 190603.\n[3] A. Borodin\, I. Corwin and T. Sasamoto\, From duality to determinants for q-TASEP and ASEP\, arXiv:1207.5035. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-120@lptms.universite-paris-saclay.fr DTSTART:20130405T140000Z DTEND:20130405T140000Z DTSTAMP:20130418T124006Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-chase-broedersz/ SUMMARY:Physics-Biology interface seminar : Chase Broedersz - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 5 Avr 13 1 4:00 DESCRIPTION:Localization and condensation of the parB-DNA complex in the ba cterial chromosome\nChase Broedersz (Princeton University)\nThe molecular machinery responsible for faithful segregation of the chromosome in bacter ia such as Caulobacter crescentus and Bacillus subtilis includes the ParAB S a.k.a. Spo0J/Soj partitioning system. In Caulobacter\, prior to division \, hundreds of ParB proteins bind to the chromosome near the origin of rep lication\, and localize to one pole of the cell. Subsequently\, the ParB-D NA complex is translocated to the far pole by the binding and retraction o f the ParA spindle-like apparatus. Remarkably\, the localization of ParB p roteins to specific regions of the chromosome appears to be controlled by only a few centromeric parS binding sites. Although lateral interactions b etween DNA-bound ParB are likely to be important for their localization\, the long-range order of ParB domains on the chromosome appears to be incon sistent with a picture in which protein-protein interactions are limited t o neighboring DNA-bound proteins. We propose a simple model to study the l ocalization and condensation of the ParB-DNA complex\, which includes both lateral and 3D protein-protein interactions among DNA-bound ParB proteins . Our model shows how such interactions can condense and organize the chro mosome spatially\, and can control both the localization and the long-rang e order of the DNA-bound proteins. Interestingly\, the condensed ParB-DNA complex adopts a topology in which loops of DNA extend outside the cluster exposed for transcription\; this structure may have implications for expr ession levels of genes in the vicinity of the parS site. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-141@lptms.universite-paris-saclay.fr DTSTART:20130408T120000Z DTEND:20130408T124500Z DTSTAMP:20130418T123956Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-andrey-lokhov/ SUMMARY:Journal Club du LPTMS: Andrey Lokhov - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 8 Avr 13 12:00 DESCRIPTION:Andrey Lokhov: Ph.D. Student LPTMS\nImproved contact prediction in proteins: Using pseudolikelihoods to infer Potts models\nM. Ekeberg\, C. Lovkvist\, Y. Lan\, M. Weigt\, E. Aurell\,  Phys. Rev. E 87\, 012707 ( 2013)\n \nIn this paper inference methods of inverse statistical mechanic s are applied to the 21-state Potts model for predicting amino-acid cont acts in proteins. This problem is important in biology since a successful estimation of contacts is essential for a prediction of proteins' 3D struc ture and\, therefore\, of its biological function.\n \nSee also \nPNAS D ecember 6\, 2011 vol. 108 no. 49 E1293-E1301\nPNAS 106(1)\, 67-72 (2009)\n http://arxiv.org/abs/1212.3281\n \n \nAbstract of the paper:\n\n\n\n\nSp atially proximate amino acids in a protein tend to coevolve. A protein’s 3D structure hence leaves an echo of correlations in the evolutionary rec ord. Reverse engineering 3D structures from such correlations is an open p roblem in structural biology\, pursued with increasing vigor as more and m ore protein sequences continue to fill the data banks. Within this task li es a statistical inference problem\, rooted in the following: correlation between two sites in a protein sequence can arise from firsthand interacti on\, but can also be network-propagated via intermediate sites\; observed correlation is not enough to guarantee proximity. To separate direct from indirect interactions is an instance of the general problem of inverse sta tistical mechanics\, where the task is to learn model parameters (fields\, couplings) from observables (magnetizations\, correlations\, samples) in large systems. In the context of protein sequences\, the approach has been referred to as direct-coupling analysis. Here we show that the pseudolike lihood method\, applied to 21-state Potts models describing the statistica l properties of families of evolutionarily related proteins\, significantl y outperforms existing approaches to the direct-coupling analysis\, the la tter being based on standard mean-field techniques. This improved performa nce also relies on a modified score for the coupling strength. The results are verified using known crystal structures of specific sequence instance s of various protein families. Code implementing the new method can be fou nd at http://plmdca.csc.kth.se/.\n\n\n\n\n  LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-98@lptms.universite-paris-saclay.fr DTSTART:20130409T110000Z DTEND:20130409T120000Z DTSTAMP:20130418T123936Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-p-soule-et-p-e-larre/ SUMMARY:Séminaire du LPTMS: P. Soulé et P.-E. Larré - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 9 Avr 13 11:00 DESCRIPTION:Wave pattern generated by an obstacle moving in a one-dimension al polariton condensate\nPierre-Elie Larré\, LPTMS\nMotivated by recent e xperiments on generation of wave patterns in polariton condensates\, we an alyze superfluid and dissipative characteristics of the one-dimensional fl ow of a nonresonantly-pumped polariton condensate past a localized obstacl e. We consider the response of the condensate flow in the weak-perturbatio n limit\, but also by means of the Whitham averaging theory in the nonline ar regime. One of the results of this work is the identification of a new time-dependent regime separating two types of stationary flows (a mostly v iscous one and another one dominated by Cherenkov radiation).\nI will also present results obtained by including polarization effects in the descrip tion of the polariton condensate\, and I will argue that similar effects i n presence of an acoustic horizon offer possibilities for demonstrating Ha wking-like radiation in polariton condensates.\nMany-body study of a quant um point contact in the fractional quantum Hall regime\nPaul Soulé\, LPTM S\nFractional Quantum Hall (FQH) fluids have a low-energy effective theory localized at their edges. The edge states are expected to form a very spe cial one-dimensional strongly interacting electronic system\, a chiral Lut tinger liquid. Depending on FQH phases\, a variety of 1D models has been p roposed. But only poor experimental agreements have been found yet. Using exact diagonalizations in the cylinder geometry we identify the edge modes in the presence of a parabolic confining potential at Landau level fillin g factors v=1/3 and v=5/2. If we change the sign of the potential we can a ccess both the tunneling through the bulk of the fluid and the tunneling b etween spatially separated droplets\, and measure numerically Luttinger pa rameters in both cases. These phenomena are at the basis of tunneling expe riments in quantum point contact devices of two-dimensional electron gases .\nP. Soulé\, T. Jolicoeur\, Phys. Rev. B 86\, 115214 (2012)P. Soulé\, T . Jolicoeur\, in preparation LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-119@lptms.universite-paris-saclay.fr DTSTART:20130419T140000Z DTEND:20130419T140000Z DTSTAMP:20130421T053955Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-emanuele-helfer/ SUMMARY:Physics-Biology interface seminar: Emmanuèle Helfer - Amphi BLANDI N du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 19 Avr 13 14:00 DESCRIPTION:Polymerization of actin branched networks controls the organiza tion of WASH domains at the surface of endosomes\nEmmanuèle Helfer (Labor atoire d'Enzymologie et de Biochimie Structurales - Gif-sur-Yvette)\nSorti ng of cargoes in endosomes occurs through their selective enrichment into sorting platforms\, where transport intermediates are generated. The WASH complex\, which is recruited from the cytosol to endosomes\, activates the Arp2/3 complex and hence actin polymerization onto such sorting platforms .\nHere\, we analyzed the role of actin polymerization in the physiology o f endosomal domains containing WASH using quantitative image analysis. Usi ng a novel colocalization method that is insensitive to the heterogeneity of size and shape of endosomes\, we show that preventing the generation of branched actin networks induces endosomal accumulation of the WASH comple x. Moreover\, we found that actin depolymerization induces a dramatic decr ease in the recovery of endosomal WASH after photobleaching. These results suggest a built-in turnover\, where the actin network\, i.e. the product of the WASH complex\, contributes to the dynamic cytosol/endosome exchange of the WASH complex. Our data also suggest a role of actin in the lateral compartmentalization of endosomes: discrete WASH domains coalesce upon ac tin depolymerization or Arp2/3 depletion. Thus\, branched actin networks a re involved in the regulation of WASH domain size.\nI will finally discuss the potential role of lipid repartitioning in these sorting platforms and of the ensuing line tension that could develop at the domain boundary. Th is may provide a dynamin-independent contribution to membrane scission.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-143@lptms.universite-paris-saclay.fr DTSTART:20130422T120000Z DTEND:20130422T124500Z DTSTAMP:20130418T123051Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-dmitry-petrov/ SUMMARY:Journal Club du LPTMS: Dmitry Petrov - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 22 Avr 13 12:00 DESCRIPTION:Dmitry Petrov\, CNRS researcher LPTMS\nTitle: Quantum annealing with more than one hundred qubits\nAuthors: Sergio Boixo\, Troels F. Ronn ow\, Sergei V. Isakov\, Zhihui Wang\, David Wecker\, Daniel A. Lidar\, Joh n M. Martinis\, and Matthias Troyer\nThe paper is not publicly available a s it is submitted to Nature\, but I explained Matthias our Journal Club id ea and he sent me the preprint asking to keep it for our private use. I wi ll put the preprint on our coffee table together with the D-Wave Systems w ikipedia page. Enjoy.\nAbstract: At a time when quantum effects start to p ose limits to further miniaturisation of devices and the exponential perfo rmance increase due to Moore's law\, quantum technology is maturing to the point where quantum devices\, such as quantum communication systems\, qua ntum random number generators and quantum simulators\, may be built with p owers exceeding the performance of classical computers. A quantum annealer \, in particular\, finds solutions to hard optimisation problems by evolvi ng a known initial configuration towards the ground state of a Hamiltonian that encodes an optimisation problem. Here\, we present results from expe riments on a 108 qubit D-Wave One device based on superconducting flux qub its. The correlations between the device and a simulated quantum annealer demonstrate that the device performs quantum annealing: unlike classical t hermal annealing it exhibits a bimodal separation of hard and easy problem s\, with small-gap avoided level crossings characterizing the hard problem s. To assess the computational power of the quantum annealer we compare it to optimised classical algorithms. We discuss how quantum speedup could b e detected on devices scaled to a larger number of qubits where the limits of classical algorithms are reached.\nSee also http://en.wikipedia.org/wi ki/D-Wave_Systems http://www.nytimes.com/2013/03/22/technology/testing-a-n ew-class-of-speedy-computer.html?pagewanted=all&\;_r=2&\; http://www .nature.com/nature/journal/v473/n7346/full/nature10012.html http://arxiv.o rg/abs/1302.5843 http://arxiv.org/abs/1102.1296 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-139@lptms.universite-paris-saclay.fr DTSTART:20130423T103000Z DTEND:20130423T113000Z DTSTAMP:20130418T123119Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sebastien-balibar/ SUMMARY:Séminaire du LPTMS: Sébastien Balibar - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 23 Avr 13 10:30 DESCRIPTION:La Plasticité Géante d'un Cristal Quantique \nSébastien Bal ibar\, Laboratoire de Physique Statistique de l'ENS\nNous avons découver t [1] que les cristaux d'hélium 4 présentent une plasticité géante à très basse température si l'on élimine toutes leurs impuretés. Ils ne résistent pratiquement pas au cisaillement dans une direction particuliè re\, même sous contrainte extrêmement faible (1 nanobar) et au voisinage du zéro absolu (0.01 Kelvin). Ce phénomène est un exemple spectaculair e de "plasticité" car c'est une conséquence du mouvement libre des dislo cations dans une direction que nous avons identifiée\, ce qui réduit l'u n des coefficients élastiques d'environ 80% même sous l'effet de contrai ntes extrêmement faibles (1 nanobar). On notera cependant que\, contraire ment à la plasticité classique\, il s'agit d'un effet réversible. Il di sparaît dès que des traces d'impuretés s'attachent aux dislocations ou si la température augmente ce qui induit des collisions entre les disloca tions en mouvement et les phonons thermiques. Ce dernier phénomène nous a permis[2] de mesurer la densité de ces dislocations et leur longueur li bre qui est très grande (50 à 200 microns) ce qui prouve que les disloca tions sont peu connectées entre elles\, plus probablement alignées paral lelement les unes aux autres. Toutes ces observations récentes [1\,2] dé montrent que ces cristaux ne sont vraisemblablement pas "supersolides" com me cela avait été proposé en 2004\, et qu'au contraire\, leurs apparent es anomalies de rotation sont des artefacts dus à la plasticité géante que nous avons mise en évidence.\n[1] A. Haziot\, X. Rojas\, A. Fefferman \, J. Beamish and S. Balibar\, Phys. Rev. Lett. 110\, 035301 (2013) [2] A. Haziot\, A. Fefferman\, J. Beamish\, and S. Balibar\, Phys. Rev. B 90\, 0 60509(R) (2013). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-145@lptms.universite-paris-saclay.fr DTSTART:20130514T110000Z DTEND:20130514T120000Z DTSTAMP:20130521T070300Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christophe-texier/ SUMMARY:Séminaire du LPTMS: Christophe Texier - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Mai 13 11:00 DESCRIPTION:Distribution du temps de Wigner dans des cavités chaotiques\nC hristophe Texier\, LPTMS\nThe Wigner time delay captures temporal aspect o f the scattering process. Due to its relation with the density of states o f the open system (here a chaotic cavity)\, it is also of great interest f or the study of coherent electronic transport in mesoscopic devices. Usin g the joint distribution for proper time-delays of a chaotic cavity derive d by Brouwer\, Frahm &\; Beenakker [Phys. Rev. Lett. 78\, 4737 (1997)]\ , we obtain\, in the limit of large number of channels N\, the large devia tion function for the distribution of the Wigner time-delay (the sum of pr oper times) by a Coulomb gas method. We show that the existence of a powe r law tail originates from narrow resonance contributions\,  related  to a (second order) freezing transition in the Coulomb gas. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-118@lptms.universite-paris-saclay.fr DTSTART:20130517T140000Z DTEND:20130517T140000Z DTSTAMP:20130507T074746Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-rut-carballido-lopez/ SUMMARY:Physics-Biology interface seminar : Karen Perronet - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 17 Mai 13 1 4:00 DESCRIPTION:Cinétique de traduction de ribosomes individuels par microscop e de fluorescence\nKaren Perronet (Laboratoire Charles Fabry\, Institut d' Optique) \n \nLe ribosome est le moteur moléculaire traduisant le code génétique de l’ARNm en protéine. La dynamique de ce processus asynchr one primordial est encore mal connue\, surtout chez les eucaryotes. Pouvoi r suivre des ribosomes individuels pendant la traduction est donc un enjeu important.\nNous présentons dans ce séminaire différentes stratégies permettant d’étudier la vitesse d’élongation de ribosomes individuel s par microscopie de fluorescence en réflexion totale.\nNous avons tout d ’abord utilisé des ribosomes procaryotes mutants que nous avons marqué s avec un nano-cristal semi-conducteur fluorescent. Nous avons ainsi pu me surer la vitesse globale de traduction d’une protéine.\nNous avons ensu ite hybridé des oligonucléotides fluorescents sur l’ARNm\, les départ s des marqueurs signalant alors le passage des ribosomes à leurs emplacem ents. Nous avons alors utilisé des ribosomes eucaryotes\, encore très pe u étudiés à l’échelle de la molécule unique. Les ribosomes sont ini tialement immobilisés sur l’ARNm grâce à une IRES\, structure seconda ire spécifique permettant une initiation non canonique du ribosome. Puis suite à l’injection d’un système de traduction in-vitro\, ils peuven t traduire la protéine et atteindre les oligonucléotides marqués\, qu ’ils détachent grâce à leur activité hélicase. Ces dissociations se traduisent par une disparition du signal de fluorescence des marqueurs qu i diffusent hors de l’onde évanescente. Nous avons ainsi pu observer la distribution des durées de traduction jusqu’à des endroits spécifiqu es de l’ARNm. Nous avons pu extraire deux durées caractéristiques pour l’élongation. La première (typ. 40 s) est associée au premier cycle d’élongation\, ralentie par le fait que le ribosome doit s’extraire d e l’IRES. La seconde (~1s) correspond à un cycle d’élongation normal . LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-133@lptms.universite-paris-saclay.fr DTSTART:20130521T110000Z DTEND:20130521T120000Z DTSTAMP:20130521T070159Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-edouard-hannezo/ SUMMARY:Séminaire du LPTMS: Edouard Hannezo - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 21 Mai 13 11:00 DESCRIPTION:Epithelial sheet morphologies\nE. Hannezo\, Institut Curie\nUnd erstanding morphogenesis during the development of the embryo requires an understanding of how mechanical forces coordinate to generate the macrosco pic shape of organs. Although it is acknowledged that adhesion and mechani cal forces play a crucial role in determining the morphology of a cell\, a precise model remains elusive. We propose a simple theoretical model base d on adhesion and acto-myosin generated forces to study the morphology of epithelial cells and the 3D topology of epithelial sheets. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-147@lptms.universite-paris-saclay.fr DTSTART:20130527T143000Z DTEND:20130527T160000Z DTSTAMP:20130513T070512Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-jesper-jacobsen/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Jesper Jacobsen - IPhT\ , CEA-Saclay\, salle Itzykson - 27 Mai 13 14:30 DESCRIPTION:Critical manifolds for percolation and Potts models from graph polynomials\nJesper Jacobsen (Labo. de Physique Théorique de l'Ecole Norm ale Supérieure\, Paris)\n \nThe first parameter to be fixed when studyin g a phase transition is the critical temperature. Somewhat surprisingly\, this parameter is only known analytically for the simplest two-dimensional models (Ising model)\, or for more complicated models (Potts and O(n) vec tor models) on the simplest possible lattices. The known critical temperat ures are invariably given by simple algebraic curves. Some of these result s have very recently been proved mathematically by the technique of discre te holomorphicity.\nFor Potts and (bond or site) percolation models on any desired two-dimensional lattice we define a graph polynomial whose roots turn out to give very accurate approximations to the critical temperature s\, or even yield the exact result in the exactly solvable cases. This pol ynomial depends on a basis (unit cell) and its embedding into the infinite lattice. As the size of the basis is increased the approximation becomes increasingly accurate. This\, on the one hand\, gives strong evidence that the critical temperature for the lattices with no known analytical soluti on may not be algebraic numbers\, and that conformal invariance will not h ave any counterpart in finite size (discrete holomorphicity). On the other hand\, the method determines the critical temperature to unprecedented ac curacy\, typically 12-13 significant digits for bond percolation threshold s. It also shows that the phase diagram of the Potts model in the antiferr omagnetic regime has an intricate and highly lattice-dependent structure.\ n \;\n \;\n \; LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-138@lptms.universite-paris-saclay.fr DTSTART:20130528T110000Z DTEND:20130528T120000Z DTSTAMP:20130521T070240Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marie-helene-genest/ SUMMARY:Séminaire du LPTMS: Marie-Hélène Genest - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 28 Mai 13 11:00 DESCRIPTION:Supersymmetry and dark matter at the LHC\nMarie-Hélène Genest \, LPSC Grenoble\nThe presence of Cold Dark Matter in the universe has bee n evinced by a number of astrophysical experiments. Direct and indirect de tection experiments are looking for evidences of the presence of this elus ive new particle. In a completely complementary approach\, one can look fo r the production of such weakly interacting massive particles (WIMPs) at t he LHC\, either by looking for direct production of such WIMPs or by looki ng for supersymmetry\, an appealing theory beyond the Standard Model of pa rticles which provides a natural Cold Dark Matter candidate. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-117@lptms.universite-paris-saclay.fr DTSTART:20130531T140000Z DTEND:20130531T140000Z DTSTAMP:20130521T070226Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-claire-wilhelm/ SUMMARY:Physics-Biology interface seminar : Claire Wilhelm - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 31 Mai 13 1 4:00 DESCRIPTION:Magnetic living cells: New tools for cell imaging\, tissue engi neering and cell therapies\nClaire Wilhelm (Université Paris 7)\nRecent a dvances in cell therapy and tissue engineering opened new windows for rege nerative medicine\, but still necessitate innovative techniques to create and image functional tissues. One promising approach is to associate magne tic nanoparticles with cells in order to supply them with sufficient magne tization to be detectable by MRI or manipulated by magnetic forces\, while maintaining cell viability and functionalities. A few years ago\, we prop osed the use of anionic iron oxide nanoparticles as efficient agents for c ell internalisation without impacting cell functions. Recently we examined the influence of the amount of internalized iron and the state of nanopar ticle aggregation on the capacity for mesenchymal stem cell differentiatio n and MRI single cell tracking. We then demonstrated that high resolution Magnetic Resonance Imaging (MRI) allowed combining cellular-scale resoluti on with the ability to detect two cell types simultaneously at any tissue depth. In parallel\, we addressed the challenge to create a functional tis sue from stem cells in vitro. The aim was to confine stem cells in three d imensions at the millimetric scale by using home-designed miniaturized mag netic devices\, in order to create cellular patterns for stem cell differe ntiation and tissue engineering.\nFinally magnetic nanoparticles show also great promises for antitumor cell therapies\, in particular using the mag netic hyperthermia modality. Cellular internalization of magnetic nanopart icles localizes the source of heat in the internal volume of the cell\, wi th direct application for tumor cell therapies. The combination of cell-de rived vesicles with magnetic nanoparticles creates multifunctional bio-ins pired nanovectors with promising potential for diagnosis and therapy. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-152@lptms.universite-paris-saclay.fr DTSTART:20130603T110000Z DTEND:20130603T121500Z DTSTAMP:20130530T121205Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-andrey-yanovsky/ SUMMARY:Séminaire exceptionnel du LPTMS : Andrey Yanovsky - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 3 Juin 13 11:00 DESCRIPTION:Effect of winding edge currents\nAndrey Yanovsky (B. Verkin Ins titute for Low Temperature Physics and Engineering of the NAS of Ukraine)\ nSome degrees of freedom “interact”' with the velocity winding of traj ectories\, e.g. spin.  We discuss the connection between spintronics and winding: namely its relation to Spin-hall effect and Thomas precession. Fu rther we discuss persistent currents for particles with internal degrees o f freedom. The currents arise because of winding properties essential for the chaotic motion of the particles in a confined geometry. The currents d o not change the particle concentrations or thermodynamics\, similar to th e skipping orbits in a magnetic field. One of the possible realization are persistent currents in conditions of “extrinsic”' spin Hall effect. T he effect is classical in contrast to similar currents predicted for condi tions of quantum “intrinsic” spin Hall effect. An analytical solution has been found in an Ornstein-Uhlenbeck process. Weak dependence of the wi nding currents on the form of confined potential has been uncovered. The r esults can be of interest beyond the scope of phenomena associated with th e spin Hall effect.\nS. Ouvry\, L .Pastur\, A. Yanovsky\, Physics Letters A 377 (2013)\, pp. 804-809 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-134@lptms.universite-paris-saclay.fr DTSTART:20130604T110000Z DTEND:20130604T120000Z DTSTAMP:20130723T102103Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s/ SUMMARY:Séminaire du LPTMS: Véronique Terras - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 4 Juin 13 11:00 DESCRIPTION:Algberaic Bethe Ansatz approach to correlation functions of int egrable \nsystems: a review LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-153@lptms.universite-paris-saclay.fr DTSTART:20130606T140000Z DTEND:20130606T151500Z DTSTAMP:20130604T093530Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-francois-landes/ SUMMARY:Journal Club du LPTMS : François Landes - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 6 Juin 13 14:00 DESCRIPTION:François Landes (PhD student LPTMS)\n She\, Z.\, Aurell\, E. &\; Frisch\, U. The inviscid Burgers equation with initial data of Brow nian type. Communications in Mathematical Physics 148\, 623–641 (1992). Freely available at : http://projecteuclid.org/DPubS?service=UI&\;versi on=1.0&\;verb=Display&\;handle=euclid.cmp/1104251047\nTitle: The inv iscid Burgers equation with initial data of Brownian type.\nAuthors: Zhen- su She\, Erik Aurell and Uriel Frisch.\n \nIn my presentation (aimed main ly at the sutdents) I will introduce Burgers' equation\, its link with Nav ier-Stokes and the phase-diffusion equation\, and show how its inviscid li mit can be simply solved using a Cole-Hopf transform. In this limit\, at l ong times\, the velocity field develops shocks (singularities)\, which hav e interesting statistical properties (e.g. they are scale-free distributio ns). I will motivate the use of non-smooth\, random initial conditions\, t hen present a few results obtained with this kind of initial condition. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-137@lptms.universite-paris-saclay.fr DTSTART:20130607T140000Z DTEND:20130607T140000Z DTSTAMP:20130418T123213Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-david-dulin/ SUMMARY:Physics-Biology interface seminar : David Dulin - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 7 Juin 13 14:0 0 DESCRIPTION:Dynamics of transcription and error incorporation in a viral RN A-dependent RNA polymerase\nDavid Dulin (Delft University of Technology)\n RNA-dependent RNA polymerases (RdRPs) are essential enzymes that govern tr anscription and replication in RNA viruses. While RNA elongation forms an important therapeutic target against viral infection\, little is known abo ut elongation dynamics at the single-molecule level. Here\, we study the w ell-established RdRP model system of P2 from the double-stranded RNA bacte riophage Φ6 using high-throughput single-molecule force-spectroscopy comb ined with theoretical modeling. We show that P2 elongation dynamics is irr egular\, with rapid transcription repeatedly interrupted by pauses whose d urations vary from seconds to thousands of seconds. Exploiting the discrim inatory power offered by our large datasets\, together with specifically-a dapted analysis\, we introduce a stochastic dynamical model of P2 transcri ptional elongation. Our results imply that the majority of pauses result f rom nucleotide misincorporation\, providing a direct link between RdRP dyn amics and error rates—rates that offer potential drug targets\, as they must be finely tuned to confer both genome stability between generations a nd adaptability to bypass host defense systems. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-146@lptms.universite-paris-saclay.fr DTSTART:20130613T110000Z DTEND:20130613T121500Z DTSTAMP:20130507T080831Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-3/ SUMMARY:Séminaire du LPTMS : Bernard Hellfer - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Juin 13 11:00 DESCRIPTION:Opérateurs d'Aharonov-Bohm et Partitions Spectrales Minimales\ nBernard Hellfer (Dept Math Paris Sud)\n \;\n"Si l'effet d'Aharonov-Bo hm fut au départ une expérience dans un domaine non-borné non simplemen t connexe interprêté par le scattering\, l'étude des propriétés spect rales de l'opérateur d'Aharonov-Bohm dans un domaine borné apparaît dan s beaucoup d'autres questions en particulier dans l'étude du diamagnétis me et du paramagnétisme. Une situation très particulière correspond au cas où les flux créés aux pôles sont des multiples impairs de Pi. Nous discuterons de ce cas en liaison avec la question des parties spectrales minimales\, question qui apparaît comme situation limite en dynamique des populations." LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-154@lptms.universite-paris-saclay.fr DTSTART:20130613T143000Z DTEND:20130613T160000Z DTSTAMP:20130607T052009Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-remi-monasson/ SUMMARY:Séminaire de la Fédération PHYSTAT-SUD : Rémi Monasson - LPTMS\ , salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Juin 13 14:30 DESCRIPTION:Cross-talk and transitions between spatial charts in a neuronal model of the hippocampus\nRémi Monasson (LPTENS\, Paris)\n Understanding the mechanisms by which space gets represented in the brain is a fundamen tal problem in neuroscience. The experimental discovery of so-called "plac e cells" and "grid cells"\, encoding specific positions in space\, provide essential elements in this context. How a spatial chart i.e. a relation b etween different points in space\, may be built and memorized? In this tal k I will present a model of neural network capable of storing several spat ial charts. This model may be solved with the help of the techniques of St atistical Physics of Disordered Systems. We will discuss the different pos sible phases of the system and the essential features of its dynamics (act ivated diffusion in one chart and transitions between charts)\, in relatio n with recent experiments. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-140@lptms.universite-paris-saclay.fr DTSTART:20130614T140000Z DTEND:20130614T140000Z DTSTAMP:20130628T083047Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-michael-murrell/ SUMMARY:Physics-Biology interface seminar : Michael Murrell - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 14 Juin 13 14:00 DESCRIPTION:Mechanical Force Generation and Turnover in the Cell Cytoskelet on\nMichael Murrell (University of Wisconsin\, Madison)\nMyosin II motors drive contractility of the cortical actin network\, enabling shape change and cytoplasmic flows underlying diverse physiological processes ranging f rom cell division and migration to tissue morphogenesis. Yet\, despite its importance\, the mechanisms that describe contractility and the generatio n of mechanical forces within the cortex are not well understood. We recap itulate contractility in vitro\, through the development of a minimal mode l of the cell actomyosin cortex by coupling a two-dimensional\, cross-link ed F-actin network decorated by myosin thick filaments to a model cell mem brane. Myosin motors generate both compressive and tensile stresses on F-a ctin and consequently\, induce large bending fluctuations. Over a large ra nge of crosslinking\, we show the extent of network contraction correspond s exactly to the extent of individual F-actin shortening via buckling. Thi s demonstrates an essential role of buckling in facilitating local compres sion to enable mesoscale network contraction of up to 80% strain. Buckled F-actin at high curvatures are prone to severing and thus\, compressive st resses mechanically coordinate contractility with F-actin severing\, the i nitial step of F-actin turnover. Finally\, the F-actin curvature acquired by myosin-induced stresses can be further constrained by adhesion of the n etwork to a membrane\, accelerating filament severing but inhibiting the l ong-range transmission of the stresses necessary for network contractility . Thus\, the extent of membrane adhesion can regulate the coupling between network contraction and F-actin severing. These data demonstrate the esse ntial role of the non-linear response of Factin to compressive stresses in potentiating both myosin-mediated contractility and filament dynamics. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-132@lptms.universite-paris-saclay.fr DTSTART:20130618T110000Z DTEND:20130618T120000Z DTSTAMP:20130628T083036Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-rodolfo-jalabert/ SUMMARY:Séminaire du LPTMS: Rodolfo Jalabert - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Juin 13 11:00 DESCRIPTION:Scattering Phase of Quantum Dots: Emergence of Universal Behavi or\nRodolfo Jalabert\, Institut de Physique et Chimie des Materiaux de St rasbourg\nIn a coherent conductor like a quantum dot\, the transmission ph ase is of key importance in determining the transport properties. Unlike t he conductance\, the transmission phase is not directly measurable. Nevert heless\, phase-sensitive experiments have been performed by embedding a qu antum dot in one of the arms of an Aharonov-Bohm interferometer. These exp eriments\, observing in-phase behavior between consecutive Coulomb-blockad e resonances\, have remained unexplained for more than a decade. We provid e a solution of this puzzle by showing that wave-function correlations exi sting in chaotic ballistic quantum dots are responsible for the emergence of large universal sequences of in-phase resonances in the short wavelengt h limit [1]. In quantum dots with at least one hundred electrons the descr iption of Coulomb blockade physics within a constant charging energy model allows for an effective one-particle description. Smaller dots require go ing beyond mean-field approaches by including the effect of electronic cor relations. We develop a numerical method\, using the Density Matrix Renorm alization Group algorithm\, in order to obtain the transmission phase of a strongly interacting system. We demonstrate that electronic correlations do not generically lead to the in-phase behavior and that small dots are a lways in the mesoscopic regime of random relative transmission phases [2]. \n[1] R.A. Molina\, R.A. Jalabert\, D. Weinmann\, and Ph. Jacquod\; Phys. Rev. Lett. 108\, 076803 (2012).\n[2] R.A. Molina\, P. Schmitteckert\, D. W einmann\, R.A. Jalabert\, and Ph. Jacquod\; arXiv:1212.2114 (2012). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-150@lptms.universite-paris-saclay.fr DTSTART:20130620T140000Z DTEND:20130620T154500Z DTSTAMP:20130628T083023Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-guillaume-roux/ SUMMARY:Journal Club du LPTMS : Guillaume Roux - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Juin 13 14:00 DESCRIPTION:"Quantum quenches through experimental examples"\n Guillaume R oux (LPTMS)\n"The subject of quantum quenches is introduced through two re cent experimental results:\nhttp://fr.arxiv.org/abs/1111.0776 Nature 481\, 484 (2012)\nhttp://fr.arxiv.org/abs/1211.0545 Science 339\, 52 (2013)\nTh e program will be to briefly recall the physics of cold atoms loaded in an optical lattice\, to focus on some general questions concerning the time- evolution of closed quantum many-body systems (thermalization\, relaxation and non-equilibrium physics)\, and to explain in more details the results obtained in these two experiments. " LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-142@lptms.universite-paris-saclay.fr DTSTART:20130625T110000Z DTEND:20130625T120000Z DTSTAMP:20130628T083009Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-raoul-s/ SUMMARY:Séminaire du LPTMS: Max Atkin - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 25 Juin 13 11:00 DESCRIPTION:From Instantons to Large Deviations in Hermitian Random Matrice s\nMax Atkin (University of Bielefeld)\nThe typical fluctuations of the la rgest eigenvalue of a Hermitian random matrix about its mean has been know n for a long time to be given by the Tracy-Widom distribution. More recent ly interest has focused on the 'atypical' fluctuations in which an eigenva lue appears very far from the bulk spectrum. This problem has been attacke d using saddle point methods\, loop equations and\, to a much lesser exten t\, orthogonal polynomials. In this talk we review recent progress in the orthogonal polynomial approach which makes contact with instanton effects in the string theory literature. We use this framework to derive the distr ibution for large deviations in the case of multi-critical potentials. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-127@lptms.universite-paris-saclay.fr DTSTART:20130628T140000Z DTEND:20130628T140000Z DTSTAMP:20130628T082908Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-abdul-barakat/ SUMMARY:Physics-Biology interface seminar : Abdul Barakat - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 28 Juin 13 14:00 DESCRIPTION:Mechanotransduction in Vascular Endothelial Cells: Mechanisms a nd Implications\nAbdul Barakat (École Polytechnique)\nThe ability of arte rial endothelial cells\, the cells lining the inner surfaces of blood vess els\, to respond to mechanical forces associated with blood flow is essent ial for normal vascular function. Abnormalities in endothelial cell mechan otransduction play a critical role in the development and progression of c ardiovascular disease. The mechanisms governing how endothelial cells sens e mechanical forces on their surfaces and how they subsequently transmit t hese forces within the intracellular space remain poorly understood. In th is talk\, I will present experimental and computational results in support of a central role for the cellular cytoskeleton in force transmission wit hin endothelial cells. Because endothelial cells are often simultaneously exposed to multiple biophysical stimuli\, I will show data that demonstrat e that endothelial cells integrate biophysical stimuli derived from simult aneous apical cellular stimulation by flow and basal stimulation by nano-s cale substrate patterning. Finally\, I will discuss the role of proteins t hat link the cytoskeleton to the nucleus in modulating mechanotransduction in endothelial cells. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-155@lptms.universite-paris-saclay.fr DTSTART:20130702T110000Z DTEND:20130702T120000Z DTSTAMP:20130628T082841Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-m-kardar/ SUMMARY:Séminaire du LPTMS: M. Kardar - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 2 Juil 13 11:00 DESCRIPTION:Levitation by Casimir forces in and out of equilibrium\nMehran Kardar\, MIT\nA generalization of Earnshaw's theorem constrains the possib ility of levitation by Casimir forces in equilibrium. The scattering forma lism\, which forms the basis of this proof\, can be used to study fluctuat ion-induced forces for different materials\, diverse geometries\, both in and out of equilibrium. In the off-equilibrium context\, I shall discuss n on-classical heat transfer\, and some manifestations of the dynamical Casi mir effect. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-151@lptms.universite-paris-saclay.fr DTSTART:20130704T140000Z DTEND:20130704T144500Z DTSTAMP:20130628T082824Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-olivier-giraud/ SUMMARY:Journal Club du LPTMS: Olivier Giraud - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 4 Juil 13 14:00 DESCRIPTION:Orbiting walkers\nOlivier Giraud (LPTMS)\n"Trajectory eigenmode s of an orbiting wave source"\, E. Fort and Y. Couder\, EPL 102\, 16005 (2 013)"Level splitting at Macroscopic scale"\, A. Eddi\, J. Moukhtar\, S. Pe rrard\, E. Fort and Y. Couder\, PRL 108\, 264503 (2012)\nDes surfaces liqu ides soumises à une vibration verticale périodique peuvent soutenir le r ebond de gouttelettes liquides pendant des temps longs. Ces gouttelettes p euvent être animées de mouvements horizontaux dus à leur interaction av ec l'onde qu'elles génèrent à chaque rebond\, se transformant ainsi en "marcheurs". Diverses analogies avec le comportement de particules quantiq ues ont été observées (quantification des orbites\, effet tunnel). Nous rappellerons les principes de base de ces expériences et présenterons d es résultats récents sur le mouvement et les propriétés de marcheurs s oumis à une force centrale. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-148@lptms.universite-paris-saclay.fr DTSTART:20130709T110000Z DTEND:20130709T120000Z DTSTAMP:20130704T102157Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-anupam-kundu/ SUMMARY:Séminaire du LPTMS : Anupam Kundu - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 9 Juil 13 11:00 DESCRIPTION:Exact distributions of the number of distinct and common sites visited by N independant random walkers\nAnupam Kundu (LPTMS)\n \;\n&n bsp\; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-163@lptms.universite-paris-saclay.fr DTSTART:20130710T143000Z DTEND:20130710T153000Z DTSTAMP:20130709T082402Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-du-lptms/ SUMMARY:Séminaire "Fluides quantiques" du LPTMS - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 10 Juil 13 14:30 DESCRIPTION:Dopon-spinon confinement in the t-J model\nAlvaro Ferraz (Depar tment of Theoretical and Experimental Physics\, Federal University of Rio Grande do Norte\, Brasil) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-157@lptms.universite-paris-saclay.fr DTSTART:20130710T150000Z DTEND:20130710T160000Z DTSTAMP:20130706T052951Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-christoph-cremer/ SUMMARY:Physics-Biology interface seminar : Christoph Cremer - Amphi BLANDI N du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 10 Juil 1 3 15:00 DESCRIPTION:Fluorescence Microscopy of Biostructures @ Molecular Optical Re solution\nChristoph Cremer (Institute of Molecular Biology (IMB)\, Mainz\; Kirchhoff-Institute for Physics (KIP) and Institute for Pharmacy and Mole cular Biotechnology (IPMB)\, University Heidelberg )\nSPECIAL DATE &\; TIME Seminar hosted by Olivier Acher &\; Guillaume Dupuis\nConventional epifluorescence microscopy is limited in resolution (to about 200 nm late rally\, 600 nm axially) by the shere nature of light (by diffraction)\, an d is hence insufficient to study the nanostructure of subcellular componen ts.\nAt IMB-Mainz and Heidelberg University we have established a variety of superresolution microscopy ("nanoscopy") methods\, for example Structur ed Illumination SMI and Localisation microscopy SPDMphmyd with blinking dy es\, like standard GFP. Our microscope systems can and have been applied t o study the composition\, function and metabolism of many biomolecular str uctures and small paticles like single viruses in high densities. Currentl y we reach a resolution down to 5 nm in 2D and 40 nm in 3D in the co-local ization mode.\nThere are various applications in the fields of molecular b iology\, (clinical) medicine\, diagnosis and pathology.\n\nChristoph Creme r\, Barry R. Masters (2013) Resolution enhancement techniques in microscop y\, The European Physical Journal H 38\, 3\, pp 281-344\nKaufmann R\, Mull er P\, Hausmann M and Cremer C (2011). Imaging label-free intracellular st ructures by localisation microscopy. Micron\, 42\, 348-352.\nKaufmann R\, Müller P\, Hildenbrand G\, Hausmann M and Cremer C (2011) Analysis of Her 2/neu membrane protein clusters in different types of breast cancer cells using localization microscopy. Journal of Microscopy\, 242\, 46-54.\nGunke l M\, Erdel F\, Rippe K\, Lemmer P\, Kaufmann R\, Hoermann C\, Amberger R and Cremer C (2009). Dual color localization microscopy of cellular nanost ructures. Biotechnology Journal\, 4\, 927-938.\n\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-159@lptms.universite-paris-saclay.fr DTSTART:20130717T143000Z DTEND:20130717T153000Z DTSTAMP:20130723T101951Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-4/ SUMMARY:Séminaire exceptionnel du LPTMS : Adélaïde Raguin - LPTMS\, sall e 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 17 Juil 13 14:30 DESCRIPTION:Traffic regulated by junctions: A statistical model motivated b y cytoskeletal transport\nAdélaïde Raguin\, Université Montpellier 2\nA ctive intracellular transport of motor proteins along the cytoskeleton is an important mechanism essential to accomplish many biological functions i n eukaryotic cells. For instance\, motor protein transport is involved in cell migration\, feeding of the cell\, and cell contractions. Importantly\ , several neurodegenerative diseases are a consequence of the malfunctioni ng of motor protein transport.\nMotor protein transport forms as well a ch allenge in statistical physics. It consists in the study of a non-equilibr ium transport process along a complex and dynamic network. The totally asy mmetric simple exclusion process (TASEP) can be considered as a minimal mo del to study motor protein transport. Along a single segment this model ha s been well studied\, but how active particles organize along a complex ne tworks has not been studied extensively. Motivated by recent experimental works based on tracer experiments of motor proteins moving along junctions of intersecting cytoskeletal filaments we formulate the TASEP along a jun ction. The first part of my talk will deal with how the microscopic traffi c dynamics at a junction can modulate the transport on the whole network. In the second part of my talk I will introduce a more realistic model of m otor protein transport at the junctions. Using the tools developed earlier I can characterize the various stationary states of motors moving along c omplex junctions as arising in living cells. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-161@lptms.universite-paris-saclay.fr DTSTART:20130718T110000Z DTEND:20130718T121500Z DTSTAMP:20130723T101936Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-paolo-malgaretti/ SUMMARY:Séminaire exceptionnel du LPTMS : Paolo Malgaretti - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Juil 13 11:00 DESCRIPTION:Molecular motors: velocity speed-up\, bidirectional motion and confinement-induced rectification\nPaolo Malgaretti (University of Barcelo na)\nThe energy-consuming motion of molecular  motors is responsible form many cellular tasks\, ranging from cargo transport\, cellular signalling and cellular division. The performances of single motors are strongly affe cted by the environment in which they work. Variation in ATP concentration \, viscosity of the cytoplasm due to molecular crowding and motor-motor in teractions can strongly affect the overall performances of molecular motor s. Here I will focus on how the cytoplasm molecular motors move in affects single as well collective molecular motors dynamics. On one hand I will s how that\, due to their reduced sizes and velocities\, molecular motors mo ve in the low Reynolds regime where the large range of the hydrodynamic in teraction  lead to collective behaviour not captured by the rigid-couplin g picture. Such interaction lead to large velocity speed-up that can be up to two order of magnitude as compared to the single motor case[1]. On the other hand hydrodynamic coupling can lead to spontaneous symmetry breakin g when motors pulling on opposite direction act on the same cargo[2].\nOn the other hand the high concentration of suspended molecules and proteins in the cytoplasm as well as local geometrical confinement imposed by organ elles or large vesicles in suspension can affect molecular motors dynamics .\nI will show that the effective space motors can explore while moving al ong a filament lead to a local bias that\,  coupling to the motor intrins ic stepping mechanism\, provides an alternative route to control molecular motors velocity[3].\n[1] P. Malgaretti\, I. Pagonabarraga\, D. Frenkel `` Running  faster together: Huge Speed up of Thermal Ratchets due to Hydrod ynamic Coupling\, Phys. Rev. Lett. 109\, 168101 (2012)\n[2] P.Malgaretti\, I. Pagonabarraga\, J-F. Joanny\, in preparation\n[3] P.Malgaretti\, I. Pa gonabarraga\, J. M. Rubi\, Confined Brownian ratchets\, J. Chem. Phys. 138 \, 194906 (2013)\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-158@lptms.universite-paris-saclay.fr DTSTART:20130719T100000Z DTEND:20130719T130000Z DTSTAMP:20130712T050700Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-arthur-lavarelo/ SUMMARY:Soutenance de thèse : Arthur Lavarélo - LPTMS-batiment 100\, sall e des conseils - 19 Juil 13 10:00 DESCRIPTION:Frustration and disorder in quantum spin chains and ladders\nAr thur Lavarélo\nIn quantum spins systems\, frustration and low-dimensional ity generate quantum fluctuations and give rise to exotic quantum phases. This thesis studies a spin ladder model with frustrating couplings along t he legs\, motivated by experiments on cuprate BiCu2PO6.\nFirst\, we presen t an original variational method to describe the low-energy excitations of a single frustrated chain. Then\, the phase diagram of two coupled chains is computed with numerical methods. The model exhibits a quantum phase tr ansition between a dimerized phase and resonating valence bound (RVB) phas e. The physics of the RVB phase is studied numerically and by a mean-field treatment. In particular\, the onset of incommensurability in the dispers ion relation\, structure factor and correlation functions is discussed in details. Then\, we study the effects of non-magnetic impurities on the ma gnetization curve and the Curie law at low temperature. A low-energy effec tive model is derived within the linear response theory and is used to exp lain the behaviors of the magnetization and Curie constant. Eventually\, we study the effect of bonds disorder\, on a single frustrated chain. The variational method\, introduced in the non-disordered case\, gives a low d isorder picture of the dimerized phase instability\, which consists in the formation of Imry-Ma domains delimited by localized spinons. LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-162@lptms.universite-paris-saclay.fr DTSTART:20130723T110000Z DTEND:20130723T120000Z DTSTAMP:20130723T101835Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giulia-foffano/ SUMMARY:Séminaire du LPTMS: Giulia Foffano - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 23 Juil 13 11:00 DESCRIPTION:Stokes' law violation and negative drag in active fluids\nGiuli a Foffano\, University of Edinburgh\nActive fluids are suspensions of part icles that absorb energy from their surroundings or from an internal tank\ , in order to do work. Main examples can be found in biological contexts a nd are e.g. bacteria suspensions and the actomyosin solution\, that consti tutes the cytoskeleton. I will present simulations where a small constant force is applied to a spherical colloid embedded in an active liquid cryst al. In the linear regime the dissipative force acting on the particle embe dded in a simple fluid is described by Stokes' law. Here instead we find a strong non-linearity with respect to the size of the probe and\, striking ly\, a regime where the colloid reaches a steady state of negative drag. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-160@lptms.universite-paris-saclay.fr DTSTART:20130726T140000Z DTEND:20130726T150000Z DTSTAMP:20130723T101912Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-matthieu-caruel/ SUMMARY:Physics-Biology interface seminar: Matthieu Caruel - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 26 Juil 13 14:00 DESCRIPTION:Muscle power-stroke as a collective mechanical phenomenon\nMatt hieu Caruel (Inria and École Polytechnique)\nThe mechanism of muscle cont raction\, residing in nano-scale interaction between actin and myosin fila ments\, was intensely studied by using fast loading protocols. These exper iments revealed the important mechanical role of the internal conformation al change inside protruding myosin heads known as the power-stroke. It was realized that fast force recovery after abrupt loading\, taking place at 1 ms time scale\, is a purely mechanical phenomenon linked exclusively to the power-stroke and not limited by metabolic fuel delivery.\nIn this pres entation\, we explore previously unnoticed difference in fast force recove ry taking place in hard and soft loading devices and propose a purely mech anical model that explains the origin of this unusual behavior. We link th e inequivalence of soft and hard loading ensembles to the presence of long range interactions between the individual actin-myosin cross-links known as cross-bridges. Our fit of experimental data suggests that 'muscle mater ial' is finely tuned to perform close to a critical point which explains l arge fluctuations observed at stall forces. The proposed mean field model clarifies the collective nature of the power-stroke and reveal new propert ies of the celebrated Huxley and Simmons 1971 model. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-168@lptms.universite-paris-saclay.fr DTSTART:20130903T110000Z DTEND:20130903T120000Z DTSTAMP:20130902T053645Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-maxim-imakaev/ SUMMARY:Séminaire du LPTMS: Maxim Imakaev - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 3 Sep 13 11:00 DESCRIPTION:Three dimensional architecture of human chromosomes: from data analysis to polymer models\nMaxim Imakaev\, MIT\nThe three-dimensional and physical organization of genomes within cells plays critical roles in reg ulating chromosomal processes\, including gene regulation\, DNA replicatio n\, and genome stability. A recently developed method\, Hi-C\, provides a comprehensive whole-genome information about physical contacts between gen omic region. Analysis of these data has begun to reveal determinants of 3D genomic organization.\nChromosomes can be understood as long polymers. We use a combination of data analysis and polymer modelling to pinpoint main determinants of the 3D genomic organization in several studied organisms. We build polymer models based on the known or suggested principles of chr omosomal organization and validate them against the Hi-C data. In particul ar\, we have shown that yeast chromosomal organization can be well-describ ed by a star-polymer model. The model we developed is consistent with the yeast Hi-C data\, microscopy observations and diffusion measurements of ye ast chromosomes.\nWe also study folding of the human chromosomes during me taphase\, which is vital for completion of cell division. Here\, polymer m odelling allowed us to discriminated between the two long-studied models o f metaphase chromosomes: "bottle-brush" model of loops emanating from a ce ntral scaffold\, and an hierarchical folding principle. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-164@lptms.universite-paris-saclay.fr DTSTART:20130910T110000Z DTEND:20130910T120000Z DTSTAMP:20130901T063702Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-antonio-prados/ SUMMARY:Séminaire du LPTMS: Antonio Prados - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 10 Sep 13 11:00 DESCRIPTION:A general class of dissipative models: fluctuating hydrodynamic s and large deviations\nA. Prados\, Universidad de Sevilla\nWe consider a general class of models\, described at the mesoscopic level by a fluctuati ng balance equation for the local energy density. This balance equation ha s a diff usive term\, with a current that fluctuates around its average be haviour given by Fourier's law\, and a dissipation term which is a general function of the local energy density. The latter does not include a fluct uating term\, as the dissipation fluctuations are enslaved to those of the density due to the (assumed) quasi-elasticity of the underlying microscop ic dynamics. This quasi-elasticity of the microscopic dynamics is compatib le with the existence of a finite dissipation over the di ffusive time sc ale which is relevant at the mesoscopic level.This general fluctuating hyd rodynamic picture [1]\, together with an "additivity conjecture" [2]\, mak es it possible to write the functional giving the probability of large dev iations of the dissipated energy from the average behaviour. The functiona l has the same form as in the non-dissipative case\, due to the subdominan t role played by the dissipation noise. The above hydrodynamic description is shown to emerge from a general class of models\, with stochastic dissi pative dynamics at the microscopic level\, in the large system size limit. Both the average macroscopic behaviour and the noise properties of the hy drodynamic fields are obtained from the microscopic dynamics. Finally\, t his general scheme is applied to the simplest dissipative version of the s o-called KMP model [3] for heat transport. The theoretical predictions are compared to extensive numerical simulations\, and an excellent agreement is found [4-6].\n1. L. Bertini\, A. De Sole\, D. Gabrielli\, G. Jona-Lasin io and C. Landim\, Phys. Rev. Lett. 87\, 040601 (2001)\; Phys. Rev. Lett. 94\, 030601 (2005)\; J. Stat. Mech. P07014 (2007)\; J. Stat. Phys. 135\, 8 57 (2009).2. T. Bodineau and B. Derrida\, Phys. Rev. Lett. 92\, 180601 (20 04).3. C. Kipnis\, C. Marchioro and E. Presutti\, J. Stat. Phys. 27\, 65 ( 1982).4. A. Prados\, A. Lasanta and P. I. Hurtado\, Phys. Rev. Lett. 107\, 140601 (2011).5. A. Prados\, A. Lasanta and P. I. Hurtado\, Phys. Rev. E 86\, 031134 (2012).6. P. I. Hurtado\, A. Lasanta\, and A. Prados\, Phys. R ev. E 88\, 022110 (2013). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-167@lptms.universite-paris-saclay.fr DTSTART:20130913T134500Z DTEND:20130913T150000Z DTSTAMP:20130912T180956Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-marie-doumic-jauffret/ SUMMARY:Physics-Biology interface seminar: Marie Doumic-Jauffret - Amphi BL ANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 13 Se p 13 13:45 DESCRIPTION:Division Control in Escherichia coli is Based on a Size-sensing rather than Timing Mechanism\nMarie Doumic-Jauffret (INRIA Rocquencourt)\ nModels describing the growth of cell populations have been developed bas ed on assumptions on the stochastic mechanisms underlying growth and divis ion at the single cell level. In particular\, two different models have be en widely used for decades\, assuming that cell division probability depen ds respectively on cell age (the renewal equation) or cell size (the size- structured or growth-fragmentation equation) - or both.\nWe confront these models with data on E. coli single cells growth\, and develop a new estim ation methodology\, based on nonparametric functional testing within the P DE models\, in order to test the hypothesis of an age-dependent versus siz e-dependent division rate. We conclude that in E. Coli\, the division is c ontrolled by a size-sensing rather than timing mechanism.\nThis is a joint work with L. Robert and M. Hoffmann.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-156@lptms.universite-paris-saclay.fr DTSTART:20130917T110000Z DTEND:20130917T120000Z DTSTAMP:20130902T183718Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-tom-witten/ SUMMARY:Séminaire du LPTMS: Tom Witten - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 17 Sep 13 11:00 DESCRIPTION:A colloidal dance: synchronizing motion of brownian particles\n Thomas A. Witten\, University of Chicago\nWatch a small flake of plastic g radually sink in a glass of water. The asymmetric flake pivots into a pref erred orientation and then rotates steadily as it sinks. The reason for th is rotational response to gravity is independent of length scale\; thus it applies to microscopic colloidal objects as well. Analogous responses occ ur under other forces\, eg from electric fields. The response is governed by a 3x3 matrix called the twist matrix that depends on the object's shape and its mass distribution. The twist matrix controls the motion in much t he same way as the (symmetric) inertia tensor controls the free tumbling m otion of a body. However\, the twist matrix gives a richer response becaus e it is not symmetric. In this talk we explore ways to use this rotational response to organize a sample of objects so that they all rotate in uniso n\, with the same orientation. This complete orientation can be achieved w ithout using interaction between the particles\; instead we exploit the tr ansient pivoting response before the object settles into a fixed rotationa l axis. We demonstrate two types of programmed\, time-dependent forcing th at bring a set of randomly oriented particles into a common orientation. T he first is a simple alternating rocking motion. The second is a rotating force analogous to the rotating magnetic field in an NMR device. Once orie nted\, the objects must respond identically to further forcing\; they tran slate and rotate in unison.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-175@lptms.universite-paris-saclay.fr DTSTART:20130919T140000Z DTEND:20130919T150000Z DTSTAMP:20130917T083727Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-srikanth-h-sastry/ SUMMARY:Séminaire exceptionnel du LPTMS: Srikanth H. Sastry - LPTMS\, sall e 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Sep 13 14:00 DESCRIPTION:Dynamical transition and memory in cyclically deformed amorphou s solids\nSrikanth H. Sastry (TIFR Centre for Interdisciplinary Sciences\, Hyderabad)\nAmorphous solids are microscopically disordered materials tha t arise in diverse contexts\, with polymeric glasses and soft glassy mater ials like gels and metallic glasses being some typical examples. The mecha nical response of amorphous solids is distinct in microscopic detail from that of crystalline solids\, and is of practical interest because of the r elevance of the elastic and plastic response and rheology of these substan ces to a variety of processes and applications. A computational investigat ion of the response of a model amorphous solid to oscillatory deformation is presented\, after a brief overview of current approaches to understandi ng mechanical response of amorphous solids. A dynamical transition is obse rved as the amplitude of the deformation is varied: For large values of th e amplitude the system exhibits diffusive behavior and loss of memory of t he initial conditions\, whereas localization is observed for small amplitu des. The formation of memory in such systems of single and multiple inputs is also described. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-173@lptms.universite-paris-saclay.fr DTSTART:20130920T110000Z DTEND:20130920T130000Z DTSTAMP:20130912T104106Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-pierre-elie-larre/ SUMMARY:Soutenance de thèse : Pierre-Elie Larré - LPTMS-batiment 100\, sa lle des conseils - 20 Sep 13 11:00 DESCRIPTION:Fluctuations quantiques et effets non-linéaires dans les conde nsats de Bose-Einstein : des ondes de choc dispersives au rayonnement de H awking acoustique\nPierre-Elie Larré\nCette thèse est dédiée à l'étu de de l'analogue du rayonnement de Hawking dans les condensats de Bose-Ein stein. Dans un premier temps\, on présente de nouvelles configurations da ns lesquelles l'écoulement d'un condensat atomique réalise l'équivalent acoustique d'un trou noir gravitationnel. Nous donnons dans chaque cas un e description analytique du profil de l'écoulement\, des fluctuations qua ntiques associées et du spectre du rayonnement de Hawking. L'analyse des corrélations à deux corps dans l'espace des positions et des impulsions fournit des signatures caractérisant l'occurrence du rayonnement de Hawki ng. Dans une deuxième partie\, nous analysons les propriétés superfluid es et/ou dissipatives de condensats de polaritons s'écoulant autour d'un obstacle. L'étude des ondes de polarisation dans ces systèmes nous perme t enfin de proposer des signatures prometteuses pour l'observation de l'ef fet Hawking dans les gaz de polaritons et les condensats atomiques à deux composantes. LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-180@lptms.universite-paris-saclay.fr DTSTART:20130923T110000Z DTEND:20130923T121500Z DTSTAMP:20130917T115357Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-du-lptms-shimshon-bar-ad/ SUMMARY:Séminaire exceptionnel du LPTMS : Shimshon Bar-Ad - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 23 Sep 13 11:00 DESCRIPTION:Transonic flow of light\, sonic horizons and analogue gravity  \nShimshon Bar-Ad\, Tel Aviv University\nIn 1981 W.G. Unruh predicted that a thermal spectrum of sound waves would be emitted from the sonic horizon in transonic fluid flow\, in analogy to black-hole evaporation. Based on this idea\, extended to the realm of nonlinear optics\, we explore an opti cal analog of the Laval nozzle\, in which light propagation through a suit ably shaped waveguide\, filled with a self-defocusing nonlinear medium\, m imics the transonic acceleration of a real fluid expanding through a propu lsive exhaust nozzle. Experimental demonstrations of transonic flow in pro totype optical nozzles will be presented\, and the prospect of observing f luctuations that are classical analogs of Hawking radiation will be discus sed. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-165@lptms.universite-paris-saclay.fr DTSTART:20130924T110000Z DTEND:20130924T120000Z DTSTAMP:20130730T130916Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-oleg-borisov/ SUMMARY:Séminaire du LPTMS: Oleg Borisov - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 24 Sep 13 11:00 DESCRIPTION:Poisson-Boltzmann theory of polyelectrolyte brushes\nOleg Boris ov\,  IPREM\, Université de Pau\nThe polyelectrolyte brush results if lo ng flexible ionic polymer chains are attached by one end onto an impermeab le solid surface or onto the surface of a colloidal particle and immersed in a solvent. Understanding of the structure-properties relation in polyme r and polyelectrolyte brushes is important for their applications for surf ace modification\, in particular\, in the field of biomaterial engineering . Functional polymer brush-like structures are found in biological systems . Examples of natural biopolyelectrolyte brushes include extracellular pol ysaccharides on bacterial surfaces\, neurofilaments and microtubules with associated proteins\, aggrecan macromolecules in articular cartilage\, cas ein micelles etc. The possibility to trigger conformational transitions in surface-attached polymeric layers by external physical (temperature\, ele ctrical voltage\, etc.) or chemical (pH\, salinity\, solvent composition\, etc.) fields opens a perspective for design of stimuli-responsive interfa ces. Theory of equilibrium structural properties  of polyelectrolyte brus hes is developed in the frame of self-consistent field Poisson-Boltzmann a pproximation. We analyze the influence of ionic strength and (in the case of weak polyacid or polybase brushes) pH in the solution on the chain conf ormations in the brush. The effect of the counterion localization in the p olyelectrolyte brush is most essential and governing the brush properties. The repulsive forces acting between surfaces or colloidal particles with grafted polyelectrolytes are calculated.  Furthermore\, we discuss intera ction of polyelectrolyte brushes with multivalent counterions and with glo bular proteins and the effect of their accumulation in the brushes. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-172@lptms.universite-paris-saclay.fr DTSTART:20130927T134500Z DTEND:20130927T150000Z DTSTAMP:20130925T194429Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-timo-betz/ SUMMARY:Physics-Biology interface seminar: Timo Betz - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 27 Sep 13 13:45 DESCRIPTION:The mechanics of active and passive cellular assemblies: How bi omimetic reconstitution can help to understand living cell\nTimo Betz (Ins titut Curie - Paris)\nUnderstanding the intriguing complexity of living sy stems is one of the main driving forces of science. To gain insight we use biomimetic systems that reconstitute well defined cellular assemblies and compare these to the living system. Our main interests are the mechanical properties and the generation of forces\, both mediated by the cytoskelet on and its interaction with the plasma membrane. Recent advances allow to mimic structures such as the actin cortex\, sparse actin networks and acti n bundles\, and we use optical tweezers to quantify the mechanical propert ies of these structures and to compare them to living cells. While sparse actin networks and polymerizing actin bundles show rather passive behavior \, we apply the same measurement methods to living cells such as cell bleb s and red blood cells which allow to study the out-of-equilibrium mechanic s of these systems\, and to determine the timescale at which the system's activity becomes evident. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-178@lptms.universite-paris-saclay.fr DTSTART:20131001T110000Z DTEND:20131001T120000Z DTSTAMP:20130923T101215Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-denis-basko/ SUMMARY:Séminaire du LPTMS: Denis Basko - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 1 Oct 13 11:00 DESCRIPTION:Weak chaos and Arnold diffusion in the strongly disordered nonl inear Schroedinger chain\nDenis Basko\, LPMMC - Université Joseph Fourier \nI will discuss the long-time equilibration dynamics of a strongly disord ered one-dimensional chain of coupled weakly anharmonic classical oscillat ors\, which is one of the simplest models allowing to study the effect of a classical nonlinearity on the Anderson localization. The system has chao tic behavior\, and it is shown that chaos in this system has a very partic ular spatial structure: it can be viewed as a dilute gas of chaotic spots. Each chaotic spot corresponds to a stochastic pump which drives the Arnol d diffusion of the oscillators surrounding it\, thus leading to their rela xation and thermalization. The most important mechanism of relaxation at l ong distances is provided by random migration of the chaotic spots along t he chain\, which bears analogy with variable-range hopping of electrons in strongly disordered solids. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-183@lptms.universite-paris-saclay.fr DTSTART:20131001T140000Z DTEND:20131001T150000Z DTSTAMP:20130930T110447Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-daniel-axelrod/ SUMMARY:Physics-Biology interface seminar: Daniel Axelrod - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 1 Oct 13 14 :00 DESCRIPTION:Molecule motion inside secretory granules before and during exo cytosis\nDaniel Axelrod (University of Michigan)\nSPECIAL DATE &\; TIME \nDespite ~10% of the human genome being comprised of secretory proteins\, little is known about the dynamics of proteins inside the secretory granu le before and during fusion with the plasma membrane. This talk presents early results on measuring the diffusion coefficient of two proteins withi n that submicroscopic and closed space\, and relates the results to secret ion and local membrane deformation rates during the fusion event. The tec hniques used\, TIR-FRAP\, TIR-FCS\, and pol-TIRF have general applicabilit y\, and the theory and practice of especially the first two is discussed.\ n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-182@lptms.universite-paris-saclay.fr DTSTART:20131007T150000Z DTEND:20131007T163000Z DTSTAMP:20130924T083851Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-sergey-nazarenko/ SUMMARY:Tri-Séminaire de Physique Statistique : Sergey Nazarenko - IPhT\, CEA-Saclay\, salle Itzykson - 7 Oct 13 15:00 DESCRIPTION:Condensation &\; BKT transition in 2d defocusing nonlinear S chrödinger equation.\nSergey Nazarenko (Mathematics Institute\, Universit y of Warwick)\n \;\nI will consider a 2D nonlinear Schrödinger equati on model in a periodic box and truncated in Fourier space and study conde nsation phenomenon\, Berezinskii-Kousterlitz-Thouless transition\, and the ir links with the Wave Turbulence theory.\n \; LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-174@lptms.universite-paris-saclay.fr DTSTART:20131008T110000Z DTEND:20131008T120000Z DTSTAMP:20131001T085716Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-yasar-atas-et-francois-landes/ SUMMARY:Séminaire du LPTMS: Yasar Atas et François Landes - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 8 Oct 13 11:00 DESCRIPTION:Distribution of the ratio of level spacings in random matrix en sembles.\nYasar Atas\, LPTMS\nInitially introduced as a description of ene rgy levels of heavy atomic nuclei by Wigner\, Random Matrix Theory (RMT) i s nowadays an active field of theoretical physics with ramification in var ious disciplines such as number theory\, quantum chaos and finance to cite just a few. In RMT\, the distribution of level spacings plays a very impo rtant role: it has been widely used since the inception of the theory and is considered as the "reference" measure of spectral statistics. Since dif ferent models may and do have different level densities\, one has to perfo rm a procedure on the spectrum called unfolding in order to obtain the spa cing distribution. This procedure is not unique and the choice of the unfo lding procedure is quite arbitrary. It seems then natural to search for an other measure which is independent of the level density. This has been don e quite recently by Oganesyan and Huse [1]: instead of looking at the spac ing they prefer to look at the ratio of two consecutive level spacings. Th is quantity has the advantage that it does not require any unfolding.\nIn this talk\, I will make few remarks on random matrix theory and the unfold ing procedure. I will then derive simple expressions for the probability d istribution of the ratio of two consecutive spacings for the classical ens embles of random matrices [2]. These expressions\, which were lacking in t he literature\, will  be compared to numerical data from a quantum many-b ody lattice model and from zeros of Riemann zeta function.\n[1] V. Oganesy an and D. A. Huse\, Phys. Rev. B 75\, 155111 (2007). [2] Y. Y. Atas\, E. B ogomolny\, O. Giraud\, and G. Roux\, Phys. Rev. Lett. 110\, 084101 (2013)\ n \;\nAvalanche statistics in disordered visco-elastic interfaces\nFra nçois Landes\, LPTMS\nMany complex systems respond to a continuous input of energy by an accumulation of stress over time\, and sudden energy relea ses\, called avalanches. Recently\, it has been pointed out that several b asic features of avalanche dynamics are induced at the microscopic level b y relaxation processes\, usually neglected by conventional models. I will present a minimal model with relaxation and its mean field treatment\, and a quick snapshot of the finite dimension results. In mean-field\, our mod el yields a periodic behavior (with a new\, emerging time scale)\, with ev ents that span the whole system. In finite dimension (2D)\, the mean-field system-sized events become local\, and numerical simulations give qualita tive and quantitative results similar to the earthquakes observed in reali ty. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-166@lptms.universite-paris-saclay.fr DTSTART:20131011T140000Z DTEND:20131011T150000Z DTSTAMP:20131005T185343Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-roberto-toro/ SUMMARY:Physics-Biology interface seminar: Roberto Toro - Moyen Amphi\, Bui lding 510\, Université Paris-Saclay Orsay - 11 Oct 13 14:00 DESCRIPTION:Role of mechanical constraints on the establishment of neocorti cal organisation\nRoberto Toro (Institut Pasteur)\nThe mammalian brain is astonishingly diverse. Not only its size varies several orders of magnitud e – from the 3 grams of the mouse brain to the 6 kg of the blue whale br ain – but also its geometry and function. There is indeed a striking\, l argely unexplained\, relationship between the folding of the mammalian bra in and its cellular\, functional and connective organisation. Brain foldin g appears as much more than a mere mechanical epiphenomenon\, and besides its major evolutionary relevance\, many psychiatric disorders such as auti sm or schizophrenia\, are related to changes in brain folding.\nI will pre sent a brief overview of the developmental processes leading to the foldin g of the brain\, and show some examples of functional correlates of brain folding in humans and other mammalian species. Finally\, I will discuss so me of the current theories proposed to explain the mechanism underlying th e relationship between brain geometry and brain organisation\, including o ur ongoing project on computational modelling and analysis of the developm ent of the ferret brain. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-191@lptms.universite-paris-saclay.fr DTSTART:20131014T110000Z DTEND:20131014T113000Z DTSTAMP:20131011T091715Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-vinc ent-michal/ SUMMARY:Journal-Club : Vincent Michal - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Oct 13 11:00 DESCRIPTION:Dynamics of a quantum phase transition: exact solution of the q uantum Ising Model Jacek Dziarmaga\, PRL 95\, 245701 (2005)\nVincent Micha l (Post doc LPTMS)\n \;\nIt will be based on the paper "Dynamics of a quantum phase transition: exact solution of the quantum Ising Model"\, by Jacek Dziarmaga\, PRL 95\, 245701 (2005).\nAbstract of the paper:\nThe Qua ntum Ising model is an exactly solvable model of quantum phase transition. This Letter gives an exact solution when the system is driven through the critical point at a finite rate. The evolution goes through a series of L andau-Zener level anticrossings when pairs of quasiparticles with opposite pseudomomenta get excited with a probability depending on the transition rate. The average density of defects excited in this way scales like a squ are root of the transition rate. This scaling is the same as the scaling o btained when the standard Kibble-Zurek mechanism of thermodynamic second o rder phase transitions is applied to the quantum phase transition in the I sing model. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-169@lptms.universite-paris-saclay.fr DTSTART:20131015T110000Z DTEND:20131015T130000Z DTSTAMP:20131007T111124Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-olga-vlaba/ SUMMARY:Soutenance de thèse : Olga Valba - LPTMS-batiment 100\, salle des conseils - 15 Oct 13 11:00 DESCRIPTION:Statistical analysis of networks and biophysical systems of com plex architecture\nOlga Valba (LPTMS)\nComplex organization is found in ma ny biological systems. For example\, biopolymers could possess hierarchic structure\, which provides their functional peculiarity. Artificially cons tructed biological networks are other common objects of statistical physic s with rich functional properties. The aim of this thesis is to develop so me methods for studying statistical systems of complex architecture with e ssential biological significance.\nThe first part addresses to the statist ical analysis of random biopolymers. Apart from the evolutionary context\, our study covers more general problems of planar topology appeared in des cription of various systems\, ranging from gauge theory to biophysics.\nIn the second part of this work we focus our investigation on statistical pr operties of artificial and real networks. The importance of obtained resul ts in applied biophysics is discussed. Also\, the formation of stable patt ers of motifs in random networks under selective evolution in context of c reation of islands of "superfamilies" is considered. LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-186@lptms.universite-paris-saclay.fr DTSTART:20131017T131500Z DTEND:20131017T141500Z DTSTAMP:20131001T060725Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-emmanuel-margeat/ SUMMARY:Physics-Biology interface seminar: Emmanuel Margeat - Institut d'Op tique: Campus Polytechnique - 17 Oct 13 13:15 DESCRIPTION:Looking at transcription mechanisms with single molecule FRET\n Emmanuel Margeat (Centre de Biochimie Structurale\, Montpellier)\nExceptio nal seminar hosted by Karen Perronet\nSPECIAL DATE\, TIME AND LOCATION\nF örster Resonance Energy Transfer (FRET) allows measuring the distance bet ween two spectrally distinct fluorophores\, in the 20-100 Å range. When m onitored at the single molecule level\, smFRET is useful in resolving subp opulations\, or observing conformational changes as a function of time wit hin single macromolecular complexes in vitro. I will describe here the met hodologies used to measure FRET accurately on single biomolecular complexe s\, freely diffusing in solution or immobilized on surfaces. I will then f ocus on our studies on the mechanism of prokaryotic transcription such as antitermination control by the antiterminator LicT\, and Rho-induced trans cription termination.\n LOCATION:Institut d'Optique: Campus Polytechnique\, 2 avenue Augustin Fres nel\, orsay\, 91405\, France GEO:48.7141488;2.204672100000039 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS= 2 avenue Augustin Fresnel\ , orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Institut d'Optique: Ca mpus Polytechnique:geo:48.7141488,2.204672100000039 END:VEVENT BEGIN:VEVENT UID:1-193@lptms.universite-paris-saclay.fr DTSTART:20131017T143000Z DTEND:20131017T154500Z DTSTAMP:20131014T125839Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-eugene-sukhorukov/ SUMMARY:Séminaire exceptionnel du LPTMS : Eugene Sukhorukov - LPTMS\, sall e 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 17 Oct 13 14:30 DESCRIPTION:Fermi Edge Singularity in Quantum Hall Systems far from Equilib rium\nEugene Sukhorukov (Geneva University)\nWe study non-equilibrium one dimensional physics on an example of a minimal setup inspired by the recen t experiment based around a Mach-Zender interferometer composed of quantum Hall  edge channels at integer filling factor\, one of which is in Coul omb interaction with an artificial impurity. The fluctuations of the impur ity charge due to the tunneling transitions lead to resonant suppression o f coherence on the channel and of the visibility of the interference patte rn. We consider the regime where the transitions are induced by the non-eq uilibrium partitioning noise created in the interferometer itself by the b eam splitter\, and describe the strong effects of both the orthogonality c atastrophe and the non-equilibrium noise\, that are revealed in the shape of the transition rates\, in the asymmetry of the visibility dip and in th e non-trivial dependence of the dip position on the transparency LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-192@lptms.universite-paris-saclay.fr DTSTART:20131021T113000Z DTEND:20131021T120000Z DTSTAMP:20131015T104441Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-pier re-ronceray/ SUMMARY:Journal-Club : Pierre Ronceray - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 21 Oct 13 11:30 DESCRIPTION:Improving the Density of Jammed Disordered Packings Using Ellip soids\nA. Donev\, I. Cisse\, D. Sachs\, E. A. Variano\, F. H. Stillinger\, R. Connelly\, S. Torquato\, and P. M. Chaikin\, Science\, 303\, pp 990-99 3 (2004).\nPacking problems\, such as how densely objects can fill a volum e\, are among the most ancient and persistent problems in mathematics and science. For equal spheres\, it has only recently been proved that the fac e-centered cubic lattice has the highest possible packing fraction f=Pi/sq rt(18) ~ 0.74. It is also well known that certain random (amorphous) jamme d packings have  f~0.64. Here\, we show experimentally and with a new sim ulation algorithm that ellipsoids can randomly pack more densely— up to f~0.68 to 0.71 for spheroids with an aspect ratio close to that of M&\; M’s Candies—and even approach f~ 0.74 for ellipsoids with other aspect ratios. We suggest that the higher density is directly related to the hig her number of degrees of freedom per particle and thus the larger number o f particle contacts required to mechanically stabilize the packing. We mea sured the number of contacts per particle Z~10 for our spheroids\, as comp ared to Z~ 6 for spheres. Our results have implications for a broad range of scientific disciplines\, including the properties of granular media and ceramics\, glass formation\, and discrete geometry. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-189@lptms.universite-paris-saclay.fr DTSTART:20131022T110000Z DTEND:20131022T120000Z DTSTAMP:20131009T071949Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-fabio-deelan-cunden/ SUMMARY:Séminaire du LPTMS: Fabio Deelan Cunden - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 22 Oct 13 11:00 DESCRIPTION:Polarized ensembles of random pure states\n \nFabio  Deelan C unden\, Dipartimento di Matematica\, Università di Bari\nIn the last year s many researchers  have been investigating  the typical properties of r andom pure states\, i.e. unit vectors drawn at ``random'' from the Hilbert space associated to a quantum system. This subject has attracted the atte ntion in several directions\, and some important results have been achieve d. The standard ensemble which has been intensively investigated is that o f random pure states  with measure induced by the Haar measure on the uni tary group. This ensemble\, being the maximally symmetric one\, implements in a natural way the  case of minimal knowledge on a quantum state. We recently presented a new family of polarized ensembles of random pure quan tum states. Our idea is to move beyond the unbiased ensemble by using a na tural operation at hand in the Hilbert space\, namely  superposition of v ector states. These ensembles are quite manageable and manifestly show tha t the unitarily invariant measures interact nicely with the operation of l inear superposition of states. Our approach has been oriented to the study of  typical bipartite entanglement between subsystems\, as measured by t he local purity. This strategy yields an efficient and simple sampling of random pure states with fixed value of purity\, and paves the way to furth er explorations and a deeper characterization of the geometry of isopurity manifolds. Cunden F D\, Facchi P\, Florio G (2013) J. Phys. A: Math. Theo r. 46\, 315306. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-136@lptms.universite-paris-saclay.fr DTSTART:20131105T110000Z DTEND:20131105T120000Z DTSTAMP:20131022T050337Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-2/ SUMMARY:Séminaire du LPTMS: Anders Carlsson - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 5 Nov 13 11:00 DESCRIPTION:Self-Organizing Waves and Patterns of Proteins in Biological Ce lls\n Anders Carlsson (Washington University)\nSelf-organized patterns\, such as traveling waves and symmetry-breaking distributions of chemical sp ecies\, demonstrate how simple laws of motion can lead to complex behavior s in physical systems. Such patterns result from a combination of positive and negative feedback effects with different time scales. The talk will d iscuss the example of waves of the protein actin in biological cells. Acti n\, the most abundant intracellular protein in mammals\, occurs either as an isolated protein in solution\, or in the form of filaments which have m echanical rigidity and are crosslinked into a gel. Recent experiments have shown that filamentous actin forms spontaneous waves that cause protrusio n of the cell membrane. Such waves may serve as a “clock” that helps a cell explore its environment. A theoretical model of actin waves will be presented\, based on the three-dimensional structure of the gel formed by actin filaments\, interacting reciprocally with proteins in the cell membr ane. Implementation of this model shows that positive feedback is inherent in the growth process of the actin gel\, while negative feedback arises f rom the actin-membrane interaction. As the concentration of key proteins i n the cell is varied\,  the  model predicts phase transitions between di fferent phases including traveling waves or patches\, and static symmetry- breaking polarization of the cell. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-176@lptms.universite-paris-saclay.fr DTSTART:20131108T140000Z DTEND:20131108T150000Z DTSTAMP:20131030T125154Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-aurelien-bancaud/ SUMMARY:Physics-Biology interface seminar: Aurélien Bancaud - Amphi BLANDI N du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 8 Nov 13 14:00 DESCRIPTION:Conformation and dynamics of DNA in confined environments: cros s-talk between chromosomes in the nucleus and polymers in nanochannels\nAu rélien Bancaud (Laboratoire d'analyse et d'architecture des systèmes\, T oulouse)\n\nGenome structure and dynamics attacts considerable attention i n the biology community to eludicate genome regulation principles\, but al so for biological physicists who aim to develop models of DNA in vivo. The challenges of this research is conceptual but also economical because of expected impact of DNA sequencing or DNA microarrays technologies in perso nalized diagnostics.\nOur research is carried out at the nexus of technolo gy and biology and aims to provide a physical description of the genome st ructural properties. We will first overview our results on chromosome dyna mics in living yeast\, showing the unexpected flexibility of these structu res in vivo. We will then focus on new methods for chromosome analysis in vitro based on micro- and nano-fluidics\, and we will finally emphasize th at that these two topics are not so unrelated\, given that the physics of DNA confined environment can be used as a common research framework.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-181@lptms.universite-paris-saclay.fr DTSTART:20131112T110000Z DTEND:20131112T120000Z DTSTAMP:20130920T120743Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-claire-lemarchand/ SUMMARY:Séminaire du LPTMS: Claire Lemarchand - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Nov 13 11:00 DESCRIPTION:Molecular composition and mechanical properties of bitumen : a molecular dynamic study\nClaire Lemarchand\, Université de Roskilde\nBitu men is one of the essential components of roads.  Its mechanical properti es need to be controlled in order to reduce the rolling resistance develop ed between the tyre and the road as a vehicle is travelling on the road. I n this presentation\, I will speak about the link between the molecular co mposition and the mechanical properties of "Cooee" bitumen. This model bit umen is composed of four realistic molecule types: saturated hydrocarbon\, resinous oil\, resin\, and asphaltene. It is studied with molecular dynam ic (MD) simulations. Asphaltene molecules are large and flat aromatic mole cules. The molecular dynamic simulations are able to reproduce the aggrega tion of asphaltene molecules into nanoaggregates. The size of the nanoaggr egates was estimated in the simulations and shown to be comparable to expe rimental results. The dynamics of the nanoaggregates was precisely quantif ied in MD\, giving new insights about their formation. Finally\, the influ ence of these nanoaggregates on the bitumen mechanical properties and over all dynamics was investigated. This last part of the work enables us to se t some rules about bitumen chemical composition to lower its viscosity. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-199@lptms.universite-paris-saclay.fr DTSTART:20131112T140000Z DTEND:20131112T151500Z DTSTAMP:20131016T115654Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-matteo-zaccanti/ SUMMARY:Séminaire "Fluides quantiques" : Matteo Zaccanti - LPTMS\, salle 2 01\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Nov 13 14:00 DESCRIPTION:Ultracold 6Li-40K Fermi mixtures with resonant interactions\nMa tteo Zaccanti (LENS\, Florence) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-170@lptms.universite-paris-saclay.fr DTSTART:20131114T143000Z DTEND:20131114T160000Z DTSTAMP:20131025T062920Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-la-f ederation-phystat-sud-2/ SUMMARY:Tri-Séminaire de Physique Statistique : David Holcman - LPTMS\, sa lle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Nov 13 14:30 DESCRIPTION:Analysis of superresolution data using Langevin equation. Brown ian receptortrafficking on neuronal cells\nDavid Holcman (Institut de Biol ogie\, Ecole Normale Supérieure - IBENS)\n What is the basis of learning and memory in the brain? Neurons are the main players and synapses that a re micro-contact between them play a critical role. How synapses are organ ized at a molecular level and what defines their synaptic strength at a mo lecular level remains unclear\, although it is due to the combine effect o f many molecules together. Thus the number of receptors and molecules must be well regulated. I will present here an integrative modeling approach o f synaptic transmission that accounts for receptor dynamics and a novel me thod to extract local biophysical properties from thousands of individual trajectories obtained from superresolution microscopy data. This talk summ arizes our long lasting effort in integrating key parameters involved in r egulating synaptic transmission and plasticity. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-207@lptms.universite-paris-saclay.fr DTSTART:20131115T110000Z DTEND:20131115T120000Z DTSTAMP:20131113T124234Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-dmytro-fil/ SUMMARY:Séminaire "Fluides quantiques" : Dmytro Fil - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Nov 13 11:00 DESCRIPTION:Superfluidity of electron-hole pairs in bilayers\nDmytro Fil (I nstitute for Single Crystals\, NASU\, Kharkov)\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-209@lptms.universite-paris-saclay.fr DTSTART:20131118T113000Z DTEND:20131118T113000Z DTSTAMP:20131114T132337Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-hao- lee/ SUMMARY:Journal-Club : Hao Lee - LPTMS\, salle 201\, 2ème étage\, Bât 10 0\, Campus d'Orsay - 18 Nov 13 11:30 DESCRIPTION:Multi-orbital and density-induced tunneling of boson in optical lattices\nHao Lee (doctorant au LPTMS)\n Article de  Dirk-Soren Luhmann \, Ole Jurgensen and Klaus Sengstock\, New Journal of Physics 14 ( 2012) 0 33021\nWe show that multi-orbital and density-induced tunneling have a sig nificant impact on the phase diagram of bosonic atoms in opticallattices. Off-site interactions lead to density-induced hopping\, the so-called bond -charge interactions\, which can be identified with an effective tunneling potential and can reach the same order of magnitude as conventional tunne ling. In addition\, interaction-induced higher-band processes also give ri se to strongly modified tunneling\, on-site and bond-charge interactions.W e derive an extended occupation-dependent Hubbard model with multiorbitall yrenormalized processes and compute the corresponding phase diagram.It sub stantially deviates from the single-band Bose–Hubbard model andpredicts strong changes of the superfluid-to-Mott-insulator transition. In general\ ,the presented beyond-Hubbard physics plays an essential role in bosonicla ttice systems and has an observable influence on experiments with tunablei nteractions.\n  LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-185@lptms.universite-paris-saclay.fr DTSTART:20131119T110000Z DTEND:20131119T120000Z DTSTAMP:20131107T074848Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thomas-barthel/ SUMMARY:Séminaire du LPTMS: Thomas Barthel - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 19 Nov 13 11:00 DESCRIPTION:Algebraic versus exponential decoherence in dissipative many-pa rticle systems\nThomas Barthel\, LPTMS\nUltimately\, every quantum system of interest is coupled to some form of environment which leads to decohere nce. Until our recent study\, it was assumed that\, as long as the environ ment is memory-less (i.e. Markovian)\, the temporal coherence decay is alw ays exponential -- to a degree that this behavior was synonymously associa ted with decoherence.\nHowever\, the situation can change if the system it self is a many-body system. In this case\, the interplay between dissipati on and internal interactions gives rise to a wealth of novel phenomena. In particular\, the coherence decay can change to a power law.\nAfter recapi tulating the mathematical framework and basic notions of decoherence\, I w ill discuss an open XXZ chain for which the decoherence time diverges in t he thermodynamic limit. The coherence decay is then algebraic instead of e xponential. In contrast\, decoherence in the open transverse-field Ising m odel is found to be always exponential. In this case\, the internal intera ctions can both facilitate and impede the environment-induced decoherence. The results are based on quasi-exact simulations using the time-dependent density matrix renormalization group (tDMRG) and explained on the basis o f perturbative treatments.\nReference: Z. Cai and T. Barthel\, PRL 111\, 1 50403 (2013) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-208@lptms.universite-paris-saclay.fr DTSTART:20131120T143000Z DTEND:20131120T153000Z DTSTAMP:20131114T094605Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giovanni-acquaviva/ SUMMARY:Séminaire du LPTMS : Giovanni Acquaviva - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 20 Nov 13 14:30 DESCRIPTION:Semi-classical and quantum effects in curved metrics\nGiovanni Acquaviva\, University of Trento\nSince the work by Hartle and Hawking\, b lack hole spacetimes constituted an excellent playground for the study of quantum effects in curved metrics: in this context a great deal of theoret ical tools have been employed in order to unveil the connections between g eneral relativity and the quantum realm.  In the seminar I will present t wo approaches that allow to highlight this aspect: i) the semi-classical t unneling method and ii) the quantum field-theoretical modeling of Unruh-De Witt detectors.  One of the open questions in this field regards the ever present role of thermodynamics: does it just constitutes a parallel arisin g from a fundamentally statistical treatment?  Or is there some more prof ound link? LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-177@lptms.universite-paris-saclay.fr DTSTART:20131122T140000Z DTEND:20131122T150000Z DTSTAMP:20131105T134320Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-pascal-martin/ SUMMARY:Physics-Biology interface seminar: Pascal Martin - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 22 Nov 13 14: 00 DESCRIPTION:The hair-cell bundle as a mechanosensor and amplifier for heari ng\nPascal Martin (Institut Curie - Paris)\nThe ear works as a remarkable sound detector. Hearing can indeed operate over six orders of magnitudes of sound-pressure levels\, with exquisite sensitivity and sharp frequency selectivity to weak sound stimuli. Curiously\, the ear does not work as a high-fidelity sound receiver\, introducing in the auditory percept “pha ntom” tones that are not present in the sound input. In this talk\, I w ill present micromechanical experiments at the level of the cellular micro phone of the inner ear – the hair cell – whose function is to transduc e sound-evoked vibrations into electrical nervous signals. In particular\ , I will show that hair cells can power spontaneous oscillations of their mechanoreceptive hair bundles\, a tuft of cylindrical protrusions that pro trudes from the apical surface of each cell. The oscillatory instability is thought to result from a dynamical interplay between ion channels\, ela stic proteinous linkages and active molecular motors. We find that oscill ations of the hair bundle allow the hair cell to actively resonate with it s mechanical input at the expense of distortions with properties that are characteristic of hearing. I will conclude by arguing that our results pr omote a general principle of sound detection that is based on nonlinear am plification by self-sustained “critical” oscillators in the inner ear\ , i.e. active dynamical systems that operate on the brink of a Hopf bifurc ation.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-184@lptms.universite-paris-saclay.fr DTSTART:20131128T140000Z DTEND:20131128T150000Z DTSTAMP:20131115T074533Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jon-keating/ SUMMARY:Séminaire du LPTMS: Jon Keating - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 28 Nov 13 14:00 DESCRIPTION:\nRandom Matrix Theory and quantum spin chains\nJon Keating (Br istol University)\n\nI will discuss a random matrix model for understandin g statistical features of the spectrum and excited states of certain famil ies of quantum spin chains.  In the case of the states\, this provides in formation about entanglement properties. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-214@lptms.universite-paris-saclay.fr DTSTART:20131202T143000Z DTEND:20131202T153000Z DTSTAMP:20131125T082707Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-den is-bernard/ SUMMARY:Tri-séminaire de Physique Statistique : Denis Bernard - IPhT\, CEA -Saclay\, salle Itzykson - 2 Déc 13 14:30 DESCRIPTION:Real Time Imaging of Quantum and Thermal Fluctuations : a Detou r into Quantum Noise\nDenis Bernard\, LPTENS\nIn the last decade progresse s have been achieved in realising and manipulating stable and controllable quantum systems\, and these made possible to experimentally study fundame ntal questions posed in the early days of quantum mechanics. We shall theo retically discuss recent cavity QED experiments on non-demolition quantum measurements. While they nicely illustrate the possibility to implement ef ficient quantum state manipulations\, these experiments pose a few questio ns such as: What does it mean to observe a progressive wave function colla pse in real time? How to describe it? What do we learn from them? Their an alysis will allow us on the one hand to link these experiments to basics n otions of probability or information theory\, and on the other hand to tou ch upon notions of quantum noise.\nAs an illustration\, we shall also look at quantum systems in contact with a heat bath and we shall describe the main physical features of thermally activated quantum jumps. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-198@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20131203 DTEND;VALUE=DATE:20131205 DTSTAMP:20131016T110353Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/comite-aeres/ SUMMARY:Comité AERES - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campu s d'Orsay - 3 Déc 13 00:00 DESCRIPTION: LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-200@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20131204 DTEND;VALUE=DATE:20131205 DTSTAMP:20131017T051932Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/comite-aeres-2/ SUMMARY:Comité AERES - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campu s d'Orsay - 4 Déc 13 00:00 DESCRIPTION: LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-171@lptms.universite-paris-saclay.fr DTSTART:20131206T110000Z DTEND:20131206T120000Z DTSTAMP:20131114T104956Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-francois-nedelec/ SUMMARY:Physics-Biology interface seminar: François Nédélec - Laboratoir e d'enzymologie et biochimie structurales - 6 Déc 13 11:00 DESCRIPTION:Optimal Design of Elongating Yeast Spindles\nFrançois Nédéle c (EMBL Heidelberg)\nJoint seminar with LEBS Gif-sur-Yvette\nSPECIAL TIME AND LOCATION\nBundles of filaments are universal elements that belong to t he intracellular skeleton of eukaryotic cells. The anaphase spindle from f ission yeast is an excellent example of such bundle that assembles repeate dly in the same manner at every cell division. It is also an excellent exp erimental system since yeast cells can easily be perturbed genetically\, a nd their spindle is visualized using electron or light microscopy. The spi ndle is under compression at anaphase and based on electron tomographic re constructions of its constituent microtubules\, we calculated that the len gth and organization of microtubules within the fission yeast spindle are optimized to achieve maximal strength while minimizing the use of material . A combination of simulations and live cell imaging further indicated whi ch of the properties of the microtubule cross-linkers are likely to be res ponsible for such a precise regulation of spindle morphology\, and the syn ergy that exists between the cross-linkers in fission yeast.\n LOCATION:Laboratoire d'enzymologie et biochimie structurales\, Bâtiment 3 4 - Avenue de la Terrasse\, Gif-sur-Yvette\, 91190\, France GEO:48.704609;2.132356 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS= Bâtiment 34 - Avenue de l a Terrasse\, Gif-sur-Yvette\, 91190\, France;X-APPLE-RADIUS=100;X-TITLE=La boratoire d'enzymologie et biochimie structurales:geo:48.704609,2.132356 END:VEVENT BEGIN:VEVENT UID:1-217@lptms.universite-paris-saclay.fr DTSTART:20131209T113000Z DTEND:20131209T121500Z DTSTAMP:20131206T065854Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-clel ia-de-mulatier/ SUMMARY:Journal Club : Clélia de Mulatier - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 9 Déc 13 11:30 DESCRIPTION:\n\n\nB. Houchmandzadeh\, Phys. Rev. E 80\, 051920 (2009): Theo ry of neutral clustering for growing populations\nClélia de Mulatier (PhD student LPTMS)\n\nThe spatial distribution of most species in nature is n onuniform. We have shown recently [ B. Houchmandzadeh Phys. Rev. Lett. 101 078103 (2008)] on an experimental ecological community of amoeba that the most basic facts of life—birth and death—are enough to cause consider able aggregation which cannot be smoothened by random movements of the org anisms. This clustering\, termed neutral and always present\, is independe nt of external causes and social interaction. We develop here the theoreti cal groundwork of this phenomenon by explicitly computing the pair-correla tion function and the variance to mean ratio of the above neutral model an d its comparison to numerical simulations.\nSee also :\n\nW. R. Young\, A. J. Roberts &\; G. Stuhne\, Nature 412\, 328-331 (19 July 2001)\n\n\n\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-194@lptms.universite-paris-saclay.fr DTSTART:20131210T110000Z DTEND:20131210T120000Z DTSTAMP:20131202T084516Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-haggai-landa/ SUMMARY:Séminaire du LPTMS: Haggai LANDA - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 10 Déc 13 11:00 DESCRIPTION:Solitons and nonlinearity with trapped ions\nHaggai Landa\, LPT MS\nSolitons are ubiquitous in many areas of physics and the natural scien ces. Quantum dynamics of solitons\, however\, has proven experimentally ch allenging to measure. A system in which state-of-the-art quantum control o ver individual degrees of freedom has been demonstrated is the ion trap\, where\, due to the time-dependent trapping fields and the Coulomb interact ion\, trapped ions manifest rich nonlinear dynamics. I will present some t heoretical work and collaboration with experimental groups from recent yea rs\, focusing in particular on the study of discrete solitons with trapped ions\, and more generally\, other nonlinear phenomena\, both classical an d quantum mechanical. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-210@lptms.universite-paris-saclay.fr DTSTART:20131217T110000Z DTEND:20131217T120000Z DTSTAMP:20131205T151116Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-eduardo-sanz/ SUMMARY:Séminaire du LPTMS: Eduardo Sanz - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 17 Déc 13 11:00 DESCRIPTION:Crystallization in molecular and colloidal systems by means of computer simulations\nEduardo Sanz\, Universidad Complutense de Madrid\nCr ystallization is often used in separation and purification industrial proc esses. Most drugs\, for instance\, are stored and delivered in a crystalli ne form. Moreover\, climate change is strongly influenced by the crystalli zation of water in tropospheric clouds. It is therefore important to deepl y understand the kinetics of this phase transition\, and computer simulati ons is a very suitable tool for this purpose. The reason is that crystalli zation starts by a nucleation step that consists in the emergence of a sma ll embryo of the crystal phase in the bulk of the parent fluid phase. In m olecular systems\, such embryo is rather small (contains of the order of 1 0^2-10^3 molecules) and short-lived (lasts for ~10^-9 seconds) and it can not therefore be directly visualized experimentally. In this talk I will d iscuss several numerical studies of crystallization. First\, I will discus s a case study in which several crystal phases (polymorphs) compete to nuc leate in a metastable fluid of oppositely charged colloids. Then\, I will present a computational study of homogeneous ice nucleation at low superco olings. Finally\, I will present a study of the mechanism by which a collo idal glass becomes crystalline. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-187@lptms.universite-paris-saclay.fr DTSTART:20131220T140000Z DTEND:20131220T150000Z DTSTAMP:20131210T124637Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-yang-si/ SUMMARY:Physics-Biology interface seminar: Yang Si - Amphi BLANDIN du LPS d e la Faculté des Sciences d’Orsay (Bâtiment 510) - 20 Déc 13 14:00 DESCRIPTION:Fluorescent Nano-objects For Bioimaging Applications\nYang Si ( ENS Cachan)\nSpecial seminar: poster prize from the NOMBA workshop\n\nBact eria are the most abundant organisms in the world. Studying models of bact erial chromosome dynamics in the cytoplasm is very important to understand how bacteria adapt to different growth environments and in response to st imuli. \n\nOptical labeling is one of the most common methodologies used for bioanalytical purposes. The fundamental issues for any fluorescent mat erial are the same: brightness and stability. In the quest for very bright and stable labels\, novel polymer-based\, self-stabilized\, fluorescent n anoparticles (FNPs) and fluorescent polymer chains (FPCs) have been develo ped in the PPSM laboratory. They are brighter\, more stable\, photobleach slowly and are more easily functionalized compared with other fluorescent labels like GFP and QDs. \nA methodology to insert these FNPs (60nm) into E.coli bacteria was developed. To control if the FNP are indeed internali zed\, we developed a protocol based upon FNP luminescence quenching by met hylene blue.\n\nBiotin conjugated FNPs could be used to study specific mem brane proteins. By using a strepdavidin-biotin link\, we made a “Sandwic h” to build a bridge between particles\, specific antibodies and bacteri a.\n\nNegatively charged FPCs can easily enter into E.coli bacteria. It is found that FPCs can label the cytoplasm but not the DNA\, which appears t o be more compact. These unique properties will allow the study of DNA an d cytoplasm viscosity changes during bacterial growth.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-188@lptms.universite-paris-saclay.fr DTSTART:20140107T110000Z DTEND:20140107T120000Z DTSTAMP:20131219T101524Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-francis-corson/ SUMMARY:Séminaire du LPTMS: Francis Corson - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 7 Jan 14 11:00 DESCRIPTION:A geometric approach to biological patterning\nFrancis Corson\, Institut Pasteur\nUnderstanding how developmental patterns arise remains a central question in developmental biology. While genetic studies have re vealed lists of genes and molecules involved in this process\, it is often difficult to assemble them into predictive models. The theory of dynamica l systems suggests a geometric approach that focuses on the qualitative st ructure of dynamics\, yet allows quantitative predictions. We have applied this approach to the vulva of C. elegans\, a simple organ that forms from a small number of cells. The model can be used to predict a “phase diag ram” of the system\, i.e. the outcome of development in different condit ions\, and these predictions largely recapitulate the experimentally obser ved outcomes. A similar approach naturally extends to the patterning of la rger assemblies of cells\, and I will discuss its application to the devel opment of mechanosensory hair in Drosophila. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-222@lptms.universite-paris-saclay.fr DTSTART:20140109T143000Z DTEND:20140109T163000Z DTSTAMP:20131219T074901Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-semianaire-de -physique-marc-potters/ SUMMARY:Tri-sémianaire de Physique Statistique : Marc Potters - LPTMS\, sa lle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Jan 14 14:30 DESCRIPTION:A Random Matrix Bayesian framework for out-of-sample quadratic optimization\nMarc Potters\, Capital Fund Management (CFM)\, Paris\nLarge empirical sample covariance matrices exhibit a distribution of eigenvalues well described by the work of Marcenko and Pastur. As a consequence\, mea n-variance optimization using the sample-covariance matrix gives disastrou s out-of-sample results as the methods overweighs modes of spuriously low variance.  We propose here a Bayesian framework for the true covariance m atrix whose conditional expectation should be used for mean-variance optim ization. While the framework is quite general\, we explore a few rotationa lly invariant priors\, namely shifted-Wigner\, Wishart and inverse-Wishart . While the latter is easily solved and leads to linear shrinkage the othe r two give rise to interesting matrix integrals. A naïve matrix saddle po int gives an approximate solution\, the zeroth order term in a systematic expansion in planar Feynman diagrams.  The first few terms of this expans ion can be computed. The eigenvalue saddle point involves the orthogonal v ersion of the Itzykson-Zuber integral that we solve exactly only in a very special case. We also discuss a numerical method that allows the computat ion of the conditional mean by Monte Carlo simulation. The methodology pre sented here has direct applications in finance (portfolio optimization) an d should be applicable to other fields of “big data.” LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-221@lptms.universite-paris-saclay.fr DTSTART:20140114T110000Z DTEND:20140114T120000Z DTSTAMP:20131218T134439Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-marie-stephan/ SUMMARY:Séminaire du LPTMS: Jean-Marie Stephan - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Jan 14 11:00 DESCRIPTION:Entropy and Mutual information in low-dimensional classical and quantum critical systems\nJean-Marie Stephan\, University of Virginia\nIn studies of new and exotic phases of quantum matter\, the Renyi entangleme nt entropy has established itself as an important resource. For example it is universal at one-dimensional quantum critical points: the leading term can be used to extract the central charge c of the underlying conformal f ield theory\, and thus identify the universality class.\nIn this talk I wi ll show how an analogous quantity defined for classical systems\, the Reny i Mutual Information (RMI)\, can be used to access universality classes in 2d. In particular for a rectangle cut into two rectangles\, the shape dep endence of the RMI can be computed exactly and is proportional to c. This makes it possible to extract c from (transfer-matrix) Monte Carlo simulati ons.I will also discuss how this Mutual information is related to the enta nglement entropy of certain Resonating valence bond states in 2d\, as well as other basis-dependent entropies in 1d quantum systems. Reference: arX iv:1312.3954 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-195@lptms.universite-paris-saclay.fr DTSTART:20140115T143000Z DTEND:20140115T153000Z DTSTAMP:20140108T070328Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-anna-minguzzi/ SUMMARY:Séminaire du LPTMS : Anna Minguzzi - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 15 Jan 14 14:30 DESCRIPTION:Optimal persistent currents for ultracold bosons stirred on a r ing\nAnna Minguzzi (LPMMC Grenoble)\nWe study persistent currents for inte racting bosons on a tight ring trap\, subjected to an artificial gauge fie ld induced by a rotating barrier potential. We show that at intermediate i nteractions the persistent current response is maximal\, due to a subtle i nterplay of effects due to the barrier\, the interaction and quantum fluct uations. These results are relevant for ongoing experiments with ultracold atomic gases on mesoscopic rings. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-205@lptms.universite-paris-saclay.fr DTSTART:20140117T140000Z DTEND:20140117T150000Z DTSTAMP:20140114T180109Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-alexis-gautreau/ SUMMARY:Physics-Biology interface seminar: Alexis Gautreau - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 17 Jan 14 14:00 DESCRIPTION:Inhibitory signalling to the Arp2/3 complex steers cell migrati on\nAlexis Gautreau (LEBS - Gif-sur-Yvette)\nCell migration requires the g eneration of branched actin networks that power the protrusion of the plas ma membrane in lamellipodia. The Arp2/3 complex is the molecular machine t hat nucleates these branched actin networks. This machine is activated at the leading edge of migrating cells by the WAVE complex. The WAVE complex is itself directly activated by the small GTPase Rac\, which induces lamel lipodia. However\, how cells regulate the directionality of migration is p oorly understood. Here we identify a novel protein that inhibits the Arp2/ 3 complex in vitro\, Arpin\, and show that Rac signalling recruits and act ivates Arpin at the lamellipodial tip\, like WAVE. Consistently\, upon dep letion of the inhibitory Arpin\, lamellipodia protrude faster and cells mi grate faster. A major role of this inhibitory circuit\, however\, is to co ntrol directional persistence of migration. Indeed\, Arpin depletion in bo th mammalian cells and Dictyostelium discoideum amoeba resulted in straigh ter trajectories\, whereas Arpin microinjection in fish keratocytes\, one of the most persistent systems of cell migration\, induced these cells to turn. The coexistence of the Rac-Arpin-Arp2/3 inhibitory circuit with the Rac-WAVE-Arp2/3 activatory circuit can account for this conserved role of Arpin in steering cell migration. Loss of this inhibitory circuit promotes exploratory behaviors and might commit carcinoma cells to the invasive st ate.\n LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-215@lptms.universite-paris-saclay.fr DTSTART:20140121T110000Z DTEND:20140121T120000Z DTSTAMP:20140116T115530Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-julia-meyer/ SUMMARY:Séminaire du LPTMS: Julia Meyer - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 21 Jan 14 11:00 DESCRIPTION:Disordered topological metals\nJulia Meyer (CEA Grenoble)\nTopo logical behavior can be masked when disorder is present. A topological ins ulator\, either intrinsic or interaction induced\, may turn gapless when s ufficiently disordered. Nevertheless\, the metallic phase that emerges onc e a topological gap closes retains several topological characteristics. By considering the self-consistent disorder-averaged Green function of a top ological insulator\, we derive the condition for gaplessness. We show that the edge states survive in the gapless phase as edge resonances and that\ , similar to a doped topological insulator\, the disordered topological me tal also has a finite\, but non-quantized topological index. We then consi der the disordered Mott topological insulator. We show that within mean-fi eld theory\, the disordered Mott topological insulator admits a phase wher e the symmetry-breaking order parameter remains non-zero but the gap is cl osed\, in complete analogy to 'gapless superconductivity' due to magnetic disorder. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-201@lptms.universite-paris-saclay.fr DTSTART:20140128T110000Z DTEND:20140128T120000Z DTSTAMP:20140116T115642Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-clement-sire/ SUMMARY:Séminaire du LPTMS: Clément Sire - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 28 Jan 14 11:00 DESCRIPTION:Universal statistical properties of competitive systems: applic ation to poker tournaments\, sport championships (baseball\, football)\, a nd tree games\nClément Sire (LPT Toulouse)\nWe present a simple model of Texas hold'em poker tournaments\, a toy realization of a (greedy!) human s ociety\, which retains the two main aspects of the game: a) the minimal be t grows exponentially with time\, mimicking inflation\; b) players have a finite probability to bet all their fortune (a risky but potentially rewar ding investment). The distribution of the fortunes of players not yet elim inated is found to be universal and independent of time during most of the tournament\, and reproduces very accurately data obtained from Internet t ournaments and world championship events. The properties of the "chip lead er" (the richest player at a given time) are also considered. This model m akes the connection between poker and the persistence problem widely studi ed in physics (the probability for a temporal signal to remain above a giv en threshold)\, as well as some models of biological evolution (the number of "leaders" in a competition)\, and extreme value statistics. Finally\, the modelization of other competitive systems (baseball and football champ ionships\; tree games\, like tic-tac-toe or chess\, and their link with a random polymer model and wavefront propagation...) will be briefly address ed.\nUne page de vulgarisation sur ce thème avec d'autres liens utiles : http://www.lpt.ups-tlse.fr/spip.php?article239 \n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-196@lptms.universite-paris-saclay.fr DTSTART:20140131T140000Z DTEND:20140131T150000Z DTSTAMP:20140118T183953Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-aurelien-roux/ SUMMARY:Physics-Biology interface seminar: Aurélien Roux - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 31 Jan 14 14:00 DESCRIPTION:Role of membrane elasticity in clathrin-mediated endocytosis\nA urélien Roux (Université de Genève\, Suisse)\nIn Clathrin-mediated endo cytosis\, Clathrin assembles into a soccerball-like structure at the plasm a membrane that was proposed to deform the membrane by scaffolding. Howeve r\, controversies in the community have appeared on the exact role of Clat hrin: does its polymerization force is sufficient to curve the membrane\, or deformation by other means (protein insertion) is required? We studied the formation of Clathrin buds from Giant Unilamellar Vesicles\, and found that the pits can be flattened when membrane tension is increased. This s uggested that the Clathrin polymerization force could be counteracted by m embrane tension\, which we further proved by directly measuring Clathrin p olymerization force: by pulling a membrane tube out of a GUV aspirated in a micropipette\, we can measure the force required to hold the tube throug h an optical tweezer system. When Clathrin is added\, it polymerizes onto the GUV predominantly\, and the force drops. From these measurements\, we can deduce that the polymerization strength of Clathrin is in the range of a few hundred micronewtons per meter. This value confirms that clathrin p olymerization can be counteracted efficiently by membrane tension. \nTo fi nalize endocytosis\, the clathrin-bud needs to be separated from the plasm a membrane. Membrane fission requires the constriction and breakage of a t ransient neck\, splitting one membrane compartment into two. The GTPase Dy namin forms a helical coat that constricts membrane necks of Clathrin-coat ed pits to promote their fission. Dynamin constriction is necessary but no t sufficient\, questioning the minimal requirements for fission. Here we s how that fission occurs at the edge of the Dynamin coat\, where it is conn ected to the uncoated membrane. At this location\, the specific shape of t he membrane increases locally its elastic energy\, facilitating fission by reducing its energy barrier. We predict that fission kinetics should depe nd on tension\, bending rigidity and the Dynamin constriction torque. We v erify that fission times depend on membrane tension in controlled conditio ns in vitro and in Clathrin-mediated endocytosis in vivo. By numerically e stimating the energy barrier from the increased elastic energy\, and measu ring the Dynamin torque\, we show that: 1- Dynamin torque\, ≈1nN.nm\, is huge but necessary to achieve constriction\, and 2- Dynamin work sufficie ntly reduces the energy barrier to promote spontaneous fission. \n LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-226@lptms.universite-paris-saclay.fr DTSTART:20140203T143000Z DTEND:20140203T153000Z DTSTAMP:20140121T145702Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-martin-evans/ SUMMARY:Tri-séminaire de Physique Statistique : Martin Evans - IPhT\, CEA- Saclay\, salle Itzykson - 3 Fév 14 14:30 DESCRIPTION:Speed selection in coupled Fisher waves\nMartin Evans\, Univers ity of Edinburgh\, Institute for Condensed Matter and Complex Systems\, Sc hool of Physics\nThe Fisher equation describes the spread of a population or the spread of an advantageous gene through a population. It is well kno wn as a simple nonlinear equation which exhibits travelling wave solutions . Within statistical physics It has played a major role in our understandi ng of phase ordering dynamics and random first order phase transitions. In this talk we review the selection mechanism for the speed of the travelli ng waves which was established some time ago. We go on to consider two cou pled Fisher equations representing two populations e.g. sub-populations of bacteria which are susceptible or resistant to antibiotic. We show that a subtle coupling between two population waves gives rise to a novel speed selection mechanism. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-203@lptms.universite-paris-saclay.fr DTSTART:20140204T110000Z DTEND:20140204T120000Z DTSTAMP:20140116T115502Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-zoran-ristivojevic/ SUMMARY:Séminaire du LPTMS: Zoran Ristivojevic - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 4 Fév 14 11:00 DESCRIPTION:Decay of excitations in interacting one-dimensional Bose gases\ nZoran Ristivojevic (CPhT\, Ecole Polytechnique\, Palaiseau)\nExcitation s pectrum in weakly-interacting systems of bosons have the Bogoliubov form. In three dimensions\, those excitations are unstable due to residual weak interactions. The resulting process is known as Beliaev decay [1\,2] and h as been experimentally observed [3]. The related problem of decay of excit ations in one-dimensional Bose gases is a fundamental long-standing proble m. In this talk I will present its solution [4]. As a result of the conser vation laws in one dimension\, at zero temperature the leading mechanism o f decay of a quasiparticle excitation is its disintegration into three oth ers. We find that a phonon excitation has a decay rate proportional to the seventh power of momentum. In the integrable case of contact interaction between the bosons\, the decay rate vanishes. Our theory is based on study ing the anharmonic effects produced by the leading integrability breaking perturbations to the Lieb-Liniger model. It is not limited to the decay of lowest momentum phonon excitations and can describe full crossover as mom entum increases and the excitation spectrum approaches its quadratic form. \n[1] S. T. Beliaev\, Sov. Phys. JETP 7\, 299 (1958). [2] L. D. Landau and E. M. Lifshitz\, Statistical Physics\, Part 2 (Pergamon Press\, Oxford\, 1980). [3]  N. Katz\, J. Steinhauer\, R. Ozeri\, and N. Davidson\, Phys. Rev. Lett. 89\, 220401 (2002). [4] Z. Ristivojevic and K. A. Matveev\, arx iv:1312.5322 (2013). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-225@lptms.universite-paris-saclay.fr DTSTART:20140205T143000Z DTEND:20140205T160000Z DTSTAMP:20140116T115442Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lih-king-lim/ SUMMARY:Séminaire du LPTMS : Lih-King Lim - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 5 Fév 14 14:30 DESCRIPTION:Mass and chirality inversion of a Dirac cone pair in Stückelbe rg interferometry\nLih-King LIM (Institut d'Optique\, Palaiseau)\nThe aim of the present work is to show that a Stückelberg interferometer made of two massive Dirac cones can reveal information on band eigenstates such as the chirality and mass sign of the cones. For a given spectrum featuring two gapped cones\, we propose several low-energy Hamiltonians differing by their eigenstates properties. The corresponding inter-band transition pro bability is affected by such differences in its interference fringes being shifted by a new phase of geometrical origin. This phase can be a useful bulk probe for cold atoms in topological optical lattices. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-233@lptms.universite-paris-saclay.fr DTSTART:20140210T113000Z DTEND:20140210T120000Z DTSTAMP:20140206T170712Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-andr iy-gudyma/ SUMMARY:Journal-Club: Andriy Gudyma - LPTMS\, salle 201\, 2ème étage\, B ât 100\, Campus d'Orsay - 10 Fév 14 11:30 DESCRIPTION:Journal-Club: A superheated Bose-condensed gas\nAndriy Gudyma\, LPTMS\nPaper: Alexander L. Gaunt\, Richard J. Fletcher\, Robert P. Smith &\; Zoran Hadzibabic\, A superheated Bose-condensed gas\, Nature Physic s 9\, 271–274 (2013). \nAbstract :Our understanding of various states of matter usually relies on the assumption of thermodynamic equilibrium. How ever\, the transitions between different phases of matter can be strongly affected by non-equilibrium phenomena. Here we demonstrate and explain an example of non-equilibrium stalling of a continuous\, second-order phase t ransition. We create a superheated atomic Bose gas\, in which a Bose–Ein stein condensate (BEC) persists above the equilibrium critical temperature \, Tc\, if its coupling to the surrounding thermal bath is reduced by tuni ng interatomic interactions. For vanishing interactions the BEC persists i n the superheated regime for a minute. However\, if strong interactions ar e suddenly turned on\, it rapidly boils away. Our observations can be unde rstood within a two-fluid picture\, treating the condensed and thermal com ponents of the gas as separate equilibrium systems with a tunable inter-co mponent coupling. We experimentally reconstruct a non-equilibrium phase di agram of our gas\, and theoretically reproduce its main features. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-232@lptms.universite-paris-saclay.fr DTSTART:20140210T143000Z DTEND:20140210T154500Z DTSTAMP:20140206T152747Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-natalia-matveeva/ SUMMARY:Séminaire "Fluides Quantiques" : Natalia Matveeva - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Fév 14 14:30 DESCRIPTION:Ultracold atoms with dipolar interaction: a quantum Monte Carlo perspective\nNatalia Matveeva (BEC Center\, University of Trento\, Italie )\nUltracold gases with dipolar interactions became a hot topic in the fie ld of ultracold atoms due to the recent experimental progress towards the creation of polar molecules in the quantum degenerate regime. In the stro ngly interacting regime the beyond mean-field effects can play an importan t role\, therefore the use of numerical techniques\, such as quantum Monte Carlo methods\, becomes preferable. In my talk I present the results of t he Fixed-Node Diffusion Monte Carlo study of dipolar fermions in two dimen sions at zero temperature [1\,2]. I discuss the liquid-crystal phase trans ition\, the impurity problem and BCS-BEC crossover phenomenon. [1] N. Mat veeva and S. Giorgini\, Phys. Rev. Lett. 109\, 200401\, 2012 [2] N. Matvee va and S. Giorgini\, Phys. Rev. Lett. 111\, 220405\, 2013 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-206@lptms.universite-paris-saclay.fr DTSTART:20140211T110000Z DTEND:20140211T120000Z DTSTAMP:20140127T090931Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marine-thiebaud/ SUMMARY:Séminaire du LPTMS: Marine Thiébaud - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Fév 14 11:00 DESCRIPTION:Some nonlinear effects in soft matter\nMarine Thiébaud\, Unive rsité Joseph Fourier (Grenoble)\nI am going to present my PhD Work about nonequilibrium properties of low surface tension interfaces. This analytic al and numerical work is based on experimental study on colloidal fluid in terfaces\, made by Derks et al [1]. I will focus on the last part of my wo rk about moderate and large shear rates. A numerical study shows similarit es between Burgers phenomenology and the studied model which made the mode l a promising object of study. Then\, I am going to introduce some results about the bidimensional rheological properties of vesicle suspension at f ixed concentration\, the object of my post-doc work. After a few words on the numerical method\, I am going to show the relationship between vesicle organisation and apparent viscosity.\n[1] Derks\, Aarts\, Bonn\, Lekkerke rker\, and Imhof\, Suppression of Thermally Excited Capillary Waves by She ar Flow\, Phys. Rev. Lett. 97\, 038301 (2006) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-197@lptms.universite-paris-saclay.fr DTSTART:20140214T140000Z DTEND:20140214T150000Z DTSTAMP:20140206T152836Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-eric-raspaud/ SUMMARY:Physics-Biology interface seminar: Éric Raspaud - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 14 Fév 14 14:00 DESCRIPTION:Elasticity and wrinkled morphology of Bacillus subtilis pellicl es\nÉric Raspaud (LPS Orsay)\nBacterial biofilms refer to communities of bacteria that self-assemble into an extracellular cohesive matrix on a sur face. We are recently interested in floating biofilms formed by wild strai ns of Bacillus subtilis on liquid medium. Wrinkles appear during their mat uration. We have studied the formation of wrinkles in relation to their me chanical property and have shown that they could be due to a buckling inst ability. In this talk I will present our experimental results and their th eoretical interpretations.\n[caption id="attachment_22671" align="aligncen ter" width="300"] Top view of bacterial pellicles floating on liquid media . Two wild strains of Bacillus subtilis are shown in Figure A and B.[/capt ion]\nTrejo M.\, C. Douarche\, V. Bailleux\, C. Poulard\, S. Mariot\, C. R egeard\, E. Raspaud\, Elasticity and wrinkled morphology of Bacillus subti lis pellicles. Proc Natl Acad Sci USA 110 (2013)\, 2011-2016. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-223@lptms.universite-paris-saclay.fr DTSTART:20140218T110000Z DTEND:20140218T120000Z DTSTAMP:20140212T021131Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-liza-huijse/ SUMMARY:Séminaire du LPTMS: Liza Huijse - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 18 Fév 14 11:00 DESCRIPTION:Emergent supersymmetry at the Ising-Kosterlitz-Thouless multicr itical point\nLiza Huijse\, Stanford University\nSupersymmetry is a powerf ul concept in high-energy physics\, but is often thought to require too mu ch fine-tuning to be relevant for condensed matter systems. However\, in t his talk\, I will show that supersymmetry emerges in a large class of mode ls with a Z2 and U(1) symmetry at the multicritical point where the Ising and Kosterlitz-Thouless transition coincide. To arrive at this result we p erformed a detailed renormalization group analysis of the multicritical th eory including all perturbations allowed by symmetry. I will sketch this a nalysis and show how it reveals an intricate flow diagram with a marginall y irrelevant direction that preserves part of the supersymmetry of the fix ed point. The flow along this special line is very slow and we discuss the implications of this slow flow. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-235@lptms.universite-paris-saclay.fr DTSTART:20140224T113000Z DTEND:20140224T120000Z DTSTAMP:20140210T120713Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-mart in-lenz/ SUMMARY:Journal-Club : Martin Lenz - LPTMS\, salle 201\, 2ème étage\, Bâ t 100\, Campus d'Orsay - 24 Fév 14 11:30 DESCRIPTION:\nPaper: J. A. Hanna and C. D. Santangelo\, "Slack Dynamics on an Unfurling String"\, Phys. Rev. Lett. 109\, 134301 (2012)\nAbstract: An arch will grow on a rapidly deployed thin string in contact with a rigid p lane. We present a qualitative model for the growing structure involving t he amplification\, rectification\, and advection of slack in the presence of a steady stress field\, validate our assumptions with numerical experim ents\, and pose new questions about the spatially developing motions of th in objects.\n\nSee also:http://www.youtube.com/watch?v=6ukMId5fIi0http://p eople.umass.edu/csantang/images/DFD11_slackjump_small.mpg LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-229@lptms.universite-paris-saclay.fr DTSTART:20140225T110000Z DTEND:20140225T120000Z DTSTAMP:20140131T103433Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-roberto-bondesan/ SUMMARY:Séminaire du LPTMS: Roberto Bondesan - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 25 Fév 14 11:00 DESCRIPTION:Pure scaling operators at the integer quantum Hall plateau tran sition\nRoberto Bondesan\, Universität Köln\nStationary wave functions a t the transition between plateaus of the integer quantum Hall effect are k nown to exhibit multi-fractal statistics. In this talk I will discuss this critical behavior for the case of scattering states of the Chalker-Coddin gton model with point contacts. I will argue that moments formed from the wave amplitudes of critical scattering states decay as pure powers of the distance between the points of contact and observation. These moments in t he continuum limit are proposed to be correlation functions of primary fie lds of an underlying conformal field theory. Characterizations of such a t heory and extensions of our methods to other systems will be presented. Th is is joint work in collaboration with D. Wieczorek (Cologne) and M. Zirnb auer (Cologne). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-230@lptms.universite-paris-saclay.fr DTSTART:20140226T143000Z DTEND:20140226T153000Z DTSTAMP:20140220T071132Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-abhi-sharma/ SUMMARY:Séminaire exceptionnel du LPTMS: Abhi Sharma - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 26 Fév 14 14:30 DESCRIPTION:Nonlinear elasticity in filamentous networks: a critical phenom enon\nAbhi Sharma\, Amsterdam University\nMost biological materials exhibi t highly nonlinear mechanics apparent as striking increase in the stiffnes s under application of strain. In non-thermal networks such as collagen\, the nonlinear behavior arises from the collective non-affine deformations. I will show that stiffening in such networks can be regarded as a strain- driven phase transition with rich critical behavior analogous to the ferro magnetic phase transition. The critical exponents obtained are non mean-fi eld and are independent of the detailed structure of the network. Moreover \, the exponents are independent of the dimensionality of the system. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-216@lptms.universite-paris-saclay.fr DTSTART:20140304T110000Z DTEND:20140304T120000Z DTSTAMP:20140218T071842Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-laura-foini/ SUMMARY:Séminaire du LPTMS: Laura Foini - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 4 Mar 14 11:00 DESCRIPTION:Relaxation dynamics of a coherently split one-dimensional gas\n Laura Foini\, LPT ENS\nNon-equilibrium dynamics and relaxation processes i n isolated quantum systems represent\, at present\, a vivid research direc tion both theoretically and experimentally. Such interest is sustained by the overwhelming progress in the field of cold atoms that allows to invest igate the unitary dynamics of the system. \nIn this talk I will review an experiment that has considered the splitting of a one-dimensional Bose ga s into two coherent gases\, where\, ultimately\, the properties of the sys tem are probed by matter-wave interference. \nWhile previous works have f ocused on the independent dynamics of the two systems after the splitting\ , in our study we take into account the effect of a finite tunneling coupl ing between the two. Comparisons between the results obtained for such non -equilibrium problem and the thermal ones will be drawn. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-243@lptms.universite-paris-saclay.fr DTSTART:20140310T113000Z DTEND:20140310T120000Z DTSTAMP:20140306T093247Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-du-l ptms-francois-landes-2/ SUMMARY:Journal club: François Landes - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Mar 14 11:30 DESCRIPTION:Paper: A. Celani &\; M. Vergassola\, "Bacterial strategies f or chemotaxis response"\, Proc. Natl. Acad. Sci. U. S. A. 107\, 1391–6 ( 2010).\nFrançois Landes\, PhD student LPTMS\nRegular environmental condit ions allow for the evolution of specifically adapted responses\, whereas c omplex environments usually lead to conflicting requirements upon the orga nism’s response. A relevant instance of these issues is bacterial chemot axis\, where the evolutionary and functional reasons for the experimentall y observed response to chemoattractants remain a riddle. Sensing and motil ity requirements are in fact optimized by different responses\, which stro ngly depend on the chemoattractant environmental profiles. It is not clear then how those conflicting requirements quantitatively combine and compro mise in shaping the chemotaxis response. Here we show that the experimenta l bacterial response corresponds to the maximin strategy that ensures the highest minimum uptake of chemoattractants for any profile of concentratio n. We show that the maximin response is the unique one that always outcomp etes motile but nonchemotactic bacteria. The maximin strategy is adapted t o the variable environments experienced by bacteria\, and we explicitly sh ow its emergence in simulations of bacterial populations in a chemostat. F inally\, we recast the contrast of evolution in regular vs. complex enviro nments in terms of minimax vs. maximin game-theoretical strategies. Our re sults are generally relevant to biological optimization principles and pro vide a systematic possibility to get around the need to know precisely the statistics LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-242@lptms.universite-paris-saclay.fr DTSTART:20140311T110000Z DTEND:20140311T120000Z DTSTAMP:20140307T085633Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-5/ SUMMARY:Séminaire du LPTMS: Enrique Abad - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 11 Mar 14 11:00 DESCRIPTION:Fractional equation approaches to subdiffusion problems: a tale of tails\nEnrique Abad\, Dpto. de Física Aplicada (Univ. de Extremadura) \nAnomalous transport (in the sense of a nonlinear growth of the mean squa re displacement) is ubiquitous in nature\, notably in biological systems. A widely used model to mimic anomalous transport processes with a large di spersion of waiting times is the celebrated Continuous Time Random Walk (C TRW). The CTRW with a long-tailed waiting time distribution and a jump len gth distribution of finite variance (both decoupled from one another) is k nown to become equivalent to a fractional diffusion equation in the long-t ime limit. While the fractional diffusion equation is an integrodifferenti al equation\, it is nevertheless amenable to exact solution via Laplace tr ansform methods or a variable separation ansatz.\nWe consider a number of first-passage problems of interest involving the solution of the fractiona l diffusion equation with absorbing boundary conditions. The solutions are characterized by a very detailed memory of the initial condition persisti ng even in the long-time regime\; the solutions are also peculiar from a m athematical viewpoint as a) the long-time decay modes can be used to const ruct new polynomial approximations for Bessel functions and b) for a prope r choice of the system parameters divergent series are seen to emerge in t he solution. Such series must be suitably regularized to recover the physi cally correct solutions.\nFinally\, we shall also give an overview on how to deal with problems where the absorption process is not constrained to a boundary\, but is delocalized in space. In this case one must use highly non-intuitive reaction-subdiffusion equations which find a proper justific ation in the framework of a mesoscopic approach. We shall discuss the appl ication of this type of equations to understand a key process in developme ntal biology\, namely\, the formation of morphogen concentration gradients by means of subdiffusive transport. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-219@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20140313 DTEND;VALUE=DATE:20140314 DTSTAMP:20131212T151834Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference-in-hon our-of-oriol-bohigas/ SUMMARY:Conference in honour of Oriol Bohigas - IPN-batiment 100\, Auditori urm - 13 Mar 14 09:00 DESCRIPTION: LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-220@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20140314 DTEND;VALUE=DATE:20140315 DTSTAMP:20131212T151904Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference-in-hon our-of-oriol-bohigas-2/ SUMMARY:Conference in honour of Oriol Bohigas - IPN-batiment 100\, Auditori urm - 14 Mar 14 09:00 DESCRIPTION: LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-204@lptms.universite-paris-saclay.fr DTSTART:20140314T140000Z DTEND:20140314T150000Z DTSTAMP:20140306T165943Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jean-marc-allain/ SUMMARY:Physics-Biology interface seminar: Jean-Marc Allain - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 14 Mar 14 14:00 DESCRIPTION:Etude multi-échelle des tissus riches en collagène\nJean-Marc Allain (École Polytechnique)\nNous nous intéressons au lien entre l'org anisation du collagène dans les tissus mous (comme la peau ou les tendons ) et leurs propriétés mécaniques. Pour cela\, nous avons mis au point a vec le LOB de l'Ecole Polytechnique un montage original qui combine une ma chine de traction avec un microscope à Génération de Seconde Harmonique . Cette microscopie non-linéaire permet d'image les fibrilles de collagè ne en 3D et sans marquage dans un tissu\, donnant accès à son organisati on à l'échelle micrométrique. We avons validé ce dispositif sur le ten don\, avant de l'utiliser sur d'autres tissus.\n LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-224@lptms.universite-paris-saclay.fr DTSTART:20140318T110000Z DTEND:20140318T120000Z DTSTAMP:20140311T094915Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-luca-tagliacozzo/ SUMMARY:Séminaire du LPTMS: Luca Tagliacozzo - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Mar 14 11:00 DESCRIPTION:Physics of the 1D long range Ising model in a transverse field\ nLuca Tagliacozzo\, ICFO Barcelone\nLong range interacting systems can sho w different behaviour from their short range version. Recently experiments with trapped ions have started to investigate them. I will charaterize   the ground state and low energy excitations of the long range Ising model in a transverse field\, the simplest interacting long range model in 1D. I n particular I will focus on the complexity of the ground state wave funct ion in terms of entanglement measure and more traditional spin correlation s. I will also present some results about the violation of causality when the long range interactions decay slowly enough with the distance. I will also briefly review the experiments with trapped ions that have confirmed our predictions. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-237@lptms.universite-paris-saclay.fr DTSTART:20140320T143000Z DTEND:20140320T153000Z DTSTAMP:20140220T080904Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-thierry-giamarchi/ SUMMARY:Tri-séminaire de Physique Statistique : Thierry Giamarchi - LPTMS\ , salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Mar 14 14:30 DESCRIPTION:Quantum magnets as quantum simulators\nThierry Giamarchi (Unive rsité de Genève)\nThe ability to control the properties of magnetic insu lators by magnetic fields large enough to fully polarize the system has op ened a host of possibilities. In addition to the intrinsic interest of suc h questions for magnetic systems\, is has been shown that such systems cou ld be efficiently used as quantum simulators to emulate problems pertainin g to itinerant fermionic or bosonic systems. The magnetic field can then b e viewed as similar to a gate voltage controlling the number of ``particle s'' allowing an unprecedented level of control. In parallel with the exper imental developments\, progress on the theoretical front both on the numer ical and the analytical side\, have allowed a remarkable level of accuracy in obtaining the physical properties and in particular the correlation fu nctions of these systems. A comparison between theoretical predictions wit hout adjustable parameters or fudging with results from NMR\, Neutrons or other probes such as ESR is thus now possible. This has allowed for exampl e to test quantitatively the physics of Tomonaga-Luttinger liquids and als o to tackle the effects of the interactions between spinons by comparing t he physics of weak rung ladders with the one of strong rung ones.\nI will review the recent results obtained in this domain with the different exper imental compounds and will discuss the open questions and challenges. This concerns in particular the issues of finite temperatures\, higher dimensi onal systems and effects of disorder. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-246@lptms.universite-paris-saclay.fr DTSTART:20140321T110000Z DTEND:20140321T121500Z DTSTAMP:20140314T080543Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-maciej-nowak/ SUMMARY:Séminaire exceptionnel : Maciej Nowak - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 21 Mar 14 11:00 DESCRIPTION:"Burgers dynamics  in hermitian and nonhermitian RMM".\nMaciej Nowak\, Jagellonian University\, Cracovie.\n \nWe obtain several classes of non-linear partial differential equations for various random matrix en sembles undergoing Brownian type of random walk. These equations for spect ral flow of eigenvalues as a function of dynamical parameter ("time") are exact for any finite size N of the random matrix ensemble and resemble vis cid Burgers-like equations known in the theory of turbulence. In the limit of infinite size of the matrix\, these equations reduce complex inviscid Burgers equations\, proposed originally by Voiculescu in the context of fr ee processes. We identify spectral shock waves for these equations in the limit of the infinite size of the matrix\, and then we solve exact\, finit e N nonlinear equations in the vicinity of the shocks\, obtaining in this way universal\, microscopic scalings equivalent to Airy\, Bessel and cuspo id kernels. Finally\, we show that similar but  hidden Burgers-like struc tures appear (surprisingly)  also in nonhermitian random matrix models\, e.g. in the Ginibre-Girko ensemble\, where they govern the concurent  evo lution of both eigenvalues and eigenvectors. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-236@lptms.universite-paris-saclay.fr DTSTART:20140325T110000Z DTEND:20140325T120000Z DTSTAMP:20140327T080419Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-chiara-cammarota/ SUMMARY:Séminaire du LPTMS: Chiara Cammarota - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 25 Mar 14 11:00 DESCRIPTION:Quantitative theory of the random pinning glass transition and cooperative length scales\nChiara Cammarota\, Sapienza\, Rome\nFirst direc t observations of the ideal glass transition may be realized through the s tudy of randomly-pinned systems\, systems where a fraction of the particle s are frozen in the position they have in an equilibrium configuration. As an initial guideline for experimental tests of the glass transition induc ed by this construction\, aka Random Pinning Glass Transition (RPGT)\, I w ill show the results of first-principles computations by the Hypernetted c hain approximation for Hard Sphere glasses which confirm the expected enha ncement of glassy behaviour under the procedure of random pinning. I will present the phase diagram as a function of the concentration of pinned par ticles and of the global packing fraction\, showing a line of RPGT and two spinodal lines for the competing liquid and glass phases. The other main results I will highlight are the first microscopic computation of cooperat ive length-scales characterizing amorphous order in glass-formers and quan titative information on a key thermodynamic quantity defined in proximity of the ideal glass transitions\, the amorhpous surface tension. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-248@lptms.universite-paris-saclay.fr DTSTART:20140326T140000Z DTEND:20140326T151500Z DTSTAMP:20140318T083130Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fluides -quantiques-du-lptms-peter-forgacs/ SUMMARY:Séminaire "Fluides quantiques" du LPTMS : Peter Forgacs - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 26 Mar 14 14:00 DESCRIPTION:Plane waves as tractor beams\nPéter Forgacs (LMPT\, Universit é de Tours\, Wigner Center Budapest)\nThe subject of the talk is a simple but somewhat surprising effect\, when an incident plane wave exerts a pul ling force on the scatterer instead of the expected pushing. This effect\, which goes under the names of "tractor beam" or "negative radiation press ure"\, appears in a number of systems in 1 and 2 spatial dimensions. The u nderlying physical mechanism for the appearance of the pulling force is th e sufficiently strong scattering of the incoming wave into another propaga ting mode in the forward direction carrying away more momentum than that c ontained in the incoming wave. In such a case a "surplus" of momentum is c reated behind the scatterer leading to the eeffect. Such a negative radia tion pressure is found to appear in nonlinear field theoretical systems ( kinks\, vortices)\, also in optical (birefringent) systems\, and it may al so be relevant for more exotic objects like cosmic strings. Talk based on P. Forgács\, Á. Lukács\, T. Romanczukiewicz\, Plane waves as tractor b eams\, Phys. Rev. D88\, 125007 (2013). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-228@lptms.universite-paris-saclay.fr DTSTART:20140327T143000Z DTEND:20140327T153000Z DTSTAMP:20140305T155458Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-serena-bradde/ SUMMARY:Séminaire exceptionnel du LPTMS: Serena Bradde - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Mar 14 14:30 DESCRIPTION:Emergence of global patterns in bacterial growth: from single c ells to communities\nSerena Bradde\, City University of New York\nUndersta nding how phenomenological behaviors observed in biological systems emerge from molecular interactions of many individual units and how these inter actions shape the response of living systems to a changing environment are   challenging questions which lie at the interface between multiple dis ciplines.\nIn this talk I will draw an example from the human gut microb iome\, the full consortium of microbes living in association with the huma n gut. Recent developments in DNA sequencing have made it possible to mon itor how the compositions of microbial species change in time.\nAnalysis of healthy adults under antibiotic treatment showed that the gut microb iota could take several weeks to recover after treatment cessation. This s uggests that the combination of inter-species and host-microbe interaction s and external perturbations could lead to hysteresis phenomena. \nWe in vestigate this possibility and propose an out of equilibrium stochastic mo del able to explain this phenomenon in terms of a first-order phase transi tion scenario. Our study reveals the importance of noise-activated dynami cs in the recovery from antibiotic-perturbed states.  \n  LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-240@lptms.universite-paris-saclay.fr DTSTART:20140328T140000Z DTEND:20140328T150000Z DTSTAMP:20140318T070742Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-lukas-kapitein/ SUMMARY:Physics-Biology interface seminar: Lukas Kapitein - Amphi BLANDIN d u LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 28 Mar 14 14 :00 DESCRIPTION:Navigating the cytoskeleton: novel tools to dissect and direct intracellular transport\nLukas Kapitein (Universiteit Utrecht\, The Nether lands)\nActive transport is important for proper cellular organization and functioning. Such transport is driven by a large variety of molecular mot or proteins that can walk over cytoskeletal biopolymers such as microtubul es and F-actin. Whereas controlled biophysical experiments using purified components have revealed many of the basic properties of these fascinating machines\, much less is known about their specific intracellular activity and about the interplay between cytoskeletal organization and transport. To address these questions\, we have developed novel tools to control the activity of specific motors inside cells. These experiments have revealed different mechanisms by which the underlying organization of the microtubu le network guides motor transport to specific destinations. In addition\, these tools enabled us to remote-control intracellular transport and alter cellular behavior using light.\nLukas Kapitein is assistant professor at the Division of Cell Biology of Utrecht University\, where his group devel ops novel approaches to understand how the cytoskeleton and their associat ed motor proteins contribute to cellular organization and morphology. The combined use of well-controlled\, inducible intracellular transport assays and fluorescence nanoscopy of the cytoskeleton offers unique insights int o the interplay between cytoskeletal organization and motor-driven transpo rt. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-250@lptms.universite-paris-saclay.fr DTSTART:20140402T143000Z DTEND:20140402T153000Z DTSTAMP:20140325T143339Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-raphael-chetrite/ SUMMARY:Séminaire du LPTMS: Raphaël Chétrite - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 2 Avr 14 14:30 DESCRIPTION:Grande Déviation et Hors d'Equilibre\nRaphaël Chétrite\, Uni versité de Nice\nCe séminaire contiendra deux parties. La première sera une ''scratch'' présentation de la théorie des Grandes Déviations. La deuxième partie portera sur des résultats récents\, obtenus avec Hugo T ouchette (PRL 111\, 120601 (2013)) portant sur des processus de Markov con ditionnés à des événements rares. Je démontrerai\, à l'aide de la th éorie des grandes déviations\, qu'un tel processus conditionné peut êt re représenté par un processus markovien sans conditionnement\, appelé processus équivalent\, ayant les mêmes propriétés typiques que le proc essus conditionné.  La motivation physique pour l'étude de tels process us conditionnés découle de la question de l'équivalence et de la simula tion d'ensembles microcanoniques et canoniques hors d'équilibre. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-249@lptms.universite-paris-saclay.fr DTSTART:20140403T143000Z DTEND:20140403T154500Z DTSTAMP:20140325T071247Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jasleen-lugani/ SUMMARY:Séminaire du LPTMS : Jasleen Lugani - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 3 Avr 14 14:30 DESCRIPTION:Transmission spectra of an optical cavity coupled with ultracol d atoms in an optical  lattice.\nJasleen Lugani (IIT Delhi\, New Delhi\, India)\nWe consider the transmission characteristics of an optical cavity loaded with ultracold atoms in an optical lattice at absolute zero tempera ture. In particular\, I will talk about the situation when the many body q uantum state of the ultra cold atoms is an insulating state with fixed num ber of atoms at each site\, which can be either density wave (DW) or Mott insulator (MI) phase\, each showing different type of discrete lattice tra nslational symmetry. We will see how transmission spectra of the cavity ca n serve as a tool to distinguish between such insulating phases. Further\, I will also discuss how the respective spectrum changes when these insula ting phases make a crossover to the superfluid (SF) phase with the changin g depth of the optical lattice potential. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-252@lptms.universite-paris-saclay.fr DTSTART:20140407T110000Z DTEND:20140407T113000Z DTSTAMP:20140327T104118Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-ra oul-santachiara/ SUMMARY:Cours du LPTMS : Raoul Santachiara - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 7 Avr 14 11:00 DESCRIPTION:Cours du LPTMS\nIntroduction to Conformal Field Theory\nThe con formal field theory (CFT) approach aims to find the solutions of the infin ite set of equations imposed by conformal invariance. This approach has be en successfully employed in diverse areas of physics and mathematics for a lmost thirty years. We will survey the basics ideas of the CFT approach tr ying to minimize as much as possible the many technicalities hidden behind . We will see some (recent) applications on these concepts on 1D(2D) quant um(statistical) systems and in quantum topological states . LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-251@lptms.universite-paris-saclay.fr DTSTART:20140407T143000Z DTEND:20140407T153000Z DTSTAMP:20140401T081905Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ian-mcculloch/ SUMMARY:Séminaire du LPTMS: Ian McCulloch - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 7 Avr 14 14:30 DESCRIPTION:Topological insulating phase in the molecular compound $mathrm{ Mo_3 S_7 (dmit)_3}$\nIan McCulloch (University of Queensland\, Australie)\ nUsing the infinite-size density matrix renormalization group (iDMRG) appr oach\, we show that a Hubbard-like model on a triangular cluster\, represe ntative of the compound $mathrm{Mo_3 S_7 (dmit)_3}$\, is in the universall y class of the symmetry-protected topological 1D Haldane insulator\, despi te the presence of itinerant fermions which would normally destroy the sym metry protection. I will also illustrate a new technique\, to calculate cu mulant expansions of order parameters using iDMRG\, which gives detailed i nformation on quantum phase transitions and has many potential uses\, eg f ull-counting statistics through a quantum quench. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-254@lptms.universite-paris-saclay.fr DTSTART:20140407T143000Z DTEND:20140407T160000Z DTSTAMP:20140327T080339Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-vin cent-vargas/ SUMMARY:Tri-séminaire de Physique Statistique : Vincent Vargas - IPhT\, CE A-Saclay\, salle Itzykson - 7 Avr 14 14:30 DESCRIPTION:Complex Gaussian multiplicative Chaos\nVincent VARGAS (Dépt. d e Mathématique (DMA)\, Ecole Normale Supérieure Paris)\n The mathematic al theory of Gaussian multiplicative chaos was founded by J. P. Kahane in 1985. This theory has numerous applications in mathematical physics: 2d Li ouville quantum gravity in the conformal gauge (boundary and non boundary Liouville measure\, KPZ equation)\, the Kolmogorov-Obukhov model of energy dissipation in 3d turbulence\, the maximum of log-correlated fields\, etc ... In this talk\, we will review the theory of Kahane and discuss numerou s extensions that have been developed the past few years\, in particular t o the complex case. Special emphasis will be made on applications which mo tivate these extensions. This is based on joint works with B. Duplantier\, H. Lacoin\, T. Madaule\, R. Rhodes\, S. Sheffield. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-202@lptms.universite-paris-saclay.fr DTSTART:20140411T140000Z DTEND:20140411T150000Z DTSTAMP:20140401T124227Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-gijsje-koenderink/ SUMMARY:Physics-Biology interface seminar: Gijsje Koenderink - Amphi BLANDI N du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 11 Avr 14 14:00 DESCRIPTION:Living soft matter\nGijsje Koenderink (FOM Institute AMOLF)\nOn e of the defining qualities of soft matter is that it is readily driven fa r from thermodynamic equilibrium by external stress. Driving forces such a s those due to an electric field or shear can drive colloidal suspensions and polymer networks into fascinating non-equilibrium patterns\, such as b anded or ordered steady states. By contrast\, living cells naturally exhib it a unique form of internal driving in the form of chemomechanical activi ty. A prominent example is the cytoskeleton\, a meshwork of protein polyme rs and force-generating motor proteins that constitutes the scaffold of ce lls. The cytoskeleton is responsible for driving vital cellular functions such as growth\, division\, and movement. In this talk\, I will present tw o examples of our research on active cytoskeletal polymer gels. The first example concerns active contractility of the actin cortex\, which lies und erneath the cell membrane and drives shape changes by means of myosin moto rs. By reconstituting a simple model system composed of purified proteins\ , we could show how myosin motors and actin filaments collectively self-or ganize into force-generating arrays. We discovered that motors contract ac tin networks only above a sharp threshold in crosslink density\, correspon ding to a connectivity percolation transition. Surprisingly\, the motors t end to drive initially well-connected networks robustly to this critical p oint. The second example I will discuss concerns cell shape polarization d irected by interactions of actin filaments with microtubules. I will show that active force generation by growing and shrinking microtubules leads t o feedback between the organization of the actin filaments and microtubule s\, explaining earlier observations made in living cells. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-253@lptms.universite-paris-saclay.fr DTSTART:20140414T110000Z DTEND:20140414T113000Z DTSTAMP:20140327T104224Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-ra oul-santachiara-2/ SUMMARY:Cours du LPTMS : Raoul Santachiara - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 14 Avr 14 11:00 DESCRIPTION:Cours du LPTMS\nIntroduction to Conformal Field Theory\nThe con formal field theory (CFT) approach aims to find the solutions of the infin ite set of equations imposed by conformal invariance. This approach has be en successfully employed in diverse areas of physics and mathematics for a lmost thirty years. We will survey the basics ideas of the CFT approach tr ying to minimize as much as possible the many technicalities hidden behind . We will see some (recent) applications on these concepts on 1D(2D) quant um(statistical) systems and in quantum topological states . LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-227@lptms.universite-paris-saclay.fr DTSTART:20140415T110000Z DTEND:20140415T120000Z DTSTAMP:20140407T054253Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-a-de-luca-2/ SUMMARY:Séminaire du LPTMS: A. de Luca - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 15 Avr 14 11:00 DESCRIPTION:Anderson localization on a Bethe lattice: non-ergodicity of ext ended states\nAndrea De Luca\, LPT ENS\nStatistical analysis of the eigenf unctions of the Anderson tight-binding model with on-site disorder on regu lar random graphs strongly suggests that the extended states are multifrac tal at any disorder. The spectrum of fractal dimensions f(α) remains posi tive for α noticeably far from 1 even when the disorder is several times weaker than the one which leads to the Anderson localization\, i.e. the er godicity can be reached only in the absence of disorder. The one-particle multifractality on the Bethe lattice signals on a possible inapplicability of the equipartition law to a generic many-body quantum system as long as it remains isolated. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-262@lptms.universite-paris-saclay.fr DTSTART:20140423T110000Z DTEND:20140423T130000Z DTSTAMP:20140415T124435Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-ra oul-santachiara-3/ SUMMARY:Cours du LPTMS : Raoul Santachiara - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 23 Avr 14 11:00 DESCRIPTION:Cours du LPTMS\nIntroduction to Conformal Field Theory\nThe con formal field theory (CFT) approach aims to find the solutions of the infin ite set of equations imposed by conformal invariance. This approach has be en successfully employed in diverse areas of physics and mathematics for a lmost thirty years. We will survey the basics ideas of the CFT approach tr ying to minimize as much as possible the many technicalities hidden behind . We will see some (recent) applications on these concepts on 1D(2D) quant um(statistical) systems and in quantum topological states . LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-263@lptms.universite-paris-saclay.fr DTSTART:20140428T110000Z DTEND:20140428T133000Z DTSTAMP:20140415T124552Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/cours-du-lptms-ra oul-santachiara-4/ SUMMARY:Cours du LPTMS : Raoul Santachiara - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 28 Avr 14 11:00 DESCRIPTION:Cours du LPTMS\nIntroduction to Conformal Field Theory\nThe con formal field theory (CFT) approach aims to find the solutions of the infin ite set of equations imposed by conformal invariance. This approach has be en successfully employed in diverse areas of physics and mathematics for a lmost thirty years. We will survey the basics ideas of the CFT approach tr ying to minimize as much as possible the many technicalities hidden behind . We will see some (recent) applications on these concepts on 1D(2D) quant um(statistical) systems and in quantum topological states . LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-266@lptms.universite-paris-saclay.fr DTSTART:20140429T110000Z DTEND:20140429T120000Z DTSTAMP:20140424T062543Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sanjib-sabhapandit-3/ SUMMARY:Séminaire du LPTMS : Sanjib Sabhapandit - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 29 Avr 14 11:00 DESCRIPTION:High-energy tail of the velocity distribution of driven inelast ic Maxwell gases\nSanjib Sabhapandit\, Raman Research Institute\, Bangalor e\n\n\n\nA model of homogeneously driven dissipative system\, consisting o f a collection of $N$ particles that are characterized by only their veloc ities\, is considered. Adopting a discrete time dynamics\, at each time st ep\, a pair of velocities is randomly selected. They undergo inelastic col lision with probability $p$. With probability $(1-p)$\, energy of the syst em is changed by changing the velocities of both the particles independent ly according to $v\\rightarrow -r_w v +\\eta$\, where $\\eta$ is a Gaussia n noise drawn independently for each particle as well as at each time step s. For the case $r_w=- 1$\, although the energy of the system seems to sat urate (indicating a steady state) after time steps of $O(N)$\, it grows li nearly with time after time steps of $O(N^2)$\, indicating the absence of a eventual steady state. For $ -1 <\;r_w \\leq 1$\, the system reaches a steady state\, where the average energy per particle and the correlation of velocities are obtained exactly. In the thermodynamic limit of large $N $\, an exact equation is obtained for the moment generating function. In t he limit of nearly elastic collisions and weak energy injection\, the velo city distribution is shown to be a Gaussian. Otherwise\, for $|r_w| <\; 1$\, the high-energy tail of the velocity distribution is Gaussian\, with a different variance\, while for $r_w=+1$ the velocity distribution has an exponential tail.\n \n\n\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-244@lptms.universite-paris-saclay.fr DTSTART:20140506T110000Z DTEND:20140506T120000Z DTSTAMP:20140428T053239Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-paul-zinn-justin/ SUMMARY:Séminaire du LPTMS: Paul Zinn-Justin - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Mai 14 11:00 DESCRIPTION:Discrete holomorphicity and quantized affine algebras\nPaul Zin n-Justin\, LPTHE\nThis is joint work with I. Ikhlef\, R. Weston and M. Whe eler. I will discuss the interplay between two properties of two-dimension al statistical models\, namely integrability (or exact solvability) and di screte holomorphicity. After introducing these concepts\, I will explain h ow the Bernard-Felder construction of nonlocal currents out of quantized a ffine algebras provides a link between them\, relating the discrete holomo rphicity equation with conservation of these nonlocal currents. I will dis cuss as an example the case of the Temperley--Lieb (dense) loop model. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-270@lptms.universite-paris-saclay.fr DTSTART:20140507T140000Z DTEND:20140507T150000Z DTSTAMP:20140505T115129Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-oleksandr-gamayan/ SUMMARY:Séminaire du LPTMS : Oleksandr Gamayun - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 7 Mai 14 14:00 DESCRIPTION:Mobile impurity propagation in a one-dimensional quantum gas\nO leksandr Gamayun\, Lancaster University\nWe investigate the time evolution of the momentum of an impurity atom injected into a degenerate Tonks-Gira rdeau gas. We establish that given an initial momentum p0 the impurity rel axes to a steady state with a non-vanishing momentum p∞. The nature of t he steady state is found to be drastically different for integrable and no n-integrable impurity models\, which is due to multiple coherent scatterin g processes leading to a resonant interaction between the impurity and the host in the integrable case. The dependence of $p_\\infty$ on $p_0$ remai ns non-trivial even in the limit of vanishing interaction between the impu rity and host particles. In this limit $p_\\infty(p_0)$ is found explicitl y and the case of the external force applied to the impurity is analyzed a s well. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-269@lptms.universite-paris-saclay.fr DTSTART:20140512T113000Z DTEND:20140512T123000Z DTSTAMP:20140505T115235Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-mart in-trulsson/ SUMMARY:Journal club : Martin Trulsson - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Mai 14 11:30 DESCRIPTION:Paper : Why glass elasticity affects the thermodynamics and fra gility of supercooled liquids. PNAS 113 (2013) Le Yan\, Gustavo Düring\, and Matthieu Wyart\nMartin Trulsson \, LPTMS\nSupercooled liquids are char acterized by their fragility: The slowing down of the dynamics under cooli ng is more sudden and the jump of specific heat at the glass transition is generally larger in fragile liquids than in strong ones. Despite the impo rtance of this quantity in classifying liquids\, explaining what aspects o f the microscopic structure controls fragility remains a challenge. Surpri singly\, experiments indicate that the linear elasticity of the glass—a purely local property of the free energy landscape—is a good predictor o f fragility. In particular\, materials presenting a large excess of soft e lastic modes\, the so-called boson peak\, are strong. This is also the cas e for network liquids near the rigidity percolation\, known to affect elas ticity. Here we introduce a model of the glass transition based on the ass umption that particles can organize locally into distinct configurations t hat are coupled spatially via elasticity. The model captures the mentioned observations connecting elasticity and fragility. We find that materials presenting an abundance of soft elastic modes have little elastic frustrat ion: Energy is insensitive to most directions in phase space\, leading to a small jump of specific heat. In this framework strong liquids turn out t o lie the closest to a critical point associated with a rigidity or jammin g transition\, and their thermodynamic properties are related to the probl em of number partitioning and to Hopfield nets in the limit of small memor y.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-213@lptms.universite-paris-saclay.fr DTSTART:20140515T143000Z DTEND:20140515T161500Z DTSTAMP:20140422T071633Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-3/ SUMMARY:Tri-Séminaire de Physique Statistique : Merouane Debbah - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Mai 14 14:30 DESCRIPTION:Random matrices for wireless communications : when Wigner meets Shannon\nMerouane Debbah\, Alcatel-Lucent Chair on Flexible Radio\, Supé lec\nThe asymptotic behaviour of the eigenvalues of large random matrices has been extensively studied since the fifties. One of the first related r esult was the work of Eugène Wigner in 1955 who remarked that the eigenva lue distribution of a standard Gaussian hermitian matrix converges to a de terministic probability distribution called the semi-circular law when the dimensions of the matrix converge to infinity. Since that time\, the stud y of the eigenvalue distribution of random matrices has triggered numerous works\, in the theoretical physics as well as probability theory communit ies. However\, as far as communications systems are concerned\, until the mid 90’s\, intensive simulations were thought to be the only technique t o get some insight on how communications behave with many parameters. All this changed in 1997 when large system analysis based on random matrix the ory was discovered as an appropriate tool to gain intuitive insight into c ommunication systems. In particular\, the self-averaging effect of random matrices was shown to be able to capture the parameters of interest of com munication schemes. Since the year 2000\, the results led to very active r esearch in many fields such as MIMO systems currently used in 4G technolog ies. This talk is intended to give a comprehensive overview of random matr ices and their application to the analysis and design of wireless communic ation systems (4G and 5G systems). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-256@lptms.universite-paris-saclay.fr DTSTART:20140519T093000Z DTEND:20140519T180000Z DTSTAMP:20140512T065638Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference/ SUMMARY:Conférence "Disordered quantum systems: from electrons to cold ato ms" - LPTMS-batiment 100\, salle des conseils - 19 Mai 14 09:30 DESCRIPTION:see more information: http://lptms.u-psud.fr/workshop/dqs/\nPre sentation\nDuring more than 50 years since the discovery of Anderson local ization of particles\, the physics of disordered quantum systems underwent tremendous developments. At present\, the localization of interacting par ticles remains one of the global problems in condensed matter physics. The key issues concern metal-insulator transitions in mesoscopic systems\, el ectron-phonon interaction and transport in the insulating and metallic sta tes\, superconductor-insulator transitions\, disordered Josephson arrays. In the last decade\, localization of interacting particles became one of t he key problems in ultracold atomic quantum gases\, which have temperature s in the nanokelvin regime and eight orders of magnitude lower densities t han liquid helium. After first successful experiments in Orsay and Florenc e\, the domain of quantum gases in disorder is rapidly growing. The aim of the present workshop is to bring together leading experts in condensed ma tter and atomic physics and to discuss recent developments in the field of disordered quantum systems.\nDownload Poster\nOrganizing Committee\n\n Bo ris Altshuler\nColumbia University\, USA\nbla@phys.columbia.edu\n Vincent Michal\nLaboratoire de Physique Théorique et Modèles Statistiques\nUnive rsité Paris Sud\nvincent.michal@lptms.u-psud.fr\n Gora Shlyapnikov\nLabor atoire de Physique Théorique et Modèles Statistiques\nUniversité Paris Sud\ngeorgy.shlyapnikov@lptms.u-psud.fr\n\nInvited speakers:\n\n Alain Asp ect (Institut d'Optique\, Palaiseau)\n Giulio Biroli (CEA\, Saclay)\n Hél ène Bouchiat (LPS\, Orsay)\n Vincent Bouchiat (Institut Néel\, Grenoble) \n Dominique Delande (LKB ENS\, Paris)\n Benoît Douçot (LPTHE\, Paris)\n Sergey Flach (Massey University\, Auckland\, New Zealand)\n Antoine Georg es (Collège de France\, Paris)\n Thierry Giamarchi (University of Geneva\ , Switzerland)\n Igor Lerner (University of Birmingham\, UK)\n Charly Marc us (University of Copenhagen\, Denmark)\n Giovanni Modugno (LENS\, Florenc e\, Italy)\n Gilles Montambaux (LPS\, Orsay)\n Hugues Pothier (CEA\, Sacla y)\n Benjamin Sacépé (Institut Néel\, Grenoble)\n Laurent Sanchez-Palen cia (Institut d'Optique\, Palaiseau)\n Andrey Varlamov (Rome University To r Vergata\, Italy)\n Vladimir Yudson (RQC\, Moscow\, Russia)\n\nContact\nF or more information :\n Tel: +33 1 69 15 31 82\n Fax: +33 1 69 15 65 25\ n vincent.michal@lptms.u-psud.fr LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-257@lptms.universite-paris-saclay.fr DTSTART:20140520T093000Z DTEND:20140520T180000Z DTSTAMP:20140512T065600Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference-disord ered-quantum-systems-from-electrons-to-cold-atoms/ SUMMARY:Conférence "Disordered quantum systems: from electrons to cold ato ms" - LPTMS-batiment 100\, salle des conseils - 20 Mai 14 09:30 DESCRIPTION:see more information: http://lptms.u-psud.fr/workshop/dqs/\nPre sentation\nDuring more than 50 years since the discovery of Anderson local ization of particles\, the physics of disordered quantum systems underwent tremendous developments. At present\, the localization of interacting par ticles remains one of the global problems in condensed matter physics. The key issues concern metal-insulator transitions in mesoscopic systems\, el ectron-phonon interaction and transport in the insulating and metallic sta tes\, superconductor-insulator transitions\, disordered Josephson arrays. In the last decade\, localization of interacting particles became one of t he key problems in ultracold atomic quantum gases\, which have temperature s in the nanokelvin regime and eight orders of magnitude lower densities t han liquid helium. After first successful experiments in Orsay and Florenc e\, the domain of quantum gases in disorder is rapidly growing. The aim of the present workshop is to bring together leading experts in condensed ma tter and atomic physics and to discuss recent developments in the field of disordered quantum systems.\n\nDownload Poster\nOrganizing Committee\n\n Boris Altshuler\nColumbia University\, USA\nbla@phys.columbia.edu\n Vincen t Michal\nLaboratoire de Physique Théorique et Modèles Statistiques\nUni versité Paris Sud\nvincent.michal@lptms.u-psud.fr\n Gora Shlyapnikov\nLab oratoire de Physique Théorique et Modèles Statistiques\nUniversité Pari s Sud\ngeorgy.shlyapnikov@lptms.u-psud.fr\n\nInvited speakers:\n\n Alain A spect (Institut d'Optique\, Palaiseau)\n Giulio Biroli (CEA\, Saclay)\n H élène Bouchiat (LPS\, Orsay)\n Vincent Bouchiat (Institut Néel\, Grenob le)\n Dominique Delande (LKB ENS\, Paris)\n Benoît Douçot (LPTHE\, Paris )\n Sergey Flach (Massey University\, Auckland\, New Zealand)\n Antoine Ge orges (Collège de France\, Paris)\n Thierry Giamarchi (University of Gene va\, Switzerland)\n Igor Lerner (University of Birmingham\, UK)\n Charly M arcus (University of Copenhagen\, Denmark)\n Giovanni Modugno (LENS\, Flor ence\, Italy)\n Gilles Montambaux (LPS\, Orsay)\n Hugues Pothier (CEA\, Sa clay)\n Benjamin Sacépé (Institut Néel\, Grenoble)\n Laurent Sanchez-Pa lencia (Institut d'Optique\, Palaiseau)\n Andrey Varlamov (Rome University Tor Vergata\, Italy)\n Vladimir Yudson (RQC\, Moscow\, Russia)\n\nContact \nFor more information :\n Tel: +33 1 69 15 31 82\n Fax: +33 1 69 15 65 25\n vincent.michal@lptms.u-psud.fr LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-258@lptms.universite-paris-saclay.fr DTSTART:20140521T093000Z DTEND:20140521T160000Z DTSTAMP:20140411T102958Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference-disord ered-quantum-systems-from-electrons-to-cold-atoms-2/ SUMMARY:Conférence "Disordered quantum systems: from electrons to cold ato ms" - LPTMS-batiment 100\, salle des conseils - 21 Mai 14 09:30 DESCRIPTION:see more information: http://lptms.u-psud.fr/workshop/dqs/\n\nP resentation\n\nDuring more than 50 years since the discovery of Anderson l ocalization of particles\, the physics of disordered quantum systems under went tremendous developments. At present\, the localization of interacting particles remains one of the global problems in condensed matter physics. The key issues concern metal-insulator transitions in mesoscopic systems\ , electron-phonon interaction and transport in the insulating and metallic states\, superconductor-insulator transitions\, disordered Josephson arra ys. In the last decade\, localization of interacting particles became one of the key problems in ultracold atomic quantum gases\, which have tempera tures in the nanokelvin regime and eight orders of magnitude lower densiti es than liquid helium. After first successful experiments in Orsay and Flo rence\, the domain of quantum gases in disorder is rapidly growing. The ai m of the present workshop is to bring together leading experts in condense d matter and atomic physics and to discuss recent developments in the fiel d of disordered quantum systems.\n\n\nDownload Poster\n\nOrganizing Commit tee\n\n\n\nBoris Altshuler\nColumbia University\, USA\nbla@phys.columbia.e du\nVincent Michal\nLaboratoire de Physique Théorique et Modèles Statist iques\nUniversité Paris Sud\nvincent.michal@lptms.u-psud.fr\nGora Shlyapn ikov\nLaboratoire de Physique Théorique et Modèles Statistiques\nUnivers ité Paris Sud\ngeorgy.shlyapnikov@lptms.u-psud.fr\n\n\n\nInvited speakers :\n\n\nAlain Aspect (Institut d'Optique\, Palaiseau)\nGiulio Biroli (CEA\, Saclay)\nHélène Bouchiat (LPS\, Orsay)\nVincent Bouchiat (Institut Née l\, Grenoble)\nDominique Delande (LKB ENS\, Paris)\nBenoît Douçot (LPTHE \, Paris)\nSergey Flach (Massey University\, Auckland\, New Zealand)\nAnto ine Georges (Collège de France\, Paris)\nThierry Giamarchi (University of Geneva\, Switzerland)\nIgor Lerner (University of Birmingham\, UK)\nCharl y Marcus (University of Copenhagen\, Denmark)\nGiovanni Modugno (LENS\, Fl orence\, Italy)\nGilles Montambaux (LPS\, Orsay)\nHugues Pothier (CEA\, Sa clay)\nBenjamin Sacépé (Institut Néel\, Grenoble)\nLaurent Sanchez-Pale ncia (Institut d'Optique\, Palaiseau)\nAndrey Varlamov (Rome University To r Vergata\, Italy)\nVladimir Yudson (RQC\, Moscow\, Russia)\n\n\nContact\n \n For more information :\n  \;Tel: +33 1 69 15 31 82\n  \;Fax: +33 1 69 15 65 25\n  \;vincent.michal@lptms.u-psud.fr\n\n\n LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-247@lptms.universite-paris-saclay.fr DTSTART:20140523T140000Z DTEND:20140523T150000Z DTSTAMP:20140521T054623Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-marie-pierre-valignat/ SUMMARY:Physics-Biology interface seminar: Marie-Pierre Valignat - Amphi BL ANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 23 Ma i 14 14:00 DESCRIPTION:Leukocyte sensing of flow direction\nMarie-Pierre Valignat (Lab oratoire Adhésion Cellulaire et Inflammation\, Marseille)\nAs they leave the blood stream and travel to lymph nodes or sites of inflammation\, leuk ocytes are captured by the endothelium and migrate along the vascular wall to permissive sites of transmigration. These processes are supposedly orc hestrated by chemical signals and take place under the influence of a stro ng hemodynamic shear stress. The role of flow on leukocyte crawling and ex travasation remains generally an unsolved question\, however crawling T ly mphocytes were recently reported in vivo and in vitro to orient against th e direction of flow and to move upstream like salmons in a river. This non -intuitive behavior is manifestly not a passive drift of cells pushed by t he flow\, and we sought here to clarify the origin\, role and mechanism of this upstream flow mechanotaxis behavior. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-261@lptms.universite-paris-saclay.fr DTSTART:20140527T110000Z DTEND:20140527T120000Z DTSTAMP:20140520T124840Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-remy-dubertrand/ SUMMARY:Séminaire du LPTMS: Remy Dubertrand - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 27 Mai 14 11:00 DESCRIPTION:Two scenarios of multifractality breakdown\nRemy Dubertrand\, L PT Toulouse\nMultifractality is a powerful tool to describe non trivial fl uctuations of a field. One seminal example is provided by the Anderson tra nsition due to disorder in 3D: at the critical point the eigenstates of th e Hamiltonian display multifractality\, leading i.e. to anomalous diffusio n. We have been interested in the effect of a perturbation on the multifra ctality in a quantum system. Considering two generic models I will show th at multifractality disappears following two well identified scenarios. I w ill describe these scenarios in details and discuss their consequences in order to achieve a better understanding of multifractality in quantum mech anics. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-268@lptms.universite-paris-saclay.fr DTSTART:20140528T140000Z DTEND:20140528T150000Z DTSTAMP:20140429T103722Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ennio-gozzi/ SUMMARY:Séminaire du LPTMS : Ennio Gozzi - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 28 Mai 14 14:00 DESCRIPTION:On the geometry of geometric quantization\nEnnio Gozzi\, Univer sity of Trieste\nIn this talk we will pedagogically review the Hilbert spa ce approach to Classical Mechanics pioneered by Koopman and von Neumann. N ext we will build its associated Classical Path Integral and study geometr ically the many extra variables which make their appearance beside the pha se-space ones. Quantization turns then out to be nothing else than a prope r dimensional reduction and to be at the same time the functional counterp art of Geometric Quantization. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-274@lptms.universite-paris-saclay.fr DTSTART:20140602T143000Z DTEND:20140602T153000Z DTSTAMP:20140520T104742Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-nalini-anantharaman/ SUMMARY:Tri-séminaire de Physique Statistique: Nalini Anantharaman - IPhT\ , CEA-Saclay\, salle Itzykson - 2 Juin 14 14:30 DESCRIPTION:Quantum ergodicity\nNalini Anantharaman\, Département de Math ématiques d'Orsay\, Université Paris-Sud\nQuantum ergodicity deals with the (de)localization of eigenfunctions of Schrödinger operators\, for cla ssically chaotic systems. In this talk I will review the rigourous results on the subject. I will also talk about my recent work with Etienne Le Mas son\, where we studied the delocalization of eigenfunctions on large regul ar (discrete) graphs. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-245@lptms.universite-paris-saclay.fr DTSTART:20140605T143000Z DTEND:20140605T153000Z DTSTAMP:20140528T111449Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-marc-luck/ SUMMARY:Séminaire du LPTMS: Jean-Marc Luck (Attention\, horaire inhabituel ) - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 5 Juin 14 14:30 DESCRIPTION:On the frequencies of patterns of rises and falls\nJean-Marc Lu ck\, IPhT Saclay\nWe investigate the probability of observing a given patt ern of rises and falls in a random stationary data series. The data can be modelled as a sequence of independent and identically distributed random numbers or\, equivalently\, as a uniform random permutation. The probabili ty of observing a long pattern decays exponentially with its length in gen eral. The associated decay rate is interpreted as the embedding entropy of the pattern. This rate is evaluated exactly for all periodic patterns\, g eneralizing thus the pioneering work by André on alternating permutations . In the most general case\, it is expressed in terms of a determinant of generalized hyperbolic or trigonometric functions. The probabilities of un iformly chosen random patterns are observed to obey multifractal statistic s. The typical value of the rate\, corresponding to the endpoint of the mu ltifractal spectrum\, plays the role of a Lyapunov exponent. A wide range of examples of patterns\, either deterministic or random\, is also investi gated (Physica A 407 (2014) 252-275). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-239@lptms.universite-paris-saclay.fr DTSTART:20140606T140000Z DTEND:20140606T150000Z DTSTAMP:20140528T192351Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-gero-steinberg/ SUMMARY:Physics-Biology interface seminar: Gero Steinberg - Amphi BLANDIN d u LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 6 Juin 14 14 :00 DESCRIPTION:SEMINAR CANCELLED LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-267@lptms.universite-paris-saclay.fr DTSTART:20140610T110000Z DTEND:20140610T120000Z DTSTAMP:20140603T080446Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrey-lokhov/ SUMMARY:Séminaire du LPTMS: Andrey Lokhov - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 10 Juin 14 11:00 DESCRIPTION:Dynamic message-passing equations and applications to epidemic and information spreading on networks\nAndrey Lokhov\, LPTMS\nUnderstandin g and quantifying the out-of-equilibrium dynamics is one of the major task s of today's science. Using dynamic cavity method on time trajectories\, w e show how to derive dynamic message-passing (DMP) equations for a large c lass of models with irreversible dynamics - the key point that makes the p roblem solvable. These equations are asymptotically exact for locally tree -like graphs and generally provide a good approximation for real-world net works. We illustrate the approach by applying the DMP equations for suscep tible-infected-recovered (SIR) and ignorant-spreader-stifler models (ISS) models to the problems of inference of epidemic origin and optimal informa tion spreading with awareness. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-265@lptms.universite-paris-saclay.fr DTSTART:20140617T110000Z DTEND:20140617T120000Z DTSTAMP:20140605T081646Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-edouard-boulat-2/ SUMMARY:Séminaire du LPTMS: Edouard Boulat - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 17 Juin 14 11:00 DESCRIPTION:Exact results on the out-of-equilibrium Kondo model\nEdouard Bo ulat\, Université Paris Diderot\nTransport in nanoscale quantum devices c an be described in many situations by quantum impurity models in which the low energy regime is a strong coupling (SC) regime\, an archetypical exam ple being the Kondo model. Equilibrium properties in this regime are non p erturbative but nevertheless fully accessible using integrability.\nAfter discussing why the exact solution *at equilibrium* cannot be in general ex tended to describe the out-of-equilibrium situations\, I will describe a r ecently developed framework for integrable quantum impurity models [1]\, i n which we can exactly tackle various out-of-equilibrium situations in the ir SC regime\, using their equilibrium integrability properties. It allows to compute directly the expansion of the universal scaling functions for physical quantities (like the electrical current)\, in principle to arbitr arily high order in the driving out-of-equilibrium\, be it voltage\, frequ ency... In particular\, we show how to apply this to the Kondo model : our approach successfully goes beyond known results for the electrical curren t and noise.\n[1] L.Freton and E.Boulat\, PRL 112\, 216802 (2014). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-255@lptms.universite-paris-saclay.fr DTSTART:20140620T140000Z DTEND:20140620T150000Z DTSTAMP:20140612T103321Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-francesco-piazza/ SUMMARY:Physics-Biology interface seminar: Francesco Piazza - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 20 Juin 14 14:00 DESCRIPTION:Diffusion-controlled reactions in complex media\nFrancesco Piaz za (Université d'Orléans)\nIn all biochemical reactions occurring in liv ing tissues\, reactants have to form an encounter complex before the speci fic chemical step. Invariably\, in order to reach their binding partners\, biomolecules have to diffuse in complex environments\, both very crowded with all sorts of other biomolecules and organelles and confining\, due to the presence of different membranes and cytoskeletal structures that stro ngly compartimentalize the available space.\nUnder such conditions\, the s tandard Smoluchowski theory for biomolecular encounters valid in ideal sol utions is no longer applicable and the need emerges for more sophisticated theoretical paradigms accounting explcitly for crowding and confinement i n the computation of encounter rates.\nIn this talk\, I will illustrate a general theoretical paradigm that we are developing in our group to solve this problem. Using addition theorems for spherical harmonics\, we compute the diffusion rate to a sink in the presence of crowding agents that we m odel as spheres of arbitrary radius and endowed with arbitrary reactivity\ , from fully reflecting (purely excluded volume) to fully absorbing (compe titive binding partners). We consider both diffusion in an unbounbded doma in and diffusion occurring within a spherical domain\, as an attempt to mo del encounters occurring within a cell. Different applications will be dis cussed\, such as diffusion to a binding pocket in a coarse-grained model o f protein and reactions occurring in vesicles and other kinds of nanoreact ors. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-278@lptms.universite-paris-saclay.fr DTSTART:20140626T143000Z DTEND:20140626T153000Z DTSTAMP:20140619T080141Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alberto-parola/ SUMMARY:Séminaire du LPTMS: Alberto Parola - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 26 Juin 14 14:30 DESCRIPTION:A microscopic implementation of non Functional Renormalization Group in classical and quantum models\nAlberto Parola\, Universita' dell'I nsubria\, Como\, Italy\nA general framework for implementing the Renormali zation Group ideas to microscopic models in classical and quantum statisti cal physics is presented. The method\, referred to as HRT\, is devised so to retain information on non universal properties throughout the renormali zation process by avoiding any coarse-graining procedure and the mapping o nto effective models. Different implementations of HRT are briefly reviewe d pointing out the close relationship with non-perturbative renormalizatio n group methods. The critical properties of HRT for a O(n) order parameter are summarized\, together with the behavior of the theory at first-order phase transitions. Applications to simple microscopic models in classical and quantum statistical physics\, both on and off lattice\, are discussed. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-241@lptms.universite-paris-saclay.fr DTSTART:20140704T140000Z DTEND:20140704T150000Z DTSTAMP:20140918T122636Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-manuel-thery/ SUMMARY:Physics-Biology interface seminar: Manuel Théry - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 4 Juil 14 14:00 DESCRIPTION:Relaxation in Cell Cytoskeleton\nManuel Théry (Hôpital Saint- Louis\, Paris)\nUsing combinations of in vivo and in vitro approaches we t ry to unravel the mechanisms regulating actin bundle and microtubule mecha nical properties in response to geometrical and/or mechanical stimulations . LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-276@lptms.universite-paris-saclay.fr DTSTART:20140708T110000Z DTEND:20140708T120000Z DTSTAMP:20140701T100336Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gabriel-tellez/ SUMMARY:Séminaire du LPTMS: Gabriel Tellez - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 8 Juil 14 11:00 DESCRIPTION:Screening in 1D Coulomb systems\nGabriel Tellez\, Universidad d e los Andes\nWe study a system of two like-charges screened by N counter-i ons\, living on a line and interacting through the 1D Coulomb potential. W e obtain explicit analytic expressions for the canonical partition functio n and the effective force between the like-charges. It is shown that this force can be attractive depending on the distance between the charges and the parity of the number of counter-ions N. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-280@lptms.universite-paris-saclay.fr DTSTART:20140711T143000Z DTEND:20140711T153000Z DTSTAMP:20140707T054501Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-pierpaolo-vivo/ SUMMARY:Séminaire exceptionnel du LPTMS: Pierpaolo Vivo - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Juil 14 14:30 DESCRIPTION:Phase transitions in the condition number distribution of Gauss ian random matrices\nPierpaolo Vivo\, LPTMS\nWe study the statistics of th e condition number k (the ratio between largest and smallest squared singu lar values) of NxM Gaussian random matrices. Using a Coulomb fluid techniq ue\, we derive analytically and for large N its cumulative P(k<\;x) and tail-cumulative P(k>\;x) distributions. We find the decay of these distr ibution. The left and right rate functions are calculated exactly for any choice of the rectangularity parameter M/N-1. Interestingly\, they show a weak non-analytic behavior at their minimum <\;k>\; (corresponding to the average condition number)\, a direct consequence of a phase transition in the associated Coulomb fluid problem.  Matching the behavior of the r ate functions around <\;k>\;\, we determine exactly the scale of typic al fluctuations and the tails of the limiting distribution of  k. The ana lytical results are in excellent agreement with numerical simulations. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-279@lptms.universite-paris-saclay.fr DTSTART:20140717T103000Z DTEND:20140717T130000Z DTSTAMP:20140715T080450Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/visite-lyceens/ SUMMARY:Visite lycéens - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Ca mpus d'Orsay - 17 Juil 14 10:30 DESCRIPTION: LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-281@lptms.universite-paris-saclay.fr DTSTART:20140722T110000Z DTEND:20140722T120000Z DTSTAMP:20140717T070754Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-tba/ SUMMARY:Séminaire du LPTMS: Anna Bodrova - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 22 Juil 14 11:00 DESCRIPTION: Aggregation and fragmentation in granular mixtures\nAnna Bodr ova\, Moscow State University\nGranular materials\, such as gravel sand or different types of powders\, are ubiquitous in nature and widely used in industry. Rarified granular systems\, where the volume of a solid phase is small as compared to the total volume\, are termed as granular gases. In the Earth conditions these may be obtained by placing granular matter into a container with vibrating or rotating walls\, applying electrostatic or magnetic forces etc. Extraterrestrial granular gases are also common. Many astrophysical objects\, like protoplanetary discs\, Planetary Rings and i nterstellar dust clouds contain granular gases as one of the important com ponent.\nGranular materials represent a polydisperse mixture of grains of different mass and size. We investigate size and kinetic energy distributi on in granular mixtures\, arising due to interplay of aggregation and frag mentation of granular particles. We also discuss application of our theory to dense planetary rings and compare our results with data\, available fr om the observations. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-277@lptms.universite-paris-saclay.fr DTSTART:20140910T100000Z DTEND:20140910T130000Z DTSTAMP:20140731T120007Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-francois-landes/ SUMMARY:Soutenance de thèse : François Landes - IPN-batiment 100\, Audito riurm - 10 Sep 14 10:00 DESCRIPTION:Viscoelastic interfaces Driven in Disordered Media &\; Appli cation to Friction\nFrançois Landes\, LPTMS\nMany complex systems respond to a continuous input of energy by an accumulation of stress over time\, interrupted by sudden energy releases called avalanches. Recently\, it has been pointed out that several basic features of avalanche dynamics are in duced at the microscopic level by relaxation processes\, which are neglect ed by most models. During my thesis\, I studied two well-known models of a valanche dynamics\, modified minimally by the inclusion of some forms of r elaxation.\nThe first system is that of a viscoelastic interface driven in a disordered medium. In mean-field\, we prove that the interface has a pe riodic behaviour (with a new\, emerging time scale)\, with avalanche event s that span the whole system. We compute semi-analytically the friction fo rce acting on this surface\, and find that it is compatible with classical friction experiments. In finite dimensions (2D)\, the mean-field system-s ized events become local\, and numerical simulations give qualitative and quantitative results in good agreement with several important features of real earthquakes.\nThe second system including a minimal form of relaxatio n consists in a toy model of avalanches: the Directed Percolation process. In our study of a non-Markovian variant of Directed Percolation\, we obse rved that the universality class was modified but not completely. In parti cular\, in the non-Markov case an exponent changes of value while several scaling relations still hold. This picture of an extended universality cla ss obtained by the addition of a non-Markovian perturbation to the dynamic s provides promising prospects for our first system. LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-286@lptms.universite-paris-saclay.fr DTSTART:20140916T110000Z DTEND:20140916T110000Z DTSTAMP:20140915T072213Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kinya-takahashi/ SUMMARY:Séminaire du LPTMS : Kin'ya Takahashi - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Sep 14 11:00 DESCRIPTION:Competition between instanton and non-instanton tunneling in mu ltidimensional systems\nKin'ya Takahashi\, Kyushu Institute of Technology\ nThere are two types of tunneling mechanisms working for mutli-dimensional barrier tunneling. One is well known instanton which induces barrier pene tration. The other is non-instanton tunneling\, in which tunneling particl es go over a barrier top. It is explained by multiphoton assisted tunnelin g\, while from the semiclassical view point it is interpreted by ’Stable -unstable manifold guided tunneling\, say SUMGT as an abbreviation.In this talk\, we investigate instanton type tunneling and non-instanton tunnelin g from the view points of quantum and semiclassical dynamics.Taking period ically perturbed step potential and barriers as models\, we give the inter pretation between quantum and semiclassical explanations of non-instanton tunneling and we discuss the problem: How do the transitions between insta nton and non-instanton tunneling occur with change of the perturbation fre quency? Further taking a periodically perturbed resonance potential\, we c onsider the problem: How does the resonance affect the properties of insta nt type tunneling and non-instanton tunneling? LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-285@lptms.universite-paris-saclay.fr DTSTART:20140918T143000Z DTEND:20140918T153000Z DTSTAMP:20140911T081533Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-du- lptms-steven-h-simon/ SUMMARY:Tri-séminaire de Physique Statistique : Steven H. Simon - LPTMS-ba timent 100\, salle des conseils - 18 Sep 14 14:30 DESCRIPTION:Topological matter and why you should be interested\nSteven H. Simon\, Oxford University\nIn two dimensional topological phases of matter \, processes depend on gross topology rather than detailed geometry. Think ing in 2+1 dimensions\, particle world lines can be interpreted as knots o r links\, and the amplitude for certain processes becomes a topological in variant of that link. While sounding rather exotic\, we believe that such phases of matter not only exist\, but have actually been observed in quant um Hall experiments\, and could provide a uniquely practical route to buil ding a quantum computer.   Possibilities have also been proposed for cre ating similar physics in systems ranging from superfluid helium to stronti um ruthenate to semiconductor-superconductor junctions to quantum wires to spin systems to cold atoms. LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-272@lptms.universite-paris-saclay.fr DTSTART:20140919T140000Z DTEND:20140919T170000Z DTSTAMP:20140909T123439Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-paul-soule/ SUMMARY:Soutenance de thèse : Paul Soulé - LPTMS-batiment 100\, salle des conseils - 19 Sep 14 14:00 DESCRIPTION:Edges of Fractional Quantum Hall Phases in a Cylindrical Geomet ry\nPaul Soulé\, LPTMS\nFractional Quantum Hall (FQH) phases are exotic i ncompressible fluids which support gapless chiral edge excitations. I will present a microscopic study of those edges states in a cylindrical geomet ry where quasiparticles are able to tunnel between edges.\nWe first study the principal FQH phase at the filling fraction 1/3 whose ground state is well described by the Laughlin wave function. For an energy scale lower th an the bulk gap\, the effective theory is given by a very special one dime nsional electron fluid localized at the edge: a chiral Luttinger liquid. U sing numerical exact diagonalizations\, we study the spectrum of edge mode s formed by the two counter-propagating edges on each side of the cylinder . We show that the two edges combine to form a non-chiral finite-size Lutt inger liquid\, where the current term reflects the transfer of quasipartic les between edges. Then\, we estimate numerically the Luttinger parameter for a small number of particles and find it coherent with the one predicte d by X. G. Wen theory.\nWe then analyse edge modes of the FQH phase at fil ling fraction 5/2. From a Conformal Field Theory (CFT) based construction\ , Moore and Read (Nucl. Phys. B\, 1991) proposed that this phase is well d escribed by a P-wave paired state of composite fermions. A striking proper ty of this state is that emergent excitations braid with non-abelian stati stics. When localized along the edge\, those excitations are described thr ough a chiral boson and a Majorana fermion. In the cylinder geometry\, we show that the spectrum of edge excitations is composed of all conformal to wers of the IsingXU(1) model. Interestingly\, the non-abelian tower is nat urally observed as opposed to the usual disk geometry. In addition\, with a Monte Carlo method\, we estimate the various scaling dimensions for larg e systems (about 50 electrons)\, and find them consistent with the CFT pre dictions.\n \; LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-282@lptms.universite-paris-saclay.fr DTSTART:20140923T111500Z DTEND:20140923T121500Z DTSTAMP:20141203T132428Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-peter-schlagheck/ SUMMARY:Séminaire du LPTMS: Peter Schlagheck - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 23 Sep 14 11:15 DESCRIPTION:Coherent backscattering in the Fock space of a disordered Bose- Hubbard system\nPeter Schlagheck\, Université de Liège\nCoherent backsca ttering in disordered or chaotic systems is an ubiquitous wave phenomenon that arises in a number of physical contexts involving classical (e.g. ele ctromagnetic) or quantum (matter) waves. It essentially refers to the cohe rent enhancement of the backscattering intensity in the direction that is opposite to the propagation of the incident wave. From a semiclassical poi nt of view\, this enhancement is caused by the constructive interference o f backscattered classical paths with their time-reversed counterparts.\nIn my talk I shall discuss the generalization of this wave interference phen omenon to the many-body dynamics that takes place within an interacting Bo se-Hubbard system. In this particular context\, the "classical" paths are given by solutions of a discrete nonlinear Gross-Pitaevskii equation and t heir "quantum" interference arises within the Fock space of the Bose-Hubba rd system. As a consequence\, an initially prepared Fock state is\, in the course of time evolution (and after averaging over random on-site energie s)\, twice as often encountered as other Fock states of the system with co mparable total energy. This semiclassical prediction represents a signific ant departure from the principle of quantum ergodicity in finite systems a nd is indeed confirmed by numerical simulations. We argue that an experime ntal detection of many-body coherent backscattering using ultracold bosoni c atoms in optical lattices is within reach.\nRef.: T. Engl\, J. Dujardin\ , A. Argüelles\, P. Schlagheck\, K. Richter\, and J. D. Urbina\, Phys. Re v. Lett. 112\, 140403 (2014) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-275@lptms.universite-paris-saclay.fr DTSTART:20140924T100000Z DTEND:20140924T130000Z DTSTAMP:20140911T105525Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-yasar-atas/ SUMMARY:Soutenance de thèse : Yasar Atas - LPTMS-batiment 100\, salle des conseils - 24 Sep 14 10:00 DESCRIPTION:Some aspects of quantum chaos in many body interacting systems. Quantum spin chain and random matrices.\nYasar Atas\, LPTMS\nMy thesis is devoted to the study of some aspects of many body quantum interacting sys tems. In particular we focus on quantum spin chains. I addressed especiall y questions related to the structure of eigenfunctions\, the level densiti es and the spectral properties of spin chain Hamiltonians.\nIt is known th at the level densities of most integrable models tend to the Gaussian in t he thermodynamic limit. However\, it appears that in certain limits of cou pling of the spin chain to the magnetic field and for finite number of spi ns on the chain\, one observes peaks in the level density.  I show that t he knowledge of the first two moments of the Hamiltonian in the degenerate subspace associated with each peak gives a good approximation to the leve l density both in the case of integrable and non integrable models.\nNext\ , I study the statistical properties of the eigenvalues of spin chain Hami ltonians. One of the main achievements in the study of the spectral statis tics of quantum complex systems concerns the universal behaviour of the fl uctuation of measure such as the distribution of spacing between two conse cutive eigenvalues. By following the Wigner surmise for the computation of the level spacing distribution\, I obtained approximation for the distrib ution of the ratio of consecutive level spacings in the three canonical en sembles of random matrices. The prediction are compared with numerical res ults obtained by exact diagonalization of spin Hamiltonians and with zeros of the Riemann zeta function showing excellent agreement.\nFinally\, I in vestigate eigenfunction statistics of some canonical spin-chain Hamiltonia ns. Eigenfunctions together with the energy spectrum are the fundamental o bjects of quantum systems: their structure is quite complicated and not we ll understood. Due to the exponential growth of the size of the Hilbert sp ace\, the study of eigenfunctions is a very difficult task from both analy tical and numerical points of view. I demonstrate that the groundstate eig enfunctions of all canonical models of spin chain are multifractal\, by co mputing numerically the Rényi entropy and extrapolating it to obtain the multifractal dimensions.\nKey words: Quantum spin chains\, quantum Ising m odel\, spectral statistics\, level density\, quantum chaos\, random matric es\, Wigner surmise\, spacing distribution\, multifractality\, Rényi entr opy.\n \; LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-287@lptms.universite-paris-saclay.fr DTSTART:20141001T140000Z DTEND:20141001T150000Z DTSTAMP:20140930T074633Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-huan-cheng-chang/ SUMMARY:Physics-Biology interface seminar: Huan-Cheng Chang - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 1 Oct 14 14:00 DESCRIPTION:Bioimaging and quantum sensing with ion-irradiated nanodiamonds \nHuan-Cheng Chang (Academia Sinica\, Taiwan)\nSeminar co-hosted by Franç ois Treussart\nSPECIAL TIME AND LOCATION\nAs a wide band-gap material\, di amond can contain a variety of atomic defects or impurities as color cente rs. Some of the color centers are highly luminescent\, while others are lu minescent with a very low quantum yield. For nanoscale diamonds (NDs) cont aining a high-density ensemble of vacancy-related defect centers\, they ar e useful as nanoprobes for bioimaging and quantum sensing both in vitro an d in vivo. In this seminar\, we will show how ion-irradiated NDs can be ro utinely produced in our laboratory. Three examples of the applications by utilizing nitrogen-vacancy (NV−) centers and neutral vacancy (V0 or GR1) centers in NDs are discussed. First\, we will present our results of usin g fluorescence lifetime imaging microscopy to achieve background-free real -time imaging of fluorescent NDs (denoted as FNDs) in living organisms suc h as C. elegans. With 100-nm FNDs conjugated with yolk lipoprotein complex es\, we demonstrate that the nanoparticles serve well as a biomolecular na nocarrier without significantly altering the functionality of the cargos f or intercellular transport\, cell-specific targeting\, and long-term imagi ng applications in vivo. Second\, we report our recent work on the develop ment of highly ion-irradiated NDs (denoted as INDs) as a photoacoustic con trast agent for deep-tissue imaging. The particles are so extensively dama ged that graphitization occurs concurrently with the generation of the GR1 centers. Although the IND of ~40 nm in diameter has a much smaller absorp tion coefficient than gold nanorods (GNRs) of similar dimensions at 1064 n m\, it shows a better performance due to higher thermal stability and a lo wer nanobubble formation threshold of the carbon-based nanomaterial. Final ly\, we apply the NV− centers in 100-nm FNDs for nanoscale temperature s ensing by optically detected magnetic resonance. We conjugate FNDs with GN Rs and employ them as both a nanoheater and a nanothermometer in solution and cells. The integration of heating and temperature sensing functions on the same particles opens an opportunity for active and high-precision con trol of temperature at the nanoscale by pure optical means. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-284@lptms.universite-paris-saclay.fr DTSTART:20141002T143000Z DTEND:20141002T153000Z DTSTAMP:20140918T125029Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-joyjit-kundu/ SUMMARY:Séminaire exceptionnel du LPTMS: Joyjit Kundu - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 2 Oct 14 14:30 DESCRIPTION:Phase transitions in hard core lattice gas models of anisotropi c particles\nJoyjit Kundu\, Institute of Mathematical Sciences\, Chennai\n Hard core lattice gas models of particles interacting only through exclude d volume interaction continue to be of interest in Statistical Physics. Th ey are minimal models to study entropy driven phase transitions\, have dir ect realizations in adsorption of gas particles on metal surfaces and are closely related to the freezing transition. In this talk\, I will discuss the system of hard rectangles of size m x m k on a two dimensional lattice \, where k is the aspect ratio. The phase diagram of this model for arbitr ary m and k is determined using Monte-Carlo simulations\, entropic argumen ts\, and analytical calculations based on the Bethe approximation. In part icular\, it will be shown that\, with increasing density\,  the system un dergoes three entropy driven phase transitions for large enough k. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-292@lptms.universite-paris-saclay.fr DTSTART:20141006T143000Z DTEND:20141006T153000Z DTSTAMP:20140922T101912Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-semianire-de- physique-statistique-francesco-zamponi/ SUMMARY:Tri-séminaire de Physique Statistique : Francesco Zamponi - IPhT\, CEA-Saclay\, salle Itzykson - 6 Oct 14 14:30 DESCRIPTION:Exact computation of the critical exponents of the jamming tran sition\nFrancesco Zamponi\, LPTENS\nThe jamming transition marks the emerg ence of rigidity in a system of amorphous and athermal grains. It is chara cterized by a divergent correlation length of the force-force correlation and non-trivial critical exponents that are independent of spatial dimensi on\, suggesting that a mean field theory can correctly predict their value s. I will discuss a mean field approach to the problem based on the exact solution of the hard sphere model in infinite dimension. An unexpected ana logy with the Sherrington-Kirkpatrick spin glass model emerges in the solu tion: as in the SK model\, the glassy states turn out to be marginally sta ble\, and are described by a Parisi equation. Marginal stability has a dee p impact on the critical properties of the jamming transition and allows o ne to obtain analytic predictions for the critical exponents. The predicti ons are consistent with a recently developed scaling theory of the jamming transition\, and with numerical simulations. Finally\, I will briefly dis cuss some possible extensions of this approach to other open issues in the theory of glasses. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-260@lptms.universite-paris-saclay.fr DTSTART:20141007T110000Z DTEND:20141007T120000Z DTSTAMP:20140929T082218Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kirone-mallick/ SUMMARY:Séminaire du LPTMS: Tridib Sadhu - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 7 Oct 14 11:00 DESCRIPTION:Large deviation in single-file diffusion\nTridib Sadhu\, IPhT S aclay\nSingle-file diffusion is referred to the motion of many particles i n narrow channel where particles can not pass each other. As a consequence of the forbidden mutual passage the motion of individual particles is sub -diffusive. I shall apply the macroscopic fluctuation theory to analyse th e probability distribution of position of a tracer particle in a large cla ss of single-file systems. For Brownian point particles with hard-core rep ulsion this macroscopic approach leads to a parametric expression of the l arge deviation function of tracer position. I shall compare the results wi th that obtained in our exact microscopic analysis. I shall emphasise the unusual dependence of the statistics of the tracer position on the initial state. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-238@lptms.universite-paris-saclay.fr DTSTART:20141014T090000Z DTEND:20141014T173000Z DTSTAMP:20141013T105405Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference-en-lho nneur-dalain-comtet/ SUMMARY:Conférence en l'honneur d'Alain Comtet - - 14 Oct 14 09:00 DESCRIPTION:à l'IHP Paris END:VEVENT BEGIN:VEVENT UID:1-259@lptms.universite-paris-saclay.fr DTSTART:20141015T090000Z DTEND:20141015T173000Z DTSTAMP:20140331T122541Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference-en-lho nneur-dalain-comtet-2/ SUMMARY:Conférence en l'honneur d'Alain Comtet - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Oct 14 09:00 DESCRIPTION:à l'IHP Paris LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-291@lptms.universite-paris-saclay.fr DTSTART:20141021T110000Z DTEND:20141021T120000Z DTSTAMP:20141017T104002Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giacomo-gradenigo/ SUMMARY:Séminaire du LPTMS: Giacomo Gradenigo - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 21 Oct 14 11:00 DESCRIPTION:Glassy properties of a XOR-SAT model in finite dimensions\nGiac omo Gradenigo\, LPTMS\nTwo competing scenarios have been proposed since a long time as alternative to explain the critical slowing down of glass-for ming materials:  the dynamic facilitation scenario\, well represented by kinetically constrained models (KCM)\, where glassiness arise just as a dy namical phenomenon\, and the thermodynamic scenario of the Random First-Or der Transition (RFOT) theory\, according to which the slowing down of dyna mics is the signature of a true thermodynamic transition\, the glass trans ition.\nIn this talk I will review and discuss some properties of a finite dimensional XOR-SAT model\, the triangular plaquette model\, which is a t ypical example of kinetically constrained model. In particular I will expl ain the mechanism by which the addition of an arbitrarily small  perturba tion in the Hamiltonian of this system may induce a finite temperature gla ss transition. I discuss therefore how the model studied\, just by tuning a parameter\, can be either representative of the dynamic facilitation sce nario or of the thermodynamic one: this result suggest that the two scenar ios should be regarded not as alternative but just as two complementary wa ys to explain the same kind of phenomenology. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-295@lptms.universite-paris-saclay.fr DTSTART:20141028T110000Z DTEND:20141028T120000Z DTSTAMP:20141016T100003Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kabir-ramola-2/ SUMMARY:Séminaire du LPTMS: Kabir Ramola - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 28 Oct 14 11:00 DESCRIPTION:Correlated Extreme Values in Branching Brownian Motion\nKabir R amola\, LPTMS\nWe investigate one dimensional branching Brownian motion in which at each time step particles either diffuse (with diffusion constant D)\, die (with rate d)\, or split into two particles (with rate b). When the birth rate exceeds the death rate (b >\; d)\, there is an exponentia l proliferation of particles and the process is explosive. When b <\; d\ , the process eventually dies. At the critical point (b = d) this system i s characterized by a fluctuating number of particles with a constant avera ge. Quite remarkably\, although the individual positions of these particle s have a non-trivial finite time behaviour\, the average distances between successive particles (the gaps) become stationary at large times\, implyi ng strong correlations between them. We compute the probability distributi on functions (PDFs) of these gaps\, by conditioning the system to have a f ixed number of particles at a given time t. At large times we show that th ese PDFs are characterized by a power law tail ~1/g^3 (for large gaps g) a t the critical point and ~exp(- g/c) otherwise\, with a correlation length c~\\sqrt(D/|b - d|). We discuss the emergence of these two length scales\ , the dominant overall length scale of the individual positions\, and the sub-dominant gap length scale in this system. Direct Monte Carlo simulatio ns confirm our predictions. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-299@lptms.universite-paris-saclay.fr DTSTART:20141031T113000Z DTEND:20141031T121500Z DTSTAMP:20141017T104058Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-hagg ai-landa/ SUMMARY:Journal Club : Haggai Landa - LPTMS\, salle 201\, 2ème étage\, B ât 100\, Campus d'Orsay - 31 Oct 14 11:30 DESCRIPTION:Nanofriction in cold ion traps\, A. Benassi\, A. Vanoss &\; E. Tosatti\, Nature Communications 2\, 236 (2011)\nHaggai Landa (post doc LPTMS)\nSliding friction between crystal lattices and the physics of cold ion traps are so far non-overlapping fields. Two sliding lattices may eith er stick and show static friction or slip with dynamic friction\; cold ion s are known to form static chains\, helices or clusters\, depending on the trapping conditions. Here we show\, based on simulations\, that much coul d be learnt about friction by sliding\, through\, for example\, an electri c field\, the trapped ion chains over a corrugated potential. Unlike infin ite chains\, in which the theoretically predicted Aubry transition to free sliding may take place\, trapped chains are always pinned. Yet\, a proper ly defined static friction still vanishes Aubry-like at a symmetric–asym metric structural transition\, found for decreasing corrugation in both st raight and zig-zag trapped chains. Dynamic friction is also accessible in ringdown oscillations of the ion trap. Long theorized static and dynamic o ne-dimensional friction phenomena could thus become accessible in future c old ion tribology. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-300@lptms.universite-paris-saclay.fr DTSTART:20141103T110000Z DTEND:20141103T120000Z DTSTAMP:20141021T140320Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-guillaume-tresset/ SUMMARY:Physics-Biology interface seminar: Guillaume Tresset - Moyen Amphi\ , Building 510\, Université Paris-Saclay Orsay - 3 Nov 14 11:00 DESCRIPTION:Understanding the self-assembly of simple icosahedral viruses\n Guillaume Tresset (Université Paris-Sud)\nViruses are ubiquitous pathogen s in all kingdoms of life and are major public health issues as well as ec onomic and veterinary concerns worldwide. Despite a huge body of work dedi cated to the molecular biology of viral life cycles\, there are currently no physical models accounting reliably for the mechanisms by which the hun dreds of molecular building blocks making up a virus fit into the final st ructure with a pinpoint accuracy. I will first present the self-assembly p athway of empty icosahedral capsids derived from a bovine virus. A kinetic model constructed from time-resolved X-ray scattering data reveals a coop erative mechanism involving an unexpected long-lived intermediate species. Then\, I will give some insights into the packaging of polyelectrolytes b y capsid proteins derived from a plant virus. Accurate measurements of the mass of packaged polyelectrolyte demonstrate a nonspecific selectivity th at may play a crucial role for genome packaging in host cells. Quite gener ally\, physics provides a useful framework to describe viral self-assembly and should eventually support the development of novel therapeutic strate gies. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-273@lptms.universite-paris-saclay.fr DTSTART:20141104T110000Z DTEND:20141104T120000Z DTSTAMP:20141017T132329Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sam-safran/ SUMMARY:Séminaire du LPTMS: Sam Safran - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 4 Nov 14 11:00 DESCRIPTION:Non-linearities and interactions of cells with their mechanical environment\nSam Safran\nDept. Materials and Interfaces\, Weizmann Instit ute of Science\, Rehovot\, Israel\nMany experiments have shown that the el astic substrates upon which cells are placed or the extracellular matrix ( ECM) in which cells reside in 3D can regulate cellular structure and funct ion. From fate “decision making” of stem cells to rigidity-driven moti on\, cells actively sense and transduce elastic signals\, which in turn de pends on the elastic properties of the substrate or ECM. We review experim ental evidence to demonstrate that cell structure and function is regulate d by its mechanical environment (the presence of other cells\, external st retch\, matrix rigidity) and present a generic\, theoretical model for ce ll response that combines mechanics and cell activity. We predict that eve n symmetric cells on or in isotropic substrates interact elastically\, in contrast to the vanishing interactions for the case of “dead inclusions ” under these situations.  The theory is extended to the biologically r elevant case of “strain stiffening”\, non-linear \, elastic substrates where the local cell deformations are amplified far from their origin. Fi nally\, we show how cell deformations can orient the surrounding medium wh ich in turn\, can provide guidance cues for cell motility. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-289@lptms.universite-paris-saclay.fr DTSTART:20141107T100000Z DTEND:20141107T170000Z DTSTAMP:20141024T105215Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-hdr-gu illaume-roux-et-mini-workshop/ SUMMARY:Soutenance HDR Guillaume Roux et mini-workshop - LPTMS-batiment 100 \, salle des conseils - 7 Nov 14 10:00 DESCRIPTION:10h Habilitation à diriger les recherches – Salle des consei ls RDC bât 100\n\nSome numerical investigations on strongly-correlated sy stems: from quantum quenches to disordered models. Guillaume Roux\n\n12h B uffet – Salle Bohigas au LPTMS\, 2ème étage bât 100\n\n13h10 LPTMS Wo rkshop – Salle des conseils RDC bât 100\nChairman: Thierry Jolicoeur\n\ n13h15 - Competition between the Haldane insulator\, superfluid and supers olid phases in the one-dimensional Bosonic Hubbard Model. George Batrouni\ n\n13h45 - The 2d Bose Hubbard model: Phase diagrams and new applications. Heiko Rieger\n\n14h15 - Pause café\n\n14h30 - On cold atom quasicrystals and their curious quantum behavior. Anu Jagannathan\n\n15h00 - Skew scatt ering and the spin Hall effect in correlated materials. Tim Ziman\n\n15h30 - Spin Meissner Effect\, Mott Physics and Artificial Gauge Fields. Karyn Le Hur\n\n16h00 - Fin LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-309@lptms.universite-paris-saclay.fr DTSTART:20141113T143000Z DTEND:20141113T153000Z DTSTAMP:20141103T073914Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-viktor-eisler/ SUMMARY:Tri-séminaire de Physique Statistique : Viktor Eisler - LPTMS\, sa lle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Nov 14 14:30 DESCRIPTION:Free-fermion entanglement and random matrices\nViktor Eisler\, Institute for Theoretical Physics\, Eötvös University\, Budapest\nEntang lement properties of quantum many-body systems have attracted considerable attention in the last decade. A particularly well studied case is a chain of free fermions where one has a very good analytical understanding of th en entanglement structure in the ground state. The studies can also be ext ended to simple out-of-equilibrium situations such as quantum quenches or the time-evolution from a step-initial condition. Interestingly\, in the c ourse of these investigations several connections to random matrix theory appeared. The purpose of this talk is to give an overview about these rela tions and to point out how certain aspects of RMT can give useful input to the studies of free-fermion entanglement. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-288@lptms.universite-paris-saclay.fr DTSTART:20141114T093000Z DTEND:20141114T123000Z DTSTAMP:20141103T125729Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-andrey-lokhov/ SUMMARY:Soutenance de thèse : Andrey Lokhov - IPN-batiment 100\, Auditoriu rm - 14 Nov 14 09:30 DESCRIPTION:Dynamic cavity method and problems on graphs\nAndrey Lohhov\, L PTMS\nA large number of optimization\, inverse\, combinatorial and out-of- equilibrium problems\, arising in the statistical physics of complex syste ms\, allow for a convenient representation in terms of disordered interact ing variables defined on a certain network. Although a universal recipe fo r dealing with these problems does not exist\, the recent years have seen a serious progress in understanding and quantifying an important number of hard problems on graphs. A particular role has been played by the concept s borrowed from the physics of spin glasses and field theory\, that appear ed to be extremely successful in the description of the statistical proper ties of complex systems and in the development of efficient algorithms for concrete problems.\nIn the first part of the thesis\, we study the out-of -equilibrium spreading problems on networks. Using dynamic cavity method o n time trajectories\, we show how to derive dynamic message-passing equati ons for a large class of models with unidirectional dynamics -- the key pr operty that makes the problem solvable. These equations are asymptotically exact for locally tree-like graphs and generally provide a good approxima tion for real-world networks. We illustrate the approach by applying the d ynamic message-passing equations for susceptible-infected-recovered model to the inverse problem of inference of epidemic origin.\nIn the second par t of the manuscript\, we address the optimization problem of finding optim al planar matching configurations on a line. Making use of field-theory te chniques and combinatorial arguments\, we characterize a topological phase transition that occurs in the simple Bernoulli model of disordered matchi ng. As an application to the physics of the RNA secondary structures\, we discuss the relation of the perfect-imperfect matching transition to the k nown molten-glass transition at low temperatures\, and suggest generalized models that incorporate a one-to-one correspondence between the contact m atrix and the nucleotide sequence\, thus giving sense to the notion of eff ective non-integer alphabets. LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-307@lptms.universite-paris-saclay.fr DTSTART:20141117T110000Z DTEND:20141117T120000Z DTSTAMP:20141112T202023Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-julien-heuvingh/ SUMMARY:Physics-Biology interface seminar: Julien Heuvingh - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 17 Nov 14 11:00 DESCRIPTION:Mechanics and growth of the actin cytoskeleton probed by magnet ic micro-objects\nJulien Heuvingh (PMMH\, ESPCI)\nThe ability of cells to perform essential processes such as migration or deformation relies on the ir cytoskeleton\, and especially on the structures and networks formed by the actin polymer and its associated proteins. Understanding the dynamics and the mechanics of the actin filaments and its multiple partner is a maj or goal at the frontier of biology and physics. Our team developed a new e xperimental setup to study the mechanics of in vitro reconstituted actin n etworks\, with an unprecedented throughput. This technique is based on sel f-organized chains of micron-size magnetic beads or cylinders where the co ntrolled attractive dipolar force between the colloids deforms the actin n etworks. We characterized for the first time the mechanics of actin networ ks reconstituted with different concentrations of purified proteins\, lead ing to networks of different architectures\, and drew conclusions on the o rigin of the elasticity on these networks (Pujol et al PNAS 2012). We are now measuring mechanical properties of networks reconstituted from yeast e xtract which allows comparison between a wild type containing hundred diff erent actin binding proteins to mutants lacking some of them. Our experime ntal setup was decisively improved by the fabrication of magnetic micro-ob jects of cylindrical or cubic shape (Tavacoli et al. Soft Matter 2013) all owing the deformation of actin networks between two flat surfaces. In this way\, we can access properties of dense branched networks such as non-lin ear elasticity and Poisson modulus\, which are required to test theoretica l models of fiber networks (Mikado). We are currently studying the growth velocity of the actin gel as a function of an applied mechanical stress an d the architecture of the networks. I will also present other applications of our magnetic methods to probe the mechanics of whole cells.\n\n[captio n id="attachment_26491" align="aligncenter" width="502"] Actin networks (g reen) growing from the side of magnetic cylinders. Superimposition of brig ht field image (gray) and fluorescent image (green). Cylinder length is ~1 2µm.[/caption] LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-283@lptms.universite-paris-saclay.fr DTSTART:20141118T110000Z DTEND:20141118T120000Z DTSTAMP:20141103T123316Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lisa-manning/ SUMMARY:Séminaire du LPTMS: Lisa Manning - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 18 Nov 14 11:00 DESCRIPTION:Dynamical arrest of cell motion in tissues: a constant-density rigidity transition\nLisa Manning\, Syracuse University\nFor important bio logical functions such as wound healing\, embryonic development\, and canc er tumorogenesis\, cells must initially rearrange and move over relatively large distances\, like a liquid. Subsequently\, these same tissues must u ndergo buckling and support shear stresses\, like a solid. Our work sugges ts that biological tissues can accommodate these disparate requirements be cause the tissues are close to glass or jamming transition. While recent s elf propelled particle models generically predict a glass/jamming transiti on that is driven by packing density φ and happens at some critical φc & lt\; 1\, many confluent biological tissues appear to undergo a jamming tra nsition at a constant density (φ = 1). I will discuss a new theoretical f ramework for predicting energy barriers and rates of cell migration in 2D tissue monolayers\, and show that this model predicts a novel type of rigi dity transition\, which takes place at constant φ = 1 and depends only on single cell properties such as cell-cell adhesion\, cortical tension and cell elasticity. I will discuss the implications of these ideas for unders tanding cancer tumor boundaries and metastasis and pattern formation durin g development. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-304@lptms.universite-paris-saclay.fr DTSTART:20141120T113000Z DTEND:20141120T121500Z DTSTAMP:20141023T073536Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-silv io-franz-et-raoul-santachiara/ SUMMARY:Journal Club : Silvio Franz et Raoul Santachiara - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Nov 14 11:30 DESCRIPTION:Solving the 3D Ising Model with the Conformal Bootstrap\nSilvio Franz\, Raoul Santachiara\narXiv:1203.6064\nSheer El-Showk\, Miguel F. Pa ulos\, David Poland\, Slava Rychkov\, David Simmons-Duffin\, Alessandro Vi chi LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-313@lptms.universite-paris-saclay.fr DTSTART:20141120T150000Z DTEND:20141120T160000Z DTSTAMP:20141117T124239Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-jesper-levinsen/ SUMMARY:Séminaire exceptionnel : Jesper Levinsen - LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay - 20 Nov 14 15:00 DESCRIPTION:Strong-coupling ansatz for the one-dimensional Fermi gas in a h armonic potential\nJesper Levinsen (Aarhus Institute of Advanced Studies\, Aarhus University)\nThe one-dimensional (1D) Fermi gas with repulsive sho rt-range interactions provides an important model of strong correlations a nd is often amenable to exact methods. However\, in the presence of confin ement\, no exact solution is known for an arbitrary number of strongly int eracting fermions. Here\, we propose a novel ansatz for generating the low est-energy wavefunctions of the repulsive 1D Fermi gas in a harmonic poten tial near the Tonks-Girardeau limit of infinite interactions. We specializ e to the case of a single $\\down$ particle interacting with $N_\\up$ part icles\, where we may derive analytic forms of the approximate wavefunction s. Comparing with exact numerics\, we show that the overlap between the wa vefunctions from our ansatz and the exact ones in the ground-state manifol d exceeds $0.9997$ for $N_\\up\\leq8$. Moreover\, the overlap for the grou nd-state wavefunction at strong repulsion extrapolates to $\\sim0.9999$ as $N_\\up\\to\\infty$. Thus\, our ansatz is essentially indistinguishable f rom numerically exact results in both the few- and many-body limits.\n\nRe ference: J. Levinsen\, P. Massignan\, G. M. Bruun\, and M. M. Parish\, arx iv:1408.7096 LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-301@lptms.universite-paris-saclay.fr DTSTART:20141125T110000Z DTEND:20141125T120000Z DTSTAMP:20141119T090627Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mikhail-tamm/ SUMMARY:Séminaire du LPTMS: Mikhail Tamm - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 25 Nov 14 11:00 DESCRIPTION:Genome packing and fractal globules: some new developments\nMik hail Tamm (Physics department\, Moscow State University)\nThe idea that ge nome packing in a cell nucleus is to a large extent governed by topologica l constraints has been around for many years: the corresponding topologica lly controlled state\, known as a fractal globule\, was first predicted in the late 1980s. Recently with the development of the new experimental tec hniques\, especially the so-called Hi-C contact maps\, a lot of new eviden ce appeared concerning the statistics of the genome spatial structure. Thi s new data seems to support the fractal globule model\, and therefore it c aused a significant renewed interest in the physics of the fractal globule state in the recent years. In my talk\, I will overview the ideas behind the fractal globule model and the current state of art in the theory of ge nome packing. After that\, I will discuss two more narrow questions we hav e been trying to develop recently. In particular\, first\, I will talk abo ut the fine structure of the Hi-C contact maps and possible ways to explai n it by combining the hierarchical folding intrinsic to the fractal globul e idea and the assumption about quenched block-copolymer structure of the genome. Second\, I will discuss the dynamic of self-diffusion in the fract al globule and develop a scaling theory predicting it to be a subdiffusion with a scaling index 0.4. I will also discuss the implications of this re sult for the search processes in the fractal globule. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-314@lptms.universite-paris-saclay.fr DTSTART:20141127T143000Z DTEND:20141127T153000Z DTSTAMP:20141118T130358Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-v-kravtsov/ SUMMARY:Séminaire exceptionnel du LPTMS: Vladimir Kravtsov - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Nov 14 14:30 DESCRIPTION:Multifractality of random eigenfunctions and generalization of Jarzynski equality\nV. E. Kravtsov\, Abdus Salam ICTP\, Trieste\nSystems d riven out of equilibrium experience large fluctuations of the dissipated w ork. The same is true for wave function amplitudes in disordered systems c lose to the Anderson localization transition. In both cases the probabilit y distribution function (PDF) is given by the large deviation ansatz. We e xploit the analogy between the PDF of work dissipated in a driven single-e lectron box (SEB) and that of random multifractal wave function amplitudes and uncover new relations which generalize the Jarzynski equality. We che cked the new relations experimentally by measuring the dissipated work in a driven SEB and found a remarkable correspondence. The results represent an important universal feature of the work statistics in systems out of eq uilibrium and help to understand the nature of the symmetry of multifracta l exponents in the theory of Anderson localization. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-312@lptms.universite-paris-saclay.fr DTSTART:20141128T113000Z DTEND:20141128T123000Z DTSTAMP:20141124T065724Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-clel ia-de-mulatier-2/ SUMMARY:Journal-club : Haggai Landa - LPTMS\, salle 201\, 2ème étage\, B ât 100\, Campus d'Orsay - 28 Nov 14 11:30 DESCRIPTION:Nanofriction in cold ion traps\, A. Benassi\, A. Vanossi\, E. T osatti\, Nature Communications 2\, 236 (2011)\nHaggai Landa\nSliding frict ion between crystal lattices and the physics of cold ion traps are so far non-overlapping fields. Two sliding lattices may either stick and show sta tic friction or slip with dynamic friction\; cold ions are known to form s tatic chains\, helices or clusters\, depending on the trapping conditions. Here we show\, based on simulations\, that much could be learnt about fri ction by sliding\, through\, for example\, an electric field\, the trapped ion chains over a corrugated potential. Unlike infinite chains\, in which the theoretically predicted Aubry transition to free sliding may take pla ce\, trapped chains are always pinned. Yet\, a properly defined static fri ction still vanishes Aubry-like at a symmetric–asymmetric structural tra nsition\, found for decreasing corrugation in both straight and zig-zag tr apped chains. Dynamic friction is also accessible in ringdown oscillations of the ion trap. Long theorized static and dynamic one-dimensional fricti on phenomena could thus become accessible in future cold ion tribology. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-305@lptms.universite-paris-saclay.fr DTSTART:20141201T110000Z DTEND:20141201T120000Z DTSTAMP:20141201T094021Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-nikta-fakhri/ SUMMARY:Physics-Biology interface seminar: Nikta Fakhri - Moyen Amphi\, Bui lding 510\, Université Paris-Saclay Orsay - 1 Déc 14 11:00 DESCRIPTION:Hitching a ride at the nanometer scale: transport in passive an d active complex media\nNikta Fakhri (Georg-August-Universität Göttingen )\nTransport in crowded and complex media is a ubiquitous phenomenon in na ture\, which poses fundamental questions in statistical and soft matter ph ysics. In particular\, transport in the bustling interior of living cells is fascinating and far from understood. On a molecular scale\, transport c an be diffusive or driven\, either externally or by local force generators . In this talk\, I will introduce single-walled carbon nanotubes (SWNTs) a s highly versatile multi-scale probes to investigate different modes of tr ansport in media of increasing complexity: from the confined dynamics of s emiflexible polymers in crowded environments to random stirring generated by non-equilibrium dynamics of the cell cytoskeleton. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-290@lptms.universite-paris-saclay.fr DTSTART:20141202T110000Z DTEND:20141202T120000Z DTSTAMP:20141201T094042Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marcello-porta/ SUMMARY:Séminaire du LPTMS: Marcello Porta - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 2 Déc 14 11:00 DESCRIPTION:Mean-Field Evolution of Fermionic Systems\n\nMarcello Porta\, U niversité de Zurich\nIn this talk I will discuss the dynamics of interact ing fermionic systems in the mean-field regime. Compared to the bosonic ca se\, fermionic mean-field scaling is naturally coupled with a semiclassica l scaling\, making the analysis more involved. From a physical point of v iew\, as the number of particles grows one expects the quantum evolution of the system to be effectively described by Hartree-Fock theory. The nex t degree of approximation is provided by a classical effective dynamics\, corresponding to the Vlasov equation.\nI will consider initial data which are close to quasi-free states\, both at zero and at positive temperature\ , with an appropriate semiclassical structure. Under some regularity ass umptions on the interaction potential I will show that the time evolution of such initial data stays close to a quasi-free state\, with reduced on e-particle density matrix given by the solution of the time-dependent Har tree-Fock equation. The result holds for all (semiclassical) times\, and gives effective bounds on the rate of convergence towards the Hartree-Fock dynamics as the number of particles goes to infinity. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-315@lptms.universite-paris-saclay.fr DTSTART:20141208T143000Z DTEND:20141208T160000Z DTSTAMP:20141126T082229Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-christian-van-den-broeck/ SUMMARY:Tri-séminaire de Physique statistique : Christian Van den Broeck - IPhT\, CEA-Saclay\, salle Itzykson - 8 Déc 14 14:30 DESCRIPTION:The unlikely Carnot efficiency\nChristian Van den Broeck\, Univ ersité Hasselt\, Belgique\n\nThe efficiency of a heat engine is tradition ally defined as the ratio of its average output work over its average inpu t heat. Its highest possible value was discovered by Carnot in 1824 and is a cornerstone concept in thermodynamics. It led to the discovery of the s econd law and to the definition of the Kelvin temperature scale. Small-sca le engines operate in the presence of highly fluctuating input and output energy fluxes. They are therefore much better characterized by fluctuating efficiencies. In this study\, using the fluctuation theorem\, we identify universal features of efficiency fluctuations. While the standard thermod ynamic efficiency is\, as expected\, the most likely value\, we find that the Carnot efficiency is\, surprisingly\, the least likely in the long tim e limit in the case of a symmetric driving protocol. More generally\, the long-time probability for observing a reversible efficiency in a given eng ine is identical to that for the same engine working under the time-revers ed driving. Furthermore\, the probability distribution for the efficiency assumes a universal scaling form when operating close-to-equilibrium. We i llustrate our results analytically and numerically on several model system s\, including the work-to-work conversion via a Brownian particle\, effusi on as a thermal engine\, and an asymmetrically driven quantum dot. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-308@lptms.universite-paris-saclay.fr DTSTART:20141209T110000Z DTEND:20141209T120000Z DTSTAMP:20141201T093939Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mario-collura/ SUMMARY:Séminaire du LPTMS: Mario Collura - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 9 Déc 14 11:00 DESCRIPTION:Interaction quenches in 1D Bose gas\nMario Collura\, SISSA Trie ste\nWe study the non-equilibrium quench dynamics from free to hard-core o ne-dimensional bosons\, in which the relation between modes is nonlinear\, and consequently Wick’s theorem does not hold. We provide exact analyti cal results for the time evolution of the dynamical density-density correl ation function. We prove that its stationary value is described by a Gener alized Gibbs Ensemble (GGE). We analyze the entanglement properties of the the asymptotic steady state after the quench providing exact analytical r esults for both the leading extensive parts and the subleading terms for t he entropies as well as for the cumulants of the particle number fluctuati ons. Finally\, we extended the quench protocol in the presence of a hard-w all confining potential. We characterize the density profile and the two-p oint fermionic correlation function in the stationary state as well as the ir full time evolution. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-316@lptms.universite-paris-saclay.fr DTSTART:20141212T140000Z DTEND:20141212T150000Z DTSTAMP:20141128T141119Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-pier re-ronceray-2/ SUMMARY:Journal-Club : Pierre Ronceray - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Déc 14 14:00 DESCRIPTION:Efficient\, Multiple-Range Random Walk Algorithm to Calculate t he Density of States\nPhys. Rev. Lett. *86*\, 2050 - Published 5 March 200 1\nFugao Wang and D. P. Landau\nWe present a new Monte Carlo algorithm tha t produces results of high  accuracy with reduced simulational effort. In dependent random walks are performed (concurrently or serially) in differe nt\, restricted ranges of   energy\, and the resultant density of states is modified continuously to produce locally flat histograms. This method p ermits us to directly access the free energy and entropy\, is independent of temperature\, and is  efficient for the study of both 1st order and 2n d order phase transitions.  It should also be useful for the study of com plex systems with a rough energy landscape. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-296@lptms.universite-paris-saclay.fr DTSTART:20141215T110000Z DTEND:20141215T120000Z DTSTAMP:20141208T094731Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-gilles-charvin/ SUMMARY:Physics-Biology interface seminar: Gilles Charvin - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 15 Déc 14 11:00 DESCRIPTION:Single cell analysis of entry into replicative senescence in bu dding yeast\nGilles Charvin (IGBMC Strasbourg)\nBudding yeast cells have a n asymmetrical division pattern. Each mother cell produces a limited numbe r of smaller daughter cells before entering senescence and eventually dyin g. The detailed mechanisms that govern entry into senescence in mothers an d daughter cell rejuvenation are still poorly understood. In this context\ , we have developed a microfluidic system that lets one monitor the succes sive divisions of single yeast cells in real-time under the microscope. Us ing this device\, we have revisited classical paradigms associated with th e age-dependent control of cell proliferation in this unicellular organism . Our results indicate that cells undergo a sharp transition to senescence \, which is not related to the the loss of mitochondrial membrane potentia l\, as previously proposed. Other applications of our methodology to the s tudy of senescence induced by telomeres attrition and in other cellular bi ology contexts will be presented during the talk. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-293@lptms.universite-paris-saclay.fr DTSTART:20141216T110000Z DTEND:20141216T120000Z DTSTAMP:20141209T145014Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-oleg-lisovyy/ SUMMARY:Seminaire du LPTMS: Oleg Lisovyy - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 16 Déc 14 11:00 DESCRIPTION:Isomonodromic tau functions from Liouville conformal blocks\nOl eg Lisovyy\, LMPT Université de Tours\nI will show that the Riemann-Hilbe rt problem to find multivalued analytic functions with SL(2\,C)-valued mon odromy on n-punctured Riemann sphere can be solved by taking suitable line ar combinations of the conformal blocks of Liouville theory at c=1. This i mplies a similar representation for the isomonodromic tau function. In the case n=4 we will thereby express the general solution of Painlevé VI equ ation in terms of 4-point conformal blocks. Time permitting\, I will discu ss how the c=1 fusion kernel can be calculated explicitly using this Painl evé/CFT relation. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-302@lptms.universite-paris-saclay.fr DTSTART:20150106T110000Z DTEND:20150106T120000Z DTSTAMP:20141217T111911Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-florian-angeletti/ SUMMARY:Séminaire du LPTMS: Florian Angeletti - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Jan 15 11:00 DESCRIPTION:Matrix-correlated random variables: a dialogue between statisti cal\nphysics and signal processing\nFlorian Angeletti\, National Institute for Theoretical Physics\, Stellenbosch\nFinding statistical descriptions of non-equilibrium stationary state is often an arduous task. For specific systems\, like ASEP or 1D diffusion-reaction systems\, stationary solutio ns have been characterized using matrix product representations. These rep resentations generalize the product structure of independent random variab le to matrices\; the non-commutativity of matrices generates correlation w hile preserving many of the algebraic properties of expectation. Depending on the matrix structure\, the correlation can vary from short-range to lo ng-range correlation. Moreover\, from a signal processing perspective\, th ese matrix-correlated random variables can be recast as specific Hidden Ma rkov Models. In this talk\, we propose to investigate the general statisti cal properties of this mathematical framework\, with the long-term hope to improve our understanding of related physical systems.\nIn particular\, w e shall focus on the statistical properties of sums of such random variabl es. Do we have a large deviation principle for this sum? Can we find analo gous of the law of large number or the central limit theorem? LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-320@lptms.universite-paris-saclay.fr DTSTART:20150108T143000Z DTEND:20150108T160000Z DTSTAMP:20141215T125033Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-pascal-viot/ SUMMARY:Tri-séminaire de Physique statistique : Pascal Viot - LPTMS\, sall e 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 8 Jan 15 14:30 DESCRIPTION: Stochastic flow models\nPascal Viot (LPTMC\, UPMC)\nFiltratio n\, and flow in micro/nano-channels and traffic flow are examples of proce sses subject to blocking when the channel conveying the particles becomes too crowded. We investigate a concurrent flow model where particles enter a channel randomly. If at any time two particles are simultaneously presen t in the channel\, failure occurs. We obtain the exact solution for the su rvival probability\, the distribution of the number of particles that pass before failure\, and the instantaneous flux exiting the channel. Several generalizations of this simple model are also studied. We also consider  a counterflow model with two opposing Poisson streams. There is no restric tion on the number of particles passing in the same direction\, but blocka ge occurs if\, at any time\, two opposing particles are simultaneously pre sent in the passage. All relevant quantities have been obtained exactly.\n [1] Non-Markovian Models of Blocking in Concurrent and Countercurrent Flow s\, A. Gabrielli\, J. Talbot and P. Viot Phys. Rev. Lett\,  110\, 170601 (2013)\n[2] Stochastic model of single-file flow with reversible blockage\ , Chloé Barré\, Julian Talbot and Pascal Viot EPL\, 104 60005 (2013)\n[3 ] Irreversible Blocking in Single-File Concurrent and Countercurrent Parti culate Flows\, J. Talbot\, A. Gabrielli  and P. Viot J Stat Mech  to be published (2015) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-345@lptms.universite-paris-saclay.fr DTSTART:20150112T004500Z DTEND:20150112T004500Z DTSTAMP:20150304T121330Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/test-2/ SUMMARY:test - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Jan 15 00:45 DESCRIPTION: CATEGORIES:physbio LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-294@lptms.universite-paris-saclay.fr DTSTART:20150112T110000Z DTEND:20150112T120000Z DTSTAMP:20150105T152904Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-thomas-gibaud/ SUMMARY:Physics-Biology interface seminar: Thomas Gibaud - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 12 Jan 15 11:00 DESCRIPTION:Shape controlled filaments suspensions – rheology and dynamic s\nThomas Gibaud (ENS Lyon)\nThe mechanical behavior of a suspension of ri gid and semiflexible filaments has been studied in great detail. In compar ison the effect of the filament geometry has been relatively unexplored. H ere\, we hijack flagellar filaments from their original purpose in order t o develop a versatile model rod-like bio-colloid whose shape and length ca n be tuned. We present experimental results on the rheological behavior of suspensions of (1) straight\, (2) curly and (3) semi-straight/semi-curly flagella with an identical average contour length. We find that (1) and (2 ) show an elastic behavior at intermediate time but that (3) remains elast ic and does not flow at long times. Using fluorescence microscopy\, we tra ck individual filament and find that this elastic plateau is related to a cage in which the filament is trapped for a certain among of time. Taken together\, this highlights the role of filament geometry in suspension mec hanics. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-323@lptms.universite-paris-saclay.fr DTSTART:20150114T143000Z DTEND:20150114T153000Z DTSTAMP:20150106T133106Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-saffas-zafeiropoulos/ SUMMARY:Séminaire du LPTMS: Savvas Zafeiropoulos - LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay - 14 Jan 15 14:30 DESCRIPTION:Chiral Random Matrix Theories for Wilson Fermions\nSavvas Zafei ropoulos\, Institut für Theoretische Physik - Goethe-Universität Frankfu rt\n\nWe introduce Random Matrix Models for the Wilson-Dirac operator of Q uantum Chromodynamics (QCD) and QCD-like theories. We show that they are e quivalent to the epsilon-limit of the chiral Lagrangian for Wilson chiral perturbation theory (WchPT)\, which is the low energy effective theory des cribing lattice QCD with Wilson fermions. Results are obtained for the Her mitian Dirac operator of two-color QCD with quarks in the fundamental repr esentation of the color group as well as the non-Hermitian Dirac operator of SU(3) QCD. For the latter case we propose a novel way for the derivatio n of the Low Energy constants of WchPT. Comparisons of our analytical resu lts with direct numerical simulations of random matrices are shown. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-318@lptms.universite-paris-saclay.fr DTSTART:20150119T140000Z DTEND:20150119T173000Z DTSTAMP:20141210T130414Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/phds-days/ SUMMARY:PhDs' days - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d 'Orsay - 19 Jan 15 14:00 DESCRIPTION: LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-324@lptms.universite-paris-saclay.fr DTSTART:20150120T110000Z DTEND:20150120T120000Z DTSTAMP:20150113T090842Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-davide-porcello/ SUMMARY:Séminaire du LPTMS: Davide Forcella - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 20 Jan 15 11:00 DESCRIPTION:Electromagnetic properties of viscous charged fluids\nDavide Fo rcella (Université Libre de Bruxelles)\nRecently the gauge/gravity corres pondence has provided new interesting applications to high energy strongly coupled plasmas and strongly correlated condensed matter systems. At the same time\, in an apparently unrelated field\, there have been enormous pr ogresses in the ability to engineer electromagnetic devices with exotic pr operties: such as negative refraction (energy and phase velocity for the e lectromagnetic field in the medium are in opposite directions)\, cloaking\ , photonics black-holes\, etc.\nIn the talk\, building on these two recent developments\, I will discuss the electromagnetic properties of viscous c harged fluids\, consisting for example of electrons in certain solids or h igh energy physics plasmas. In particular I will show that finite viscosit y leads to multiple modes of evanescent electromagnetic waves at a given f requency\, one of which is characterised by a negative index of refraction .\nI will then underline the concept of electron viscosity in actual elect ron systems (rarely discussed in literature and not measured in experiment s yet) in condensed matter and its consequences on the electromagnetic res ponse. In particular I will discuss how optical spectroscopy can be used t o probe the electron viscosity. Indeed finite viscosity has the effect to decrease the reflectivity of a metallic surface\, and support the occurren ce\, in a half-infinite sample\, of oscillations of the electromagnetic fi eld intensity as a function of distance from the interface.\nI will conclu de with some comments on future perspectives and applications. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-319@lptms.universite-paris-saclay.fr DTSTART:20150120T140000Z DTEND:20150120T173000Z DTSTAMP:20141210T130437Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/phds-days-2/ SUMMARY:PhDs' days - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d 'Orsay - 20 Jan 15 14:00 DESCRIPTION: LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-328@lptms.universite-paris-saclay.fr DTSTART:20150121T143000Z DTEND:20150121T160000Z DTSTAMP:20150115T104710Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-grigory-astrakharchik/ SUMMARY:Séminaire du LPTMS : Grigory Astrakharchik - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 21 Jan 15 14:30 DESCRIPTION:Lieb's soliton-like excitations in harmonic traps\nGrigory Astr akharchik (Universitat Politècnica de Catalunya\, Barcelona)\nWe study th e solitonic Lieb II branch of excitations the in one-dimensional Bose gas in homogeneous and trapped geometry. Using Bethe-ansatz Lieb's equations w e calculate the "effective number of atoms'' and the "effective mass'' of the excitation. The equations of motion of the excitation are defined by t he ratio of these quantities. The frequency of oscillations of the excitat ion in a harmonic trap is calculated. It changes continuously from its "so liton-like'' value $\\omega_h/\\sqrt{2}$ in the high density mean field re gime to $\\omega_h$ in the low density Tonks-Girardeau regime with $\\omeg a_h$ the frequency of the harmonic trapping. Particular attention is paid to the effective mass of a soliton with velocity near the speed of sound.\ nG. E. Astrakharchik and L. P. Pitaevskii Lieb’s soliton-like excitation s in harmonic traps EPL\, 102\, 30004 (2013) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-311@lptms.universite-paris-saclay.fr DTSTART:20150126T110000Z DTEND:20150126T120000Z DTSTAMP:20150113T160908Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-olivier-rivoire/ SUMMARY:Physics-Biology interface seminar: Olivier Rivoire - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 26 Jan 15 11:00 DESCRIPTION:How history shapes geometry in a model of protein evolution\nOl ivier Rivoire (Laboratoire interdisciplinaire de Physique\, UJF Grenoble)\ n\nThe interactions between amino acids in a protein are heterogeneous but not arbitrary: they enable proteins to perform specific biochemical "func tions". Understanding these interactions may require\, however\, looking b eyond current functional requirements\, to the evolutionary history of pro teins. I will illustrate this point with a simple statistical mechanics mo del\, which I will motivate with observations and experiments on natural p roteins. The model relates the parameters controlling the evolution of a p rotein to the organization of the interactions inside its structure. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-325@lptms.universite-paris-saclay.fr DTSTART:20150127T110000Z DTEND:20150127T120000Z DTSTAMP:20150107T120618Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jonas-ranft/ SUMMARY:Séminaire du LPTMS: Jonas Ranft - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 27 Jan 15 11:00 DESCRIPTION:Dynamics of synaptic domains: scaffold-protein aggregation at t he postsynaptic membrane\nJonas Ranft\, Laboratoire de Physique Statistiqu e de l'ENS\nThe dynamic nature of synaptic receptor populations poses the question of how the number of receptors can be reliably controlled in spit e of their continuous dynamic reorganization. Increasing evidence points t o the stabilizing role of submembranous scaffold clusters that are formed by oligomerization of specific proteins. However\, it is not clear in turn how these scaffold clusters form\, what controls their sizes and what is their lifetime as compared to the protein turnover they are themselves sub ject to. Here\, we investigate the dynamics of synaptic domains by studyin g a simplified model of the scaffold dynamics at the postsynaptic neuronal membrane. We find by using particle-based simulations\, as well as analyt ic calculations\, that for all parameter regimes\, the system eventually r eaches a non-equilbrium stationary state with a characteristic distributio n of cluster sizes. The typical cluster size scales with the turnover rate and depends on how the diffusive mobility of clusters varies with their s izes. Lateral desorption of scaffold molecules can give rise to a critical size below which clusters dissolve\, thus favoring a bimodal distribution of synapse sizes. The results provide a basis for the stability of cluste rs in the face of molecular noise\, which is a necessary requirement for l ong-term memory and learning. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-321@lptms.universite-paris-saclay.fr DTSTART:20150203T110000Z DTEND:20150203T120000Z DTSTAMP:20141216T161955Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandre-lazarescu/ SUMMARY:Séminaire du LPTMS: Alexandre Lazarescu - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 3 Fév 15 11:00 DESCRIPTION:Fluctuations of the current and optimal profiles in the open As ymmetric Simple Exclusion Process\nAlexandre Lazarescu\, Institute for The oretical Physics\, KU Leuven\nThe asymmetric simple exclusion process (ASE P)\, where particles perform biased random walks with hard core repulsion\ , is one of the most studied model in non-equilibrium statistical physics. It has the mathematical property of being integrable\, which makes it a g ood candidate for in-depth exact calculations. The quantity of particular interest there is the current of particles that flows through the system d ue to the bias of the jumps.\nIn this presentation\, we will see how we ca n obtain information about the distribution of that current\, through vari ous techniques: integrability\, macroscopic fluctuation theory\, and asymp totic direct diagonalisation. This allows us to build the phase diagram fo r the large deviations of the current\, and examine the corresponding dens ity profiles in each of its five phases. We show that two situations arise : in most phases\, the system can be described hydrodynamically\, but in o ne phase\, where the current is larger than the limit set by hydrodynamics \, the system becomes highly correlated. If time allows it\, we will also see how these techniques and results could be generalised to some other ob servables or models. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-330@lptms.universite-paris-saclay.fr DTSTART:20150206T140000Z DTEND:20150206T150000Z DTSTAMP:20150203T083051Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms/ SUMMARY:Séminaire exceptionnel du LPTMS - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 6 Fév 15 14:00 DESCRIPTION:The Self-Journal of Science : an ethical and realistic alternat ive for scientific publishing\n\nMichaël Bon\, CEA Saclay\n\nToday\, the publication industry hurts Science : extremely high costs\, unreliable pee r review\, Science output decided by self-righteous scientific authorities \, addiction to impact factor\, chaotic management of the ever-increasing number of papers... Unscientific stakes have a much too big importance in the evolution of Science and outsiders\, i.e. younger generations of scien tists\, are the one who suffer mostly from this situation.\n\nI will defen d the idea that all these flaws root in the pyramidal organization of scie ntific edition. I will present a solution which allows theoretically and o verall practically to set the system right. It comes in the form a reposit ory (like arXiv) equipped with novel ideas and tools allowing an horizonta l self-management of Science by the whole scientific community\, to make a n optimal peer review as well as an objective and unfalsifiable evaluation of articles. Its social logic makes it always self-regulated towards scie ntific quality. This new platform\, "The Self-Journal of Science" is readi ly available and just has to be used\, as it is free and as its particular nature makes it viral.\n\nI therefore welcome all scientist concerned wit h the global quality and credibility of Science to attend this lecture.\n\ n\nLe site du journal : http://sjscience.org/ LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-306@lptms.universite-paris-saclay.fr DTSTART:20150209T110000Z DTEND:20150209T120000Z DTSTAMP:20150203T065957Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-andrew-callan-jones/ SUMMARY:Physics-Biology interface seminar: Andrew Callan-Jones - Moyen Amph i\, Building 510\, Université Paris-Saclay Orsay - 9 Fév 15 11:00 DESCRIPTION:The Cytoskeleton as an Active Gel: Modelling Cell Polarization\ , Shape Change\, and Migration\nAndrew Callan-Jones (Université Paris-Did erot)\nCell polarization and shape change are required for large-scale mov ements during embryo development and cancer metastasis. I will present rec ent work to understand these phenomena by studying two model systems: zebr afish embryos during gastrulation and confined HeLa cells. In both cases\, individual cells are observed to undergo a novel type of polarization and transformation to a motile state that is crucially dependent on elevated levels of contractility in the actomyosin cortex. Polarization of zebrafis h cells in vitro can be triggered by stimulating myosin activity: initiall y quasi-spherical\, immobile cells switch to a polarized state characteriz ed by a high cortical density at the cell rear\, persistent cortical actin flows\, and a distinctive pear-like morphology. Compressing HeLa cells be tween two plates results in a transition from a well-spread\, mesenchymal- type migration mode to a rounded-up one sustained by cortical flow\, and d isplaying an actin rich uropod at the rear\, reminiscent of zebrafish.\n\n We have modeled these cell mechanical responses using active gel theory\, a continuum-level description of out-of-equilibrium behavior of the cytosk eleton. In this talk\, I will first provide a summary of this theory\, and will then show how it accounts for the principal features of contractilit y-based polarization: cortical flow and density changes\, cell shape chang e\, and migration. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-329@lptms.universite-paris-saclay.fr DTSTART:20150209T143000Z DTEND:20150209T160000Z DTSTAMP:20150122T100147Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-camille-aron/ SUMMARY:Tri-séminaire de Physique Statistique : Camille Aron - IPhT\, CEA- Saclay\, salle Itzykson - 9 Fév 15 14:30 DESCRIPTION:Driven-dissipative phyics: the relaxing virtues of a bath\nCami lle Aron (Princeton University)\nDespite being ubiquitous from nano to mac roscale\, far-from-equilibrium physics remains largely an uncharted territ ory in which the standard toolbox of equilibrium statistical mechanics is a priori unavailable. Besides its fundamental relevance\, nonequilibrium p hysics can also be viewed as a resource to achieve a new type of control o ver matter. In this talk\, I will review recent developments in our unders tanding of driven-dissipative physics and illustrate how "bath engineering " offers a promising route to realize exotic many-body states in a nonequi librium fashion\, such as large-scale long-lived quantum entanglement or h igh-temperature superconductivity. LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-322@lptms.universite-paris-saclay.fr DTSTART:20150210T110000Z DTEND:20150210T120000Z DTSTAMP:20150126T091930Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-stanislao-gualdi/ SUMMARY:Séminaire du LPTMS: Stanislao Gualdi - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Fév 15 11:00 DESCRIPTION:Tipping points and monetary policy in a stylized macroeconomic agent-based model\nStanislao Gualdi\, Centrale Supélec\nTraditional appro aches in economics rely on the assumption that economic agents are identic al\, non-interacting and rational. Within this framework\, economic instab ilities would require large exogenous shocks\, when in fact small local sh ocks can trigger large systemic effects when heterogeneities and interacti ons are taken into account. The need to include these effects motivate the development of agent-based models (ABMs)\, which are extremely versatile and allow to take into account more realistic behavioural rules. In this t alk we introduce a simple ABM\, explore the possible types of phenomena th at it can reproduce and propose a methodology that characterizes a model t hrough its phase diagram. We then generalize the model with the aim of inv estigating the role and efficacy of the monetary policy of a central bank. We show that the existence of different equilibrium states of the economy can cause the monetary policy itself to trigger instabilities and be coun ter-productive.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-333@lptms.universite-paris-saclay.fr DTSTART:20150224T110000Z DTEND:20150224T120000Z DTSTAMP:20150216T152506Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrii-gudyma/ SUMMARY:Séminaire du LPTMS: Andrii Gudyma - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 24 Fév 15 11:00 DESCRIPTION:Breathing modes of one-dimensional trapped BEC\nAndrii Gudyma ( LPTMS)\nWe calculate the breathing mode frequency in a one-dimensional Bos e gas confined to a harmonic trap. We predict a smooth crossover from Thom as–Fermi Bose–Einstein condensate (BEC) regime to Gaussian BEC regime using Hartree approximation and sum rules approach\, adopted to small syst em sizes. Local density approximation (LDA) correctly captures the crossov er from Tonks-Girardeau to Thomas-Fermi BEC regimes. Hartree and LDA predi ctions can be continuously matched for N >\; 25 particles\, providing a complete zero-temperature description for large number of particles and re sulting in a non-monotonic reentrant behavior of the breathing frequency. For smaller number of particles (ranging from N = 2 to N = 25) we perform extensive diffusion Monte Carlo simulations. This permits us to obtain a c omplete picture\, applicable to arbitrary number of particles and any repu lsive interaction strength. We provide perturbative analysis for both weak and strong coupling regimes. We revisit Innsbrick group experiment [Scien ce 325\, 1224 (2009)]\, analyzing the measurements done in Thomas–Fermi Gaussian BEC crossover\, and demonstrate that the breathing frequency foll ows a reentrant behavior as a function of the interaction strength in full agreement with our theory.\n\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-327@lptms.universite-paris-saclay.fr DTSTART:20150303T110000Z DTEND:20150303T120000Z DTSTAMP:20150211T150020Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-iacopo-mastromatteo/ SUMMARY:Séminaire du LPTMS: Iacopo Mastromatteo - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 3 Mar 15 11:00 DESCRIPTION:Latent liquidity models: an universal mechanism for the anomalo us response of financial markets\nIacopo Mastromatteo\, CMAP Ecole polytec hnique\nFinancial markets are remarkable information-processing systems: e ven though they are driven out-of-equilibrium by long-range correlated for ces\, they can swiftly remove predictability from their drive and output a diffusive price signal. As empirical results seem to indicate\, this is d ue to anomalous response properties which are to a large extent universal. Yet\, the details about the onset of such a peculiar response have not ye t been modeled in a fully consistent way. I will first present a general f ramework in which such universality is justified on the basis of general p rinciples (dimensionality and existence of a price). I will then character ize the response of market to trades (price impact) in a specific reaction -diffusion model which can account for several stylized facts characterizi ng the microstructure of financial markets. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-340@lptms.universite-paris-saclay.fr DTSTART:20150305T143000Z DTEND:20150305T153000Z DTSTAMP:20150223T115115Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-vincent-hakim/ SUMMARY:Tri-séminaire de Physique Statistique: Vincent Hakim - LPTMS\, sal le 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 5 Mar 15 14:30 DESCRIPTION:Collective cell motion and statistical mechanics : global modes and fluctuations in confined cell assemblies.\nVincent Hakim (Laboratoire de Physique Statistique\, ENS\, Paris)\nIn different biological processes \, cells move in a coordinated way. Several experiments have quantitativel y investigated this phenomenon. I will describe experimental results obtai ned by the team of P Silberzan (Institut Curie\, Paris) as well as a simpl e model of interacting persistent random walkers that we have developed to phenomenologically describe collective cell motion. The model helps to ex plain the observed dynamics of a confined cell assembly which displays sto chastic reversals of global rotational motion and pulsatile collective mod es. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-326@lptms.universite-paris-saclay.fr DTSTART:20150310T110000Z DTEND:20150310T120000Z DTSTAMP:20150127T081639Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cesare-nardini/ SUMMARY:Séminaire du LPTMS: Cesare Nardini - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 10 Mar 15 11:00 DESCRIPTION:Non-Equilibrium long-range interacting systems : kinetic theory and large deviations\nCesare Nardini\, Edinburgh University\nLong-range i nteracting systems include gravitational systems\, plasma in the low densi ty limit\, two-dimensional and geophysical fluid models. In many physical contexts\, long-range interacting systems are found to be out of equilibri um because of external driving. Examples come from climate dynamics\, plas ma physics and\, recently\, experimental setups with cold atoms driven by laser light. Geophysical flows\, for example\, are characterised by their self-organisation into large-scale coherent structures such as jet-streams \, cyclones and anti-cyclones. The description of these structures\, of th eir evolution and of extreme events they undergo (such as the sudden switc h of the system between multiple attractors) are outstanding problems at t he interface between climate science and statistical mechanics. In order t o address the description of driven long-range interacting systems in a th eoretical way\, we concentrate in this talk on models as simple as possibl e that still retain the following two main characteristics: non-local (i.e . long-range) nature of the interactions and broken detailed balance (i.e. non-equilibrium dynamics). We present results both for particle systems a nd quasi two-dimensional flows\, and we show that their dynamics can be de scribed very accurately in the limit where there is a separation of time s cales between the evolution of the mean state and the evolution of the flu ctuations around it. The main theoretical tools developed are kinetic theo ry and large deviations techniques: the accuracy of the results obtained w ill be compared to direct numerical simulations. Ongoing work and perspect ives on a combination of kinetic theory and large deviations theory to des cribe multistability in a very performant way will also be described. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-343@lptms.universite-paris-saclay.fr DTSTART:20150317T110000Z DTEND:20150317T120000Z DTSTAMP:20150303T095919Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sergej-moroz/ SUMMARY:Séminaire du LPTMS: Sergej Moroz - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 17 Mar 15 11:00 DESCRIPTION:Few- and many-body quantum physics of p-wave interacting fermio ns in two dimensions\nSergej Moroz\, University of Colorado\, Boulder\nDue to the current search of Majorana fermions\, the quantum physics of two-d imensional identical fermions with short-range p-wave interactions is of i mmediate interest. In the first part of the seminar\, I will talk about th e effective theory of a chiral p+ip fermionic superfluid at zero temperatu re. This theory naturally incorporates the parity and time reversal violat ing effects such as the Hall viscosity and the edge current. In the second part\, I will concentrate on the few-body physics near a p-wave resonance and introduce the super Efimov effect- a new type of few-body universalit y manifesting itself by a tower of three-body bound states with a double-e xponential scaling. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-298@lptms.universite-paris-saclay.fr DTSTART:20150323T110000Z DTEND:20150323T120000Z DTSTAMP:20150325T212853Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-arezki-boudaoud/ SUMMARY:Physics-Biology interface seminar: Arezki Boudaoud - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 23 Mar 15 11:00 DESCRIPTION:Stochasticity and robustness in growth and morphogenesis\nArezk i Boudaoud (ENS Lyon)\nHow do organisms cope with natural variability to a chieve well-defined morphologies and architectures? We addressed this ques tion by combining experiments with live plants and analyses of stochastic models that integrate cell-cell communication and tissue mechanics. This l ed us to counterintuitive results on the role of noise in development\, wh ereby noise is either filtered or enhanced according to the level at which it is acting. CATEGORIES:seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-331@lptms.universite-paris-saclay.fr DTSTART:20150324T110000Z DTEND:20150324T120000Z DTSTAMP:20150316T125006Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-erik-sorensen/ SUMMARY:Séminaire du LPTMS: Erik Sorensen - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 24 Mar 15 11:00 DESCRIPTION:Dynamics at a Quantum Critical Point: Combining Quantum Monte C arlo and Holography\nErik Sorensen\, LPT Toulouse\nThe real time dynamics near quantum critical points have proven very\nchallenging to obtain both from a numerical and analytical perspective. Here we\nfocus on the superfl uid-insulator transition occurring for bosons on a lattice.\nNew large-sca le QMC results have made it possible to obtain very precise\nresults for m any quantities in particular the frequency dependent conductivity\nat imag inary frequencies.  Since the numerical results remain confined to\nimagi nary times/frequencies additional tools are needed to extend the results\n to the rest of the complex plane. Here\, recent insights from conformal fi eld\ntheory and holography have yielded a wealth of information that combi ned with\nthe QMC results yield quantitative and experimentally testable r esults for the\nfrequency-dependent conductivity near the quantum critical point. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-338@lptms.universite-paris-saclay.fr DTSTART:20150327T110000Z DTEND:20150327T121500Z DTSTAMP:20150317T143556Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-pierre-charles-upmc/ SUMMARY:Séminaire exceptionnel : Pierre Charles (UPMC) - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Mar 15 11:00 DESCRIPTION:Pensée antique et science contemporaine\nPierre Charles (UPMC) \nLa science contemporaine nous amène à reconsidérer certains textes an ciens. La mécanique quantique\, tout particulièrement\, utilise de nombr eux concepts que l’on retrouve dans les philosophies de Pythagore\, Hér aclite\, Platon\, Aristote et Carnéade. Les théories modernes du langage et de la signification\, la nature des nombres et des propositions logiqu es\, nous offrent l’opportunité d’une confrontation. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-347@lptms.universite-paris-saclay.fr DTSTART:20150331T110000Z DTEND:20150331T120000Z DTSTAMP:20150311T151216Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-vincent-michal/ SUMMARY:Séminaire du LPTMS: Vincent Michal - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 31 Mar 15 11:00 DESCRIPTION:Many-body physics of bosons in (quasi)disorder\nVincent Michal (LPTMS)\nAnderson's localization was introduced more than fifty years ago in the context of single-particle physics: the eigenstates of the Shrödin ger equation with a random potential may be localized in space leading to the absence of particle transport. It was realized quite recently that the localization idea is actually much more general and applies to a variety of situations. This program was put forward to solve the problem of electr on lifetime in a quantum dot and lead to the discovery of the many-body lo calization physics (Anderson localization in the many-body Fock space). In the solid state context this approach has proven to be very useful to tac kle the long-standing problem of the transport of interacting localized si ngle-particle states in the absence of phonons. This gave rise to the demo nstration of the energy threshold between the insulating and metallic regi mes [1]. The physics of interacting bosons [2] is also very interesting pa rticularly in connection with ongoing experiments on cold atomic gases. In this seminar I would like to show to you very recent results on the finit e-temperature fluid-insulator transition of bosons in one dimension (1D). On the one hand I will present the case of the quasiperiodic potential (su perposition of two incommensurate periodic potentials) and give prediction s regarding the transport phase diagram including the unexpected freezing with heating behaviour [3]. On the other hand I will talk about the transp ort of strongly-interacting 1D bosons in the random potential and I will s how the reentrance of the insulating state at strong interaction\, hence c ompleting the transport phase diagram of interacting disordered bosons at finite temperature [4].\n\nReferences:\n[1] D.M. Basko\, I.L. Aleiner\, an d B.L. Altshuler\, Metal–insulator transition in a weakly interacting ma ny-electron system with localized single-particle states\, Annals of Physi cs 321\, 1126 (2006). See references therein.\n[2] I. L. Aleiner\, B. L. A ltshuler\, and G. V. Shlyapnikov\, A finite-temperature phase transition f or disordered weakly interacting bosons in one dimension\, Nature Physics 6\, 900 (2010).\n[3] V.P. Michal\, B.L. Altshuler and G.V. Shlyapnikov\, D elocalization of Weakly Interacting Bosons in a 1D Quasiperiodic Potential \, Phys. Rev. Lett. 113\, 045304 (2014).\n[4] V.P. Michal\, I.L. Aleiner\, B.L. Altshuler\, G.V. Shlyapnikov\, Finite-Temperature Fluid-Insulator Tr ansition of Strongly Interacting 1D Disordered Bosons\, arXiv:1502.00282. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-344@lptms.universite-paris-saclay.fr DTSTART:20150407T150000Z DTEND:20150407T163000Z DTSTAMP:20150331T082800Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-tba-3/ SUMMARY:Soutenance d'HDR: Olivier Giraud - LPTMS-batiment 100\, salle des c onseils - 7 Avr 15 15:00 DESCRIPTION:Critical systems and quantum multifractality CATEGORIES:seminars LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-349@lptms.universite-paris-saclay.fr DTSTART:20150408T100000Z DTEND:20150408T111500Z DTSTAMP:20150326T103409Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-victor-yakovenko/ SUMMARY:Séminaire du LPTMS : Victor Yakovenko - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 8 Avr 15 10:00 DESCRIPTION:Economic inequality from statistical physics point of view\nVic tor Yakovenko (Department of Physics\, University of Maryland\, College Pa rk\, USA)\nSimilarly to the probability distribution of energy in physics\ , the probability distribution of money among the agents in a closed econo mic system is also expected to follow the exponential Boltzmann-Gibbs law\ , as a consequence of entropy maximization. Analysis of empirical data sho ws that income distributions in the USA\, European Union\, and other count ries exhibit a well-defined two-class structure. The majority of the popul ation (about 97%) belongs to the lower class characterized by the exponent ial ("thermal") distribution. The upper class (about 3% of the population) is characterized by the Pareto power-law ("superthermal") distribution\, and its share of the total income expands and contracts dramatically durin g booms and busts in financial markets. Globally\, data analysis of energy consumption per capita around the world shows decreasing inequality in th e last 30 years and convergence toward the exponential probability distrib ution\, in agreement with the maximal entropy principle. Similar results a re found for the global probability distribution of CO2 emissions per capi ta. All papers are available at http://physics.umd.edu/~yakovenk/econophys ics/. For recent coverage in Science magazine\, see http://www.sciencemag. org/content/344/6186/828 CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-339@lptms.universite-paris-saclay.fr DTSTART:20150414T110000Z DTEND:20150414T120000Z DTSTAMP:20150303T100315Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexey-sossinsky/ SUMMARY:Séminaire du LPTMS : Alexey Sossinsky - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Avr 15 11:00 DESCRIPTION:Energetic reduction of elastic knots to normal form: Gradient d escent along the Euler functional\n\n Alexey Sossinsky\, Independent Univ ersity of Moscow\, Laboratoire Poncelet\n\nSimple physical experiments sho w that a deformed knotted resilient elastic wire always returns to its equ ilibrium shape (which we call the normal form of the wire knot). The aim o f this research (joint work with S.Avvakumov and O.Karpenkov) is to const ruct a mathematical model of such physical knots. This is done by supplyin g the space of knots with an energy functional and performing gradient des cent w.r.t. the functional. The energy functional that we use is the sum o f the Euler functional (the integral along the curve defining the knot of the square of the curvature) and a simple repulsive functional (that forbi ds crossing changes). Using a discretized version of gradient descent alon g that functional\, we construct an algorithm that brings the knot to the shape that minimizes its energy. The algorithm is implemented in a compute r animation that shows the isotopy bringing the knot to normal form.\n\nWe will show some of these animations and demonstrate a few of the physical experiments with wire knots\, compare the results of physical and mathemat ical experiments\, and outline how our algorithm can be used in practice t o recognize knots and to unravel trivial knots. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-341@lptms.universite-paris-saclay.fr DTSTART:20150414T110000Z DTEND:20150414T120000Z DTSTAMP:20150224T173235Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-gerald-g-fuller/ SUMMARY:Physics-Biology interface seminar: Gerald G. Fuller - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 14 Avr 15 11:00 DESCRIPTION:The Dynamics of Two Biological Interfaces\nGerald G. Fuller (St anford University)\nSeminar co-hosted by Éric Raspaud—SPECIAL TIME\n\nB iological systems are normally high-interface systems and these surfaces a re laden with biological molecules and cells that render them mechanically complex. The resulting nonlinearities with response to surface stresses a nd strain are often essential to their proper function and these are explo red using recently developed methods that reveal an intricate interplay be tween applied stress and dynamic response. Two applications are discussed. \n\n1. Vascular endothelial cells are nature's "rheologists" and line the interior walls of our blood vessels and are sensitive to surface shear str esses. These stresses are known to affect the shape and orientation of end othelial cells. It is evident that the spatial homogeneity of flow can aff ect vascular health and it is well-documented that lesions form in regions of high curvature\, bifurcations\, and asperities in blood vessels. Exper iments are described where stagnation point flows are used to create regio ns of well controlled flow stagnation and spatial variation of wall shear stresses. Live-cell imaging is used to monitor the fate of cells attached to surfaces experiencing flow impingement and it is revealed that endothel ial cells migrate and orient in such flows to create remarkable patterns o f orientation and cell densification. This response\, termed "rheotaxis"\, is used to explore mechano-transduction pathways within these cells.\n\n2 . The tear film of the eye is a composite structure of an aqueous solution of protein and biomacromolecules. This thin layer is further covered by a film comprised of meibomian lipids excreted during each blink. The purpos e of the meibum has been largely unexplained although one prevailing sugge stion is that it suppresses evaporation. Recent measurements in our labora tory demonstrate that this layer is strongly viscoelastic and this propert y has dramatic effects on the dynamics of the moving contact line and stab ility against dewetting.\n\n—\n\nGerald Fuller is the Fletcher Jones Pro fessor of Chemical Engineering at Stanford University. He joined Stanford in 1980 following his graduate work at Caltech where he acquire his MS and PhD degrees. His undergraduate education was obtained at the University o f Calgary\, Canada. Professor Fuller's interests lie in studies of rheolog y and interfacial fluid mechanics. His work has been recognized by receipt of the Bingham Medal of The Society of Rheology\, membership in the Natio nal Academy of Engineering\, and honorary doctorates from the Universities of Crete\, Greece\, and Leuven\, Belgium. LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-354@lptms.universite-paris-saclay.fr DTSTART:20150420T143000Z DTEND:20150420T153000Z DTSTAMP:20150410T080258Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-amir-dembo/ SUMMARY:Tri-séminaire de Physique Statistique : Amir Dembo - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Avr 15 14:30 DESCRIPTION:Matrix optimization under random external fields\nAmir Dembo\, Stanford University\nConsider the problem of maximizing the quadratic form <\;x\,Wx>\; + <\;h\,x>\; over unit norm n-dimensional vectors x\, where W is a Wigner matrix which is independent of the Gaussian vector h whose entries are independent and identically distributed. Two recent stud ies of the large n asymptotic probability of deviations of such maximum fr om its typical value\, take very different approaches. Fyodorov and Le Dou ssal (2014) use the replica method of statistical physics\, whereas Dembo and Zeitouni (2015) rely instead on the mathematical theory of large devia tions. I will describe the main points of the latter\, using this specific example also to illustrate some of the differences\, strength and weaknes ses of each approach. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-336@lptms.universite-paris-saclay.fr DTSTART:20150421T110000Z DTEND:20150421T120000Z DTSTAMP:20150316T102908Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ao/ SUMMARY:Séminaire du LPTMS: Alfredo Ozorio de Almeida - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 21 Avr 15 11:00 DESCRIPTION:Semiclassical evolution of correlations between observables\nAl fredo Ozorio de Almeida\, Centro brasileiro de pesquisas físicas\nThe ker nel for the evolution of multiple quantum correlations between observables within the Weyl representation can be mapped onto the trace of a single c ontinous family of compound unitary operators. Thus the semiclassical limi t of this kernel can be ascribed to the periodic orbits of a corresponding family of classical compound canonical transformations\, in the celebrate d manner of Gutzwiller. Breaking these periodic orbits\, leads to an initi al value alternative that avoids both the search for orbits and singularit ies at caustics or bifurcations. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-317@lptms.universite-paris-saclay.fr DTSTART:20150504T110000Z DTEND:20150504T120000Z DTSTAMP:20150424T065551Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-stephan-grill/ SUMMARY:Physics-Biology interface seminar: Stephan Grill - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 4 Mai 15 11:00 DESCRIPTION:Actomyosin Force Generation and Pattern Formation\nStephan Gril l (MPI-CBG Dresden)\nMorphogenesis is one of the great unknowns in Biology . Much is known about molecular mechanisms of regulation\, but little is k nown about the physical mechanisms by which an unpatterned blob of cells d evelops into a fully structured and formed organism. The actomyosin cortex is a thin layer underneath the cellular membrane that can self contract\, which drives many of the large-scale morphogenetic rearrangements that ar e observed during development. How this cortex reshapes and deforms\, and how such morphogenetic processes couple to regulatory biochemical pathways is largely unclear. I will discuss two emergent physical activities of th e actomyosin cytoskeleton\, an active contractile tension and an active to rque\, both of which can serve to drive flows and large-scale chiral rotat ions of the actomyosin cytoskeleton. I will illustrate how active tension drive flows\, how molecular constituents of the cortex affect flows\, and how morphogenetic patterns can be formed by coupling regulatory biochemist ry to active cortical mechanics. A particular focus will be the investigat ion of how compressive cortical flow drives the formation of an actin fila ment alignment pattern for generating a cleavage furrow for cytokinesis. CATEGORIES:seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-359@lptms.universite-paris-saclay.fr DTSTART:20150504T143000Z DTEND:20150504T160000Z DTSTAMP:20150428T071448Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-balazs-kegel/ SUMMARY:Tri-Séminaire de Physique Statistique : Balázs Kégel - IPhT\, CE A-Saclay\, salle Itzykson - 4 Mai 15 14:30 DESCRIPTION:Learning to discover: signal/background separation and the Higg s boson challenge\nBalázs Kégel (Laboratoire de l'Accélérateur Linéai re\, Univ. d'Orsay)\nClassification algorithms have been routinely used si nce the 90s in high-energy physics to separate signal and background in pa rticle detectors. The goal of the classifier is to maximize the sensitivit y of a counting test in a selection region. It is similar in spirit but fo rmally different from the classical objectives of minimizing misclassifica tion error or maximizing AUC. We start the talk by motivating the problem on an ongoing example of detecting the Higgs boson in the tau-tau decay ch annel in the ATLAS detector of the LHC. We formalize the problem\, then go on by describing the usual analysis chain\, and explain some of the choic es physicists make when designing a classifier for optimizing the discover y significance. We derive different surrogates that capture this goal and show some simple techniques to optimize them\, raising some questions both on the statistical and on the algorithmic side. We end the talk by presen ting a data challenge we organized to draw the attention of the machine le arning and statistics communities to this important application and to imp rove the techniques used to optimize the discovery significance. With a Ph D in computer science\, Balázs Kégl has been a researcher in the Linear Accelerator Laboratory of the CNRS and the chair of the Center for Data Sc ience of the Université Paris-Saclay since 2014. He has published more th an hundred papers on unsupervised and supervised learning\, large-scale Ba yesian inference and optimization\, and on various applications. At his cu rrent position he has been the head of the AppStat team working on machine learning and statistical inference problems motivated by applications in high-energy particle and astroparticle physics. CATEGORIES:seminars LOCATION:IPhT\, CEA-Saclay\, salle Itzykson\, CEA - Saclay\, Saclay\, Franc e GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, CEA-Saclay\, salle Itzykson:geo:48.7 3668,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:1-350@lptms.universite-paris-saclay.fr DTSTART:20150505T110000Z DTEND:20150505T120000Z DTSTAMP:20150421T081416Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-antoine-sterdyniak/ SUMMARY:Séminaire du LPTMS: Antoine Sterdyniak - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 5 Mai 15 11:00 DESCRIPTION:Realization of strongly interacting topological phases on latti ces\nAntoine Sterdyniak\, Universität Innsbruck\nWhile fractional quantum Hall effect (FQHE) was realized experimentally thirty years ago in semico nductor heterostructures\, strongly interacting chiral topological phases are still at the center of an important research effort\, both as they ser ve as building blocks of more exotic phases such as fractional topological insulators and as a realization outside of semi-conductor physics is stil l missing. In this talk\, I will describe realizations of these phases in cold atoms gases and in frustrated spins systems. I will first introduce o ptical flux lattices\, which are continuous models that exhibit topologica l flat bands with a tunable Chern number and host fractional states beyond the FQHE. Then\, I will focus on chiral spin liquids whose emergence on t he kagomé lattice using local Hamiltonians has been shown very recently. Unlike itinerant particle systems where FQHE can be understood as a conseq uence of interactions in a partially filled topological band\, I will show that such a picture does not hold for this chiral spin liquid. However\, it can be described by model states obtained using a slave boson approach. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-360@lptms.universite-paris-saclay.fr DTSTART:20150506T143000Z DTEND:20150506T160000Z DTSTAMP:20150429T070901Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sandro-stringari/ SUMMARY:Séminaire du LPTMS : Sandro Stringari - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Mai 15 14:30 DESCRIPTION:Broken symmetries in spin-orbit coupled Bose Einstein condensed gases\nSandro Stringari (University of Trento and BEC Center)\nIn the sem inar I will focus on the symmetries characterizing the 1D spin-orbit coupl ed hamiltonian first realized experimentally by the team of Ian Spielman a t Nist. The nature of the new quantum phases and their dynamic properties will be discussed. Special focus will be given on the recently observed ro tonic excitation\, which follows from the breaking of time reversal and pa rity symmetry\, on the emergence of stripes which follows from the spontan eous breaking of translational invariance\, and on the dynamic instability of large amplitude oscillations which is the consequence of the violation of Galilean invariance. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-357@lptms.universite-paris-saclay.fr DTSTART:20150512T110000Z DTEND:20150512T120000Z DTSTAMP:20150429T075007Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-anthony-perret-et-caterina-de-bacco/ SUMMARY:Séminaire du LPTMS : Anthony Perret et Caterina De Bacco - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Mai 15 11:00 DESCRIPTION:Statistique d’extrêmes de variables aléatoires fortement co rrélées\nAnthony Perret\nLa statistique des valeurs extrêmes est une qu estion majeure dans divers domaines des sciences. Dans ce contexte\, une q uestion naturelle qui se pose alors est la suivante: ces valeurs extrêmes sont-elles isolées\, loin des autres variables ou bien au contraire exis te-t-il un grand nombre d'autres variables proches de ces valeurs extrême s ? Cette question a suscité l'étude de la densité d'état de ces évé nements quasi-extrêmes. Il existe pour cette quantité peu de résultats pour des variables fortement corrélées\, qui pourtant est le cas dans de nombreux modèles d'intérêt en physique statistique. Deux pistes de mod èles physiques de variables fortement corrélées pouvant être étudiés analytiquement se démarquent : les positions d’une marche aléatoire e t les valeurs propres de matrice aléatoire. Ce sont\nles deux modèles qu e j'ai étudiés dans ma thèse. Après avoir très brièvement discuté l e cas des marches aléatoires\, je me concentrerai dans cet exposé au cas où la collection de variables aléatoires est l'ensemble des valeurs pro pres d'une matrice aléatoire gaussienne hermitienne de grande taille. Je discuterai plus particulièrement la distribution de l’écart entre les deux plus grandes valeurs propres pour laquelle j’ai obtenu une formule faisant intervenir des fonctions transcendantes de Painlevé. Les comporte ments asymptotiques de cette formule permettent par exemple de trouver des nouveaux régimes intéressants dans le modèle de Sherrington-Kirkpatric k sphérique.\n\n\nThe cavity method in routing optimization problems on n etworks.\nCaterina De Bacco\n In recent years the cavity method\, or mess age-passing algorithm\, has been successfully exploited by statistical phy sicists to solve combinatorial optimization problems such as the K-satisfa bility (K-SAT). In this talk we introduce this method and outline how it i s applied to solve routing problems on communication or traffic networks. In this context the typical situation is where many users want to communic ate at the same time over a given network. One then wants to optimize the overall routing by minimizing communication path length and the traffic ov erlap either at nodes or at edges given a set of constraints. We will show how the cavity method provides the algorithmic tools to tackle these type s of optimization problems efficiently. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-348@lptms.universite-paris-saclay.fr DTSTART:20150518T110000Z DTEND:20150518T120000Z DTSTAMP:20150504T153805Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-martine-ben-amar/ SUMMARY:Physics-Biology interface seminar: Martine Ben Amar - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 18 Mai 15 11:00 DESCRIPTION:Growth of living fibrous tissues: from biofilms to fibrosis\nMa rtine Ben Amar (ENS Paris)\nMorphologies of soft materials in growth\, swe lling or drying have been extensively studied recently. Shape modification s occur as the size varies transforming ordinary spheres\, cylinders and t hin plates into more or less complex objects. Existence of fibers exacerba tes this complexity\, giving anisotropy to the growth process itself. The growth is coupled to the environment\, for bacteria the substrate\, in pa thology the healthy tissue. In pathological situations such as wound-he aling or desmoplastic tumor growth\, the immune system reacts with a batt ery of morphogenetic gradients\, making a new tissue full of collagene and eventually sending active cells. All these factors contribute to a high level of compressive stress at the origin of patterns and deformity. I w ill show how we can predict quantitatively these patterns on the simple d rop geometry of the biofilms and on the spherical shape of tumors.\n\nFor the pathological cases\, it turns out that the wrinkling process dominates the growth\, deforming the tissues and exacerbating the immune system whi ch reacts via passive (fibroblasts) and active cells (myo-fibroblasts). I will show that the consequence is a huge increase of the stiffness\, whic h stops spontaneously when the healing is achieved but not in case of impl ants or tumors. Naive estimations can be given explaining difficulties enc ounted in drug treatments\, for example.\nJoint work with Min Wu.\n CATEGORIES:seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-334@lptms.universite-paris-saclay.fr DTSTART:20150519T110000Z DTEND:20150519T120000Z DTSTAMP:20150423T073112Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thomas-quella/ SUMMARY:Séminaire du LPTMS: Thomas Quella - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 19 Mai 15 11:00 DESCRIPTION:Topological aspects of SU(N) magnetism and its cold atom realiz ation\nThomas Quella\, Universität Köln\nSU(N) spin systems exhibit a nu mber of novel topological quantum states\, including specifically a variet y of Haldane phases (in 1D) and abelian and non-abelian spin liquid phases (in 2D). In this talk we will review the classification of Haldane phases and their characterization in terms of fractionalized boundary spins and non-local string order parameters. Moreover\, we will address the possible realization of these phases in ultra-cold gases of alkaline-earth fermion s. If time permits we will also briefly comment on the systematic design o f critical and topological long-range SU(N) spin models in one and two dim ensions which are based on infinite dimensional matrix product states asso ciated with SU(N) WZW models. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-358@lptms.universite-paris-saclay.fr DTSTART:20150520T143000Z DTEND:20150520T153000Z DTSTAMP:20150511T070850Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-daniel-cabra/ SUMMARY:Séminaire exceptionnel du LPTMS : Daniel Cabra - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Mai 15 14:30 DESCRIPTION:Skyrmion Lattices in Antiferromagnetic Systems\nDaniel C. Cabra   (University of La Plata)\nOrdering of the frustrated classical Heisenbe rg model with Dzyaloshinskii-Moriya (DM) interactions on the antiferromagn etic triangular lattice is studied under a magnetic field by means of semi classical calculations and large-scale Monte Carlo simulations. We show th at even a small DM interaction induces the formation of anAntiferromagneti cSkyrmion crystal (AF-SkX) state. Unlike what is observed in ferromagnetic materials\, we show that the AF-SkX state consists of three interpenetrat ing usual Skyrmion crystals (one by sublattice)\, and most importantly\, t he AF-SkX state survives in the limit of zero temperature. To characterize the phase diagram we compute the average of the topological order paramet er\, the chirality\, which measures the numberof Skyrmions. As themagnetic fieldincreases\, this parameter presents a series of discrete jumps that m ay indicate transitions between different topological states. Increasing t he magnetic field the model exhibits a first-order transition from a spira l phase into a three-sublattice Skyrmion structure where multiple Bragg pe aks coexist in the spin structure factor. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-361@lptms.universite-paris-saclay.fr DTSTART:20150522T110000Z DTEND:20150522T121500Z DTSTAMP:20150513T113626Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-quantiq ue-informel-du-lptms-alberto-rosso/ SUMMARY:Séminaire quantique informel du LPTMS : Alberto Rosso - LPTMS\, sa lle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 22 Mai 15 11:00 DESCRIPTION:Dynamic Nuclear Polarization and the paradox of Quantum Thermal ization\nAlberto Rosso (LPTMS)\n\nDynamic Nuclear Polarization (DNP) is to date the most  effective technique to increase the nuclear polarization up to a factor 100\,000 opening disruptive perspectives for medical applic ations. In DNP\, the nuclear spins are driven to an - out of equilibrium - hyperpolarized state by microwave saturation of the electron spins in int eraction with them. Here we show that the electron dipolar interactions co mpete with the local magnetic fields resulting in two distinct dynamical p hases: for strong interactions the electron spins equilibrate to an extrem ely low effective temperature that boosts  DNP  efficiency. For weak int eraction this spin temperature is not defined and the polarization profile has an 'hole burning' shape characteristic of the non interacting case. T he study of the many-body eigenstates reveals that these two phases are in timately related to the problem of thermalization in closed quantum system s where breaking of ergodicity is expected varying the strength of the int eractions. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-362@lptms.universite-paris-saclay.fr DTSTART:20150526T110000Z DTEND:20150526T120000Z DTSTAMP:20150514T130410Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-vicente-garzo/ SUMMARY:Séminaire du LPTMS: Vicente Garzo - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 26 Mai 15 11:00 DESCRIPTION:Instabilities in granular fluids at moderate densities\nVicente Garzo\, Departamento de Fisica\, Universidad de Extremadura\nIt is well e stablished that when granular materials are externally excited (rapid flow conditions)\nthey behave like a fluid. In this regime\, binary collisions prevail and hence\, kinetic theory may\nbe considered as a quite useful t ool to describe the dynamics of grains. The main difference with\nrespect to ordinary or molecular fluids is that granular systems are constituted b y macroscopic\ngrains that collide inelastically so that the energy decrea ses with time when the system evolves\nfreely (homogeneous cooling state\, HCS). One of the most characteristic features of granular fluids\,\nas co mpared with normal fluids\, is the spontaneous formation of velocity vorti ces and density clus-\nters in the HCS. These instabilities can be well de scribed through a linear stability analysis of the\nhydrodynamic equations and follow from the presence of a dissipation or sink term in the equatio n\nfor the balance of energy. Apart from its fundamental interest\, the de termination of the critical\nlength scale Lc for the onset of instabilitie s in freely cooling flows offers one of the best opportu-\nnities to asses s the theoretical predictions of granular hydrodynamics (which are based o n kinetic\ntheory calculations) when one compares those predictions with t hose independently obtained by\nmolecular dynamics (MD) simulations. In th is talk I will give some insight into the above problem\nby determining th e critical length scale L c for granular fluids at moderate densities. The comparison\nbetween kinetic theory and MD simulations shows in general an excellent agreement for the onset\nof velocity vortices\, indicating the applicability of hydrodynamics to monodisperse and polydisperse\ngranular flows even for strong inelasticity and finite density. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-297@lptms.universite-paris-saclay.fr DTSTART:20150601T110000Z DTEND:20150601T120000Z DTSTAMP:20150224T065131Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-ulrich-schwarz/ SUMMARY:Physics-Biology interface seminar: Ulrich Schwarz - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 1 Juin 15 11:00 DESCRIPTION:Physics of active contractile matter\nUlrich S. Schwarz (Heidel berg University)\nBiological systems such as cells and tissue use non-equi librium processes to actively generate mechanical stress\, movement and gr owth. Some of these processes can actually be reconstituted in biomimetic experiments with active soft matter. In this talk\, we will first discuss why and how contractile forces are generated by biological systems and how they can be measured with soft elastic substrates ("traction force micros copy"). Because kilo-Pascal stresses are typically transmitted through mic rometer-sized contacts\, the relevant force scale is nano-Newton. We then introduce different theoretical approaches to understand and model the con tractility of biological matter. Because closed systems have to conserve m omentum\, the most central concept here is the one of a "force dipole"\, s imilarly as for the theoretical description of microswimmers\, but now cou pled to a mechanical rather than to a hydrodynamic environment. We present a stochastic theory for the biologically most relevant example of a contr actile force dipole\, namely the "myosin II minifilament". We then explain why on the large length scale of cells and tissue\, the mechanical proper ties of these systems are dominated by tensions rather than by their elast ic modulus\, with dramatic consequences for their shape and force transmis sion to the environment. LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-355@lptms.universite-paris-saclay.fr DTSTART:20150602T110000Z DTEND:20150602T120000Z DTSTAMP:20150416T133338Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-wolff/ SUMMARY:Séminaire du LPTMS: Jean Wolff - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 2 Juin 15 11:00 DESCRIPTION:Budding of domains in mixed bilayer membranes\nJ. Wolff\,  Ins titut Charles Sadron (UPR CNRS)\, Strasbourg\nWe propose a model that acco unts for budding behavior of domains in lipid bilayers\, where each of the bilayer leaflets has a coupling between its local curvature and local lip id composition. The compositional asymmetry between the two monolayers lea ds to an overall spontaneous curvature. The membrane free energy contains three contributions: bending energy\, line tension\, and a Landau free ene rgy for a lateral phase separation. Within a mean-field treatment\, we obt ain various phase diagrams which contain fully-budded\, dimpled and flat s tates.\nIn particular\, for some range of membrane parameters\, the phase diagrams exhibit a tri-critical behavior as well as three-phase coexistenc e region. The global phase diagrams can be divided into three types and ar e analyzed in terms of the curvature-composition coupling parameter and do main size.\n\n \;\n\n\n\nRef.: J.Wolff\, S. Komura\, D. Andelman\, PRE 91\, 012708 (2015) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-364@lptms.universite-paris-saclay.fr DTSTART:20150603T143000Z DTEND:20150603T153000Z DTSTAMP:20150603T102034Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-ines-de-vega/ SUMMARY:Séminaire exceptionnel du LPTMS: Ines de Vega - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 3 Juin 15 14:30 DESCRIPTION:\nOpen quantum systems: hierarchical structures\, chain mapping s and thermofield dynamics\nInes de Vega\, LMU Munich\n\nOpen quantum syst ems (OQS) cannot always be described with the Markov approximation\, which requires a large separation of system and environment time scales. In thi s talk I will give an overview of some recent advances to tackle the dynam ics of an OQS beyond the Markov approximation\, with special emphasis in h ierarchy-based [1\,2] and chain mapping-based [3] approaches. In the latte r context\, I will discuss the use of a thermofield transformation to desc ribe thermal environments [4].\n\n\n[1] Y. Tanimura. PRA 41\, 6676–6687 (1990)\n[2] I. de Vega\, J. Phys. A: Math. Theor. 48\, 145202 (2015)\n[3] A. W. Chin\, J. Prior\, S. F. Huelga\, and M. B. Plenio\, Phys. Rev. Lett. 107\, 160601\, 1102.1483 (2011).\n[4] I. de Vega and M.C. Bañuls\, arXiv :1504.07228\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-346@lptms.universite-paris-saclay.fr DTSTART:20150609T110000Z DTEND:20150609T120000Z DTSTAMP:20150602T083849Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-francoise-cornu-2/ SUMMARY:Séminaire du LPTMS: Françoise Cornu - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Juin 15 11:00 DESCRIPTION:\nFirst passage fluctuation relations rules by cycle affinities \n\nFrançoise Cornu\, LPT Orsay\n\nFor a non-equilibrium stationary state  described by a Markovian process it is well known that the entropy prod uction rate can be expressed in terms of the affinity associated with ever y transition  in the graph representation of the master equation.\n\nWe e xhibit the invariance of cycle affinities in finite state Markov processes under various natural probabilistic constructions : for instance under co nditioning and under a new combinatorial construction that we call ``drag and drop''. For semi-markovian processes whose corresponding graph is made of a single cycle\, we establish that the cycle current obeys a fluctuati on relation for first passage times at integer winding numbers\, which is dual to the fluctuation relation for the cycle current at fixed time : con trarily to seminal fluctuation relations about the probabilities for measu ring a random cumulative exchange quantity or its opposite value during a given time\, the latter fluctuation relations deal with the probabilities for the random time needed for one cycle to be  performed  in one sense or in the opposite one  with a given winding number.\n\n \;\n\nRefere nce :  M. Bauer and F. Cornu\,  J. Stat. Phys. 155 (2014) 703-736.\n\n\n  \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-310@lptms.universite-paris-saclay.fr DTSTART:20150615T110000Z DTEND:20150615T120000Z DTSTAMP:20150610T192827Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-xavier-trepat/ SUMMARY:Physics-Biology interface seminar: Xavier Trepat - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 15 Juin 15 11:00 DESCRIPTION:Control of collective cell dynamics by adhesion\, tension and f racking\nXavier Trepat (ICREA @ Institute for Bioengineering of Catalonia (IBEC)\, Barcelona)\nA broad range of biological processes such as morphog enesis\, tissue regeneration\, and cancer invasion depend on the collectiv e dynamics of epithelial cells. Such dynamics are determined by an exquisi te balance between intercellular adhesion\, cytoskeletal tension\, and int racellular pressure. To study this balance in a fully quantitative manner I will present new techniques to map physical forces between and within ce lls. Using these techniques we studied how cellular forces are regulated a nd transmitted by the proteins that comprise intercellular adhesion comple xes. To do so\, we perturbed the main molecular players of the intercellul ar adhesome using RNAi and studied how these perturbations impact physical forces and cellular velocities in epithelial cell collectives. We found t hat perturbations targeting adherens junctions\, but also tight junctions\ , gap junctions\, and desmosomes have a significant impact on cell velocit ies\, cell deformations\, cell-matrix traction forces\, and cell-cell forc es. We developed a cross-validation analysis to show that concentrations o f cell-cell adhesion proteins are significant predictors of cell-cell forc es. Finally\, I will discuss the determinants of epithelial integrity in t he presence of stretching and transepithelial pressure. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-367@lptms.universite-paris-saclay.fr DTSTART:20150615T143000Z DTEND:20150615T160000Z DTSTAMP:20150528T092217Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-abhishek-dhar/ SUMMARY:Tri-séminaire de Physique Statistique : Abhishek Dhar - LPTMS\, sa lle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Juin 15 14:30 DESCRIPTION:Waiting times for entropic fluctuations in non-equilibrium proc esses\nAbhishek Dhar (International centre for theoretical sciences\, ICTS \, Bangalore)\nNonequilibrium processes generate entropy. The total entrop y generated in a fixed  finite time interval is a fluctuating variable. A  lot of recent work have looked at the probability of observing entropic fluctuations of different sizes in a fixed time interval. These distribut ions have been discussed in the context of fluctuation relations and large deviation functions. Here\, we  ask the question: how long does one have to wait to see an entropic fluctuation of a specified size ? We present s ome results on the waiting time distribution\,  in the context of some si mple examples of non-equilibrium processes.\n\nReference: K. Saito and A. Dhar\, arXiv:1504.02187 CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-352@lptms.universite-paris-saclay.fr DTSTART:20150616T110000Z DTEND:20150616T120000Z DTSTAMP:20150612T102537Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mario-kieburg/ SUMMARY:Séminaire du LPTMS: Gernot Akemann - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 16 Juin 15 11:00 DESCRIPTION:Universal Lyapunov Exponents from Products of Random Matrices\n Gernot Akemann\, Universität Bielefeld\nRandom Matrices find many applica tions in Physics and Mathematics. In particular products of random matrice s can be used as a simple model for linear time evolution. In this talk I will review recent progress on an exact solution of this model for Gaussia n random matrices. Both the spectral statistic of its complex eigenvalues and its real positive singular values are given by a determinantal point p rocess with an underlying integrable kernel. In the limit of an infinite p roduct the Lyapunov exponents become deterministic and we compute their va riances and higher order cumulants. Remarkably the moduli of the complex e igenvalues and the singular values become identical in this limit. We will also discuss universality and possible extensions. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-363@lptms.universite-paris-saclay.fr DTSTART:20150619T130000Z DTEND:20150619T170000Z DTSTAMP:20150530T100615Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-hdr-ma rtin-lenz/ SUMMARY:Soutenance HDR : Martin Lenz - LPTMS-batiment 100\, salle des conse ils - 19 Juin 15 13:00 DESCRIPTION:On the microstructure of active cellular processes\nEukaryotic cells use a multitude of protein machines to regulate their own structure. In this thesis\, we study how the geometrical arrangement of these intera cting microscopic active elements sculpt the cell's own internal microstru cture and its membrane enclosure.\nWe first focus on the mechanisms genera ting actomyosin contractility\, a crucial driver of cell motion and organi zation. We question the current position of highly organized\, sarcomeric contractility as the only possible mechanism to drive contractility. We pr opose an alternative mechanism\, and show that only it can account for the observed contractility of disordered actomyosin assemblies. It moreover y ields qualitatively new effects in intracellular force transmission\, incl uding stress reversal and amplification\, consistent with experimentally o bservations in fiber networks.\nWe next elucidate some of the mechanisms t hrough which the cell deforms and cuts its own membrane\, thus enabling ex changes with the extracellular medium as well as between its internal comp artments. We find that the function of the proteins responsible for this r emodeling is strongly influenced by the mechanics of the membrane\, and us e these effects to elucidate the modes of operation of proteins clathrin a nd dynamin\, as well as of protein complex ESCRT-III. CATEGORIES:seminars LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-353@lptms.universite-paris-saclay.fr DTSTART:20150622T110000Z DTEND:20150622T123000Z DTSTAMP:20150609T103644Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-anthony-perret/ SUMMARY:Soutenance de thèse : Anthony Perret - IPN-batiment 100\, Auditori urm - 22 Juin 15 11:00 DESCRIPTION:Statistique d’extrêmes de variables aléatoires fortement co rrélées\nAnthony Perret\n\nLa statistique des valeurs extrêmes est une question majeure dans divers contexte scientifiques. Cependant\, la descri ption de la statistique d'un extremum global est certainement une caracté ristique importante mais celle-ci ne décrit la fluctuation que d'une seul e variable\, parmi un grand nombre de variables aléatoires. Une question naturelle qui se pose alors est la suivante: ces valeurs extrêmes sont-el les isolées\, loin des autres variables ou bien au contraire existe-t-il un grand nombre d'autres variables proches de ces valeurs extrêmes ? Ces questions ont suscité l'étude de la densité d'état de ces événements quasi-extrêmes. Il existe pour cette quantité peu de résultats pour de s variables fortement corrélées\, qui pourtant est le cas de nombreux mo dèles fondamentaux. Deux pistes de modèles physiques de variables fortem ent corrélées pouvant être étudiés analytiquement se démarquent alor s: les positions d’une marche aléatoire et les valeurs propres de matri ce aléatoire. Ce sont les deux modèles que j'ai étudiés dans ma thèse et que je vais présenter durant cette soutenance. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-370@lptms.universite-paris-saclay.fr DTSTART:20150623T110000Z DTEND:20150623T123000Z DTSTAMP:20150610T131617Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lptms-ipn-jacques-treiner/ SUMMARY:Séminaire commun LPTMS-IPN : Jacques Treiner - IPN-batiment 100\, Auditoriurm - 23 Juin 15 11:00 DESCRIPTION:Pourquoi l’objectif des 2°C appartient\, hélas\, au passé  ?\nJacques Treiner (Paris VI et Sciences Po)\n\nDepuis la conférence de Copenhague de 2009\, la référence de 2°C comme augmentation de la temp érature moyenne de la Terre apparait comme un objectif à ne pas dépasse r. Cette valeur\, choisie à la suite de négociations extrêmement diffic iles entre 26 pays seulement (notamment sans l’UE) n’a pas de caractè re contraignant\, mais c’est le seul objectif chiffré servant depuis lo rs de référence internationale. C’est asn doute la raison pour laquell e ce chiffre sert de référence pour la COP21 à Paris en décembre 2015. Mais il n’est pas difficile de se rendre compte que\, hélas\, les cond itions requises pour que ce scénario se réalise sont devenue impossibles à remplir. Quelles conséquences en tirer ? CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-351@lptms.universite-paris-saclay.fr DTSTART:20150629T110000Z DTEND:20150629T120000Z DTSTAMP:20150618T084014Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-alexis-peaucelle/ SUMMARY:Physics-Biology interface seminar: Alexis Peaucelle - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 29 Juin 15 11:00 DESCRIPTION:Looking for the mechanical control of growth in plants. Is ther e a simple law?\nAlexis Peaucelle (INRA Versailles/Cambridge University)\n Plants are strikingly good at math\, especially geometry. One could find p arts or full plants shaped as spheres\, circles\, straight lines\, and fla t surfaces\, golden and right angles and all sorts of exotic and pretty co mbination of shapes. These shapes are generated through complex tissue gro wth. We want to understand this puzzling beauty by focusing on the biophys ical properties of the cell wall and its related biochemistry. We will pre sent some of our results on dark grown hypocotyl and pavement cells demons trating that pectin methylesterification status change is necessary for ce ll and tissue differentiation\, growth and is related to changes in cell w all elasticity. Then we will expose puzzling results showing that cell gro wth rates are proportionate to the elastic stretching of the cell wall (Pr essure divided by the Young modulus) and not plastic properties of the cel l wall components. Finally\, we will present preliminary experiments that could explain this paradox as well as some others such as microtubule part ial correlation with oriented growth\, and sound-induced plant growth. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-356@lptms.universite-paris-saclay.fr DTSTART:20150630T110000Z DTEND:20150630T120000Z DTSTAMP:20150618T145532Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-emmanuel-trizac-et-christophe-texier/ SUMMARY:Séminaire du LPTMS: Emmanuel Trizac et Christophe Texier - LPTMS-b atiment 100\, salle des conseils - 30 Juin 15 11:00 DESCRIPTION:Shortcutting adiabaticity : how to change rapidly the state of a trapped gas ?\nEmmanuel Trizac\, LPTMS\nInspired from H-theorem requirem ents\, a novel class of exact solutions to the quantum or classical Boltzm ann equation is uncovered. These solutions\, valid for arbitrary collision laws\, hold for time-dependent confinement. We exploit them\, in a revers e-engineering perspective\, to work out a protocol that shortcuts any adia batic transformation between two equilibrium states in an arbitrarily shor t time span\, for an interacting system. Particle simulations corroborate the analytical predictions.\n\n \;\nTopological phase transitions in m ultichannel disordered wires in the chiral  symmetry classes\nChristophe Texier\, LPTMS\nWe have considered the one-dimensional multichannel Dirac equation where the mass is a random NxN matrix with elements uncorrelated in space. In order to analyze the spectral properties of the model\, we ha ve introduced a matricial random process (Riccati matrix)\, related to the scattering matrix describing the reflection on the semi-infinite medium.\ nWe have found that the stationary distribution of the Riccati matrix corr esponds to a generalisation of the Laguerre ensemble of random matrices. T he knowledge of this distribution has allowed us to derive explicit determ inantal representations for the density of states (DoS)\, which is shown t o present a power law behaviour at low energy.\nVarying the mass over diso rder ratio allows to drive N phase transitions where the DoS exponent vani shes and which are shown to be of topological nature as they correspond to the change of a topological quantum number (Witten index).\nReference :Au rélien Grabsch and Christophe Texier\, Topological phase transitions and superuniversality in the 1D multichannel Dirac equation with random mass\, preprint cond-mat arXiv:1506.05322 CATEGORIES:seminars LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-377@lptms.universite-paris-saclay.fr DTSTART:20150701T143000Z DTEND:20150701T160000Z DTSTAMP:20150629T132349Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexios-polychronakos/ SUMMARY:Séminaire du LPTMS : Alexios Polychronakos - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 1 Juil 15 14:30 DESCRIPTION:Field theory on fuzzy spaces: effective action and phase transi tions\nAlexios Polychronakos (City College NY) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-375@lptms.universite-paris-saclay.fr DTSTART:20150702T143000Z DTEND:20150702T160000Z DTSTAMP:20150618T060812Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-matthieu-wyart/ SUMMARY:Tri-séminaire de Physique Statistique : Matthieu Wyart - LPTMS\, s alle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 2 Juil 15 14:30 DESCRIPTION:Marginal stability and flow in granular materials\nMatthieu WYA RT (New York University)\n\nComplex systems are characterized by an abunda nce of meta-stable states.This is the case for granular materials\, that c an flow until one jammed configuration (among the exponentially many possi ble ones) is reached. I will argue that at least in popular simplified mod els of granular materials\, these dynamically-accessible configurations ar e stable\, but barely so. Such marginal stability offers a new perspective on both the solid and the liquid phase. I will discuss dense suspensions and propose to describe flow as a gas of elementary excitations\, correspo nding to the opening and closing of contact between particles. This approa ch leads to a detailed scaling description of rheological properties and l ength scales of dense flows. If time permits I will discuss a classificati on of athermal glassy systems based on the stability of low-energy excitat ions. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-365@lptms.universite-paris-saclay.fr DTSTART:20150707T110000Z DTEND:20150707T120000Z DTSTAMP:20150703T064105Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-eric-akkermans/ SUMMARY:Séminaire du LPTMS: Eric Akkermans - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 7 Juil 15 11:00 DESCRIPTION:Topology and fractals : waves and fields in quasicrystals (theo ry and experiments with polaritons)\nEric Akkermans\, Technion - Israel In stitute of Technology\nI will present recent results obtained both theoret ically and experimentally  on fractal spectral properties of a polariton gas in a Fibonacci quasi-periodic potential. The observed spectrum is\nacc urately reproduced from a theoretical model that we shall present. We have observed for the first time log-periodic oscillations and the opening of mini-gaps following the gap labeling theorem. These results illustrate the potential of cavity polaritons as a quantum simulator in complex topologi cal geometries. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-373@lptms.universite-paris-saclay.fr DTSTART:20150908T100000Z DTEND:20150908T130000Z DTSTAMP:20150901T055711Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-caterina-de-bacco/ SUMMARY:Soutenance de thèse : Caterina de Bacco - IPN-batiment 100\, Audit oriurm - 8 Sep 15 10:00 DESCRIPTION:Decentralized network control\, optimization and random walks o n networks\nIn the last years several problems been studied at the interfa ce between statistical physics and computer science. The reason being that often these problems can be reinterpreted in the language of physics of d isordered systems\, where a big number of variables interacts through loca l fields dependent on the state of the surrounding neighborhood. Among the numerous applications of combinatorial optimisation the optimal routing o n communication networks is the subject of the first part of the thesis. W e will exploit the cavity method to formulate efficient algorithms of type message-passing and thus solve several variants of the problem through it s numerical implementation. At a second stage\, we will describe a model t o approximate the dynamic version of the cavity method which allows to dec rease the complexity of the problem from exponential to polynomial in time . This will be obtained by using the Matrix Product State formalism of qua ntum mechanics. Another topic that has attracted much interest in statisti cal physics of dynamic processes is the random walk on networks. The theor y has been developed since many years in the case the underneath topology is a d-dimensional lattice. On the contrary the case of random networks ha s been tackled only in the past decade\, leaving many questions still open for answers. Unravelling several aspects of this topic will be the subjec t of the second part of the thesis. In particular we will study the averag e number of distinct sites visited during a random walk and characterize i ts behaviour as a function of the graph topology. Finally\, we will addres s the rare events statistics associated to random walks on networks by usi ng the large-deviations formalism. Two types of dynamic phase transitions will arise from numerical simulations\, unveiling important aspects of thi s problems. We will conclude outlining the main results of an independent work developed in the context of out-of-equilibrium physics. A solvable sy stem made of two Brownian particles surrounded by a thermal bath will be s tudied providing details about a bath-mediated interaction arising for the presence of the bath. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-374@lptms.universite-paris-saclay.fr DTSTART:20150914T143000Z DTEND:20150914T173000Z DTSTAMP:20150902T112747Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-silvia-grigolon/ SUMMARY:Soutenance de thèse : Silvia Grigolon - IPN : salle E\, rez-de-cha ussée-bâtiment 100 - 14 Sep 15 14:30 DESCRIPTION:Modeling and inference for biological systems: from auxin dynam ics in plants to protein evolution \n \;\nAll biological systems are m ade of atoms and molecules interacting in a non-trivial manner. Such non-t rivial interactions induce complex behaviours allowing organisms to fulfil their many vital functions. These features can be found in all biological systems at different levels\, from molecules and genes up to cells and ti ssues. In the past few decades\, physicists have been paying much attentio n to these intriguing aspects by framing them in network approaches for wh ich a number of theoretical methods offer many powerful ways to tackle sys temic problems. At least two different ways of approaching these challenge s may be considered: direct modelling methods and approaches based on i nverse methods. In this defence I am going to show how we made use of bot h approaches to study three different problems occurring on three differen t biological scales. The first part concerns the very early stages of tiss ue development in plants\; it covers the model we proposed for understandi ng which features drive the spontaneous collective behaviour in space and time of the transporters which pump the phytohormone auxin out of plant ce lls. Then\, at the cell level\, I will go through my study of the intracel lular molecular networks that implement auxin signalling in plants\, exami ning how network structures affect network functions. Finally\, I will tal k about inference problems on structural properties of proteins. I will in troduce a method we formulated to understand how conservation of protein function across different organisms constrains the evolution of protein se quences and their diversity. CATEGORIES:seminars LOCATION:IPN : salle E\, rez-de-chaussée-bâtiment 100\, 15 Rue Georges Cl emenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN : salle E\, rez-de-chaussé e-bâtiment 100:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-369@lptms.universite-paris-saclay.fr DTSTART:20150921T110000Z DTEND:20150921T120000Z DTSTAMP:20150907T062807Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-agnese-seminara/ SUMMARY:Physics-Biology interface seminar: Agnese Seminara - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 21 Sep 15 11:00 DESCRIPTION:Osmotic spreading of Bacillus subtilis biofilms\nAgnese Seminar a (LPMC\, Université de Nice)\n\nBacterial biofilms are organized communi ties of cells living in association with surfaces. The hallmark of biofilm formation is a well defined spatio-temporal pattern of gene expression\, leading to differentiation and a complex morphology. While this process re sembles the development of a multicellular organism\, biofilms are only tr ansiently multicellular. More importantly the functions associated to the biofilm phenotype are largely unknown. \n\n\nA common feature of biofilm f ormation is the secretion of a polymeric matrix rich in sugars and protein s in the extracellular space. In Bacillus subtilis\, secretion of the exop olysaccharide (EPS) component of the extracellular matrix is genetically c oupled to the inhibition of flagella-mediated motility. The onset of this switch results in slow expansion of the biofilm on a substrate. Different strains have radically different capabilities in surface colonization: Fla gella-null strains spread at the same rate as wild type\, while both are d ramatically faster than EPS mutants. Multiple functions have been attribut ed to the EPS\, but none of these provides a physical mechanism for genera ting spreading. We propose that the secretion of EPS drives surface motili ty by generating osmotic pressure gradients in the extracellular space. A simple mathematical model based on the physics of polymer solutions shows quantitative agreement with experimental measurements of biofilm growth\, thickening\, and spreading. We discuss the implications of this osmoticall y driven type of surface motility for nutrient uptake that may elucidate t he reduced fitness of the matrix-deficient mutant strains. \n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-384@lptms.universite-paris-saclay.fr DTSTART:20151005T110000Z DTEND:20151005T120000Z DTSTAMP:20151001T061444Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-christophe-le-clainche/ SUMMARY:Physics-Biology interface seminar: Christophe Le Clainche - Moyen A mphi\, Building 510\, Université Paris-Saclay Orsay - 5 Oct 15 11:00 DESCRIPTION:Regulation of actin assembly and mechanotransduction in cell-ma trix adhesion complexes: a biochemical study of the talin-vinculin complex \nChristophe Le Clainche (I2BC\, Gif-sur-Yvette)\nCell migration is involv ed in many physiological and pathological processes. Force is produced by the growth and the contraction of the actin cytoskeleton (1). To produce f orce in adherent cells\, these actin networks must be anchored to the extr acellular matrix (ECM) by adhesion complexes (1\,2). These structures cont ain transmembrane integrins that mechanically couple the ECM to the intrac ellular actin cytoskeleton via actin binding proteins (ABPs) (2). This sys tem acts as a molecular clutch that controls force transmission across adh esion complexes. This molecular clutch is a complex interface made of mult iple layers of regulated protein-protein interactions (2). The multiple ac tivities of the ABPs present in these structures play a critical role in t he dynamics of this interface. In addition to the control of actin filamen t binding and polymerization (1-3)\, these proteins sense and respond to t he force applied by the actomyosin cytoskeleton to adjust the anchoring st rength (4\,5). Our goal is to determine the molecular mechanisms by which these ABPs cooperate to control the mechanical coupling between the actin cytoskeleton and cell-matrix adhesion complexes.\n\nTo study these ABPs\, our laboratory combines the measurement of actin polymerisation kinetics i n fluorescence spectroscopy\, single actin filament observations in TIRF m icroscopy and the reconstitution of actin-based mechanosensitive processes on micropatterned surfaces. Our model system is the mechanosensitive comp lex made of the two ABPs talin and vinculin.\nOur results showed that vinc ulin controls actin filament elongation (3). More recent results revealed that talin also regulates actin polymerisation in response to integrin bin ding (unpublished data). In addition\, we have developed a microscopy assa y with pure proteins in which the self-assembly of actomyosin cables contr ols the association of vinculin to a talin-micropatterned surface in a rev ersible manner (4\, 5). This in vitro reconstitution revealed the mechanis m by which a key mechanosensitive molecular switch senses and controls the connection between adhesion complexes and the actomyosin cytoskeleton.\n\ nReferences\n\n (1) Christophe Le Clainche and Marie-France Carlier.\nReg ulation of actin assembly associated with protrusion and adhesion in cell migration.\nPhysiological Reviews (2008) Apr\;88(2):489-513.\n (2) Corina Ciobanasu\, Bruno Faivre\, Christophe Le Clainche.\nIntegrating actin dyna mics\, mechanotransduction and integrin activation: The multiple functions of actin binding proteins in focal adhesions.\nEuropean Journal of Cell B iology (2013) (92) 339-348.\n (3) Christophe Le Clainche\, Satya P Dwivedi \, Dominique Didry\, Marie-France Carlier.\nVinculin is a dually regulated actin filament barbed-end capping and side-binding protein.\nJournal of B iological Chemistry (2010) Jul 23\;285(30):23420-32.\n (4) Corina Ciobanas u\, Bruno Faivre\, Christophe Le Clainche.\nActomyosin dependent formation of the mechanosensitive talin-vinculin complex reinforces actin anchoring .\nNature Communications (2014) 5:3095\n (5) Corina Ciobanasu\, Bruno Faiv re\, Christophe Le Clainche.\nReconstituting actomyosin-dependent mechanos ensitive protein complexes in vitro.\nNature Protocols (2015) Jan \;10(1): 75-89\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-379@lptms.universite-paris-saclay.fr DTSTART:20151012T143000Z DTEND:20151012T173000Z DTSTAMP:20151006T125037Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-clelia-de-mulatier/ SUMMARY:Soutenance de thèse : Clélia de Mulatier - IPN-batiment 100\, Aud itoriurm - 12 Oct 15 14:30 DESCRIPTION:A random walk approach to stochastic neutron transport\n\n\nOne of the key goals of nuclear reactor physics is to determine the distribut ion of the neutron population within a reactor core. This population indee d fluctuates due to the stochastic nature of the interactions of the neutr ons with the nuclei of the surrounding medium: scattering\, emission of ne utrons from fission events and capture by nuclear absorption. Due to these physical mechanisms\, the stochastic process performed by neutrons is a b ranching random walk. For most applications\, the neutron population consi dered is very large\, and all physical observables related to its behaviou r\, such as the heat production due to fissions\, are well characterised b y their average values. Generally\, these mean quantities are governed by the classical neutron transport equation\, called linear Boltzmann equatio n.\n\nDuring my PhD\, using tools from branching random walks and anomalou s diffusion\, I have tackled two aspects of neutron transport that cannot be approached by the linear Boltzmann equation. First\, thanks to the Feyn man-Kac backward formalism\, I have characterised the phenomenon of "neutr on clustering" that has been highlighted for low-density configuration of neutrons and results from strong fluctuations in space and time of the neu tron population. Then\, I focused on several properties of anomalous (non- exponential) transport\, that can model neutron transport in strongly hete rogeneous and disordered media\, such as pebble-bed reactors. One of the n ovel aspects of this work is that problems are treated in the presence of boundaries. Indeed\, even though real systems are finite (confined geometr ies)\, most of previously existing results were obtained for infinite syst ems.\n CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-380@lptms.universite-paris-saclay.fr DTSTART:20151013T110000Z DTEND:20151013T120000Z DTSTAMP:20151001T114648Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-hajime-yoshino/ SUMMARY:Séminaire du LPTMS: Hajime Yoshino - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 13 Oct 15 11:00 DESCRIPTION:Hierachical rigidities of glassy systems\nHajime Yoshino\, Osak a University\nRecent progress of the replica theory for the hardsphere gla ss in large dimensional limit suggests an intriguing possibility of hierar chical energy landscape reminiscent of spin-glasses [1]. In this talk we a rgue that response of glasses to external shear would be very similar to t he response of spin-glasses to external magnetic field. First we show theo retically that  shear-modulus becomes hierarchical reflecting the hierarc hical structure of the glass order parameter [2]. Then we discuss our MD s imulations which reveal the anticipated difference between "field cooled" (FC) and "zero field cooled" (ZFC) shear-modulus [3].  Finally we show th eoretical and numerical suggestions of negatively diverging non-linear she ar-modulus associated with the marginal stability of continuous replica sy mmetry breaking.\n\n[1]  P. Charbonneau\, J. Kurchan\, G. Parisi\, P. Urb ani\, F. Zamponi\, Nat. Comm. 5\, 3725 (2014).\n[2]  H. Yoshino and F. Za mponi\, Phys. Rev. E 90\, 022302 (2014).\n[3]  D. Nakayama\, H. Yoshino a nd F. Zamponi\, in preparation. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-390@lptms.universite-paris-saclay.fr DTSTART:20151016T103000Z DTEND:20151016T120000Z DTSTAMP:20151008T100122Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-viktor-eisler-zdzislaw-burda/ SUMMARY:Séminaire du LPTMS : Viktor Eisler &\; Zdzislaw Burda - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Oct 15 10:30 DESCRIPTION:\nEntanglement in mixed states: the negativity\n\n\nDr. Viktor Eisler (TU Graz)\n\nIn pure states of many-body systems\, entanglement is routinely studied via the Renyi entropies\, which give a complete characte rization of the bipartite case. The situation becomes more complicated\, i f the system is composed of more than two parts\, and one is interested in the entanglement between two non-complementary pieces. Such a scenario ca n be studied by introducing a new entanglement measure\, the so-called neg ativity\, which has been the focus of recent interest. In this talk I woul d like to give an overview about the available methods to calculate the ne gativity\, and present some new results on mixed-state entanglement.\n---- -----------------------\nQuaternionic R transform and non-hermitian random matrices\nDr. Zdzislaw Burda (AGH University of Science and Technology)\n Using the Cayley-Dickson construction we rephrase and review the non-hermi tian diagrammatic formalism [R. A. Janik\, M. A. Nowak\, G. Papp and I. Za hed\, Nucl.Phys. B 501\, 603 (1997)]\, that generalizes the free probabili ty calculus to asymptotically large non-hermitian random matrices. The mai n object in this generalization is a quaternionic extension of the R trans form which is a generating function for planar (non-crossing) cumulants. W e demonstrate that the quaternionic R transform generates all connected av erages of all distinct powers of X and its hermitian conjugate X†:  < \;<\;(1/N) Tr [Xa X†b Xc …] >\;>\;  for N → ∞. We show that the R transform for Gaussian elliptic laws is given by a simple linear qu aternionic map R(z+wj) = x + σ² (μ e^{2iφ} z + w j) where (z\,w) is th e Cayley-Dickson pair of complex numbers forming a quaternion q=(z\,w)≡ z+ wj. This map has five real parameters Re[x]\, Im[x]\, φ\, σ and μ. W e use the R transform to calculate the limiting eigenvalue densities of se veral products of Gaussian random matrices. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-381@lptms.universite-paris-saclay.fr DTSTART:20151016T143000Z DTEND:20151016T170000Z DTSTAMP:20151008T100146Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-ricardo-marino/ SUMMARY:Soutenance de thèse : Ricardo Marino - IPN-batiment 100\, Auditori urm - 16 Oct 15 14:30 DESCRIPTION:Number statistics in random matrices and applications to quantu m systems\nRicardo Marino\nRandom matrix theory has found many application s spanning a vast number of fields in physics and mathematics in the last two decades. Most recently\, the equivalence between the statistics of eig envalues of Gaussian Hermitian matrices  and the position of ground-state harmonically confined 1-D fermionic particles has been studied to obtain many interesting and universal results in cold atoms. In my thesis\, I exp lore this connection to solve the problem of determining quantum fluctuati ons of cold fermions using techniques from random matrix theory\, expandin g previous results that were restricted only to specific scaling limits of the spectrum to yield a full picture of the behavior of fluctuations of f ermionic particles in one dimensional traps. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-389@lptms.universite-paris-saclay.fr DTSTART:20151022T143000Z DTEND:20151022T160000Z DTSTAMP:20151008T085850Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/tri-seminaire-de- physique-statistique-martin-evans-2/ SUMMARY:Tri séminaire de Physique Statistique : Martin Evans - LPTMS\, sal le 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 22 Oct 15 14:30 DESCRIPTION:Explosive condensation in nonequilibrium systems\nMartin EVANS\ , School of Physics and Astronomy\, Univ. of Edinburgh\nIn this talk I wil l discuss condensation in the zero range process (ZRP) and related models. The ZRP is a simple model of interacting classical particles hopping betw een sites of a one-dimensional lattice\, but with rates that do not obey d etailed balance and thus generate a nonequilibrium state. Real-space conde nsation is the phenomenon whereby a finite fraction of the particles are t ypically found at a single site in the limit of a large system size. I'll show how and why condensation arises and how it is related to large deviat ions of sums of random variables. I'll also discuss a variation of the mod el exhibiting `explosive condensation' - the condensate moves rapidly thro ugh the system and the relaxation time to the stationary state decreases t o zero for large system size. This provides a first example of instantaneo us gelation in a spatially extended system. If time permits I will also di scuss how condensation generally arises when there are two constraints - s ay the sum and the variance - on a collection of random variables.\n\n--  CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-382@lptms.universite-paris-saclay.fr DTSTART:20151028T140000Z DTEND:20151028T163000Z DTSTAMP:20151023T112249Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-andrii-gudyma/ SUMMARY:Soutenance de thèse : Andrii Gudyma - - 28 Oct 15 14:00 DESCRIPTION:\nNon-equilibrium dynamics of a trapped one-dimensional Bose ga s\n\nAndrii Gudyma\n\nA study of breathing oscillations of a one-dimension al trapped interacting Bose gas is presented. Oscillations are initiated b y an instantaneous change of the trapping frequency. In the thesis a 1D qu antum Bose gas in a parabolic trap at zero temperature is considered\, and it is explained\, analytically and numerically\, how the oscillation freq uency depends on the number of particles\, their repulsive interaction\, a nd the trap parameters. We have focused on the many-body spectral descript ion\, using the sum rules approximation.  The oscillation frequency is id entified as the energy difference between the ground state and a particula r excited state.\nThe existence of three regimes is demonstrated\, namely the Tonks regime\, the Thomas-Fermi regime and the Gaussian regime. The tr ansition from the Tonks to the Thomas-Fermi regime is described in the ter ms of the local density approximation (LDA). For the description of the tr ansition from the Thomas-Fermi to the Gaussian regime the Hartree approxim ation is used. In both cases the parameters where the transitions happen a re found. The extensive diffusion Monte Carlo simulations for a gas contai ning up to N = 25 particles is performed. As the number of particles incre ases\, predictions from the simulations converge to the ones from the Hart ree and LDA in the corresponding regimes. This makes the results for the b reathing mode frequency applicable for arbitrary values of the particle nu mber and interaction. The analysis is completed with the finite N perturba tive results in the limiting cases. The theory predicts the reentrant beha vior of  the breathing mode frequency when moving from the Tonks to the G aussian regime and fully explains the recent experiment of the Innsbruck g roup.\n\n CATEGORIES:seminars END:VEVENT BEGIN:VEVENT UID:1-368@lptms.universite-paris-saclay.fr DTSTART:20151102T110000Z DTEND:20151102T120000Z DTSTAMP:20151030T110046Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-romain-koszul/ SUMMARY:Physics-Biology interface seminar: Romain Koszul - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 2 Nov 15 11:00 DESCRIPTION:Insights on the regulatory principles of genome organization in unicellular microorganisms\nRomain Koszul (Institut Pasteur)\n\nChromosom es of a broad range of kingdoms\, from bacteria to mammals\, are structure d by large topological domains\, whose precise functional roles and regula tory mechanisms remain elusive. Using chromosome conformation capture tech nology\, we unraveled the higher-order organization of the Bacillus subtil is\, Escherichia coli and Vibrio cholerae genomes\, in a variety of growth and mutant conditions. Different types of topological domains were found to structure these chromosomes\, ranging from a few dozens to a thousand k b. We show that the matP/matS and parB/parS systems generate specific type s of topological structures\, regulated by replication and cell cycle prog ression. We have also functionally characterized some of the global organi zational principles of these domains\, in link with replication/segregatio n during the cell cycle. Overall\, the comparative analysis of these diffe rent species provide striking insights on the diversity of the regulatory mechanisms of genome structure of the bacterial world. In addition\, I wi ll also present and discuss recent data obtained during the cell cycle of the eukaryotic species Saccharomyces cerevisiae.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-383@lptms.universite-paris-saclay.fr DTSTART:20151103T113000Z DTEND:20151103T123000Z DTSTAMP:20151027T085821Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marie-piraud/ SUMMARY:Séminaire du LPTMS: Marie Piraud (ATTENTION horaire inhabituel) - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 3 Nov 15 11 :30 DESCRIPTION:\nInteracting bosons on ladder in the presence of gauge fields: Swimming against the tide !\n\nMarie Piraud\, Ludwig-Maximilians-Universi tät München\n\nWe present the phase diagrams of the interacting Bose-Hub bard model defined on two- and three-leg ladder geometries in the presence of a homogeneous flux. Our work is motivated by recent experiments using laser assisted-tunneling in optical lattices [1] and lattices in synthetic dimensions [2]\, which studied the regime of weak interactions. Based on extensive density matrix renormalization group simulations and a bosonizat ion analysis for the two-leg ladder\, we explore the parameter space and c alculate experimentally accessible observables.\n\nThe phase diagrams comp rise gapless and gapped Meissner and vortex phases\, with the gapped state s emerging in Mott-insulating regimes [3\,4]. We show that vortex lattices also form at certain commensurate vortex densities [4\,5]. On the two-leg ladder\, we also find the so-called 'biased leg phase'\, which shows dens ity-imbalance between the two legs [6].\n\nVery interestingly\, an enlarge d unit cell forms in the vortex lattice phases\, which can lead to the rev ersal of the current circulation-direction. We demonstrate this effect for arbitrarily weak interactions and at sufficiently low temperature\, and s how that it is significant for intermediate interactions [5].\n\n[1] Atala etal.\, Nature Phys. 10\, 588 (2014)\n[2] Mancini etal.\, Science 349\, 1 510-1513 (2015)\n[3] Piraud etal.\, PRB 91\, 140406(R) (2015)\n[4] Kolley etal.\, NJP 17\, 092001 (2015)\n[5] Greschner etal.\, to appear in PRL (20 15)\n[6] Wei and Mueller\, PRA 89\, 063617 (2014)\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-385@lptms.universite-paris-saclay.fr DTSTART:20151110T110000Z DTEND:20151110T120000Z DTSTAMP:20151106T162335Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jerry-percus/ SUMMARY:Séminaire du LPTMS: Jerome K. Percus - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Nov 15 11:00 DESCRIPTION:Random walks that generate their own environment\nJ.K. Percus\, Courant Inst and Physics Dept\, New York University\nThe term "random wal k in a random environment" covers many phenomena in applied science. Most frequently\, it refers to two independent random processes. We will look a t the opposite extreme\, in which the previous state of a - typically next neighbor walk on a lattice -changes the parameters of the current site. A primitive example that can be interpreted in this way is that of the stat istics of the maximum of a walk on the half line\, where we would expect a substantially increased mean and a substantially decreased variance over that of the underlying walk. How extreme are these? A more structured exam ple\, of relevance to synaptic strengthening\, is that of a reinforced ran dom walk\, in which the first visit to a given site strengthens the "attra ction" of that site for future visits\, and this is quite simple in the Br ownian motion limit. Still more nuanced is the situation in which the "att raction" depends upon the number of previous visits.\n\n(in collaboration with O.E. Percus) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-371@lptms.universite-paris-saclay.fr DTSTART:20151116T110000Z DTEND:20151116T120000Z DTSTAMP:20151030T073401Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jens-elgeti/ SUMMARY:Physics-Biology interface seminar: Jens Elgeti - Moyen Amphi\, Buil ding 510\, Université Paris-Saclay Orsay - 16 Nov 15 11:00 DESCRIPTION:Simulating Growing Tissues\nJens Elgeti (Forschungszentrum Jül ich)\nGrowth of solid tumors or metastasis requires\, besides massive biom edical changes\, also a spatial remodelling of the tissue. This remodellin g\, often including displacements of healthy tissue around\, requires mech anical work to be done. These mechanics of growth has attracted a lot of a ttention in recent years\, but still remains poorly understood.\n\nWe use particle based simulations to study mechanical properties and effects in g rowing and motile tissues. These simulations have been helpful in understa nding\, interpreting and designing experiments. I will present an overvie w of the simulation technique\, and how it contributed to recent developme nts in three dimensional tissue growth and collective cell migration. In a recent series of simulations and close experimental collaborations we fou nd important interfacial and surface effects that lead to novel phenomena. For example\, the tissue divides favorably at a free surface\, even witho ut any nutrient effects. This leads to the possibility and stability of a negative homeostatic pressure. In turn\, a negative homeostatic pressure l eads to naturally to finite steady states and tensile states.\n\nReference s:\n[1] M.Basan et al\, PNAS 110:2452 (2013)\n[2] F. Montel et al\, N. J. Phys. 14:055008 (2012) \n[3] F. Montel et al\, Phys. Rev. Lett. 107:18810 2\, (2011)\n[4] M. Basan et al\, Phys. Biol. 8:026014\, (2011)\n[5] J. Ran ft et al\, PNAS 107:20863\, (2010) CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-387@lptms.universite-paris-saclay.fr DTSTART:20151117T110000Z DTEND:20151117T120000Z DTSTAMP:20151029T115614Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pierre-elie-larre/ SUMMARY:Séminaire du LPTMS: Pierre-Elie Larré - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 17 Nov 15 11:00 DESCRIPTION:Superfluid and quantum features in the hydrodynamic flow of a f luid of light\nPierre-Élie Larré\, INO-CNR BEC Center\, Dipartimento di Fisica\, Università di Trento\, Via Sommarive 14\, 38123 Povo\, Italia\nI n the presence of a significant Kerr optical nonlinearity\, a many-photon light beam can behave as a quantum fluid of interacting bosons. This has o pened the way to active experimental and theoretical investigations of man y-body hydrodynamic and quantum features in photon-based systems\, the res earch field of the so-called quantum fluids of light. A promising platform to study photon-fluid physics consists in the paraxial propagation of a q uasimonochromatic light wave through a nonabsorbing cavityless nonlinear o ptical medium of Kerr type. In contrast to semiconductor-planar-microcavit y architectures where driving and dissipation play a major role in the evo lution of the fluid of light\, the photon field in a cavityless\, propagat ing\, geometry obeys a fully conservative Gross–Pitaevskii-type quantum dynamics. The statistical properties of the photon beam entering the diele ctric fix the initial conditions of the problem and the ones of the light exiting the medium determine the final state of the photon field.\nThe fir st part of my talk will be dedicated to a review of a very general quantum theory of light propagation in such a configuration. As a first applicati on of the formalism\, we will see in a second part that the occurrence of a frictionless flow of superfluid light past a solid dielectric immersed i nto a nonlinear optical liquid may be revealed from the dramatic suppressi on of the optomechanical deformation of the object\, demonstrating that\, in the optical case also\, superfluidity is associated with a drop in the force exerted by the fluid on obstacles stymying its flow. In a third part \, I will show that the paraxial-propagation geometry constitutes a very s imple platform to investigate quantum-quench physics in closed systems of many interacting bosons\, including\, e.g.\, the acoustic analog of the dy namical Casimir effect\, the light-cone-like spreading of the two-body cor relations following a quantum quench\, or the emergence of prethermalizati on features in one-dimensional configurations. Before concluding\, I will present ongoing experiments aiming at measuring the Bogoliubov dispersion relation in a one-dimensional nonlinear optical waveguide (in Trento) and at detecting superfluid features in the flow of a photon fluid past a loca lized optical defect (in Nice and Edinburgh). Finally\, I  will briefly e xpose in-progress works carried out in Trento and Trieste\, on the study o f the strong-interaction\, Tonks–Girardeau\, regime in one-dimensional c avityless geometries and on the investigation of the relaxation of a quant um-quenched photon gas towards the Bose–Einstein statistics. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-393@lptms.universite-paris-saclay.fr DTSTART:20151124T110000Z DTEND:20151124T120000Z DTSTAMP:20151104T120430Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jacopo-de-nardis/ SUMMARY:Séminaire du LPTMS: Jacopo de Nardis - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 24 Nov 15 11:00 DESCRIPTION:Time evolution of out-of-equilibrium integrable models\nJacopo de Nardis\, LPS ENS\n\nNon-equilibrium quantum mechanics has received a co nsiderable attention in the last years and in particular the dynamics obse rved after a quantum quench\, when a global parameter in the Hamiltonian o f the system is rapidly changed. We focus here on the post-quench time evo lution of the simplest interacting integrable models as the Lieb-Liniger d elta-Bose gas and the spin-1/2 XXZ spin chain. We address the problem of d etermining the steady state after a quench in the interaction strength and the time evolution towards it. While the steady state is determined by se ts of recently introduced quasi-local conserved quantities\, the time evol ution is related to the thermodynamic limit of the matrix elements and of the overlap coefficients between the eigenstates of the model and the init ial state.\n\n\n\n\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-372@lptms.universite-paris-saclay.fr DTSTART:20151130T110000Z DTEND:20151130T120000Z DTSTAMP:20151128T111622Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-christoph-schmidt/ SUMMARY:Physics-Biology interface seminar: Christoph Schmidt - Moyen Amphi\ , Building 510\, Université Paris-Saclay Orsay - 30 Nov 15 11:00 DESCRIPTION:SEMINAR CANCELLED CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-400@lptms.universite-paris-saclay.fr DTSTART:20151201T110000Z DTEND:20151201T120000Z DTSTAMP:20151124T141619Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-o-lychkovskiy/ SUMMARY:Séminaire du LPTMS: Oleg Lychkovskiy - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 1 Déc 15 11:00 DESCRIPTION:Perpetual motion and driven dynamics of a mobile impurity in a quantum fluid.\nOleg Lychkovskiy\, Russian Quantum Center\, Moscow\nWe stu dy the dynamics of a mobile impurity in a quantum fluid at zero temperatu re. Two related settings are considered. In the first setting\, the impur ity is injected in the fluid with some initial velocity v_0 (which is bel ow the critical velocity)\, and we enquire about its velocity at infinite time\, v_inf. We derive a rigorous upper bound on |v_0 − v_inf|. In the limit of vanishing impurity-fluid coupling\, this bound amounts to v_inf = v_0\, which is anticipated from the Landau criterion of superfluidity. In the case of a finite coupling\, the velocity of the impurity can decr ease\, but not to zero\; the bound quantifies the maximal possible decrea se.\nIn the second setting\, a small constant force is exerted upon the im purity. We argue that two distinct dynamical regimes exist—backscatterin g oscillations of the impurity velocity and saturation of the velocity wit hout oscillations. Which regime is realized depends on the mass of the imp urity. A nonequilibrium quantum phase transition occurs at some critical m ass. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-394@lptms.universite-paris-saclay.fr DTSTART:20151208T110000Z DTEND:20151208T120000Z DTSTAMP:20151022T114153Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-hugo-touchette/ SUMMARY:Séminaire du LPTMS: Hugo Touchette - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 8 Déc 15 11:00 DESCRIPTION:\nMarkov processes conditioned on large deviations\nHugo Touche tte\, National Institute for Theoretical Physics (NITheP)\,Stellenbosch\, South Africa\n\nI will discuss in this talk recent works with Raphael Chet rite (Université de Nice) on Markov processes conditioned on rare events - for example\, Brownian motion conditioned on having a given asymptotic v elocity or on staying positive for a very long time. I will show that a pr ocess conditioned on a large deviation can be represented in the long-time limit by a conditioning-free Markov process\, called the driven or the eq uivalent process\, which has the same typical states as the conditioned pr ocess. The driven process arises in the study of nonequilibrium processes and the simulation of large deviations. Other applications related to reac tion paths\, stochastic optimal control\, and Brownian bridges and meander s will also be mentioned.\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-399@lptms.universite-paris-saclay.fr DTSTART:20151214T110000Z DTEND:20151214T120000Z DTSTAMP:20151130T182904Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-etienne-fodor/ SUMMARY:Physics-Biology interface seminar: Étienne Fodor - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 14 Déc 15 11:00 DESCRIPTION:Tracking nonequilibrium physics in living systems\nÉtienne Fod or (Université Paris-Diderot)\nLiving systems operate far from equilibriu m due to the continuous injection of energy provided by ATP supply. The dy namics of the intracellular components is driven by both thermal equilibri um fluctuations and active stochastic forces generated by the molecular mo tors. Tracer particles are injected in living cells to study these fluctua tions. Alternatively\, vesicles which are already present in the cytoplasm serve as probes of the intracellular dynamics.\nTo sort out genuine noneq uilibrium fluctuations from purely thermal effects\, we combine passive an d active microrheology methods. They consist in measuring the spontaneous tracer fluctuations and extracting the response from an external oscillato ry perturbation. By testing the fluctuation-dissipation theorem\, we quant ify the deviation from equilibrium appearing at low frequency. Removing th e thermal contribution in the tracer fluctuations\, we estimate the spectr um of the active forces. Eventually\, we report non-Gaussian tails in the tracer displacement distribution as a result of directed motion events.\ nWe recapitulate theoretically the observed fluctuations by modeling the d ynamics with a confining harmonic potential which experiences random burst s as a result of motor activity [1]. This minimal model allows us to quant ify the time and length scales of the active forces\, along with the energ y scale injected by the ensuing fluctuations [2\, 3]. Finally\, we estimat e the energy dissipated by the tracers in the surrounding environment\, le ading us to define an efficiency of the energy conversion driving the trac er dynamics [4].\n\nReferences\n\n [1] É. Fodor et al.\, Phys. Rev. E 90\ , 042724 (2014)\n [2] É. Fodor et al.\, EPL 110\, 48005 (2015)\n [3] W. W . Ahmed et al.\, arXiv:1510.08299 \n [4] É. Fodor et al.\, arXiv:1511.009 21\n\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-386@lptms.universite-paris-saclay.fr DTSTART:20151215T110000Z DTEND:20151215T120000Z DTSTAMP:20151124T081340Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-da/ SUMMARY:Séminaire du LPTMS: Andrea Gabrielli - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Déc 15 11:00 DESCRIPTION:Estimating topological properties of weighted networks from lim ited information\n\nAndrea Gabrielli\, Dipartimento di Fisica\, Universit à di Roma La Sapienza\n\nA problem typically encountered when studying co mplex systems is the limitedness of the information available on their top ology\, which hinders our understanding of their structure and of the dyna mical processes taking place on them. A paramount example is provided by f inancial networks\, whose data are privacy protected: Banks publicly discl ose only their aggregate exposure towards other banks\, keeping individual exposures towards each single bank secret. Yet\, the estimation of system ic risk strongly depends on the detailed structure of the interbank networ k. The resulting challenge is that of using aggregate information to stati stically reconstruct a network and correctly predict its higher-order prop erties. Standard approaches either generate unrealistically dense networks \, or fail to reproduce the observed topology by assigning homogeneous lin k weights. Here [1]\, we develop a reconstruction method\, based on statis tical mechanics concepts\, that makes use of the empirical link density in a highly nontrivial way. Technically\, our approach consists in the preli minary estimation of node degrees from empirical node strengths and link d ensity\, followed by a maximum-entropy inference based on a combination of empirical strengths and estimated degrees. Our method is successfully tes ted on the international trade network and the interbank money market\, an d represents a valuable tool for gaining insights on privacy-protected or partially accessible systems.\n\n[1] G. Cimini\, T. Squartini\, A. Gabriel li\, and D. Garlaschelli\, Phys. Rev. E 92\, 040802(R)\, 2015\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-378@lptms.universite-paris-saclay.fr DTSTART:20160111T110000Z DTEND:20160111T120000Z DTSTAMP:20160104T101710Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-ruxandra-gref/ SUMMARY:Physics-Biology interface seminar: Ruxandra Gref - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 11 Jan 16 11:00 DESCRIPTION:Nanoparticules de type « cage » : applications pour lutter co ntre le cancer et les infections résistantes au traitement \nRuxandra Gre f (ISMO\, Université Paris-Sud)\nDeux exemples de vecteurs de médicament s élaborés par une « chimie douce » (sans solvant) seront présentés : i) les nanoparticules hybrides organiques-inorganiques (metal-organic fr ameworks ou MOFs)\, qui sont des assemblages supramoléculaires cristallin s hautement poreux\, et ii) les nanoparticules à base de cyclodextrines\, molécules « cage ». Avantageusement\, ces nanoparticules sont capables d’encapsuler des quantités importantes de molécules thérapeutiques d e nature chimique variée par simple imprégnation dans un milieu aqueux. La surface de ces vecteurs a été modifiée avec des éléments de reconn aissance spécifiques afin de moduler l’interaction des nanoparticules a vec le milieu vivant et d’accroitre l’internalisation de celles-ci dan s les cellules cible (cellules cancéreuses ou cellules infectées avec le VIH ou des bactéries). Finalement\, des exemples seront présentés ou l a libération des molécules thérapeutiques se fait « sur demande » sui te à l’application d’un stimulus externe. Les applications de ces tra vaux se situent dans le domaine du traitement du cancer et des infections résistantes au traitement. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-407@lptms.universite-paris-saclay.fr DTSTART:20160112T110000Z DTEND:20160112T121500Z DTSTAMP:20160107T131849Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-haggai-landa-3/ SUMMARY:Séminaire du LPTMS: Haggai Landa - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 12 Jan 16 11:00 DESCRIPTION:Quasi-bound states in periodically driven scattering\n\nHaggai Landa (LPTMS)\n\nI will discuss the interaction of a cold atom co-trapped with an ion in a Paul trap\, a platform which in recent years promises to make possible investigations of ion-neutral interactions in the ultracold regime. The main theoretical and experimental difficulty in this system is due to the time dependence of the ion trap\, which is periodically modula ted by an AC voltage. We present a general approach for obtaining eigenfun ctions of periodically driven time-dependent Hamiltonians and derive an ex plicit expansion for scattering problems with mixed cylindrical and spheri cal symmetry [1]. Using this method we study quasi-bound states of a spher ically-symmetric potential in three dimensions subject to an axial driving force. The analysis of the ion-atom system is completed by solving self-c onsistently the time-dependent wavefunctions of the atom together with the periodic force it exerts on the ion [2].\n[1]     H. Landa\, arXiv:  1506.08779\n[2]     H. Landa and G. V. Shlyapnikov\, in preparatio n\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-388@lptms.universite-paris-saclay.fr DTSTART:20160115T093000Z DTEND:20160115T181500Z DTSTAMP:20151218T143012Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-hdr-dm itry-petrov-et-mini-workshop/ SUMMARY:Soutenance HDR Dmitry Petrov et mini-workshop - IPN-batiment 100\, Auditoriurm - 15 Jan 16 09:30 DESCRIPTION:10:00 - 12:00\nSoutenance HDR Dmitry Petrov\n"Developing and ap plying the zero-range approach for few-atom problems"\n\n13:30 - 17:30\nWo rkshop on Nuclei\, atoms\, molecules: Few-body problem and beyond\n13:03 " Spin ordering in small atomic clouds'' Jean Dalibard (Collège de France)\ n\n14:05 "Few-Nucleon Systems: Universality and Lattice QCD'' Ubirajara va n Kolck (Institut de Physique Nucléaire Groupe de Physique Théorique)\n\ n14:40 "Contact modeling of the effective range in 1D quantum gases and in tegrability issue" Ludovic Pricoupenko (LPTMC - Université Pierre et Mari e Curie)\n\n15:15 Coffee break\n\n15:45 "Observation of quantum phase slip s in ultracold gases?" Giovanni Modugno (Dipartimento di Fisica e Astronom ia\, Fiorentino)\n\n16:20 "Confinement and broken scale-invariance with ul tracold atoms'' Wilhelm Zwerger (Technische Universität München - Physik Department)\n\n16:55 "Four-body long-range interactions between ultracold weakly-bound diatomic molecules" Olivier Dulieu (Laboratoire Aimé Cotton - Université Paris-Sud) CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-402@lptms.universite-paris-saclay.fr DTSTART:20160119T110000Z DTEND:20160119T121500Z DTSTAMP:20160105T093051Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-beatriz-seoane-bartolome/ SUMMARY:Séminaire du LPTMS: Beatriz Seoane Bartolome - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Jan 16 11:00 DESCRIPTION:One solid\, two glasses\nBeatriz Seoane Bartolome (LPT-ENS Pari s)\n\n\nGlasses (aka amorphous solids) exhibit various anomalies whencompa red with crystals (aka ordered solids):  they display enhanced transport\ , activated slow dynamics across energy barriers\, excess vibrational mode s with respect to Debye’s theory (the so-called Boson Peak)\, and respon d drastically to very small mechanical deformations. In this work\, we ide ntify the common\, universal origin to these anomalies in a realistic\, th ree-dimensional model of glasses. We show that in packed hard spheres\, vi brations become highly correlated in space and time at a sharply defined t hreshold\, which we call "Gardner threshold".  This work is deeply relate d with the last developments in the analytical theory of glasses\, where t he glass problem has been finally solved exactly in the artificial limit o f infinite spatial dimensions. The analytical solution predicts the existe nce of a genuine phase transition (a Gardner phase transition) within the glass\, separating the glass :and the jamming transitions. In this work we \, not only establish the  relevance of the (remanent of the) Gardner tra nsition for real glasses\, but also characterize it using well-defined obs ervables\, including time-dependent quantities and spatial correlations\, that should be experimentally measurable.\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-396@lptms.universite-paris-saclay.fr DTSTART:20160125T110000Z DTEND:20160125T121500Z DTSTAMP:20160114T121537Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-denis-grebenkov/ SUMMARY:Physics-Biology interface seminar: Denis Grebenkov - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 25 Jan 16 11:00 DESCRIPTION:Inferring anomalous diffusion from single particle trajectories \nDenis Grebenkov (PMC\, École polytechnique)\nSPECIAL LOCATION\nTranspor t of macromolecules\, organelles and vesicles in living cells \nis a very complicated process that essentially determines and controls \nmany bioche mical reactions\, growth and functioning of cells. The passive \nthermal d iffusion through the overcrowded cytoplasm is combined with \nthe active t ransport by motor proteins attached to microtubules. This \nintricate mech anism results in anomalous diffusions that found abundant \nexperimental e vidences but no consensus on the physical mechanism and \nthe appropriate mathematical model is achieved so far. Single-particle \ntracking (SPT) ex periments survey random trajectories of individual \ntracers inside living cells and can thus provide the missing information \non the intracellular transport in order to discriminate between different \nphysical mechanism s and to identify the appropriate theoretical model \nof anomalous diffusi on. In SPT\, an ensemble average of the quantities \nof interest (e.g.\, d iffusivity\, viscosity\, first passage times\, etc.) \nis often unavailabl e or even undesired\, as tracers move in spatially \nheterogeneous and tim e evolving media such as living cells. One faces \ntherefore a challenging problem of inferring dynamical\, structural and \nfunctional properties o f living cells from a limited (small) number of \nindividual random realiz ations of an unknown stochastic process.\nAfter a short introduction to th eoretical aspects of the intracellular\ntransport\, we discuss the recent progress onto probing ergodicity of\nthe tracer dynamics from a single par ticle trajectory. The proposed \nestimators are first investigated for sev eral models of anomalous \ndiffusion. In the case of nonergodic continuou s time random walks\, \nwe show analytically that both estimators do not v anish even for \ninfinitely long trajectories. The estimators are then ap plied to \ntwo sets of earlier published trajectories: mRNA molecules insi de \nlive E. coli cells and Kv2.1 potassium channels in the plasma membran e.\nThese tests suggest that the former set exhibits ergodic behavior\nwhi le the latter reveals both ergodic and nonergodic features. CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-395@lptms.universite-paris-saclay.fr DTSTART:20160126T110000Z DTEND:20160126T120000Z DTSTAMP:20160112T073716Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-elisabeth-agoritsas/ SUMMARY:Séminaire du LPTMS: Elisabeth Agoritsas - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 26 Jan 16 11:00 DESCRIPTION:\n\nRevisiting mean-field elasto-plastic models at the mesoscop ic scale\n\nElisabeth Agoritsas (Université Grenoble-Alpes)\n\nEncompassi ng very dissimilar systems (such as foams\, emulsions\, or granular materi als)\, amorphous materials are composed of constituents of different shape s and sizes\, such as bubbles in a soap foam or sand grains in a sandpile\ , so that they exhibit a structural disorder that plays a determinant role in their mechanical properties\, while challenging their very description . Several elasto-plastic models have been developed at the mesoscopic scal e\, in order to account for the plasticity in sheared amorphous materials\ , such as the Hébraud- Lequeux (HL) model [P. Hébraud &\; F. Lequeux \, Phys.Rev.Lett. 81\, 2934 (1998)]. They have proven to be rather success ful in reproducing certain features observed in amorphous systems\, but no t all at once. Moreover\, a consistent picture connecting them is still mi ssing. Here we discuss the physical ingredients that are put in such mean- field models\, distinguishing between thermal and mechanical noises in the mean-field dynamics of amorphous materials. We focus in particular on the role of structural disorder\, implemented by means of a distribution of e nergy barriers for the system to overcome locally when an external constan t shear rate is applied to the material\, and discuss specifically its imp lications for a generalization of the HL model [E. Agoritsas et al.\, Eur. Phys.J.E 38\, 71 (2015)].\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-403@lptms.universite-paris-saclay.fr DTSTART:20160202T110000Z DTEND:20160202T121500Z DTSTAMP:20160122T150852Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-marie-stephan-2/ SUMMARY:Séminaire du LPTMS: Jean-Marie Stephan - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 2 Fév 16 11:00 DESCRIPTION:\n\nFilling fraction quantum quenches and the arctic circle\n\n Jean-Marie Stephan (PKS-MPG Dresden)\n\nI consider a simple non-equilibriu m problem\, where a critical one-dimensional system is prepared in a state with two different densities on the left and on the right\, and let evolv e with a Hamiltonian that conserves the number of particles. A typical exa mple would be a fermionic system prepared with different left/right chemic al potentials. For free systems a lot can\, and has been understood by mak ing use of a semiclassical picture\, in which particles carrying a momentu m k propagate ballistically with velocity v(k). Generalization to interact ing systems is very much an open problem. I will discuss attempts at under standing such dynamics using field theory. A possible strategy is to study the behavior in imaginary time\, the real time dynamics being recovered b y performing the Wick rotation. I will show that all degrees of freedom ou tside a certain region may freeze in imaginary time\, contrary to naive ex pectations. This behavior is analogous to the celebrated "arctic circle" p henomenon found in the study of two-dimensional classical dimer or vertex models. I will also show that the fluctuating region is described by a mas sless field theory with a position-dependent metric\, a field theory in cu rved space. Such imaginary time pictures can be used to make predictions a bout the behavior of correlation functions\, entanglement entropies\, or r eturn probabilities after the quench.\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-409@lptms.universite-paris-saclay.fr DTSTART:20160208T110000Z DTEND:20160208T120000Z DTSTAMP:20160203T121536Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-paolo-pierobon/ SUMMARY:Physics-Biology interface seminar: Paolo Pierobon - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 8 Fév 16 11:00 DESCRIPTION:Mechanics of B cell response\nPaolo Pierobon (Institut Curie\, Paris)\nB lymphocytes are the antibodies producing cells and therefore ess ential effectors of adaptive immunity. In vivo\, their activation is mostl y triggered by the engagement of their B cell receptor (BCR) with antigens exposed at the surface of neighbouring antigen presenting cells. This lea ds to the formation of a signalling platform\, the immune synapse\, where cytoskeleton rearrangement are essential for the antigen extraction\, inte rnalization and processing. While it has been shown that on a hard substra te the cell follows a dynamics of spreading and contraction\, this has nev er been investigated on substrates with rigidity close to the physiologica l one. We measure for the first time the forces produced by B cells on def ormable antigen coated surfaces (traction force microscopy) and show that these forces are contractile\, specifically induced by BCR activation and Myosin II dependent. We characterize the contractile dynamics of the cell and argue that in generating pulling forces\, Myosin II plays a crucial ro le in antigen gathering and internalization. These results open interestin g perspectives on the role of mechanics in the acquisition of specific ant igen and more generally on receptor internalization. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-404@lptms.universite-paris-saclay.fr DTSTART:20160209T110000Z DTEND:20160209T121500Z DTSTAMP:20160202T113152Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-manon-michel/ SUMMARY:Séminaire du LPTMS: Manon Michel - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 9 Fév 16 11:00 DESCRIPTION:\n\nEvent-chain paradigm for Monte Carlo methods: Infinitesimal \, irreversible and rejection-free Markov chains.\n\nManon Michel (LPS-ENS )\n\nMonte Carlo methods\, by sampling high-dimensional integrals through random walks\, have revolutionized the understanding of complex systems. T he traditional Metropolis local random walks induce however a high rate of rejections\, making any simulations around a phase transition point too e xpensive. I explain how a consistent interpretation of the mathematical li fting concept and the factorized Metropolis filter yield a new paradigm of irreversible algorithms. This new class of rejection-free algorithms inde ed break detailed balance yet fulfill the global one and display moves tha t are infinitesimal\, instead of finite random local moves.\nAs an applica tion\, I exhibit how event-chain algorithms bring considerable speed-ups f or general particles systems\, but also for classical continuous spin mode l\, including the notoriously difficult problem of spin glasses. In partic ular\, recent work on Heisenberg spins system shows a qualitative reductio n of the dynamical scaling exponent\, leading to an infinite speed-up. The powerful event-chain algorithm is general yet easy to implement. Its infi nite number of samples provide direct access to observables that could not be obtained directly and complex interactions can be factorized into simp le components.\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-405@lptms.universite-paris-saclay.fr DTSTART:20160216T110000Z DTEND:20160216T121500Z DTSTAMP:20160209T071354Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giacomo-gradenigo-2/ SUMMARY:Séminaire du LPTMS: Giacomo Gradenigo - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Fév 16 11:00 DESCRIPTION:\n\nEffective thermodynamics for a driven athermal system with dry friction\n\nGiacomo Gradenigo (Grenoble-Alpes)\n \;\nWhich are the situations where an effective thermodynamic theory works even in the lack of thermal equilibrium? Which is the meaning of "temperature" for an out- of-equilibrium system?\nI present here the study of a driven athermal syst em\, i.e. a one-dimensional chain of masses connected by harmonic springs and subject to Coulomb dry friction\, where answers to the above questions can be provided. Our main result is the evidence that the configuration s pace of our system is visited under the unfluence of an external driving i n an equilibrium-like manner: configurations are sampled according to thei r energy with a Boltzmann-like probability even in presence of a dissipati ve dynamics.\nThis evidence is obtained by comparing the exact calculation of the partition function\, obtained by means of a transfer matrix approa ch\, to numerical simulations of the driven dissipative dynamics. Interest ingly enough\, the existence of a critical point at infinite effective tem perature is pointed out.\nI conclude presenting different lines along whic h the spring-block model here introduced can be exploited to investigate t he scope of validy of equilibrium statistical mechanics for a driven ather mal systems. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-410@lptms.universite-paris-saclay.fr DTSTART:20160307T110000Z DTEND:20160307T120000Z DTSTAMP:20160219T145015Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-frederic-pain/ SUMMARY:Physics-Biology interface seminar: Frédéric Pain - Petit Amphi\, Building 510\, Université Paris-Sud Orsay - 7 Mar 16 11:00 DESCRIPTION:Assessment of optimal parameters for deep optogenetic stimulati ons in non human primate\nFrédéric Pain (IMNC\, Université Paris-Sud)\n SPECIAL LOCATION (next door from the usual one)\nOptogenetics has become u biquitous in fundamental neuroscience labs as a very powerful tool to unra vel brain networks connectivity and cellular mechanisms. Yet\, its clinica l translation requires a careful assessment of the inocuity of repeated an d sustained high power light stimulations. In a preliminary studies to tra nslational research in the field deep brain stimulation for Parkinson's di sease we have studied in vivo in anesthetized rats the potential damages a nd non-physiological effects produced by high power optical neurostimulati on in typical optogenetics experiments.2D Maps of light distribution and t emperature increase were recorded in wild type anesthetized rats brains fo r relevant optical stimulation protocols used in optogenetics. The spatial profile of light distribution and heat were correlated and demonstrated a s expected a rapid attenuation with distance to the fiber. Temperature inc rease remains below physiological changes for stimulations up to 400mW/mm ². \nI will present optogenetics issues in a clinical translational conte xt. CATEGORIES:physbio,seminars LOCATION:Petit Amphi\, Building 510\, Université Paris-Sud Orsay\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.699116;2.179468 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Petit Amphi\, Building 510\, Un iversité Paris-Sud Orsay:geo:48.699116,2.179468 END:VEVENT BEGIN:VEVENT UID:1-416@lptms.universite-paris-saclay.fr DTSTART:20160308T110000Z DTEND:20160308T120000Z DTSTAMP:20160226T075934Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-patrice-hello/ SUMMARY:Séminaire du LPTMS: Patrice Hello - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 8 Mar 16 11:00 DESCRIPTION:GW150914 : la naissance de l'astronomie des ondes gravitationne lles\nPatrice Hello (LAL\, Université Paris Sud)\nOne century after the i nitial theoretical prediction\, the first direct observation of gravitatio nal waves has been announced in February the 11th by the LIGO and Virgo co llaborations. This is an extraordinary accomplishment after decades of wor ldwide instrumental efforts. I will first recall the nature of gravitation al waves and their effect on matter and then I will review the interesting astrophysical sources for LIGO and Virgo. I will then describe the interf erometric detection of gravitational waves and the LIGO-Virgo network. I w ill finally discuss the details of GW150914\, the first gravitational wave signal detected by the LIGO instruments and emitted by a Binary Black Hol e merger.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-401@lptms.universite-paris-saclay.fr DTSTART:20160315T140000Z DTEND:20160315T170000Z DTSTAMP:20160304T142551Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-hdr-ra oul-santachiara/ SUMMARY:Soutenance HDR Raoul Santachiara - IPN-batiment 100\, Auditoriurm - 15 Mar 16 14:00 DESCRIPTION:Conformal invariance in statistical and quantum physics CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-376@lptms.universite-paris-saclay.fr DTSTART:20160321T110000Z DTEND:20160321T120000Z DTSTAMP:20160310T171713Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-franck-julicher/ SUMMARY:Physics-Biology interface seminar: Franck Jülicher - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 21 Mar 16 11:00 DESCRIPTION:Shaping a fly wing\nFranck Jülicher (MPI-PKS Dresden)\nA funda mental question in Biology is to understand the morphogenetic processes by which an organism of complex shape forms from a fertilized egg. This morp hogenesis involves the dynamic remodeling of tissues consisting of many ce lls that grow and divide. The fly wing is an important model system for th e study of multicellular dynamics during tissue morphogenesis. During pupa l stages\, the early fly wing undergoes a spectacular dynamic reorganizati on that involves cell flows\, cell divisions and cell shape changes. This dynamic process generates the final shape of the wing. We characterize tis sue remodeling by the contributions of specific cellular processes such as cell shape changes and cell neighbor exchanges to macroscopic shear at di fferent times. We discuss the dynamics and the mechanics of this tissue us ing theoretical approaches that capture the essential physics of tissue re modeling. Our work suggests that local tissue contraction together with an isotropic active processes drive tissue remodeling in the fly wing. We sho w that mechanical boundary conditions play a key role in determining the f inal tissue shape. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-406@lptms.universite-paris-saclay.fr DTSTART:20160322T110000Z DTEND:20160322T121500Z DTSTAMP:20160313T162943Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-neil-ribe/ SUMMARY:Séminaire du LPTMS: Neil Ribe - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 22 Mar 16 11:00 DESCRIPTION:Acrobatics of liquid ropes\nNeil Ribe (FAST\, Université Paris -Sud)\nA thin `rope' of viscous fluid falling from a sufficient height ont o a surface forms a steadily rotating helical coil. Tabletop laboratory ex periments in combination with a numerical model for slender fluid ropes re veal that finite-amplitude coiling can occur in four distinct regimes (vis cous\, gravitational\, inertio-gravitational\, and inertial) corresponding to different balances among the three principal forces acting on the rope . The model further shows that the onset of coiling has distinct viscous\, gravitational and inertial modes that connect smoothly with the correspon ding finite-amplitude regimes. I will also discuss some striking examples of non-stationary behavior of liquid ropes\, including propagating spiral waves of air bubbles\, supercoiling\, and the `fluid mechanical sewing mac hine' wherein the rope leaves complex `stitch' patterns on a moving surfac e. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-397@lptms.universite-paris-saclay.fr DTSTART:20160329T110000Z DTEND:20160329T120000Z DTSTAMP:20160314T085326Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thimothee-thiery/ SUMMARY:Séminaire du LPTMS: Thimothée Thiery - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 29 Mar 16 11:00 DESCRIPTION:Integrable models of directed polymers on the square lattice\nT himothée Thiery (LPT ENS Paris)\n \;\n\nMotivated by the aim of gaini ng a better understanding of the KPZ universality class in 1+1 dimension ( KPZUC)\, there has recently been a strong research activity focused on fin ding exact solutions of models in the KPZUC. Indeed\, interesting properti es such as the emergence of Tracy-Widom (TW) type fluctuations in such mod els have up to now only been understood in integrable models. In this talk I will focus on one class of models believed to be in the KPZUC\, namely directed polymers (DP) on the square lattice\, and on one technique used t o find exact solutions: the coordinate Bethe Ansatz (CBA). After an introd uction to the links between KPZ and DP\, I will show how one can identify the underlying algebraic structure present in any CBA solvable model of DP \, therefore allowing to classify all such models. This classification con tains all previously known exactly solvable models of DP on the square lat tice as well as a new one\, the Inverse-Beta polymer. Finally\, I will ske tch how CBA solvability permits to show the KPZUC (critical exponents and TW fluctuations) of the Inverse-Beta polymer. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-430@lptms.universite-paris-saclay.fr DTSTART:20160329T143000Z DTEND:20160329T153000Z DTSTAMP:20160325T152509Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sanjib-sabhapandit-horaire-inhabituel/ SUMMARY:Séminaire du LPTMS: Sanjib Sabhapandit *** séminaire exceptionne l *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 29 Mar 16 14:30 DESCRIPTION:Fluctuation theorem for entropy production of a partial system in the weak coupling limit\nSanjib Sabhapandit (Raman Research Institute\, Bangalore\, India)\nSmall systems in contact with a heat bath evolve by s tochastic dynamics. Here we show that\, when one such small system is weak ly coupled to another one\, it is possible to infer the presence of such w eak coupling by observing the violation of the steady state fluctuation th eorem for the partial entropy production of the observed system. We give a general mechanism due to which the violation of the fluctuation theorem c an be significant\, even for weak coupling. We analytically demonstrate on a realistic model system that this mechanism can be realized by applying an external random force to the system. In other words\, we find a new flu ctuation theorem for the entropy production of a partial system\, in the l imit of weak coupling CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-415@lptms.universite-paris-saclay.fr DTSTART:20160330T143000Z DTEND:20160330T154500Z DTSTAMP:20160325T152532Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ritam-sinha/ SUMMARY:Séminaire du LPTMS: Ritam Sinha *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 30 Mar 16 1 4:30 DESCRIPTION:Thermalization with Chemical Potentials\, and Higher Spin Black Holes\nRitam Sinha (Tata Institute of Fundamental Research\, Mumbai)\n\n\ n\nWe study the long time behaviour of local observables following a quant um quench in 1+1 dimensional conformal field theories possessing additiona l conserved charges besidesthe energy. We show that the expectation value of an arbitrary string of local observablessupported on a finite interval exponentially approaches an equilibrium value. The equilibriumis character ized by a temperature and chemical potentials defined in terms of the quen chedstate. For an infinite number of commuting conserved charges\, the equ ilibrium ensemble isa generalized Gibbs ensemble (GGE). We compute the the rmalization rate in a systematicperturbation in the chemical potentials\, using a new technique to sum over an infinite numberof Feynman diagrams. T he above technique also allows us to compute relaxation times forthermal G reen’s functions in the presence of an arbitrary number of chemical pote ntials. Inthe context of a higher spin (hs[λ]) holography\, the partition function of the final equilibriumGGE is known to agree with that of a hig her spin black hole. The thermalization rate fromthe CFT computed in our p aper agrees with the quasinormal frequency of a scalar field inthis black hole.\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-431@lptms.universite-paris-saclay.fr DTSTART:20160331T110000Z DTEND:20160331T120000Z DTSTAMP:20160325T152549Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nizar-demni/ SUMMARY:Séminaire du LPTMS: Nizar Demni *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 31 Mar 16 11:00 DESCRIPTION:Premier temps d'atteinte de la chambre de Weyl par le processus de Dunkl radial\nNizar Demni (Institut de Recherches Mathématiques de Re nnes\, Université de Rennes)\nJ'introduirai le processus de Dunkl radial et expliquerai le lien avec les valeurs propres de certains processus matr iciels. Ensuite\, je montrerai comment calculer la loi du premier temps d' atteinte de la chambre de Weyl par ce processus et donnerai des formules e xplicites dans le cas des angles diedraux. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-408@lptms.universite-paris-saclay.fr DTSTART:20160404T110000Z DTEND:20160404T120000Z DTSTAMP:20160330T131117Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-seminar-cancelled/ SUMMARY:Physics-Biology interface seminar: Seminar cancelled - Moyen Amphi\ , Building 510\, Université Paris-Saclay Orsay - 4 Avr 16 11:00 DESCRIPTION:SEMINAR CANCELLED CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-428@lptms.universite-paris-saclay.fr DTSTART:20160405T110000Z DTEND:20160405T120000Z DTSTAMP:20160322T130744Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-remy-dubertrand-2/ SUMMARY:Séminaire du LPTMS: Rémy Dubertrand - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 5 Avr 16 11:00 DESCRIPTION:Scattering theory of walking droplets in the presence of obstac les\nRémy Dubertrand (Université de Liège\, Belgique)\nWalking droplets that are sustained on the surface of a vibrating liquid\, have attracted considerable attention during the past decade due to their remarkable anal ogy with quantum wave-particle duality. This was initiated by the pioneeri ng experiment by Y. Couder and E. Fort in 2006\, which reported the observ ation of a diffraction pattern in the angular resolved profile of droplets that propagated across a single slit obstacle geometry. While the occurre nce of this wave-like phenomenon can be qualitatively traced back to the c oupling of the droplet with its associated surface wave\, a quantitative f ramework for the description of the surface-wave-propelled motion of the d roplet in the presence of confining boundaries and obstacles still represe nts a major challenge. This problem is all the more stimulating as several experiments have already reported clear effects of the geometry on the dy namics of walking droplets.\n\nHere we present a simple model inspired fro m quantum mechanics for the dynamics of a walking droplet in an arbitrary geometry. We propose to describe its trajectory using a Green function app roach. The Green function is related to the Helmholtz equation with Neuman n boundary conditions on the obstacle(s) and outgoing conditions at infini ty.\nFor a single slit geometry our model is exactly solvable and reproduc es some of the features observed experimentally. It stands for a promising candidate to account for the presence of boundaries in the walker's dynam ics. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-434@lptms.universite-paris-saclay.fr DTSTART:20160406T143000Z DTEND:20160406T153000Z DTSTAMP:20160401T074805Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-serguei-brazovskii-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Serguei Brazovskii ***séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Avr 16 14:30 DESCRIPTION:Modeling of dynamical phase transitions in electronic systems i nduced by ultra-fast optical pumping\nSerguei Brazovskii (LPTMS)\nI shall report the recent studies on phenomenological theory of dynamical phase tr ansformations in cooperative electronic systems achieved by means of a fem to-second optical pumping.\n1. Experiments on charge density waves recover ed coherent unharmonic undulations of the order parameter\, critical slowi ng down of the collective mode\, and evolution of the particles spectra. T he numerical modeling reproduced the dynamical phase transition\, and the waves emitted by “earthquakes” from in depth annihilation events of do main walls.\n2. The special case of resonance optical pumping to excitons is realized in systems with a neutral-ionic ferroelectric transition. The modeling of the quantum-coherent quasi-condensate of excitons interacting with the order parameter recovers the dynamical realization of the “exci tonic insulator” state and spacio-temporal patterns with self-focusing\, domains segregation\, and local dynamical phase transitions. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-424@lptms.universite-paris-saclay.fr DTSTART:20160407T143000Z DTEND:20160407T153000Z DTSTAMP:20160325T152627Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-yasar-atas/ SUMMARY:Séminaire du LPTMS: Yasar ATAS *** séminaire exceptionnel *** - L PTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 7 Avr 16 14: 30 DESCRIPTION:Exact many-body dynamics of a harmonically quenched Tonks-Girad eau gas at finite temperature\nYasar ATAS (University of Queensland\, Bris bane\, Australia)\nUltracold quantum gases offer a fascinating and remarka bly insightful playground for exploring and understanding the fundamentals of out-of-equilibrium behaviour of quantum matter. Experimental systems w hose non-equilibrium dynamics can be described by exactly solvable models of quantum many-body theory play a particularly important role.  A paradi gmatic example in this realm is the Tonks-Girardeau (TG) gas  of strongly interacting bosons\, previously treated only for zero-temperature dynamic s.\nIn this talk\, I will present an exact finite temperature dynamical th eory of a harmonically trapped TG gas\, and apply it to the problem of bre athing-mode oscillations after a sudden confinement quench.  The method i s based on the Fredholm determinant expression of the density matrix at fi nite temperature and provides a straightforward and efficient technique to compute finite temperature properties of TG. I will identify physical reg imes for observing a phenomenon of frequency doubling in the oscillations of the momentum distribution of the gas.  Exact results will be compared to a finite-temperature hydrodynamic approach based on local density appro ximation with the frequency quasi-doubling phenomena surprisingly well cap tured. The exact dynamical theory developed opens the way to solving finit e-temperature problems involving anharmonic traps\, as well as arbitrary q uench protocols of the trapping potential.\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-412@lptms.universite-paris-saclay.fr DTSTART:20160412T110000Z DTEND:20160412T120000Z DTSTAMP:20160325T115748Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-noel-fuchs/ SUMMARY:Séminaire du LPTMS: Jean-Noël Fuchs - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Avr 16 11:00 DESCRIPTION:Magnetic field properties of itinerant electrons in a quasicrys tal\nJean-Noël Fuch (LPS\, Univeristé Paris-Sud &\; LPTMC\, Universit é Paris 6)\nQuasicrystals are solids with long range order but without pe riodicity. Here we study the properties of electrons moving in a 2D quasic rystal in the presence of a perpendicular magnetic field. The motion of el ectrons on a two-dimensional isometric Rauzy tiling is described by a tigh t-binding model. A magnetic field perpendicular to the plane is applied\, which couples to the orbital motion of electrons via a Peierls phase in th e hopping amplitudes and to the spin via a Zeeman coupling. For several ap proximants to the quasicrystal\, the energy spectrum in a magnetic field i s computed numerically with open or periodic boundary conditions. The resu lting Hofstadter butterfly is studied in detail (Landau levels\, labeling of gaps\, etc). The grand potential is then obtained at a given temperatur e and chemical potential and its derivatives allow us to study the orbital magnetic susceptibility as well as the spin susceptibility of the Rauzy t iling. The spin susceptibility is a temperature-smoothed version of the ze ro-field density of states. The orbital susceptibility has a complicated s tructure - it changes sign several times - as a function of the chemical p otential except near the band edges where it is approximatively described by an effective mass tensor. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-419@lptms.universite-paris-saclay.fr DTSTART:20160413T140000Z DTEND:20160413T150000Z DTSTAMP:20160405T064344Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicolas-laflorencie-horaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Nicolas Laflorencie *** séminaire exceptionne l *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Avr 16 14:00 DESCRIPTION:Recent numerical insights on the many-body localization problem \nNicolas Laflorencie (Laboratoire de Physique Théorique\, Université Pa ul Sabatier\, Toulouse)\n\n\nIn this talk\, I will discuss the problem of the many-body localization (MBL) in one-dimensional (1D) quantum interacti ng systems.\nAfter an introduction to this quite popular field\, I will fo cus on recent numerical results obtained in Toulouse on the s=1/2 random-f ield Heisenberg chain. State-of-the-art exact diagonalization techniques h ave allowed us to unveal several features of MBL physics in 1D\, in partic ular the existence of a mobility edge\, and an unexpected slow entanglemen t spreading in the ergodic regime.\n\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-413@lptms.universite-paris-saclay.fr DTSTART:20160419T110000Z DTEND:20160419T120000Z DTSTAMP:20160405T063044Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marie-chupeau/ SUMMARY:Séminaire du LPTMS: Marie Chupeau - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 19 Avr 16 11:00 DESCRIPTION:Random walks in confined geometry: convex hull and cover times\ nMarie Chupeau (LPTMC\, UPMC\, Paris)\nWhat is the impact of a confinement on random walks? To answer this question\, I will first focus on a partia l confinement\, an infinite reflecting wall\, and study how the space take n by a planar random walk is affected by the presence of the wall. The spa ce explored by a random walk in the plane can be characterized by its conv ex hull\, defined as the minimum convex polygon enclosing the trajectory\, and in particular by its perimeter. After having studied a one-dimensiona l version of the problem\, I will show that the mean perimeter of the conv ex hull of a planar random walk exhibits a non-trivial dependance on the i nitial distance of the walker to the wall\, in sharp contrast with the res ults in one dimension.\nSecond\, I will consider a random walk in total co nfinement and study the time it takes to visit all sites of a given domain . This time\, known as the cover time\, is a key observable to quantify th e efficiency of exhaustive searches\, which require a complete exploration of an area and not only the  discovery of a single target. Despite its b road relevance\, in biology\, ecology\, or robotics\, the cover time has r emained elusive and so far\, explicit results have been scarce and mostly limited to regular random walks. I will show how to determine the distribu tion of the cover time for a broad range of random search processes\, and highlight its universal features. I will conclude with an application of t his result and discuss how the cover time can be optimized for some resear ch strategies. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-414@lptms.universite-paris-saclay.fr DTSTART:20160426T110000Z DTEND:20160426T120000Z DTSTAMP:20160411T173710Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-david-mukamel-2/ SUMMARY:Séminaire du LPTMS: David Mukamel - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 26 Avr 16 11:00 DESCRIPTION:Mixed order phase transitions: from DNA denaturation to jamming processes\n\nDavid Mukamel (Weizmann Institute of Science\, Israël)\nPha se transitions of mixed nature\, which on the one hand exhibit a diverging correlation length as in second order transitions and on the other hand d isplay a discontinuous order parameter as in first order transitions have been observed in a diverse classes of physical systems. Examples include D NA denaturation\, models of wetting\, glass and jamming transitions\, rewi ring networks  and some one-dimensional models with long-range interactio ns. An exactly soluble Ising model which provides a link between some of t hese rather distinct classes of systems is introduced. Renormalization gro up analysis which provides a common framework for studying some of these s ystems\, elucidating the relation between them will be discussed as well a s the extreme value statistics of the locally ordered domains that charact erize the various phases. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-442@lptms.universite-paris-saclay.fr DTSTART:20160429T110000Z DTEND:20160429T120000Z DTSTAMP:20160426T113504Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giovanna-morigi-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Giovanna Morigi *** séminaire exceptionnel ** * - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 29 Avr 16 11:00 DESCRIPTION:Dissipation-assisted prethermalization in long-range interactin g atomic ensembles\nGiovanna Morigi (Universität des Saarlandes\, Allemag ne)\nWe theoretically characterize the semiclassical dynamics of an ensemb le of atoms after a sudden quench across a driven-dissipative second-order phase transition. The atoms are driven by a laser and interact via conser vative and dissipative long-range forces mediated by the photons of a sing le- mode cavity. These forces can cool the motion and\, above a threshold value of the laser intensity\, induce spatial ordering. The relaxation dyn amics exhibits a long prethermalizing behaviour which is first solely domi nated by coherent long-range forces\, and then by their interplay with dis sipation. Remarkably\, this final stage is orders of magnitude slower and exhibits correlations which are established by spatially-correlated noise and which go beyond mean-field. This behaviour challenges the common under standing of the role of dissipation in the relaxation dynamics. It further implies that cavity cooling of an atomic ensemble into the selforganized phase can require longer time scales than the typical duration of an exper iment. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-417@lptms.universite-paris-saclay.fr DTSTART:20160503T110000Z DTEND:20160503T120000Z DTSTAMP:20160224T101009Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cecile-monthus/ SUMMARY:Séminaire du LPTMS: Cécile Monthus - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 3 Mai 16 11:00 DESCRIPTION:Many Body Localization Transition : level statistics and entang lement entropy\nCécile Monthus (IPhT\, CEA\, Saclay)\nAt the Many-Body-Lo calization (MBL) Transition\,  the statistics of energy levels and the en tanglement entropy of eigenstates change: the Many-Body-Localized phase is characterized by the Poisson level statistics and an area-law for the ent anglement\, while the Delocalized phase is characterized by the Wigner-Dys on level statistics and a volume-law for the entanglement.\nIn the first p art of the talk\, the Dyson Brownian Motion approach for quantum spin Hami ltonians with random fields will be described: the statistics of energy le vels can be studied via Langevin and Fokker-Planck equations\, and one obt ains the level repulsion exponent $\\beta$ in terms of the Edwards-Anders on matrix elements.\nIn the second part of the talk\, we will consider the strong disorder limit of the MBL transition\, where the critical level st atistics is close to the Poisson statistics\, in order to determine the st atistical properties of the rare extensive resonances that are needed to e scape from the area-law entanglement of the Localized phase.\nAt criticali ty\, the entanglement entropy can grow with an exponent $0<\; \\alpha &l t\; 1$ anywhere between the area law $\\alpha=0$ and the volume law $\\alp ha=1$\, as a function of the resonances properties. In addition\, the corr elation length exponent takes the simple value $\nu=1$.\nIndependently of this strong disorder limit\, we will explain why for the Many-Body-Localiz ation transition concerning individual eigenstates\, the correlation lengt h exponent $\nu$ is not constrained by the usual Harris inequality $\nu\\g eq 2/d$.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-438@lptms.universite-paris-saclay.fr DTSTART:20160509T110000Z DTEND:20160509T120000Z DTSTAMP:20160430T183511Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-madan-rao/ SUMMARY:Physics-Biology interface seminar: Madan Rao - Moyen Amphi\, Buildi ng 510\, Université Paris-Saclay Orsay - 9 Mai 16 11:00 DESCRIPTION:Active Composite Cell Surface - local control of clustering and sorting\nMadan Rao (Raman Research Institute &\; National Centre for B iological Sciences-TIFR\, Bangalore)\n\nThe surface of a living cell needs to regulate and control its local composition in a variety of contexts su ch as endocytosis and signalling. We have shown that many cell surface mol ecules are organised at multiple scales by their coupling to a thin cortic al actomyosin layer\, which actively drives local cell membrane compositi on and shape. This includes both transmembrane proteins and lipid anchored proteins\, such as GPI-anchored proteins. Crucial to this engagement is t he spontaneous emergence of localized contractile platforms in the 2dim ac tive cortical fluid. Both the nanoscale clustering and the mesoscale segre gation display the unique signatures of activity. We have recently recapit ulated many of these effects in a minimal reconstituted system. I will end by discussing potential implications of this active composite cell surfac e for the processing of cellular information.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-422@lptms.universite-paris-saclay.fr DTSTART:20160517T110000Z DTEND:20160517T120000Z DTSTAMP:20160315T102656Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-dmitry-savin/ SUMMARY:Séminaire du LPTMS: Dmitry Savin - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 17 Mai 16 11:00 DESCRIPTION:Probing eigenfunction nonorthogonality by parametric shifts of resonance widths\nDmitry Savin (Brunel University\, Uxbridge\, UK)\nResona nces feature themselves in the energy-dependent S-matrix as its poles in t he complex energy plane. They can be analytically described as the complex eigenvalues of an effective non-Hermitian Hamiltonian. Notably\, the asso ciated resonance wavefunctions are known to be nonorthogonal\, which has m any important applications ranging from nuclear physics to quantum optics and solid state. This talk will consider an open (scattering) quantum syst em under the action of a perturbation of its interior. It is demonstrated that the resulting change of resonance widths is a sensitive indicator of the nonorthogonality of resonance wavefunctions\, being zero only if those were orthogonal. Focusing further on chaotic systems\, we will introduce a new type of parametric statistics in open systems\, and derive (within r andom matrix theory) the distribution of the resonance width shifts in the regime of weakly open system. Applications and recent data for microwave cavities will be also discussed. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-440@lptms.universite-paris-saclay.fr DTSTART:20160519T110000Z DTEND:20160519T120000Z DTSTAMP:20160422T201330Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-simon-scheuring/ SUMMARY:Physics-Biology interface seminar: Simon Scheuring - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 19 Mai 16 11:00 DESCRIPTION:High-Speed Atomic Force Microscopy: The dawn of dynamic structu ral biochemistry\nSimon Scheuring (INSERM &\; Aix-Marseille Université )\nThe advent of high-speed atomic force microscopy (HS-AFM [1]) has opene d a novel research field for the dynamic analysis of single bio-molecules: Molecular motor dynamics [2\,3] membrane protein diffusion [4]\, assembly [5] and conformational changes [6] could be directly visualized. Further developments for buffer exchange [7] and temperature control [8] during HS -AFM operation provide breakthroughs towards the performance of dynamic st ructural biochemistry using HS-AFM.\n\n\n[1] Ando et al.\, Chem Rev. 2014 Mar 26\;114(6):3120-88.\n[2] Kodera et al.\, Nature. 2010 Nov 4\;468(7320) :72-6.\n[3] Uchihashi et al.\, Science. 2011 Aug 5\;333(6043):755-8.\n[4] Casuso et al.\, Nat Nanotechnol. 2012 Aug\;7(8):525-9.\n[5] Chiaruttini et al.\, Cell. 2015 Nov 5\;163(4):866-79.\n[6] Ruan et al.\, 2016\, in prepa ration\n[7] Miyagi et al.\, Nat Nanotechnol. 2016\, in press\n[8] Takahash i et al.\, 2016\, in preparation\n CATEGORIES:seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-445@lptms.universite-paris-saclay.fr DTSTART:20160524T110000Z DTEND:20160524T120000Z DTSTAMP:20160517T123805Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gregory-schehr/ SUMMARY:Séminaire du LPTMS: Grégory Schehr - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 24 Mai 16 11:00 DESCRIPTION:Finite temperature free fermions and the Kardar-Parisi-Zhang eq uation at finite time\nGrégory Schehr (LPTMS\, Université Paris-Sud)\nI will consider a system of N one-dimensional free fermions confined by a ha rmonic well. At zero temperature (T=0)\, it is well known that this system is intimately connected to random matrices belonging to the Gaussian Unit ary Ensemble. In particular\, the density of fermions has\, for large N\, a finite support and it is given by the Wigner semi-circular law. Besides\ , close to the edges of the support\, the quantum fluctuations are describ ed by the so-called Airy-Kernel (which plays an important role in random m atrix theory). What happens at finite temperature T ? I will show that at finite but low temperature\, the fluctuations close to the edge\, are desc ribed by a generalization of the Airy kernel\, which depends continuously on temperature. Remarkably\, exactly the same kernel arises in the exact s olution of the Kardar-Parisi-Zhang (KPZ) equation in 1+1 dimensions at fin ite time. I will also discuss recent results for fermions in higher dimens ions.\n\n \;\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-418@lptms.universite-paris-saclay.fr DTSTART:20160530T110000Z DTEND:20160530T120000Z DTSTAMP:20160414T184706Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-david-pastre/ SUMMARY:Physics-Biology interface seminar: David Pastré - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 30 Mai 16 11:00 DESCRIPTION:Probing protein interactions on a microtubule bench by fluoresc ence microscopy: Application to YB-1\, a mRNA-binding protein\nDavid Pastr é (Université d'Évry)\nA typical procedure adopted by biologists to ana lyze protein interactions is to take advantage of the high throughput capa bility of the two hybrid system\, generally in yeast\, or that of the comb ination of affinity purification with mass spectrometry to obtain an exhau stive list of potential partners for a protein of interest. However\, the se assays require cell lysis\, antibodies and adsorption onto non physiolo gical substrates leading to false positives and false negatives. There is therefore a need to control the relevance of the proposed interactions in a context closer to native conditions\, such as in living mammalian cells. To that end\, novel methods are currently developed to provide a better v iew on protein interactions. In line with this\, we have proposed a novel technology to detect and quantify direct or indirect protein interactions by fluorescence microscopy in living mammalian cells using microtubules as platforms. Microtubules are micrometer-long rigid cylinders of about 25  nm in diameter that are present in the cytoplasm of all eukaryotic cell s. Due to their geometry\, they provide an ideal surface to probe molecula r interactions by fluorescence microscopy. As a proof of concept\, we use d microtubules to probe the interactions between mRNA-binding proteins lik e YB-1 in the cytoplasm. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-429@lptms.universite-paris-saclay.fr DTSTART:20160531T110000Z DTEND:20160531T120000Z DTSTAMP:20160519T055347Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-louis-barrat/ SUMMARY:Séminaire du LPTMS: Jean-Louis Barrat - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 31 Mai 16 11:00 DESCRIPTION:Elastoplastic models for amorphous plasticity\nJean-Louis Barra t (Université Joseph Fourier\, Grenoble)\n\n\n\nI will present our curren t understanding\, based on microscopic simulations and experiments\, of th e elementary mechanisms that govern the deformation and flow of amorphous materials. I will show how these mechanisms can be incorporated into  sim ple lattice models governed by long range elastic interactions\, discuss t he mean field analysis of these models as well as fluctuation related issu es such as the  statistics of avalanche like events.\n\n\n\nReferences:\n \n Modeling deformation and flow of disordered materials\, J-L. Barrat\, J .J. de Pablo\, MRS Bulletin 32\, 941 (2007)\n Driving rate dependence of a valanches statistics and shapes at the yielding transition\, C. Liu\, E. F errero\, F. Puosi\, J-L. Barrat\, K. Martens\, PRL 116 065201 (2016)\n On the relevance of disorder in athermal amorphous materials under shear\, E. Agoritsas\, E. Bertin\, K. Martens\, J-L. Barrat EPJE 38 15071 (2015)\n R heology of athermal amorphous solids: Revisiting simplified scenarios and the concept of mechanical noise temperature\, A. Nicolas\, K. Martens\, J- L. Barrat EPL 107 44003 (2014)\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-423@lptms.universite-paris-saclay.fr DTSTART:20160531T143000Z DTEND:20160531T170000Z DTSTAMP:20160531T070223Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-pierre-ronceray/ SUMMARY:Soutenance de thèse : Pierre Ronceray - IPN-batiment 100\, Auditor iurm - 31 Mai 16 14:30 DESCRIPTION:Active contraction in biological fiber networks\nLarge-scale fo rce generation is essential for biological functions such as cell motility \, embryonic development\, wound healing and muscle contraction. In these processes\, forces generated at the molecular level by motor proteins are transmitted by disordered fiber networks\, resulting in large-scale active stresses.  While fiber networks are well characterized macroscopically\, this stress generation by microscopic active units is not well understood . In this Thesis\, I present a comprehensive theoretical and numerical stu dy of force transmission in elastic fiber networks. I show that the linear \, small-force response of the networks is remarkably simple\, as the macr oscopic active stress depends only on the geometry of the force-exerting u nit. In contrast\, as non-linear buckling occurs around these units\, loca l active forces are rectified towards isotropic contraction\, making the l ocal geometry of force exertion irrelevant. This emergent contractility is amplified by non-linear force transmission through the network. This stre ss amplification is reinforced by the networks' disordered nature\, but sa turates for high densities of active units. Our predictions are quantitati vely consistent with experiments on reconstituted tissues and actomyosin n etworks\, and that they shed light on the role of the network microstructu re in shaping active stresses in cells and tissue. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-425@lptms.universite-paris-saclay.fr DTSTART:20160607T110000Z DTEND:20160607T120000Z DTSTAMP:20160519T055044Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-purushottam-dixit/ SUMMARY:Séminaire du LPTMS: Purushottam Dixit - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 7 Juin 16 11:00 DESCRIPTION:Metastability transition in genome evolution and population str ucture of bacterial species\nPurushottam Dixit (Columbia University\, US)\ nTwo processes govern diversification of bacterial genomes. While point mu tations always increase population diversity\, horizontal gene transfers a ct as a cohesive force at the population level. Currently\, a detailed qua ntitative understanding of how these two opposing forces shape bacterial e volution at the level of individual genes\, genomes\, and populations is l acking. In a theoretical model\, we identify two qualitatively distinct ph ases in the dynamics of genome evolution\, characterized by the second eig envalue of the Markov process describing evolution.  In the  divergent p hase the cohesion due to recombination is not sufficient to overcome mutat ional drift. As a consequence both individual genes and the entire genomes within the same species keep diverging from each other in the course of e volution.  At the population level\, transient clusters of sub-population s are continuously formed and dissolved. In contrast\, in the metastable p hase\,  the recombination has the upper hand.  In this phase\, genomes o f descendants of a pair of sister cells remain close to each other for lon g periods of time but eventually escape the pull of recombination and dive rge indefinitely.  The population of the entire species remains genetical ly cohesive and stable over time and does not fragment into sexually isola ted sub-populations. Real bacterial examples are discussed as well. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-446@lptms.universite-paris-saclay.fr DTSTART:20160609T110000Z DTEND:20160609T120000Z DTSTAMP:20160530T175719Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-vladimir-kravtsov-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Vladimir Kravtsov *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Ju in 16 11:00 DESCRIPTION:Ergodic transition on disordered random regular graph\nVladimir Kravtsov (ICTP\, Trieste\, Italy)\nWe consider statistics of eigenfunctio ns on the random regular graph with on-site disorder. The results of numer ical diagonalization show a  transition in the statistics of eigenfunctio ns deeply inside the region of extended states that is interpreted as a tr ansition from extended ergodic to extended  non-ergodic (multifractal) st ates. A comparison with the Rosenzweig-Porter random matrix theory and a g eneralized population dynamics calculations is discussed. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-420@lptms.universite-paris-saclay.fr DTSTART:20160613T110000Z DTEND:20160613T120000Z DTSTAMP:20160606T101738Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-anne-florence-bitbol/ SUMMARY:Physics-Biology interface seminar: Anne-Florence Bitbol - LPTMS\, s alle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Juin 16 11:00 DESCRIPTION:Inferring interaction partners from protein sequences\nAnne-Flo rence Bitbol (Laboratoire Jean Perrin\, UPMC)\nSPECIAL LOCATION (due to re novation work at LPS)\nSpecific protein-protein interactions play crucial roles in the stability of multi-protein complexes and in signal transducti on. Thus\, mapping these interactions is key to a systems-level understand ing of cells. However\, systematic experimental identification of protein interaction partners is still challenging\, while a large and rapidly grow ing amount of sequence data is now available. Is it possible to identify w hich proteins interact just from their sequences? We propose an approach b ased on sequence covariation\, building on methods used with success to pr edict the three-dimensional structures of proteins from sequences alone. O ur method identifies specific interaction partners with high accuracy amon g the members of two ubiquitous prokaryotic protein families\, and paves t he way to identifying novel protein-protein interactions directly from seq uence data.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-436@lptms.universite-paris-saclay.fr DTSTART:20160614T110000Z DTEND:20160614T120000Z DTSTAMP:20160608T061100Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-duo-frederic-abergel-damien-chalet/ SUMMARY:Séminaire du LPTMS: duo Frédéric Abergel-Damien Chalet - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Juin 16 11:00 DESCRIPTION:Mathematical modelling of limit order books\nFrédéric Abergel (Laboratoire MICS\, Ecole Centrale de Paris)\nThe limit order book is at the core of any modern\, electronic financial markets. In this talk\, I wi ll present some results pertaining to their statistical and mathematical p roperties. Questions such as ergodicity and stationarity\, dependencies\, relation betwen time scales... will be addressed and sometimes answered to o.\n&\;\nNonparametric statistics from cumulative sample sums\nDamien C halet (Laboratoire MICS\, Ecole Centrale de Paris)\nBuilding on recent res ults on record statistics of random walks\, a novel family of nonparametri c statistics is introduced. Single-sample statistics are shown to provide location tests\, while two-sample statistics correspond to distribution eq uality tests. The power and efficiency of such statistics are analyzed. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-439@lptms.universite-paris-saclay.fr DTSTART:20160616T110000Z DTEND:20160616T120000Z DTSTAMP:20160603T115303Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pierre-ronceray-mr-x-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Pierre Ronceray &\; Stefano Spigler *** s éminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Juin 16 11:00 DESCRIPTION:1) Stefano Spigler : "Distribution of avalanches in perturbed d isordered systems"\nDisordered systems under a perturbation usually show a stepwise response\, due to the existence of many\, sample dependent\, loc al energy minima. In this talk I will show that the distribution of the ju mps (static avalanches) of the total energy\, under some generic assumptio ns\, depends on the specific system only through its (replica symmetry bre aking) order parameter.\n2) Pierre Ronceray : "Suppression of crystalline order by competing liquid structures"\nUpon cooling\, a molecular liquid w ill eventually either crystallize\, or continuously arrest in a amorphous state known as a glass.  What features of the liquid determine this fate? Why is crystallization avoided in glass-formers?  As the liquid is coole d down\, the local arrangements of its constituent molecules will increasi ngly correspond to low-energy configurations.  It is likely that the loca l structure characterizing the crystalline ground state will be found amon g these stable arrangements\, and one can thus expect that it will accumul ate on cooling. However\, other non-crystalline structures can also be sta ble in the liquid\, and compete with the accumulation of crystalline order . On what conditions can such a competition stabilize the supercooled liqu id to the point of dynamical arrest? We tackle this question using a latti ce model where both the crystalline order and the non-crystalline structur es are explicitly specified in terms of local configuration of binary spin s.  We show that in order to efficiently suppress crystallization\, the n on-crystalline structure should be energetically and entropically favoured . Importantly\, we demonstrate that it must also geometrically antagonize crystalline order. We quantify this effect in terms of overlap of structur es: crystal-''agonist'' structures with good overlap with the crystal tend to facilitate crystallization\, while crystal-antagonist ones tend to imp ede it and dramatically increase the crystal nucleation time.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-437@lptms.universite-paris-saclay.fr DTSTART:20160621T110000Z DTEND:20160621T120000Z DTSTAMP:20160601T100517Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alessio-recati/ SUMMARY:Séminaire du LPTMS: Alessio Recati - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 21 Juin 16 11:00 DESCRIPTION:Coherently driven 2-component Bose gases\n\nAlessio Recati (Uni versità di Trento\, Italia)\n\nIn the present talk I will give an overvie w on the physics of 2-component Bose gases in presence of an spin exchange - Rabi - term. The Rabi term reduces the gauge symmetry of the system  a nd a gap opens for relative phase excitations. The latter has many consequ ences. In particular it  leads to the formation of vortex dimers coupled   through sine-Gordon solitons. Results on the dynamics of the vortex di mer are presented. The system exhibits also a second order (quantum) pha se transition between a neutral (paramagnetic) and a polarised (ferromagn etic) state\, provided the interspecies interaction is large enough. I w ill discuss some phenomena related to the phase transition and to the  tw o phases  and the interplay  between Rabi coupling and density-density interaction:\n\n (i) at a mean-field level for a continuous model - which well described atoms in a shallow trap. \n\n (ii) for a one-dimensional s ingle band Hubbard model - which should properly describe atoms  confine d in an one-dimensional optical lattice.  CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-447@lptms.universite-paris-saclay.fr DTSTART:20160623T110000Z DTEND:20160623T120000Z DTSTAMP:20160603T083418Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-steven-tomsovic-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Steven Tomsovic *** séminaire exceptionnel * ** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 23 Jui n 16 11:00 DESCRIPTION:Universality in the Entanglement and Localization of Strongly C haotic Subsystems\nSteven Tomsovic (Washington State University\, USA)\nTh e entanglement and localization in eigenstates of bipartite systems with s trongly chaotic subsystems are studied as a function of interaction streng th.  Excellent measures for this purpose are the von-Neumann entropy\, Ha vrda-Charvát-Tsallis entropies\, and the inverse participation ratio.  A ll the entropies are shown to follow a remarkably simple exponential form\ , which describes a universal and rapid transition to nearly maximal entan glement for increasing interaction strength. An unexpectedly exact relatio nship between the subsystem averaged inverse participation ratio and purit y (linear entropy) is derived that infers the transition in the localizati on as well. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-432@lptms.universite-paris-saclay.fr DTSTART:20160627T110000Z DTEND:20160627T120000Z DTSTAMP:20160622T083052Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-helene-berthoumieux/ SUMMARY:Physics-Biology interface seminar: Hélène Berthoumieux - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Juin 16 11:00 DESCRIPTION:Fluctuations in in vivo reactive systems.\nHélène Berthoumieu x (LPTMC - Université Pierre &\; Marie Curie\, Paris)\nSPECIAL LOCATIO N (due to renovation work at LPS)\n\nFor a chemist\, a living cell is a re active system in which the concentrations of biomolecules are not determin ed by the thermodynamics but are controlled by energy sources maintaining the system in an out-of-equilibrium state. Chemical reaction networks are thus perturbed by a thermal noise and the fluctuations of these energy so urces. Theoretical and experimental studies have shown that the fluctuatio ns of in vivo systems break the fluctuation-dissipation theorem\, which is a result of statistical physics at equilibrium. One can thus ask what inf ormation is contained in the correlation functions of protein concentratio ns and how they relate to the response of the reactive network to a pertur bation. Answers to these questions are of prime importance to extract mean ingful parameters from the in vivo fluorescence correlation spectroscopy d ata. Here\, we present a theoretical study of the fluctuations of the conc entration of a reactive species involved in a cyclic network that is in a non-equilibrium steady state perturbed by a noisy force\, taking into acco unt both the breaking of detailed balance and extrinsic noises that are kn own to be important in a cell.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-443@lptms.universite-paris-saclay.fr DTSTART:20160628T110000Z DTEND:20160628T120000Z DTSTAMP:20160623T045355Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giuseppe-policastro/ SUMMARY:Séminaire du LPTMS: Giuseppe Policastro - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 28 Juin 16 11:00 DESCRIPTION:AdS/CFT and condensed matter systems\nGiuseppe Policastro (LPT- ENS\, Paris)\n In this talk I will give an introduction to the idea of th e holographic correspondence and some of its applications. In recent years holography has been shown to be a very useful tool to get theoretical ins ight into systems that can not be studied by more conventional methods\, t ypically because there is no small expansion parameter\; such systems incl ude the QCD quark/gluon plasma\, high-temperature superconductors\, conden sed matter systems in the vicinity of a quantum critical point\, and stron gly correlated electron systems (non-Fermi liquids). I will discuss how\, while it is usually not possible to match any given realistic system with a corresponding holographic description\, the method is useful for derivin g results of a general nature. I will highlight the main successes of the method and some of the open questions. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-426@lptms.universite-paris-saclay.fr DTSTART:20160705T110000Z DTEND:20160705T120000Z DTSTAMP:20160628T073945Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-olivier-giraud/ SUMMARY:Séminaire du LPTMS: Olivier Giraud - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 5 Juil 16 11:00 DESCRIPTION:Weinberg representation\, coherent and anticoherent spin states \nOlivier Giraud (LPTMS)\n \;\nWe introduce a new representation for d ensity matrices of symmetric quantum states in finite-dimensional Hilbert spaces. This representation is particularly suited to the description of s pin-j states in terms of linear combinations of spin coherent states. We d escribe several applications of such a representation: identification of t he classical state closest to a given quantum state\, construction of anti coherent spin states\, classicality and separability criteria.\n\n\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-441@lptms.universite-paris-saclay.fr DTSTART:20160711T110000Z DTEND:20160711T120000Z DTSTAMP:20160708T103204Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-markus-basan/ SUMMARY:Physics-Biology interface seminar: Markus Basan - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Juil 16 11:00 DESCRIPTION:Tradeoffs between fast growth and adaptability shape microbial phenotypes\nMarkus Basan (ETH Zurich\, Switzerland &\; Harvard Universi ty\, USA)\nSPECIAL LOCATION (due to renovation work at LPS)\n\nMicroorgani sms exhibit a striking diversity of phenotypes in different conditions. Ch anges in growth rates are accompanied by large variations in metabolic str ategies\, gene expression and cell size. However\, the molecular basis and underlying rationale of many of these complex patterns remains poorly und erstood. We illustrate how a quantitative approach\, based on establishing empirical relations between cellular phenotypes\, can help to elucidate s uch questions by focusing on three long-standing biological problems: the origin of overflow metabolism\, the control of cell size and finally we pr ovide an outlook on the emergence of severe\, multi-hour lag phases. Coars e-grained models yield a quantitative and predictive understanding of phen otypic patterns under environmental as well as genetic perturbations and c an even shed light on underlying molecular mechanisms. A common theme that emerges from these seemingly diverse questions is the existence of fundam ental tradeoffs between fast growth and the ability to swiftly adapt to en vironmental changes or stress conditions.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-452@lptms.universite-paris-saclay.fr DTSTART:20160712T110000Z DTEND:20160712T121500Z DTSTAMP:20160708T101633Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-leonardo-mazza/ SUMMARY:Séminaire du LPTMS: Leonardo Mazza - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 12 Juil 16 11:00 DESCRIPTION:Interacting gases with a synthetic gauge field in the synthetic dimension\nLeonardo Mazza (Ecole Normale Supérieure / PSL Research Unive rsity\, CNRS)\nSynthetic ladders realized with one-dimensional alkaline-ea rth(-like) fermionic gases and subject to a gauge field represent a promis ing environment for the investigation of quantum Hall physics with ultraco ld atoms. We unveil the existence of a hierarchy of fractional insulating and conducting states by means of both analytical bosonization techniques and numerical methods based on the density-matrix renormalization group al gorithm. We show that such states can be exploited for constructing a topo logical Thouless pump where the charge transported after one cycle is quan tized to fractional values and demonstrate this behavior with a full many- body time-dependent calculation.\n1 - S. Barbarino\, L. Taddia\, D. Rossin i\, L. Mazza\, R. Fazio\, Nat. Commun. 6\, 8134 (2015)\n2 - S. Barbarino\, L. Taddia\, D. Rossini\, L. Mazza\, R. Fazio\, New J. Phys. 18\, 035010 ( 2016)\n3 - L. Taddia\, E. Cornfeld\, D. Rossini\, L. Mazza\, E. Sela\, R. Fazio\, in preparation CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-451@lptms.universite-paris-saclay.fr DTSTART:20160713T110000Z DTEND:20160713T120000Z DTSTAMP:20160705T200758Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mustansir-barma-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Mustansir Barma *** séminaire exceptionnel * ** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Jui l 16 11:00 DESCRIPTION:Ordered Phases in Coupled Driven Systems\nMustansir Barma (TIFR Centre for Interdisciplinary Sciences\, Tata Institute of Fundamental Res earch\, Hyderabad\, India)\nInstabilities in the hydrodynamic equations fo r coupled\, driven diffusive systems can herald macroscopic phase separati on. We study the resulting ordered phases in a lattice model of light and heavy particles sliding under gravity on a fluctuating surface in 1D or 2D .   We find strong phase separation with fluctuationless phases for part icles\, but a different organization for the landscape\, leading to intric ate steady state dynamics of interfaces between phases. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-448@lptms.universite-paris-saclay.fr DTSTART:20160906T140000Z DTEND:20160906T163000Z DTSTAMP:20160727T102822Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-joel-bun/ SUMMARY:Soutenance de thèse: Joël Bun - IPN-batiment 100\, Auditoriurm - 6 Sep 16 14:00 DESCRIPTION:\n \;\nApplications of Random Matrix Theory for high-dimens ional statistics.\n \;\nIn the present era of Big Data\, new statistic al methods are needed to decipher large dimensional data sets that are no w routinely generated in almost all fields – physics\, image analysis\, genomics\, epidemiology\, engineering and finance\, to quote only a few. I t is very natural to try to identify common causes that explain the joint dynamics of a large number of quantities. The primary aim of this thesis is to understand theoretically the so-called curse of dimensionality that describe phenomena which arise in high-dimensional space using Random Matr ix Theory. Special care is devoted to the statistics of the eigenvectors o f large noisy matrices\, which turn out to be crucial for many application s. Moreover\, I will present how to build reliable estimators that are con sistent with the dimension of the problem. In the case of correlation matr ices\, the estimator we obtain provide better performance than all previou sly proposed methods for real-world applications within financial markets. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-453@lptms.universite-paris-saclay.fr DTSTART:20160908T110000Z DTEND:20160908T120000Z DTSTAMP:20160903T184241Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christian-hagendorf-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Christian Hagendorf *** séminaire exceptionne l *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 8 S ep 16 11:00 DESCRIPTION:The spin one XXZ chain and symmetry classes of alternating sign matrices\nChristian Hagendorf (Université Catholique de Louvain\, Belgiq ue)\nThe spin 1/2 XXZ Heisenberg chain is a prototype model in the statist ical mechanics of magnetism. It describes the interaction of localised spi ns on a one-dimensional chain with anisotropy. In 2000\, Razumov and Strog anov observed for a particular anisotropy a surprising appearance of integ er sequences in the spin-chain ground state. These sequences enumerate so- called alternating sign matrices. They are well known to combinatorialists through rather different problems such as determinant calculus or the enu meration of plane partitions. In this talk\, I give an overview of the rel ation between spin chains\, models of statistical mechanics and alternatin g sign matrices. Furthermore\, I discuss the spin one XXZ chain whose grou nd state displays for any anisotropy connections to enumeration problems of alternating sign matrices with symmetries. The proof of these connecti ons uses tools from quantum integrability\, in particular the algebraic Be the ansatz and the quantum separation of variables method. (Joint work wit h Alexi Morin-Duchèsne) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-454@lptms.universite-paris-saclay.fr DTSTART:20160912T143000Z DTEND:20160912T154500Z DTSTAMP:20160908T054003Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-informe l-du-lptms-ricardo-mendonca/ SUMMARY:Séminaire informel du LPTMS: Ricardo Mendonça - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Sep 16 14:30 DESCRIPTION:Some new problems on random walks and exclusion processes\nRica rdo Mendonça (Uni. de Sao Paolo)\nIn this informal talk I am going to pre sent two problems related with random walks and exclusion processes: the l ongest-increasing subsequence (LIS) problem for random walks and the symme tric simple exclusion process in discrete time over graphs. The first prob lem corresponds to a new incarnation of the LIS problem for discrete i.i.d . variables (random permutations)\, but now with correlated variables\, wh ile the second problem touches on many interesting (and hard) problems in combinatorics\, computer science\, and graph theory. So far I have more qu estions than answers\, so your attendance\, comments and contributions are welcome! CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-449@lptms.universite-paris-saclay.fr DTSTART:20160913T110000Z DTEND:20160913T120000Z DTSTAMP:20160908T054102Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandre-nicolas/ SUMMARY:Séminaire du LPTMS: Alexandre Nicolas - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Sep 16 11:00 DESCRIPTION:Fluctuations in the flow of disordered solids and complex fluid s: the ups and downs of simple models\nAlexandre Nicolas (LPTMS)\nDisorder ed solids\, such as foams\, concentrated emulsions and metallic glasses\, are examples of complex systems made of complex entities. However\, when d escribing or modelling their macroscopic response\, most of the complexity of the entities under study can often be left aside. This applies in part icular to the fluctuations in their flow. In this talk\, I will present so me successes and caveats associated with simple descriptions of these fluc tuations.\n\nA very broad class of materials\, disordered solids span all damping regimes\, from overdamped to underdamped. This fact calls for a cl arification of the effect of inertia on their flow. The first part of my t alk will be dedicated to showing that\, macroscopically\, the effect of in ertia is identical to that of simple (but shear-rate-dependent) thermal fl uctuatiions.\nBut this does not imply that any fluctuations can be modelle d as thermal fluctuations. Accordingly\, I will then insist on a caveat as sociated with these simple models\, by questioning the popular description of the mechanical noise (i.e.\, the stress fluctuations induced local mic roruptures in the deformed material) as an effective activation temperatur e.\n\nFinally\, if time allows\, I will very briefly touch upon fluctuatio ns in a very different type of complex systems\, namely\, crowds of pedest rians\, and the statistical fluctuations in evacuation times. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-444@lptms.universite-paris-saclay.fr DTSTART:20160920T110000Z DTEND:20160920T120000Z DTSTAMP:20160907T083106Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pierre-illien/ SUMMARY:Séminaire du LPTMS: Pierre Illien - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 20 Sep 16 11:00 DESCRIPTION:Active transport in complex environments\nPierre Illien (R. Pei erls Centre for Theor. Phys.\, Oxford University\, UK)\nUnderstanding the dynamics of an active or a biased particle in a host medium which hinders its motion is an ubiquitous problem of nonequilibrium statistical physics with important applications\, from transport in biological systems to acti ve microrheology. Going beyond the usual effective descriptions of the env ironment of the active tracer\, we propose a model which takes explicitly into account the correlations between the dynamics of the tracer and the r esponse of the bath. Relying on paradigmatic models of statistical mechani cs\, we determine analytically exact and approximate solutions to this out -of-equilibrium problem. They reveal many striking effects\, such as super diffusion in the high-density limit\, velocity anomalies or negative diffe rential mobility.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-427@lptms.universite-paris-saclay.fr DTSTART:20160927T110000Z DTEND:20160927T120000Z DTSTAMP:20160922T072452Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-isabelle-guyon/ SUMMARY:Séminaire du LPTMS: Isabelle Guyon - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 27 Sep 16 11:00 DESCRIPTION:Network Reconstruction: the Contribution of Challenges in Machi ne Learning\nIsabelle Guyon (Laboratoire de Recherche en Informatique\, Un iversité Paris-Sud)\nNetworks of influence are found at all levels of phy sical\, biological\, and societal systems: climate networks\, gene network s\, neural networks\, and social networks are a few examples. These networ ks are not just descriptive of the “State of Nature”\, they allow us t o make predictions such as forecasting disruptive weather patterns\, evalu ating the possible effect of a drug\, locating the focus of a neural seizu re\, and predicting the propagation of epidemics. This\, in turns\, allows us to device adequate interventions or change in policies to obtain desir ed outcomes: evacuate people before a region is hit by a hurricane\, admin ister treatment\, vaccinate\, etc. But knowing the network structure is a prerequisite\, and this structure may be very hard and costly to obtain wi th traditional means. For example\, the medical community relies on clinic al trials\, which cost millions of dollars\; the neuroscience community en gages in connection tracing with election microscopy\, which take years be fore establishing the connectivity of 100 neurons (the brain contains bill ions).\n\nThis presentation will review recent progresses that have been m ade in network reconstruction methods based solely on observational data. Great advances have been recently made using machine learning. We will ana lyze the results of several challenges we organized\, which point us to ne w simple and practical methodologies.\n\n \;\n\nLa reconstruction du r éseau: la contribution des défis en Machine Learning : Les réseaux d'i nfluence se retrouvent à tous les niveaux des systèmes physiques\, biolo giques et sociaux: réseaux climatiques\, réseaux de gènes\, réseaux de neurones\, et réseaux sociaux en sont quelques exemples. Ces réseaux ne sont pas seulement descriptif d’un «état de la nature»\, ils nous pe rmettent de faire des prédictions telles que la prévision des conditions météorologiques\, l'évaluation de l'effet possible d'un médicament\, la localisation d’un foyer épileptique\, et la prévision de la propaga tion des épidémies. Ceci nous permet alors d'intervenir pour obtenir les résultats souhaités: évacuer les populations d'une région avant qu’ elle soit frappée par un ouragan\, administrer un traitement\, vacciner\, etc. Mais la connaissance de la structure du réseau est une condition pr éalable à l’application de ces méthodes\, et cette structure peut êt re très difficile et coûteuse à obtenir avec des moyens traditionnels. Par exemple\, la communauté médicale s’appuie sur les essais cliniques \, qui coûtent des millions de dollars\; la communauté des neurosciences analyse des images de microscopie électorale\, ce qui prendra des année s avant d'établir la connectivité de 100 neurones (alors que le cerveau en contient des milliards).\n\nCette présentation examinera les récents progrès qui ont été faits dans les méthodes de reconstruction de rése aux fondées uniquement sur des données d'observation. De grands progrès ont été récemment réalisés grâce à l'apprentissage des machines (m achine learning). Nous allons analyser les résultats de plusieurs défis que nous avons organisées\, qui nous pointent vers de nouvelles méthodes simples et pratiques. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-469@lptms.universite-paris-saclay.fr DTSTART:20161004T110000Z DTEND:20161004T120000Z DTSTAMP:20160930T111058Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-david-mukamel-3/ SUMMARY:Séminaire du LPTMS: David Mukamel - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 4 Oct 16 11:00 DESCRIPTION:Long-range correlations and anomalous heat transport in momentu m conserving models\nDavid Mukamel (Weizmann Institute of Science\, Israë l)\nReferences:\n\n Anupam Kundu\, Ori Hirschberg and &\; Mukamel Long- range correlations in stochastic transport with energy and momentum conser vation\, J.Stat.Mech.: Theor. Exp.\, 033108 (2016)\n Julien Cividini\, Anu pam Kundu\, A. Miron &\; David Mukamel\, Temperature profile and bounda ry conditions in an anomalous heat transport model\,  preprint cond-mat a rXiv:1609.06614.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-456@lptms.universite-paris-saclay.fr DTSTART:20161005T110000Z DTEND:20161005T120000Z DTSTAMP:20160913T185807Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-daan-noordermeer/ SUMMARY:Physics-Biology interface seminar: Daan Noordermeer - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 5 Oct 16 11:00 DESCRIPTION:CTCF mediates allele-specific 3D domain structure at paternally imprinted gene loci\nDaan Noordermeer (I2BC\, Gif-sur-Yvette\, France)\nN OTE THE NEW LOCATION (due to renovation work at LPS)\n\nImprinted genes ar e mammalian genes where only one copy (allele) is active\, depending on wh ether it is inherited from the mother or the father. This selective activi ty is determined by allele-specific DNA methylation at defined sites in th e genome\, so-called Imprinting Control Regions (ICRs). Recent microscopy studies by the group of Robert Feil (IGM-Montpellier\, France) have reveal ed that imprinted genes are differently organized in the cell nucleus\, de pending on their parental origin (Kota et al.\, 2014). We have used high-r esolution 4C-seq studies (Circular Chromosome Conformation Capture) to dis sect the mechanisms and dynamics of this differential organization at the Dlk1-Dio3 and Igf2-H19 loci.\n\n\nRecent studies have revealed that mammal ian genomes are organized into Topologically Associating Domains (TADs) th at demarcate ‘gene regulatory neighborhoods’ (Dixon et al.\, 2012). Th ese physical domains are formed through a mechanism of ‘loop extrusion ’ of the DNA fiber\, with borders that are demarcated by opposing bindin g sites of the architectural CTCF protein (Fudenberg et al.\, 2016). I wil l show that the imprinted Dlk1-Dio3 and Igf2-H19 loci are organized into d ifferent DNA domains\, determined by allele specific CTCF binding.\n\n\nBo th the Dlk1-Dio3 and Igf2-H19 loci are contained within large\, invariant Topologically Associating Domains (TADs). The presence of the CTCF protein at the unmethylated ICRs on the maternal allele allows the establishment of new loops within the TADs. This result in the formation of a domain tha t acts like a cage\, thereby shielding regulatory elements from nearby gen es. \n\n\nAt the paternal alleles\, DNA methylation at the ICR inhibits CT CF binding. As a result\, the paternal Igf2-H19 allele displays little spe cific organization within the TAD. In contrast\, at the paternal Dlk1-Dio3 locus\, loops are formed between more distant unmethylated CTCF sites. Th e paternal allele therefore forms a much larger subdomain that is containe d within the TAD.\n\n\nOur work\, for the first time\, shows that constitu tive TADs can have a markedly different allele-specific internal domain or ganization. Moreover\, it shows that methylation-dependent DNA binding of the CTCF protein at ICRs guides the process of loop extrusion\, thereby ch ange the 3D structure of chromatin domains. We speculate that the imprinte d patterns of gene expression at these loci are mostly imposed by the mate rnal 3D architecture\, supporting previous genetic studies.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-457@lptms.universite-paris-saclay.fr DTSTART:20161006T110000Z DTEND:20161006T120000Z DTSTAMP:20160914T052113Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-armita-nourmohammad-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Armita Nourmohammad *** séminaire exceptionn el *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Oct 16 11:00 DESCRIPTION:Statistical physics of molecular evolution: from gene regulatio n to immune system\nArmita Nourmohammad (Lewis Sigler Institute\, Princeto n University)\nMolecular phenotypes\, such as gene expression or protein b inding affinities are important targets of natural selection\, and are oft en subject to time-dependent pressure form the environment. However\, the map between encoding DNA sequences and molecular phenotypes is often too d ifficult to quantify. In this talk\, I will show that universality is an e merging property of complex phenotypes\, which are encoded by multiple gen omic loci. I will introduce a non-equilibrium framework for adaptive dynam ics of such phenotypes in time-dependent environments\, and between co-ev olving populations. In time-dependent environments\, changes in the enviro nment drive the evolution of the species\, but not vice versa. As an examp le\, I will present strong evidence that adaptation dominates the evolutio n of gene expression levels in Drosophila. Co-evolving populations recipro cally affect the fitness of each other\, acting as time-dependent environm ents with feedback. As an example\, I will show evidence of co-adaptation between interacting cellular populations of HIV viruses and the antibody r epertoire of a patient over the course of an infection. In particular\, I discuss the conditions for emergence of broadly neutralizing antibodies\, which are recognized as critical for designing an effective vaccine agains t HIV. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-455@lptms.universite-paris-saclay.fr DTSTART:20161011T110000Z DTEND:20161011T120000Z DTSTAMP:20160914T052013Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-lptms-m ikhail-zvonarev/ SUMMARY:Séminaire du LPTMS : Mikhail Zvonarev - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Oct 16 11:00 DESCRIPTION:Quantum motion of an impurity through a medium at zero temperat ure in one spatial dimension\nMikhail Zvonarev (LPTMS\, Université Paris- Sud)\nI will report on a theoretical and experimental progress in understa nding the dynamics of an impurity injected into a one-dimensional quantum liquid. I will show that the momentum distribution of the impurity subject to a constant external force exhibits characteristic Bragg reflections at the edge of an emergent Brillouin zone. As a consequence\, the impurity e xhibits periodic dynamics that is interpreted as Bloch oscillations\, whic h arise even though the quantum liquid is translationally invariant. I wil l also discuss a quantum flutter phenomenon\, whose essence is that the im purity injected into a liquid with some initial momentum sheds only a part of it to the background gas\, and forms a correlated state that no longer decays in time\; furthermore\, if the initial momentum is large enough\, the impurity undergoes long-lived oscillations.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-463@lptms.universite-paris-saclay.fr DTSTART:20161013T110000Z DTEND:20161013T120000Z DTSTAMP:20160919T071108Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-peter-karpov-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Peter Karpov *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Oct 16 11:00 DESCRIPTION:Modeling of phase transitions and patterns formation in ensembl es of solitons\nPeter Karpov (National University of Science and technolog y "MISiS"\, Moscow\, Russia)\nVulnerability of broken symmetries of cooper ative electronic states gives rise to topological defects like electronic vortices\, walls\, stripes. A typical quasi-one-dimensional architecture b rings these objects to the microscopic scale giving rise to solitons as el ementary particles taking from electrons their major roles as carriers of charge or spin. Because of the long-range ordering\, the solitons experien ce unusual super-long-range forces leading to a sequence of phase transiti ons in their ensembles: the higher-temperature transition of the confineme nt and the lower one of aggregation into macroscopic walls.\n\nIn this tal k I shall review the available analytical theory and present the recent re sults of an extensive numerical modeling for ensembles of both neutral and charged solitons in two- and three-dimensional systems. We suggest a spec ific Monte Carlo algorithm preserving the number of solitons\, which subst antially facilitates the calculations\, allows to extend them to the three -dimensional case and to include the important long-range Coulomb interact ions. The results confirm the first confinement transition\, except for a very strong Coulomb repulsion\, and demonstrate a pattern formation at the second transition of aggregation.\n\n \;\n\nReference: P. Karpov and S. Brazovskii\, PRB 94\, 125108 (2016). CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-450@lptms.universite-paris-saclay.fr DTSTART:20161018T110000Z DTEND:20161018T120000Z DTSTAMP:20160929T075146Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-lptms-f riedrich-wagner/ SUMMARY:Séminaire du LPTMS: Friedrich Wagner *** commun avec l'IPN *** - I PN-batiment 100\, Auditoriurm - 18 Oct 16 11:00 DESCRIPTION:\nOptimized and self optimized magnetic confinement\n\n\n\n\n\n Friedrich Wagner (Max-Planck-Institut für Plasmaphysik\, Teilinstitut Gr eifswald)\n\n\n\n\nMagnetic confinement in toroidal fusion systems has bee n developed to a degree\, which allows building the first fusion reactor\, ITER. The goal of ITER is the operation of a Deuterium-Tritium plasma und er conditions\, which allow the production of 500 MW fusion power with a p ower amplification of Q=10. But ITER is still an experiment and it will so lve for its basic concept – the tokamak – many fundamental research is sues. As the tokamak concept has drawbacks – prone to current driven ins tabilities and intrinsically pulsed – alternatives are pursued in parall el. The stellarator is the second most advanced toroidal magnetic confinem ent concept whereat the largest and most advanced device of this line\, We ndelstein 7-X\, has just started operation in Greifswald\, Germany. Wendel stein 7-X is an experiment for basic research\, which nevertheless should demonstrate the reactor viability of this concept. The major difference be tween tokamak and stellarator is the way the poloidal field\, essential fo r confinement\, is produced. In case of the tokamak\, it is generated by a strong toroidal current induced within the toroidal plasma ring. In stell arators\, it is produced externally by currents within strongly shaped coi ls.\n\n\n\n\nThe system optimization aims i.a. at the quality of the therm al insulation of the plasma to reach high core temperatures by economic me ans. The tokamak benefits from the reduced system symmetry with continuous symmetry in toroidal direction. The stellarator plasma is unavoidably 3-d imensional and toroidally periodic with the corollary of insufficient coll isional confinement. But with a rigorous system optimization those field p roperties which are decisive for the “laminar” radial transport can be made 2-dimensional. Systems with these features are called quasi-symmetri c and they should have similar collisional transport like truly symmetric systems\, be more stable and intrinsically suitable for steady-state opera tion.\n\n\n\n\nOn the other hand\, fusion plasmas are thermodynamically op en systems where turbulent processes govern radial transport in symmetric and quasi-symmetric systems. Like in other open systems also\, self-organi zed processes can determine important and relevant plasma characteristics. Under high plasma pressure giving rise to a large turbulence level\, the turbulent eddies can develop a coherence where ultimately the energy of th e turbulence field is transformed into the kinetic energy of a macroscopic flow. This flow turns out to be sheared acting back onto its original dri ve\, the turbulence field. Within a sub-millisecond time scale\, the turbu lence is quenched in a highly non-linear process and a quiescent regime wi th good confinement emerges. This regime is called high-confinement mode ( H-mode) and is the basis to reach the goals of ITER. Some of these mechani sms play also a role in other open systems with classical turbulence.\n\n\ n\n\nIn this seminar the physics of plasma optimization and self-optimizat ion will be presented.\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-464@lptms.universite-paris-saclay.fr DTSTART:20161019T110000Z DTEND:20161019T120000Z DTSTAMP:20161011T060931Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-aleksandra-walczak/ SUMMARY:Physics-Biology interface seminar: Aleksandra Walczak - LPTMS\, sal le 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Oct 16 11:00 DESCRIPTION:Optimal immune systems\nAleksandra Walczak (LPT-ENS\, Paris)\nN OTE THE NEW LOCATION (due to renovation work at LPS)\n\nBiological organis ms have evolved a wide range of complex strategies to defend themselves ag ainst pathogens. I will present a common evolutionary framework that balan ces the benefits and costs involved in protection against pathogenic envir onments to maximize the long growth rate of populations. I will show that such a general evolutionary perspective recovers the basic forms of known immunity. I will then focus on adaptive immunity which is based on a combi natorically encoded repertoire of receptors that protects organisms from a diverse set of pathogens. A well-adapted repertoire should be tuned to th e pathogenic environment to reduce the cost of infections. I will discuss a general approach for predicting the optimal repertoire that minimizes t he cost of infections contracted from a given distribution of pathogens.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-458@lptms.universite-paris-saclay.fr DTSTART:20161025T110000Z DTEND:20161025T120000Z DTSTAMP:20160913T054255Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mikhail-zubkov/ SUMMARY:Séminaire du LPTMS: Mikhail Zubkov - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 25 Oct 16 11:00 DESCRIPTION:Momentum space topology\, anomalous quantum Hall effect\, and t he absence of equilibrium static chiral magnetic effect\nMikhail A. Zubkov (ITEP\, Moscow\, Russia &\; LMPT\, Université François Rabelais\, To urs)\nUsing derivative expansion applied to the Wigner transform of the tw o - point Green function we analyze the anomalous quantum Hall effect (AQH E)\, and the chiral magnetic effect (CME). The corresponding currents are proportional to the momentum space topological invariants. We reproduce th e conventional expression for the Hall conductivity in the ideal tight – binding models of (2+1) D topological insulators. At the same time using this method we prove\, that in the equilibrium (3+1) D theory the static C ME is absent in a certain class of solids\, as well as in the properly reg ularized relativistic quantum field theory.\n\nReferences:\n\n “Absence of equilibrium chiral magnetic effect”\, Phys. Rev. D 93 (2016) no.10\, 105036\, doi:10.1103/PhysRevD.93.105036\, arXiv:1605.08724 [hep-ph]\, by M . A. Zubkov\n “Wigner transformation\, momentum space topology\, and ano malous transport”\, Annals Phys. 373 (2016) 298-324\, doi:10.1016/j.aop. 2016.07.011\,  arXiv:1603.03665 [cond-mat.mes-hall]\,  by M. A. Zubkov\n \n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-473@lptms.universite-paris-saclay.fr DTSTART:20161028T110000Z DTEND:20161028T120000Z DTSTAMP:20161021T104123Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-commun- lps-lptms-daniel-braun/ SUMMARY:Séminaire du LPTMS: Daniel Braun **** commun avec le LPS **** - - 28 Oct 16 11:00 DESCRIPTION:Ultimate limits of quantum measurements\nDaniel Braun (Institut für Theoretische Physik\, Universität Tübingen)\nQuantum enhanced meas urements aim at measuring physical quantities with increased precision by using quantum mechanical effects. At the heart of most theoretical efforts in the field lies quantum parameter estimation theory (q-pet)\, which pro vides a powerful and general framework for analysing the performance of me asurements in the quantum realm. Most of the work has gone into the invest igation of the benefits of entangled states\, which are\, however\, limite d in the presence of decoherence. In this talk I will give a wider perspec tive of quantum enhanced measurements\, and explore in particular possibil ities of quantum enhancement without the use of entanglement. The examples discussed range from the sensitivity of artificial noses\, over the measu rement of chemical potentials\, to measurements of the speed of light. The latter example goes well beyond q-pet\, and I will show that the ultimate precision of speed-of-light measurements is set by both quantum and gener al relativistic effects\, offering a new perspective on possible quantum f luctuations of space-time geometry.\n\n***** ATTENTION : le séminaire "th éorie de la matière condensée sur le plateau" a lieu au Parc Club\, RdC du bât.18-20  *****\n\nPlan d'accès : http://www.leparcorsayuniversite .com/uploads/plan-masse-2012.jpg CATEGORIES:seminars END:VEVENT BEGIN:VEVENT UID:1-470@lptms.universite-paris-saclay.fr DTSTART:20161104T110000Z DTEND:20161104T120000Z DTSTAMP:20161021T064523Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jacek-grela-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Jacek Grela *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 4 Nov 16 11 :00 DESCRIPTION:Dynamical non-Hermitian random matrices - Hydrodynamics and rel evance of eigenvectors\nJacek Grela (LPTMS\, Université Paris-Sud)\nI pre sent a study of non-Hermitian dynamical random matrices with special empha sis put on identifying relevant degrees of freedom. Hermitian case will be revisited and compared to and the formalism of characteristic polynomials and Green's function formalism discussed. We will present how a hydrodyna mical picture of Burgers equations arises and what a special role eigenvec tors play in it. Examples and interpretation of results in a couple of sta tistical physics models will be delivered.\n\nReferences :\n\n "Dysonian d ynamics of the Ginibre ensemble"\, Z. Burda\, J. Grela\, M. A. Nowak\, W. Tarnowski\, P. Warchol\, Phys. Rev. Lett. 113\, 104102 (2014)\n "Unveilin g the significance of eigenvectors in diffusing non-hermitian matrices by identifying the underlying Burgers dynamics"\, Z. Burda\, J. Grela\, M. A. Nowak\, W. Tarnowski\, P. Warchol\, Nucl. Phys. B 897\, 421 (2015)\n "Hy drodynamical spectral evolution for random matrices"\, P.J. Forrester\, J. Grela\, J. Phys. A: Math. Theor. 49 085203 (2016)\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-459@lptms.universite-paris-saclay.fr DTSTART:20161108T110000Z DTEND:20161108T120000Z DTSTAMP:20161021T102111Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-frederic-van-wijland/ SUMMARY:Séminaire du LPTMS: Frédéric van Wijland - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 8 Nov 16 11:00 DESCRIPTION:How far from equilibrium is active matter?\nFrédéric van Wijl and (Laboratoire Matière et Systèmes Complexes\, Université Paris 7 Den is Diderot)\nActive Matter in 2016 encompasses such a broad range of syste ms that it is almost a challenge to define what's behind this terminology. One of the unifying characteristics to all active systems is that individ ual constituents convert an external continuous supply of energy into rand om motion. On a representative model of an active system\, we will explain how\, by looking at the movie of its time evolution\, one can tell whethe r\, and how far\, the system lies away from equilibrium. We will also prov ide a microscopics based explanation of some of the macroscopic effects th at are specific to active particle systems.\n\nReference :\n\nÉ. Fodor\, C. Nardini\, M. E. Cates\, J. Tailleur\, P. Visco and F. van Wijland\, "Ho w far from equilibrium is active matter?"\, Phys. Rev. Lett. 117\, 038103 (2016) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-475@lptms.universite-paris-saclay.fr DTSTART:20161110T110000Z DTEND:20161110T110000Z DTSTAMP:20161104T070038Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-lptms-j akub-otwinowski-seminaire-exceptionnel/ SUMMARY:Séminaire LPTMS: Jakub Otwinowski *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Nov 1 6 11:00 DESCRIPTION:The diversity of evolutionary rates\nJakub Otwinowski (Departme nt of Biology\, University of Pennsylvania\, Philadelphia)\nWe have eviden ce of evolution happening over billions of years\, yet we have little unde rstanding of how long it takes for anything to evolve. In other words\, we often do not understand quantitatively what affects the rate of evolution over long time-scales. I will show how spatial structure can impede the r ate of evolution with a model related to surface growth physics. The fitne ss landscape is also an important factor in the rate of evolution\, and I will discuss how it can be approximated from high-throughput sequence-func tion experiments. Finally\, I show how the rate of evolution can be define d in coevolving populations with non-equilibrium measures of adaptation.\n \n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-466@lptms.universite-paris-saclay.fr DTSTART:20161115T110000Z DTEND:20161115T120000Z DTSTAMP:20161022T163422Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giulia-de-rosi/ SUMMARY:Séminaire du LPTMS: Giulia De Rosi - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 15 Nov 16 11:00 DESCRIPTION:Collective oscillations of trapped atomic gases in low dimensio ns: a tool for the investigation of collisional processes\nGiulia De Rosi (Università di Trento\, Italia)\n\nSince 20 years\, both theoretical and experimental investigation of collective oscillations has been carried out in trapped quantum gases. Fermionic and bosonic gases at different intera ction\, temperature\, dimensions and geometrical configurations have been studied. We show a unified description of collective modes for all above a tomic gases. All collective frequencies have been calculated by solving a single equation for the flow velocity derived starting from the hydrodynam ic equations. Moreover\, by using the sum- rule approach\, we predict a di fferent excitation signal at high temperature for the dipole compression m ode in the hydrodynamic (single frequency) and collisionless (beating of 2 frequencies) regime for a one dimension (1D) harmonically trapped Bose ga s. This theoretical prediction opens promising perspectives for the experi mental investigation of collisional effects in 1D.\n\n\nReferences:\n\n G. De Rosi and S. Stringari\, Collective oscillations of a trapped quantum g as in low dimensions\, Phys. Rev. A 92 \, 053617 (2015).\n G. De Rosi and S. Stringari\, Hydrodynamic VS collisionless dynamics of a 1D harmonically trapped Bose gas\, to appear in Phys. Rev. A\, preprint arXiv:1608.08417 \n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-465@lptms.universite-paris-saclay.fr DTSTART:20161116T110000Z DTEND:20161116T120000Z DTSTAMP:20161010T142511Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-sandrine-morlot/ SUMMARY:Physics-Biology interface seminar: Sandrine Morlot - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Nov 16 11:00 DESCRIPTION:Deficient ribosome biogenesis is an early marker of cellular se nescence\nSandrine Morlot (IGBMC\, Strasbourg)\nNOTE THE NEW LOCATION (due to renovation work at LPS)\n\nSaccharomyces cerevisiae is a powerful mode l organism to study replicative aging as asymmetric division gives rise to an aging mother cell and a rejuvenated daughter cell [Mortimer and Johnst on 1959\, Egilmez and Jazwinski 1989]. However the cellular mechanisms con trolling replicative lifespan and the rejuvenation process are still poorl y understood partly due to the technical limitations of following individu al cells from birth to death. In this context\, we have developed a high-t hroughput microfluidic device to follow up to 3200 single cells in paralle l throughout their lifespan under the microscope. Thanks to this technolog y\, we have established a timeline of events occurring successively during cellular aging. We have observed that cells experience a sharp transition into senescence. Indeed yeasts divide regularly every 90 minutes until a senescence entry point (SEP) which occurs after 20 generations. After this point\, cell cycles strongly slow down until death [Fehrmann et al. Cell Reports 2013]. Furthermore we have measured that the SEP is preceded by an abrupt increase in the nuclear volume and more specifically in the size o f nucleolus. The nucleolus is the nuclear compartment where ribosome bioge nesis is initiated. This age-dependent nuclear defect is retained by the m other only\, as daughter cells recover a normal nucleus and nucleolus\, in agreement with the daughter cell rejuvenation paradigm. We have character ized that pre-ribosome particles accumulate in the nucleolus approximately 10 hours before entering into senescence. Our analysis suggests that this deficiency in ribosome biogenesis triggers cellular senescence.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-461@lptms.universite-paris-saclay.fr DTSTART:20161122T110000Z DTEND:20161122T123000Z DTSTAMP:20161104T103358Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-rougerie/ SUMMARY:Séminaire du LPTMS: Nicolas Rougerie - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 22 Nov 16 11:00 DESCRIPTION:Emergent anyons in quantum Hall physics\nNicolas Rougerie (LPMM C\, Université de Grenoble)\nAnyons are hitherto hypothetical particles w ith quantum statistics different from those of bosons and fermions. They c an occur only in low dimensions\, 2D being the case of interest for this t alk.\nA convenient description of 2D anyons is to treat them as ordinary b osons or fermions coupled to magnetic flux tubes. This leads to a model in terms of an effective Hamiltonian\, which contains rather peculiar two- a nd three-body interactions. Recently\, we have considered the case of trac er particles immersed in a so-called Laughlin liquid. We argued that\, und er certain circumstances\, these become anyons\, as made manifest by the e mergence of the aforementioned Hamiltonian in an effective description of their motion.\nThe anyon Hamiltonian is notoriously hard to solve even in simple cases\, and well-controled simplifications are highly desirable. I will discuss a possible mean-field approximation\, that we have rigorously derived in a limit corresponding to "almost bosonic anyons".\n\n \;\n \nAnyons émergents dans le cadre de l'effet Hall quantique : Les anyons s ont des particules\, jusqu'ici hypothétiques\, avec des statistiques quan tiques différentes de celles des bosons et des fermions. Elles ne sont po ssibles qu'en basse dimension\, 2D étant le cas considéré dans cet expo sé.\nUne description pratique des anyons 2D est de les voir comme des bos ons ou des fermions couplés à des tubes de flux magnétique\, avec le Ha miltonien associé. Récemment\, nous avons considéré le cas de particul es traceuses immergées dans un liquide de Laughlin et avons montré que\, dans certaines circonstances\, les particules traceuses sont décrites pa r ce Hamiltonien effectif.\nCe dernier est notoirement difficile à étudi er\, et des simplifications bien contrôlées sont hautement désirables. Je décrirais une possible approximation de champ moyen\, que nous avons r igoureusement dérivée dans une certaine limite correspondant à des anyo ns "quasi-bosoniques".\n\nRéférence :\n\n Douglas Lundholm and Nicolas R ougerie\, "Emergence of Fractional Statistics for Tracer Particles in a La ughlin Liquid"\, Phys. Rev. Lett. 116\, 170401 (2016)\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-471@lptms.universite-paris-saclay.fr DTSTART:20161129T110000Z DTEND:20161129T120000Z DTSTAMP:20161003T085856Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-julien-tailleur/ SUMMARY:Séminaire du LPTMS: Julien Tailleur - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 29 Nov 16 11:00 DESCRIPTION:The Physics of Active Matter\nJulien Tailleur (Laboratoire Mati ère et Systèmes Complexes\, Université Denis-Diderot)\nOver the past te n years\, there has been a growing interest among physicists for 'active m atter'\, a codename that encompasses systems in which energy is taken from the environment to generate self-propulsion at the single particle level. Active particles\, such as run-and-tumble bacteria\, self-diffusiophoreti c colloids or actin filaments in motility assays\, are strongly out-of-equ ilibrium and exhibit much richer behaviours that their passive counterpart .\n\nIn this talk I will review recent progresses regarding the physics of active particles. I will show how simple concepts like pressure\, the for ce density exerted by assemblies of particles on their container\, play a new role for active systems because of the lack of equation of state. I wi ll also show how new collective phenomena emerge\, from the transition to collective motion to the existence of cohesive matter without cohesive for ces\, that have no counterpart in thermal equilibrium. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-462@lptms.universite-paris-saclay.fr DTSTART:20161130T110000Z DTEND:20161130T120000Z DTSTAMP:20161117T104639Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-david-head/ SUMMARY:Physics-Biology interface seminar: David Head - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 30 Nov 16 11:00 DESCRIPTION:High-fidelity computational modelling of biofilms and fibre net works\nDavid Head (University of Leeds\, UK)\nNOTE THE NEW LOCATION (due t o renovation work at LPS)\nMathematical models of complex systems can help develop fundamental insight and accelerate the development of\nnovel mate rials and therapeutic treatments\, but the simplifications that must neces sarily be made reduce both\nvalidity and predictability\, even for complex models that are solved numerically. Here I will describe recent\nresults in two research streams aimed at developing and validating high-fidelity i n silico models for biofilms\nand fibre networks\, aiming to reduce the re alism gap to experimental systems while maintaining sufficient\nperformanc e to permit solution for times and system sizes of interest. The first is a bespoke model for biofilms\nin which mechanical relaxation between cells replaces the "pushing" rules typically used\, and has been applied\nto th e archetypal biofilm of dental plaque\, revealing insight into long-term e cological dynamics not easily\nassayed experimentally. Secondly\, I will d iscuss dynamic simulations of peptide gels and collagen hydrogel\nscaffold s\, both having important applications as novel biomaterials but where net work formation must also be\nsimulated to better approximate the experimen ts\; reaching realistic time scales is a substantial challenge. CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-472@lptms.universite-paris-saclay.fr DTSTART:20161206T110000Z DTEND:20161206T120000Z DTSTAMP:20161124T145017Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrei-bernevig/ SUMMARY:Séminaire du LPTMS: Andrei Bernevig - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 6 Déc 16 11:00 DESCRIPTION:Topological insulators and semimetals\nAndrei Bernevig (Princet on University\, USA)\nI will review topological states of matter with spec ific emphasis on the symmetry-protected topological insulators in differen t dimensions. I will show how Majorana states can be realized at the end o f topological chains with fermionic parity\, as well as in vortex cores in 2D chiral superconductors. I will then show how some of the simplest tens or Braided categories come out of simple\, intuitive physical arguments ab out braiding vortices. I will present a slew of topological insulators pro tected by time reversal\, symmorphic\, and then nonsymmorphic symmetries. At then end\, I will present new work aiming to provide a complete and com prehensive classification of all topological insulators existent in crysta ls. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-467@lptms.universite-paris-saclay.fr DTSTART:20161213T110000Z DTEND:20161213T120000Z DTSTAMP:20161004T083353Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-duo-thibault-congyaurelien-grabsch/ SUMMARY:Séminaire du LPTMS: duo Thibault Congy/Aurélien Grabsch - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Déc 16 11:00 DESCRIPTION:Nonlinear polarization waves in two-component Bose-Einstein con densates\nThibault Congy (LPTMS\, Université Paris-Sud)\nRéf.:\nT. Congy \, A. M. Kamchatnov &\; N. Pavloff\, Dispersive hydrodynamics of nonlin ear polarization waves in two-component Bose-Einstein condensates\, prepri nt cond-mat.quant-gas arXiv:1607.08760\n\nTruncated linear statistics asso ciated with the top eigenvalues of random matrices\nAurélien Grabsch (LPT MS\, Université Paris-Sud)\nRéf.:\nA. Grabsch\, S. N. Majumdar &\; C. Texier\, Truncated linear statistics associated with the top eigenvalues of random matrices\, preprint cond-mat.stat-mech arXiv:1609.08296 CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-476@lptms.universite-paris-saclay.fr DTSTART:20161214T110000Z DTEND:20161214T120000Z DTSTAMP:20161208T135708Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-atef-asnacios/ SUMMARY:Physics-Biology interface seminar: Atef Asnacios - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Déc 16 11:00 DESCRIPTION:Mechanosensing: insights from experimental physics at the singl e-cell scale\nAtef Asnacios (MSC\, Université Paris-Diderot\, France)\nNO TE THE NEW LOCATION (due to renovation work at LPS)\nAs part of their phys iological functions\, most cells need to adapt to their mechanical environ ment. In particular\, the rigidity of the extracellular matrix was shown t o control cell traction forces\, shape\, and ultimately cell differentiati on. In this context\, most studies focused on the role of biochemical regu lation in rigidity sensing.\nIn contrast to this biochemical signaling-cen tered approach\, our aim is to reveal the physical/mechanical phenomena in volved in mechanosensing. To this end\, we have developed original single- cell techniques combining mechanical measurements (traction force\, mechan ical power…) with monitoring of cell structures (evanescent wave microsc opy). In particular\, we have designed a unique protocol allowing us to ch ange the effective stiffness felt by a single cell in real time (~0.1 seco nd)\, thus allowing us to show that an early purely mechanical response of single cell to stiffness indeed does exist.\nWe will present the results of experiments combining single-cell traction force measurements\, dynamic control of stiffness\, and monitoring of adhesion complexes\, and will di scuss how cell shape (~ contact angle) and mechanical adaptation to rigidi ty (~ impedance matching) could control cell fate.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-483@lptms.universite-paris-saclay.fr DTSTART:20161215T110000Z DTEND:20161215T120000Z DTSTAMP:20161129T184212Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-vladimir-kravtsov-seminaire-exceptionnel-2/ SUMMARY:Séminaire du LPTMS: Vladimir Kravtsov *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 D éc 16 11:00 DESCRIPTION:Phases and phase transitions on disordered Bethe lattice: analy tical treatment by one-step replica symmetry breaking\nVladimir Kravtsov ( ICTP\, Trieste\, Italy)\nWe apply the replica trick to the problem of loca lization on disordered  Bethe lattice. We show that the formulation of th e problem in terms of  the one-step replica symmetry breaking leads natur ally to existence of  the multifractal phase and to phase transitions bet ween this phase and  the localized and fully extended (ergodic) delocaliz ed phase. We prove  the symmetry m→1-m of the problem with respect to t he replica symmetry  breaking parameter m and use this symmetry to derive exact expressions  for the transition points in terms of the Lyapuniov e xponents and the  branching number K. We also suggest a simple approximat ion which allows  to compute the fractal dimension D1 in the multifractal phase and the  critical values of disorder at the phase transitions with the best known  so far accuracy.\n\nReference :\n\n \nB. L. Altshuler\, L. B. Ioffe and V. E. Kravtsov\, Multifractal states in self-consistent th eory of localization: analytical solution\, preprint arXiv:1610.00758\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-485@lptms.universite-paris-saclay.fr DTSTART:20161219T110000Z DTEND:20161219T123000Z DTSTAMP:20161212T075338Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrey-lokhov-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Andrey Lokhov ***séminaire exceptionnel*** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Déc 16 11:00 DESCRIPTION:Optimal structure and parameter learning of Ising models and ca libration of the D-Wave quantum computer\nAndrey Lokhov\, Los Alamos Natio nal Laboratory\nReconstruction of structure and parameters of a graphical model from binary samples is a problem of practical importance in a variet y of disciplines\, ranging from statistical physics and computational biol ogy to image processing and machine learning . The focus of the research c ommunity shifted towards developing universal reconstruction algorithms wh ich are both computationally efficient and require the minimal amount of e xpensive data. In this talk\, we introduce a new method\, Interaction Scre ening\, which accurately estimates the model parameters using local optimi zation problems. We provide mathematical guarantees that the algorithm ach ieves perfect graph structure recovery with an information-theoretically o ptimal number of samples and outperforms state of the art techniques\, esp ecially in the low-temperature regime which is known to be the hardest for learning. As an application\, we show how the method can be used for an e fficient calibration of the D-Wave quantum computer. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-479@lptms.universite-paris-saclay.fr DTSTART:20170111T110000Z DTEND:20170111T120000Z DTSTAMP:20170103T221103Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-leila-perie/ SUMMARY:Physics-Biology interface seminar: Leïla Perié - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Jan 17 11:00 DESCRIPTION:Deciphering the family of immune cells at the single cell level \nLeïla Perié (Institut Curie\, Paris)\n\nHow heterogeneous systems of c ells constituting multicellular organisms establish\, organize and achieve coordination persists as a central question in natural sciences. Whereas stochastic gene or protein expressions have clearly demonstrated their rol e in cellular heterogeneity and are widely studied (Wang and Bodovitz\, 20 10)\, the role of cell heterogeneity in the organization of multicellular organisms has been less interrogated. Addressing this question requires ad equate tools that quantitatively study ensembles of cells individually rat her than group of cells. \n\n\nMy research aims at addressing cell hetero geneity in dynamical and complex systems of cells using the hematopoietic system as a model of study. Strikingly hematopoietic cells (immune cells\, platelets and red blood cells) compose over 90% of total human cells and correspond to approximately ten trillions of cells (Sender R\, 2016). More importantly they all originate from the same cells\, the hematopoietic st em cells (HSC)\, through a process called hematopoiesis. In addition\, as immune and blood cells have a short life span (from hours to months) and c an response to perturbations like infections\, this process is highly dyna mical. It is therefore an interesting and challenging model to study diffe rentiation in a complex system at the single cell level. \n\n\nTo achieve this\, Leïla Perié’s lab combines different experimental and mathemati cal/computational approaches of single cell tracing to study hematopoiesis in vivo. For example cellular barcoding is one of the lineage tracing app roaches used by the Perié’s lab. It simultaneously traces the in vivo d ifferentiation of individual cells\, allowing to reconstitute the relation ship between cell lineages with single cell resolution. In this seminar\, we will discuss some of our recent results using cellular barcoding in hem atopoiesis. \n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-482@lptms.universite-paris-saclay.fr DTSTART:20170117T110000Z DTEND:20170117T120000Z DTSTAMP:20161213T084245Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-simon-pigeon/ SUMMARY:Séminaire du LPTMS: Simon Pigeon - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 17 Jan 17 11:00 DESCRIPTION:Controlling superfluid vortices in polariton fluids\nSimon Pige on (LKB\, Université Pierre et Marie Curie\, Paris)\nExciton-polaritons\, microcavity half-matter half-light quasi-particles\,  when resonantly dr iven exhibit a superfluid regime. Accordingly\,  topological excitations similar to those predicted in equilibrium  superfluids may spontaneously appear. However\, the non-equilibrium  nature of polaritons requires the system to be continuously pumped in  order to compensate for losses. This driving plays a key role in the  formation and dynamics of such topologi cal excitations. Excited through  a resonant pumping\, the coherent field driving the system imposes a  phase on the polariton fluid which inhibit s the formation of vortices or  solitons. This unique feature of coherent ly driven polariton superfluids  has been used to trap vortices. To that purpose an engineered pumping  profile\, alternating between spatial driv en and non driven regions was  proposed and successfully implemented.\n\n Based on this same idea of spatially engineered pumping profils\, many  w orks done lately focused spontaneous formation of vortices in polariton  superfluids. For practical experimental reasons\, such as high speeds\,  small propagation length and a short lifetimes\, the hydrodynamics of  th ese vortices propagating were largely ignored.\n\nI will present a recent investigation of an optical method allowing us  to overcome these difficu lties\, together with giving the unique  opportunity to directly control and manipulate the properties of the  vortices. The general idea is to su stain the superfluid polariton flow\,  something which generally does not last long outside the excitation  region\, with a secondary supporting e xcitation of low intensity. This  way the flow may propagate over a much longer distance. The vortices  formed in the superfluid are still permitt ed due to the weakness of the  support pump. This allows their propagatio n along large distances and  the observation of their hydrodynamic behavi our. However\, the secondary  coherent driving acting as a support\, allo ws for some other rich and  unique features. At the same time as increasi ng the propagation length\,  the same support driving gives direct contro l over the vortex-antivortex  pair properties\, offering a unique opportu nity to manipulate vortex  locally and accurately.\n\nThe new approach pr oposed allows for the observation of hydrodynamic  behaviour of superflui d vortices\, and initiates a new step regarding the  control of such fund amental entities\, thus paving the way toward their  practical use.\n\nRe ferences:\n\n S. Pigeon\, I. Carusotto\, and C. Ciuti\, Hydrodynamic nucle ation of vortices and solitons in a resonantly excited polariton superflui d\, Phys. Rev. B 83\, 144513 (2011)\n A. Amo\, S. Pigeon\, et al\, Polarit on Superfluids Reveal Quantum Hydrodynamic Solitons\, Science 332\, 1167-1 170 (2011)\n D. Sanvitto\, S. Pigeon\, et al\, All-optical control of the quantum flow of a polariton superfluid\, Nature Photonics 5\, 610-614 (201 1)\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-487@lptms.universite-paris-saclay.fr DTSTART:20170119T110000Z DTEND:20170119T120000Z DTSTAMP:20170110T120238Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-eric-vernier-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Eric Vernier *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Jan 17 11:00 DESCRIPTION:Non equilibrium dynamics of quantum systems : the Loschmidt ech o\nEric Vernier (SISSA\, Trieste)\nThe non-equilibrium dynamics of quantum many-body systems has attracted a large interest over  the last decade\, prompted by formidable advances in cold-atomic experiments.  While much progress has been done in understanding the relaxation mechanisms of physi cal observables and the characterization of the stationary state following \, for instance\, a quantum quench (where an isolated system is let evolve after one or several parameters have been suddenly changed)\, very few an alytical results exist about the full time dynamics despite the existence of prototypical integrable models. Indeed\, the time dynamics involves con tributions for arbitrarily excited eigenstates of the Hamiltonian\, making calculations prohibitively difficult.\n\nIn this talk I will present some progress made recently in this direction (based on the preprint arXiv:161 1.06126)\, namely an analytical computation of the Loschmidt echo\, which measures the overlap between the state of the system at a given time and i ts initial state\, for various types of quenches in the Heisenberg XXZ spi n chain. The latter has attracted a renewed interest recently in the conte xt of dynamical phase transitions\, which it signals through its non-analy ticities as a function of the time. Using a reformulation of the problem i n terms of an auxiliary boundary quantum transfer matrix and using an infi nite set of functional relations\, we write the Loschmidt echo as the solu tion of an infinite set of Non Linear Integral Equations\, which allows fo r its exact determination at arbitrarily large time. This method overcomes the time limitations experienced by numerical approaches\, and may serve as a basis for the computation of other physical observables.\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-484@lptms.universite-paris-saclay.fr DTSTART:20170124T110000Z DTEND:20170124T120000Z DTSTAMP:20170117T101336Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-laura-foini-2/ SUMMARY:Séminaire du LPTMS: Laura Foini - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 24 Jan 17 11:00 DESCRIPTION:Spatio-temporal patterns in ultra-slow domain wall creep dynami cs\nLaura Foini (LPT-ENS\, Paris)\nIn presence of impurities\, ferromagnet ic and ferroelectric domain walls slide only above a finite external field . Close to this depinning threshold\, they proceed by large and abrupt jum ps\, called avalanches\, while\, at much smaller field\, these interfaces creep by thermal activation.\nIn this talk I will present our results for the creep dynamics at vey low forces\, obtained by a novel numerical tech nique that captures this ultra-slow regime over huge time scales. We point out the existence of activated events that involve collective reorganizat ions similar to avalanches\, but\, at variance with them\, display correla ted spatio-temporal patterns that resemble the complex sequence of aftersh ocks observed after a large earthquake. Remarkably\, we show that events a ssembly in independent clusters that display at large scales the same stat istics as critical depinning avalanches. We foresee this correlated dynami cs being experimentally accessible by magneto-optical imaging of ferromagn etic films.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-489@lptms.universite-paris-saclay.fr DTSTART:20170125T110000Z DTEND:20170125T120000Z DTSTAMP:20170116T164021Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-antoine-jegou/ SUMMARY:Physics-Biology interface seminar: Antoine Jégou - LPTMS\, salle 2 01\, 2ème étage\, Bât 100\, Campus d'Orsay - 25 Jan 17 11:00 DESCRIPTION:Building and disassembling actin filaments with proteins and fo rces\nAntoine Jégou (Institut Jacques Monod\, France)\n\nThe actin cytosk eleton comprises several networks essential for the cell to perform many k ey functions (motility\, cell division\, tissue cohesion\, …). Their ass embly and disassembly is tightly regulated\, in space and time\, by a myri ad of actin binding proteins but also by the mechanical stress applied to those networks. We take advantage of a simple setup based on microfluidics and fluorescence microscopy\, to manipulate actin filaments in vitro and assay the regulation of actin assembly. Focusing first on the assembly of filaments by formins\, which are able to track filament barbed ends and ac celerate their elongation from profilin-actin\, we will show how tracking and rapid elongation are modulated by filament tension and regulatory prot eins. We will then focus on ADF/cofilin isoforms\, which play a central in filament disassembly. We will show how ADF/cofilin fragments and depolyme rizes filaments through different mechanisms\, targeting both the side and the ends of the filaments.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-492@lptms.universite-paris-saclay.fr DTSTART:20170126T140000Z DTEND:20170126T150000Z DTSTAMP:20170117T170732Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-olexander-gamayun-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Oleksandr Gamayun *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 26 J an 17 14:00 DESCRIPTION:Quantum dynamics of a mobile impurity in a one-dimensional Ferm i gas\nOleksandr Gamayun (Leiden Unversity\, The Netherlands)\nA single im purity particle in an ultracold atomic gas is a prospective model for prob ing relaxation dynamics of an interacting out-of-equilibrium quantum syste m. I will focus on a case of an impurity that propagates in a one-dimensio nal gas of free fermions and interacts with them through the contact inter action. It is the simplest and yet fundamental model capturing a peculiar physics and mathematics of the non-equilibrium processes. A particular fea ture of this model is integrable when masses of the impurity and gas parti cles are equal. In this case\, I will present a full nonpertubative soluti on and express physical quantities in terms of the Fredholm determinants o f integrable integral operators. After a detailed analysis of the mathemat ical structure of the Fredholm determinants\, I will discuss several strik ing physical phenomena such as incomplete relaxation\, Bloch oscillations\ , and momentum-dependent impurity statistics. To describe the non-integrab le case\, I will develop a kinetic theory approach. I will then present it s modification that allows description of the integrable case as well. Fin ally\, I will give some arguments about the persistence of the discussed p henomena at a finite temperature.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-468@lptms.universite-paris-saclay.fr DTSTART:20170131T110000Z DTEND:20170131T120000Z DTSTAMP:20170120T114748Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-john-martin/ SUMMARY:Séminaire du LPTMS: John Martin - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 31 Jan 17 11:00 DESCRIPTION:Cold atom superradiance\nJohn Martin (Université de Liège\, B elgique)\nIn my talk\, I will report on the derivation and resolution of a novel master equation governing the cooperative spontaneous emission from an ensemble of cold atoms [1]. Our master equation for the atomic interna l degrees of freedom incorporates the effects of the quantization of the a tomic center-of-mass motion. It provides a unifying picture of the consequ ences of recoil and indistinguishability of atoms beyond the Lamb-Dicke re gime\, both on their dissipative and conservative internal dynamics. I wil l discuss general expressions for the decay rates and dipole-dipole shifts entering our master equation. As an application of our formalism\, I will then investigate the consequences of indistinguishability of cold atoms o n two hallmarks of cooperative emission processes: Dicke super- and subrad iance [2].\nRéférences :\n\n [1] F. Damanet\, D. Braun\, and J. Martin\, Master equation for collective spontaneous emission with quantized atomic motion\, Phys. Rev. A 93\, 022124 (2016) \;\nCooperative spontaneous emis sion from indistinguishable atoms in arbitrary motional quantum states\, i bid. 94\, 033838 (2016).\n [2] R. H. Dicke\, Coherence in Spontaneous Radi ation Processes\, Phys. Rev. 93\, 99 (1954).\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-493@lptms.universite-paris-saclay.fr DTSTART:20170207T110000Z DTEND:20170207T120000Z DTSTAMP:20170126T132758Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pascal-naidon/ SUMMARY:Séminaire du LPTMS: Pascal Naidon - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 7 Fév 17 11:00 DESCRIPTION:Two impurities in a Bose-Einstein condensate: from the Yukawa t o the Efimov attraction\nPascal Naidon (RIKEN\, Japan)\nThe properties of two particles immersed in a Bose-Einstein condensate are investigated usin g a variational approach. These properties can be interpreted in terms of a boson-mediated interaction. For a weak particle-boson attractive interac tion\, the two particles form two free attractive polarons that interact t hrough a weak boson-mediated Yukawa attraction. For suffciently strong int eractions\, the boson-mediated interaction turns into an Efimov attraction leading to the binding of the two particles and one boson into Efimov tri mers. It is found that these in-medium Efimov trimers exist for weaker int eractions than in vacuum.\nReference: P. Naidon\, Two impurities in a Bose -Einstein condensate: from Yukawa to Efimov attracted polarons\, preprint cond-mat arXiv:1607.04507\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-494@lptms.universite-paris-saclay.fr DTSTART:20170214T110000Z DTEND:20170214T120000Z DTSTAMP:20170207T144643Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-duo-xiangyu-cao-kirill-plekhanov/ SUMMARY:Séminaire du LPTMS: duo Xiangyu Cao &\; Kirill Plekhanov - LPTM S\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Fév 17 11:0 0 DESCRIPTION:``Liouville field theory and log-correlated Random Energy Model s'' by Xiangyu Cao (LPTMS\, Université Paris-Sud)\nAn exact mapping is es tablished between the c ≥ 25 Liouville field theory (LFT) and the\nGibbs measure statistics of a thermal particle in a 2D Gaussian Free Field plus a logarithmic\nconfining potential. The probability distribution of the p osition of the minimum of the energy\nlandscape is obtained exactly by com bining the conformal bootstrap and one-step replica sym-\nmetry breaking m ethods. Operator product expansions in LFT allow to unveil novel universal \nbehaviours of the “log-correlated Random Energy Models” class. Appli cations will include multi-\nfractality (inverse participation ratios and their corrections) and the overlap distribution in the\ndirected polymer o n a Cayley tree model.\n\nRef.: Xiangyu Cao\, Pierre Le Doussal\, Alberto Rosso and Raoul Santachiara\, preprint arXiv:1611.02193.\n\n \;\n``Chi ral spin state of the frustrated XY model on the honeycomb lattice'' by Ki rill Plekhanov (LPTMS\, Université Paris-Sud)\nAbstract: Currently\, it w as suggested that the frustrated XY model for spin-1/2 on the honeycomb la ttice can support a chiral spin liquid (CSL) phase\, that is characterized by the spontaneous breaking of the time-reversal and parity symmetries. T he ground state of the system in the CSL phase will be characterized by th e gapped bulk and gapless chiral modes along the edges\, if open boundary conditions are used. In this talk I will present analytical arguments that lead to this conclusion and a numerical verification of analytical result s based on the calculations of local order parameters\, structure factors and scalar spin chirality using the exact diagonalization technique. An ex perimental realization of the model in the context of ultra-cold atoms and circuit-QED systems\, based on the application of time-dependent periodic (Floquet) modulations\, will be discussed. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-488@lptms.universite-paris-saclay.fr DTSTART:20170221T110000Z DTEND:20170221T120000Z DTSTAMP:20170206T131610Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-beatriz-seoane-bartolome-2/ SUMMARY:Séminaire du LPTMS: Beatriz Seoane Bartolomé - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 21 Fév 17 11:00 DESCRIPTION:Matching experiments and theory in spin glasses\nBeatriz Seoane Bartolomé (LPT-ENS\, Paris)\nThe unifying feature of glass formers (such as polymers\, supercooled liquids\, colloids\, granular materials\, spin glasses\, superconductors\, ...) is a sluggish dynamics at low temperature s. Indeed\, their dynamics is so slow that thermal equilibrium is never re ached in macroscopic samples: in analogy with living beings\, glasses are said to age. This fact suppose a difficulty to describe these systems theo retically. The reasons are two fold. One the one hand\, most of the calcul ations are obtained in the experimentally unreachable low-temperature equi librium\, and on the other hand\, they concern microscopic observables (ob tained mainly with the replica method) that are hard to measure in experim ents. In two recent works [1\,2]\, we have shown that it is possible to qu antitatively relate both realms\, using large-scale simulations on the sp ecial-purpose computers Janus and Janus II\, two dedicated supercomputers to simulate spin-glasses.\n\nIn the first work [1]\, we have performed a v ery accurate computation of the non-equilibrium fluctuation-dissipation ra tio for the three-dimensional Edwards-Anderson Ising spin glass. This rati o (computed for finite times on very large\, effectively infinite\, system s) is compared with the equilibrium probability distribution of the spin o verlap for finite sizes. The resulting quantitative statics-dynamics dict ionary\, based on observables that can be measured with current experiment al methods\, could allow the experimental exploration of important feature s of the spin-glass phase without uncontrollable extrapolations to infinit e times or system sizes.\n\nOn the other hand\, in Ref. [2]\, we have rep roduced in simulations a milestone experiment that measures the spin-glass coherence length through the lowering of free-energy barriers induced by the Zeeman effect. Secondly we determine the scaling behavior that allows a quantitative analysis of a new experiment of amorphous Ge:Mn films [3].   The value of the coherence length estimated through the analysis of mic roscopic correlation functions turns out to be quantitatively consistent w ith its measurement through macroscopic response functions. Further\, non- linear susceptibilities\, recently measured in glass-forming liquids\, sca le as powers of the same microscopic length.\n[1] Janus Collaboration (201 7)\, ``Probing the spin-glass phase with non-equilibrium measurements: sta tics-dynamics equivalence through the fluctuation-dissipation ratio''\, ac cepted for PNAS\, https://arxiv.org/abs/1610.01418\n[2] Janus Collaborati on (2017)\, ``Matching microscopic and macroscopic responses in glasses''\ , under review in PRL.\n[3] Samaresh Guchhait and Raymond L. Orbach (2017) \, ``Magnetic Field Dependence of Spin Glass Free Energy Barriers''\, unde r review in PRL. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-480@lptms.universite-paris-saclay.fr DTSTART:20170222T110000Z DTEND:20170222T120000Z DTSTAMP:20170216T085917Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-michele-castellana/ SUMMARY:Physics-Biology interface seminar: Michele Castellana - LPTMS\, sal le 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 22 Fév 17 11:00 DESCRIPTION:Enzyme clustering can induce metabolic channeling\nMichele Cast ellana (Institut Curie\, Paris)\nDirect channeling of intermediates via a physical tunnel between enzyme active sites is an established mechanism to improve the efficiency of metabolic pathways. In this seminar\, I will pr esent a theoretical model which demonstrates that coclustering multiple en zymes into proximity can yield the full efficiency benefits of direct chan neling. The model predicts the separation and size of coclusters that maxi mize metabolic efficiency\, and this prediction is in agreement with the i nter-cluster spacing in yeast and mammalian cells. In addition\, the model predicts that enzyme agglomerates can regulate steady-state flux division at metabolic branch points: we experimentally test this prediction for a fundamental branch point in Escherichia coli bacterium\, and the results c onfirm that enzyme colocalization within an agglomerate can accelerate the processing of a shared intermediate by one branch. Our studies establish a quantitative framework to understand coclustering-mediated metabolic cha nneling\, as well as its application to efficiency improvement and metabol ic regulation. CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-478@lptms.universite-paris-saclay.fr DTSTART:20170228T110000Z DTEND:20170228T120000Z DTSTAMP:20170124T201211Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-shlomi-reuveni/ SUMMARY:Séminaire du LPTMS: Shlomi Reuveni - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 28 Fév 17 11:00 DESCRIPTION:First Passage Under Restart \nShlomi Reuveni (Department of Sy stems Biology\, Harvard Medical School\, Boston)\n\nStopping a process in its midst—only to start it all over again—may prolong\, leave unchange d\, or even shorten the time taken for its completion. Among these three p ossibilities the latter is particularly interesting as it suggests that re start can be used to expedite the completion of complex processes involvin g strong elements of chance. This turned out to be important in computer s cience where restart drastically improves performance of randomized algori thms\, but is not less relevant to many physical\, chemical\, and biologic al processes since restart is inherent to the stochastic Michaelis-Menten reaction scheme and this is ubiquitous throughout the sciences. I will int roduce the problem of first passage under restart using the example of sim ple diffusion\, but will then explain why many unknowns compel us to gener alize to arbitrary first passage processes and restart mechanisms. This ha s recently led us to discover universal features of the problem which I wi ll derive and describe\, and the framework developed will also serve to ma ke the case for a much required paradigm shift in our understanding of enz ymatic catalysis and inhibition at the single-molecule level.\n\nReference s :\n\n\n S. Reuveni\, M. Urbakh and J. Klafter\, Role of Substrate Unbind ing in Michaelis–Menten Enzymatic Reactions\, PNAS 111 (12)\, 4391 (2014 ).\n T. Rotbart\, S. Reuveni and M. Urbakh\, Michaelis-Menten Reaction Sch eme as a Unified Approach Towards the Optimal Restart Problem\, Phys. Rev. E 92\, 060101(R) (2015).\n S. Reuveni\, Optimal Stochastic Restart Render s Fluctuations in First Passage Times Universal\, Phys. Rev. Lett. 116\, 1 70601 (2016).\n A. Pal and S. Reuveni\, First Passage Under Restart\, Phys . Rev. Lett. 118\, 030603 (2017).\n T. Rotbart\, S. Reuveni and M. Urbakh\ , Single-enzyme approach predicts natural emergence of inhibitor-activator duality\, bioRxiv 095562.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-486@lptms.universite-paris-saclay.fr DTSTART:20170307T110000Z DTEND:20170307T120000Z DTSTAMP:20170227T164344Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-denis-ullmo/ SUMMARY:Séminaire du LPTMS: Denis Ullmo - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 7 Mar 17 11:00 DESCRIPTION:Non-linear Schrödinger approach to mean field games\nDenis Ull mo (LPTMS\, Université Paris-Sud)\nMean field games theory is a rather re cent research area\, at the frontier between applied mathematics\, social sciences and physics. It was initiated a decade ago by Pierre-Louis Lions and Jean-Michel Lasry as a tool to model certain social phenomena involvin g a significant number of actors - through a game theory approach - while maintaining a reasonable level of simplicity thanks to the concept of mean -field imported from physics.\n\nIn this presentation\, after a general in troduction to Mean Field Games\, I will show that there is a formal\, but deep\, link between an important class of these models and the nonlinear S chrödinger equation familiar to physicists. This link makes it possible t o develop a deeper understanding of the behavior of Mean Field Games.  A specific example will be treated in details and will demonstrate how  var ious concepts developed by physicist while studying the non-linear Schröd inger equation can be used with  profit in the context of Mean Field Game s.\n\nReference:\n\n Igor Swiecicki\, Thierry Gobron\, and Denis Ullmo\, S chrödinger Approach to Mean Field Games\, Phys. Rev. Lett. 116\, 128701 ( 2016).\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-481@lptms.universite-paris-saclay.fr DTSTART:20170308T110000Z DTEND:20170308T120000Z DTSTAMP:20170303T071123Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-daniel-jost/ SUMMARY:Physics-Biology interface seminar: Daniel Jost - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 8 Mar 17 11:00 DESCRIPTION:Physical biology of chromatin: understanding the functional rol e of 3D chromosome folding using polymer physics\nDaniel Jost (Université Grenoble Alpes)\nCellular differentiation occurs during the development o f multicellular organisms and leads to the formation of many different tis sues where gene expression is modulated without modification of the geneti c information. These modulations are in part encoded by chromatin-associat ed proteins or biochemical tags that are set down at the chromatin level d irectly on DNA or on histone tails. These markers are directly or indirect ly involved in the local organization and structure of the chromatin fiber \, and therefore may modulate the accessibility of DNA to transcription fa ctors or enzymatic complexes\, playing a fundamental role in the transcrip tional regulation of gene expression. Propagation\, maintenance and inher itance of these epigenetic marks are crucial mechanisms in development\, p henotype stabilization and disease. Experimental evidence have shown that the pattern of chromatin markers along chromosomes is strongly correlated with the 3D chromatin organization inside the nucleus. This suggests a cou pling between epigenomic information and large-scale chromatin structure. Here\, I will discuss our recent works using polymer physics and numerical simulations trying to understand the basic principles behind such couplin g and and to propose possible functional roles for the 3D organization of chromosomes. CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-497@lptms.universite-paris-saclay.fr DTSTART:20170309T110000Z DTEND:20170309T120000Z DTSTAMP:20170301T201557Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-lptms-t ommaso-comparin-seminaire-exceptionnel/ SUMMARY:Séminaire LPTMS: Tommaso Comparin *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Mar 17 11:00 DESCRIPTION:Thermodynamics of the unitary Bose gas from first principles\nT ommaso Comparin (LPS-ENS\, Paris)\nUltracold atomic gases offer access to a broad class of quantum systems. The strength of interatomic interactions \, in particular\, may be tuned across a wide range\, through the Feshbach -resonance technique. In this talk\, I consider a gas of bosonic atoms in the unitary limit\, where the scattering length is infinite. For three bos ons\, unitary interactions lead to the Efimov effect\, consisting in an in finite sequence of scale-invariant three-body bound states. The Efimov sce nario (predicted in nuclear physics in the 1970s\, and first observed in 2 006 with ultracold atoms) is correctly described through a model with zero -range two-body interactions and a hard-core three-body repulsion. We use this model to describe a many-body system of unitary bosons\, which we stu dy through a dedicated path-integral quantum Monte Carlo algorithm. At the rmal equilibrium\, the phase diagram of the system includes the normal-gas phase at high temperature and two low-temperature phases: The Efimov liqu id and the Bose-Einstein condensate. We determine the critical temperature for Bose-Einstein condensation\, which is found to be 10% smaller than fo r non-interacting bosons. We also compute the momentum distribution of the gas\, and compare it with available experimental results which are part o f the current effort towards the realization of a degenerate unitary Bose gas.\n\nReference: T. Comparin and W. Krauth\, Phys. Rev. Lett. 117\, 2253 01 (2016) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-495@lptms.universite-paris-saclay.fr DTSTART:20170314T110000Z DTEND:20170314T120000Z DTSTAMP:20170308T200442Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kay-wiese/ SUMMARY:Séminaire du LPTMS: Kay Wiese - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Mar 17 11:00 DESCRIPTION:The Field theory of avalanches\nKay Wiese (LPT-ENS\, Paris)\nWh en elastic systems like contact lines on a rough substrate\, domain walls in disordered magnets\, or tectonic plates are driven slowly\, they remain immobile most of the time\, before responding with strong intermittent mo tion\, termed avalanche. I will describe the field theory behind these phe nomena\, explain why its effective action has a cusp\, and how such intric ate objects as the temporal shape of an avalanche can be obtained.\n\n&nbs p\; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-474@lptms.universite-paris-saclay.fr DTSTART:20170321T110000Z DTEND:20170321T120000Z DTSTAMP:20161021T144011Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-randy-kamien-seminaire-commun-avec-le-lps/ SUMMARY:Séminaire du LPTMS: Randy Kamien *** séminaire commun avec le LP S *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 21 Mar 17 11:00 DESCRIPTION:Developments in the Theory of Smectic Liquid Crystals\nRandy Ka mien (University of Pennsylvania)\nThe theory of liquid crystals combines principles of symmetry\, geometry\, and topology to understand materials t hat exhibit compelling\, complex configurations and textures.  In this ta lk I will provide an overview of the theory of smectic liquid crystals and will show how it touches on superconductivity\, fluid mechanics\, and spe cial relativity. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-498@lptms.universite-paris-saclay.fr DTSTART:20170322T110000Z DTEND:20170322T120000Z DTSTAMP:20170321T081600Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-greg-grason/ SUMMARY:Physics-Biology interface seminar: Greg Grason - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 22 Mar 17 11:00 DESCRIPTION:Block Copolymer Assemblies Beneath the Surface: Modeling Intra- Domain Textures and Chirality Transfer to Mesodomains\nGreg Grason (U. of Massachussets\, Amherst)\nThis seminar replaces that of Thierry Bizebard\, was rescheduled to May 31st. Please note the more soft matter focus.\n\nS elf-assembled block copolymer (BCP) melts are a chemically-versatile platf orm for generating a rich spectrum of periodically-ordered nanostructures of various morphologies\, from arrays of layers and columns to cubic array s of spheres and bicontinuous networks. They are also a model system for u nderstanding processes and properties of self-assemblies\, more broadly. D ecades of study of BCP assembly have uncovered the principles that connect molecular BCP structure to the translational order of the (scalar) compos ition profiles in the ordered states. In this talk\, I will describe recen t efforts to understand the generic\, yet poorly known\, patterns of orien tational ordering of constituent chain segments that underlie the otherwis e well-known “standard” BCP morphologies1. From generic properties of the random-walk statistics in BCPs\, we show that the direction and degree of alignment of segments varies non-trivially from place-to-place in self -organized domains\, and from one morphology to another\, leading to new o pportunities to manipulate and harness the physics sub-domain textures. Sp ecifically\, I will discuss how our efforts to model chiral BCPs2 which ha ve been observed to transfer handedness of chain chemistry to the chiral s ymmetry of mesodomain shapes that are not formed in achiral BCPs. Our gene ralized orientational self-consistent field (oSCF) theory framework3 shows that the thermodynamic drive for twisted\, or cholesteric\, packings of s egments of chiral blocks stabilizes observed helical cylinder morphologies \, and suggests new mechanisms for driving formation as of yet\, unobserve d mesochiral domain symmetries4.\n\nReferences\n\n I. Prasad\, Y. Seo\, L. Hall and G. M. Grason arxiv.org/1612.07994 (2016)\n G. M. Grason ACS Macr oLetters 4\, 526 (2015). Front Cover Story\n W. Zhao\, T. Russell and G. M . Grason\, J. Chem. Phys. 137\, 104911 (2012).\n W. Zhao\, T. Russell and G. M. Grason\, Phys. Rev. Lett. 110\, 058301 (2013).\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-501@lptms.universite-paris-saclay.fr DTSTART:20170324T140000Z DTEND:20170324T153000Z DTSTAMP:20170308T100717Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-xiangyu-cao/ SUMMARY:Soutenance de thèse: Xiangyu Cao - LPTMS-batiment 100\, salle des conseils - 24 Mar 17 14:00 DESCRIPTION:Disordered statistical physics in low dimensions: extremes\, gl ass transition\, and localization.\nXiangyu Cao\n\nThis thesis presents or iginal results in two domains of disordered statistical physics: logarithm ic correlated Random Energy Models (logREMs)\, and localization transition s in long-range random matrices.\nIn the first part devoted to logREMs\, w e show how to characterize their common properties and model--specific dat a. Then we develop their replica symmetry breaking treatment\, which leads to the freezing scenario of their free energy distribution and the genera l description of their minima process\, in terms of decorated Poisson poin t process. We also report a series of new applications of the Jack polynom ials in the exact predictions of some observables in the circular model an d its variants. Finally\, we present the recent progress on the exact conn ection between logREMs and the Liouville conformal field theory.\nThe goal of the second part is to introduce and study a new class of banded random matrices\, the broadly distributed class\, which is characterid an effect ive sparseness. We will first study a specific model of the class\, the Be ta Banded random matrices\, inspired by an exact mapping to a recently stu died statistical model of long--range first--passage percolation/epidemics dynamics. Using analytical arguments based on the mapping and numerics\, we show the existence of localization transitions with mobility edges in t he ``stretch--exponential'' parameter--regime of the statistical models. T hen\, using a block--diagonalization renormalization approach\, we argue t hat such localization transitions occur generically in the broadly distrib uted class.\n\n\nThe defense presentation will focus on the logREM--Liouvi lle connection and the broadly distributed random matrices.\n\n\nDirecteur s de thèse: Alberto Rosso\, Raoul Santachiara\n\nJury: Bertrand Georgeot\ , Jonathan Keating\, Christopher Mudry\, Didina Serban\; invité: Pierre L e Doussal\n\n CATEGORIES:seminars LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-499@lptms.universite-paris-saclay.fr DTSTART:20170328T110000Z DTEND:20170328T120000Z DTSTAMP:20170308T202234Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jean-baptiste-delfau/ SUMMARY:Séminaire du LPTMS: Jean-Baptiste Delfau - LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay - 28 Mar 17 11:00 DESCRIPTION:A counter-intuitive case of spontaneous aggregation : crystals of clusters\nJean-Baptiste Delfau (Universitat de les Illes Balears\, Palm a de Mallorca\, Spain)\n\n\nParticles interacting via purely repulsive sof t-core potentials can spontaneously aggregate\, despite repelling each oth er\, and form periodic crystals of particle clusters. We studied this phen omenon - relevant to colloidal or polymer solutions - for passive (Brownia n) and active (self-propelling) particles at two levels of description: pe rforming numerical simulations of the discrete particle dynamics\, and by linear and nonlinear analysis of the corresponding Dean-Kawasaki equations for the macroscopic particle density. In this seminar\, I will explain wh at are the mechanisms of the instability leading to clustering which turn out to be the interplay between diffusion or self-propulsion\, the intracl uster forces and the forces between neighboring clusters.\n\n\nReferences :\n\n J.-B. Delfau\, H. Ollivier\, C. López\, B. Blasius &\; E. Herná ndez-García\, Pattern formation with repulsive soft-core interactions: Di screte particle dynamics and Dean-Kawasaki equation\, Phys. Rev. E 94\, 04 2120 (2016)\n J.-B. Delfau\, C. López\, E. Hernández-García\, Active cl uster crystals\, arXiv:1701.02639 \n\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-496@lptms.universite-paris-saclay.fr DTSTART:20170411T110000Z DTEND:20170411T120000Z DTSTAMP:20170329T151604Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-deepak-bhat/ SUMMARY:Séminaire du LPTMS: Deepak Bhat - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 11 Avr 17 11:00 DESCRIPTION:Dynamics of a piston pushed by a single particle gas as a micro scopic model for Szilard engine\nDeepak Bhat (ICTS\, Bangalore\, India) \ nMotivated by the Szilard engine\, we have studied the dynamics of a pisto n of large mass M inside a 1D cylinder\, pushed by repeated elastic collis ions with a single particle (of smaller mass m) which is in contact with a thermal reservoir of temperature T. Additionally\, piston is assumed to b e moving under influence of an external force. By expanding the underlying master equation of the piston-particle system in terms of the small param eter (m/M)1/2\, we show that\, an effective equation of motion of the pist on can be deduced by integrating out the small particle. Given finite but large mass of the piston\, we show that at times of order √M the Piston ’s motion is described by a determinstic dynamics while at larger times\ , the piston’s motion becomes stochastic and is described by a Langevin equation. Interestingly\, we note that the dissipation coefficient γ depe nds on piston position X\, and is also function of time t. In particular\, it changes from an initial value (1/X)(8mkBT/π)1/2 and increases as log( t)/X asymptotically. We argue that the logarithmic increase of γ is assoc iated to the interesting and unusual slow relaxation of particle confined within the reservoir and the piston.\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-516@lptms.universite-paris-saclay.fr DTSTART:20170418T110000Z DTEND:20170418T120000Z DTSTAMP:20170414T061346Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-maurizio-fagotti/ SUMMARY:Séminaire du LPTMS: Maurizio Fagotti - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Avr 17 11:00 DESCRIPTION:Intermediate-time dynamics in 
out-of-equilibrium spin chains \nMaurizio Fagotti (LPT-ENS\, Paris)\nI discuss some aspects of quench dyn amics in quantum many-body systems. In the first part of the talk\, I pres ent an unusual mechanism of prethermalization. This is based on the presen ce of a symmetry of the pre-quench Hamiltonian which is spontaneously brok en at zero temperature and is explicitly broken by the post-quench Hamilto nian.  In the second part of the talk\, I focus on the non-equilibrium ti me evolution of piecewise homogeneous states. The inhomogeneity of the ini tial state gives rise to a peculiar intermediate-time dynamics that is cap tured by a hydrodynamic description. I present the solution to the dynamic s in the XXZ spin-1/2 chain and describe some remarkable properties of the profiles of charges and currents.\nReferences:\n\n V. Alba and M. Fagotti \, Prethermalization at low temperature: the scent of a spontaneously brok en symmetry\, arXiv:1701.05552 (2017).\n B. Bertini\, M. Collura\, J. De N ardis\, and M. Fagotti\, Transport in Out-of-Equilibrium XXZ Chains: Exact Profiles of Charges and Currents\,  Phys. Rev. Lett. 117\, 207201 (2016) .\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-500@lptms.universite-paris-saclay.fr DTSTART:20170419T110000Z DTEND:20170419T120000Z DTSTAMP:20170403T081707Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-alessandro-barducci/ SUMMARY:Physics-Biology interface seminar: Alessandro Barducci - LPTMS\, sa lle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Avr 17 11:00 DESCRIPTION:Molecular chaperones as cellular non-equilibrium machines. \nAl essandro Barducci (Centre de Biochimie Structurale-INSERM\, Montpellier)\n \nMolecular chaperones are a vast class of proteins that maintain protein homeostasis in the cell and are thus essential for cell viability. In ord er to assist protein folding and prevent misfolding\, most chaperones proc eed through conformational cycles that are regulated by complex interactio n networks and fueled by ATP-hydrolysis. A remarkable example are the 70-k Dalton heat shock proteins (Hsp70s)\, which are essential in prokaryotes a nd eukaryotes and are involved in co-translational folding\, refolding of misfolded and aggregated proteins\, protein translocation\, and protein de gradation. While the investigation of Hsp70 cycle has attracted great atte ntion in the last decades\, the actual role of ATP-hydrolysis and\, thus o f energy consumption\, in the chaperone function has been long unaddressed . Here we will prove how biochemical data\, recent single-molecule fluores cence experiments and molecular simulations can be combined into an approp riate theoretical framework to show that: i) ATP hydrolysis allows Hsp70 c haperones to increase their affinity for the client proteins beyond the bo unds imposed by equilibrium thermodynamics ii) This ultra-affinity can be exploited to perform mechanical work on client proteins thus avoiding the formation of misfolded and potentially cytotoxic species. \n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-510@lptms.universite-paris-saclay.fr DTSTART:20170425T110000Z DTEND:20170425T120000Z DTSTAMP:20170407T095839Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gregoire-misguich/ SUMMARY:Séminaire du LPTMS: Grégoire Misguich - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 25 Avr 17 11:00 DESCRIPTION:Entanglement and Shannon entropies in low dimensional magnets\n Grégoire Misguich (IPhT\, CEA\, Saclay)\nThe entanglement (von Neumann) e ntropy is now routinely used by condensed-matter theorists as a tool to pr obe quantum many-body  systems\, since it often gives access to propertie s that are not easily visible using more conventional observables. I will illustrate this using a few examples taken from the literature on 1D and 2 D spin systems. I will then discuss a related but different entropy\, the Shannon entropy\, which can also be used as a tool to probe many-body  sy stems. The Shannon entropy of a many-body state |ψ>\;  is defined by e xpanding the wave-function in some preferential configuration basis { |i&g t\; }. The projections of  |ψ>\; onto the basis states define a set of normalized probabilities p[i] = |<\;ψ|i>\;|2\, and these probabiliti es can used to define an associated Shannon entropy S = - Σi p[i]*log(p[i ]). This quantity measures hos 'localized" is |ψ>\;\, in the chosen bas is. While the entanglement entropy requires the choice of a specific subsy stem\, the Shannon entropies is basis-dependent but is defined for the sys tem as a whole. In this talk we discuss a few examples in 1D and 2D where some universal information about the long-distance physics of the system c an be obtained by analyzing the scaling of S as a function of the system s ize. In particular\, we show that the spontaneous symmetry breaking of a c ontinuous symmetry (as in Néel-ordered antiferromagnets) leads in 2D to s ome universal logarithmic terms in the Shannon entropy\n\nReference:\n\n G . Misguich\, V. Pasquier &\; M. Oshikawa\, Shannon-Rényi entropy for Nambu-Goldstone modes in two dimensions\, preprint arXiv:1607.02465\n\n&nb sp\; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-502@lptms.universite-paris-saclay.fr DTSTART:20170502T110000Z DTEND:20170502T120000Z DTSTAMP:20170403T052537Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexander-hartmann/ SUMMARY:Séminaire du LPTMS: Alexander Hartmann - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 2 Mai 17 11:00 DESCRIPTION:Large deviations for equilibrium and non-equilibrium processes\ nAlexander Hartmann (Universität Oldenburg\, Germany)\nLarge deviations a nd rare events play an ever increasing role in science\, economy and socie ty. Large deviations play a crucial role for example for the estimation of impacts of storms\, the calculation of  probabilities of stock-market cr ashes or the sampling of transition  paths for conformation change of  p roteins. More fundamentally\, when  studying any random process\, only th e full probability distribution\,  including the large-deviation tails\, gives a complete information about  the underlying system.\n\nThe basic p rincipal to study large deviations using numerical  simulations is simple : make unlikely events more probable and correct in  the end for the bias . Here\, we present a very general black-box method\,  based on  samplin g vectors of random numbers within an artificial  finite-temperature (Bol tzmann). This allows to access rare events and  large deviation for almos t arbitrary equilibrium and non-equilibrium  processes. In this way\, we obtain probabilities as  small as $10^{-500}$    and smaller\, hence ra re events and large deviation properties  can be  easily obtained.\n\nTh e method can be applied to equilibrium/static sampling problems\, e.g.\, t he distribution of the number and size of connected components of  random graphs. Here\, applications from different fields are presented:\n\n1. Di stribution of work performed for a  critical (T=2.269) two-dimensional   Ising system of size LxL=128x128 upon rapidly changing  the external magn etic field(also applying  theorems of Jarzynski and  Crooks to obtain th e free energy difference  of such a large system)\n\n2. Distribution of p erimeters and area of convex hulls of two- and  higher dimensional single and multiple random walks.\n\n3. Distribution of the flow for the Nagel-S chreckenberg traffic model. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-505@lptms.universite-paris-saclay.fr DTSTART:20170503T110000Z DTEND:20170503T120000Z DTSTAMP:20170425T090309Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-volker-bormuth/ SUMMARY:Physics-Biology interface seminar: Volker Bormuth - LPTMS\, salle 2 01\, 2ème étage\, Bât 100\, Campus d'Orsay - 3 Mai 17 11:00 DESCRIPTION:Whole-brain imaging during vestibular stimulation in zebrafish with a novel rotatable light-sheet microscope\nVolker Bormuth (Laboratoire Jean Perrin\, Université Pierre et Marie Curie)\n\nLight-sheet microscop y allows cell resolved whole-brain calcium imaging at several brain scans per second in zebrafish larvae. Currently this technique is not compatible with dynamic stimulation of the vestibular system. We developed an ultra- stable miniaturized light-sheet microscope that can be rotated while perfo rming whole-brain recordings. Rotating the microscope rotates the fish and stimulates the vestibular system while imaging always the same plane in t he brain. We demonstrate volumetric whole-brain neuronal activity recordin gs during vestibular stimulation. We mapped the brain activity with cellul ar resolution of the vestibule-ocular reflex (VOR) which drives compensato ry eyes movements to maintain clear vision during body rotation. Our long- term goal is study with this system multisensory signal processing by the vertebrate brain by combining visual with vestibular stimuli. \n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-518@lptms.universite-paris-saclay.fr DTSTART:20170509T110000Z DTEND:20170509T120000Z DTSTAMP:20170510T070004Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-tribid-sadhu-2/ SUMMARY:Séminaire du LPTMS: Tridib Sadhu - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 9 Mai 17 11:00 DESCRIPTION:Generalized arcsine law in fractional Brownian motion\nTridib S adhu (LPT-ENS\, Paris)\nThe three arcsine laws for the standard Brownian m otion are a cornerstone of extreme value statistics. For a standard Browni an motion evolving in a time window\, one can consider the following three observables: (1) the fraction of time it remained positive\, (2) the last time it crossed the origin\, (3) and the time when it reached its maximum . All three observables have the same cumulative probability distribution expressed as an arcsine function. I shall discuss how these three laws cha nge for a fractional Brownian motion. The fractional Brownian motion is a non-Markovian Gaussian process indexed by Hurst exponent H which generaliz es Brownian motion (H=1/2). I shall show that the three observables have d ifferent distributions for general H. I shall present a perturbation expan sion scheme using which one can derive these probability distributions\n\n  \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-508@lptms.universite-paris-saclay.fr DTSTART:20170516T110000Z DTEND:20170516T120000Z DTSTAMP:20170510T085524Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-satya-majumdar/ SUMMARY:Séminaire du LPTMS: Satya Majumdar - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 16 Mai 17 11:00 DESCRIPTION:KPZ story\nSatya N. Majumdar (LPTMS\, Université Paris Sud)\nT he celebrated KPZ equation (Kardar\, Parisi\, Zhang\, 1986) is an importan t  milestone in statistical physics\, originally introduced to describe t he  late time dynamics in various growth models. Over the last 30 years\, the  KPZ story has evolved in various interesting directions\, making li nks on the way to different areas of physics and mathematics. This include s in  particular the link to the famous Tracy-Widom distribution in rando m  matrix theory. The story of KPZ is a very successful one\, involving  theoretical physics\, mathematics and experiments--a fertile playground f or  interdisciplinary science. In this talk\, I will review the evolution of  the KPZ story\, pointing out the important landmarks as I go along. At the  very end\, I will discuss some recent developments establishing a nice link between the KPZ height fluctuations and the edge physics in col d atom  systems. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-490@lptms.universite-paris-saclay.fr DTSTART:20170517T110000Z DTEND:20170517T120000Z DTSTAMP:20170509T174849Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-julien-husson/ SUMMARY:Physics-Biology interface seminar: Julien Husson - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 17 Mai 17 11:00 DESCRIPTION:Single-cell leukocyte mechanics: force generation\, viscoelasti city\, and rupture mechanics\nJulien Husson (LadHyX\, École polytechnique \, France)\nLeukocytes are very soft cells that perform many diverse funct ions: they adhere\, crawl\, transmigrate\, kill\, phagocytose or interact with other cells. During their activation\, leukocytes both generate mecha nical forces and change their viscoelastic properties (i.e. they stiffen/s often\, get more or less viscous). We have developed micropipette-based se tups to quantify single-leukocyte mechanical properties and monitor them o ver time while a leukocytes gets activated by a relevant stimulus. We furt her quantify rupture properties of cell membrane\, as these help us to bet ter understand cell structure and dynamics.\n\nWe use this approach in div erse contexts involving leukocytes: activation of T lymphocytes\, phagocyt osis of a target by a neutrophil\, or transmigration of a lymphoblast acro ss an endothelial monolayer. We perform microrheology experiments with a p rofile microindentation setup [1\,2]\, measure forces generated by T lymph ocytes [3\,4]\, characterize cell-substrate adhesion [5] or establish a ru pture criteria for membrane rupture [2\,6] (Figure 1). These mechanical me asurements shed a new light on how cell mechanical properties evolve over a short period of time (seconds)\, how they adapt to the stiffness of thei r environment\, and how intracellular signaling is involved.\n\n\nT-lympho cytes in the human body routinely undergo large deformations\, both passiv ely when going through narrow capillaries and actively when transmigrating across endothelial cells or squeezing through tissue. In this artistic re ndering\, a T-lymphocyte is aspirated in a micropipette to mimic passive d eformations that occur when squeezing through narrow capillaries. The fluo rescent signal is due to the entry of propidium iodide into the cell and i ndicates membrane rupture (Image: Julien Husson\, LadHyX\, Ecole polytechn ique\, cellmechanics.jimdo.com/galleries)\n\n\n1. Guillou\, L.\, Babataher i\, A.\, Puech\, P.-H.\, Barakat\, A.I. &\; Husson\, J. Dynamic monitor ing of cell mechanical properties using profile microindentation. Scientif ic Reports 6:21529 (2016).\n\n2. Guillou\, L.\, Babataheri\, A.\, Saitakis \, M.\, Bohineust\, A.\, Dogniaux\, S.\, Hivroz\, C.\, Barakat\, A.I. & \; Husson\, J. T lymphocyte passive deformation is controlled by unfolding of membrane surface reservoirs. Molecular Biology of the Cell 27(22): 357 4-3582. (2016\, journal cover).\n\n3. Husson\, J.\, Chemin\, K.\, Bohineus t\, A.\, Hivroz\, C. &\; Henry\, N. Force Generation upon T Cell Recept or Engagement. PLoS One 6(5):e19680 (2011).\n\n4. Basu\, R.*\, Whitlock\, B.M.*\, Husson\, J.*\, Le Floc’h\, A.\, Jin\, W.\, Dotiwala\, F.\, Giann one\, G.\, Hivroz\, C.\, Lieberman\, J.\, Kam\, L.C. &\; Huse\, M. Cyto toxic T Cells Use Mechanical Force to Potentiate Target Cell Killing. Cell 165(1):100–110 (2016).\n\n5. Hogan\, B.\, Babataheri\, A.\, Hwang\, Y.\ , Barakat\, A.I. &\; Husson\, J. Characterizing Cell Adhesion by Using Micropipette Aspiration. Biophysical Journal 109(2):209-19 (2015).\n\n6. G onzalez-Rodriguez\, D.\, L. Guillou\, F. Cornat\, J. Lafaurie-Janvore\, A. Babataheri\, E. de Langre\, A.I. Barakat\, and J. Husson. Mechanical Crit erion for the Rupture of a Cell Membrane under Compression. Biophys. J. 11 1: 2711–2721 (2016). CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-513@lptms.universite-paris-saclay.fr DTSTART:20170518T110000Z DTEND:20170518T120000Z DTSTAMP:20170503T044751Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-inti-sodemann-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Inti Sodemann *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Mai 1 7 11:00 DESCRIPTION:Quantum Hall ferroelectrics and the hidden link between composi te fermions and the exciton condensate\nInti Sodemann (MIT\, Cambridge\, U SA)\nIn this talk\, I will describe two recent developments in our underst anding of phases in the quantum Hall regime. In the first part\, I will de scribe our recent discovery of a remarkable connection between the composi te fermion metal state realized in half-filled landau levels and the excit on superfluid realized in quantum Hall bilayers. Specifically\, I will sho w that the exciton condensate is identical in all its universal properties to an interlayer paired state of composite fermions\, and the two states can be connected in an analogous fashion to the BEC-BCS crossover. In the second part\, I will describe our recent proposal to realize a “quantum Hall ferroelectric”: an integer quantum Hall state that spontaneously br eaks inversion symmetry. I will argue for the ubiquity of these and nemati c states in multi-valley systems whose low energy dispersions are anisot ropic\, and discuss material platforms for these systems. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-511@lptms.universite-paris-saclay.fr DTSTART:20170523T110000Z DTEND:20170523T120000Z DTSTAMP:20170414T130937Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ken-sekimoto/ SUMMARY:Séminaire du LPTMS: Ken Sekimoto - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 23 Mai 17 11:00 DESCRIPTION:Coarse-Graining of Momentum Flow\nKen Sekimoto (MSC\, Universit é Denis Diderot &\; Gulliver\, ESPCI)\nLike the energy and mass\, the momentum is also a conserved quantity.  Usually\, however\, we pay less a ttention to the role played by the last  one as compared with the former ones. In the present talk\, I will  discuss the three examples in which t he concept of momentum flow helps  and simplifies our understanding of ph enomena.\n\nFirst we discuss the ``adiabatic-piston'' for which the physic al origin  of the non-equilibrium force has long been unclear. The consid eration of  the momentum flux of both the gases and piston allows to reac h the  central results in a few lines of elementary calculation\, elucida ting  how the non-equilibrium force emerges.\n\nSecondly we present a met hod of coarse-graining the overdamped dynamics  of dense cellular packing of matters.'' We show that the coarse graining  of the momentum and angu lar momentum fluxes leads naturally to the  Irving-Kirkwood type formula for the stress tensor irressective of the underlying dynamics.\n\nLastly w e discuss the Newton's cradle with modified repulsive laws. This  classic al 1D system can show the similarity to the quantum Mössbauer  absorptio n and emission. By considering the momentum flow through the  cluster\, w e reach the coarse-grained dynamics for the center of mass coupled with an ``evanescent'' wave. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-520@lptms.universite-paris-saclay.fr DTSTART:20170530T110000Z DTEND:20170530T120000Z DTSTAMP:20170520T113315Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-robin-guichardaz/ SUMMARY:Séminaire du LPTMS: Robin Guichardaz - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 30 Mai 17 11:00 DESCRIPTION:Dimensions fractales négatives dans des systèmes dynamiques a léatoires\nRobin Guichardaz (E.N.S Lyon)\nLes attracteurs étranges appar aissant dans des systèmes dynamiques chaotiques présentent une structure fractale\, caractérisée par une dimension fractionnaire et positive. Un e des définitions possibles de la dimension fractale\, la dimension de co rrélation\, est liée à la densité de points dans l'espace des phases a utour d'une trajectoire donnée. Cette densité évolue généralement en une loi de puissance en fonction de la séparation des trajectoires\, de s orte que la dimension de corrélation est reliée simplement à l'exposant de cette loi de puissance.\n\nNous avons étendu cette notion au cas de s ystèmes dynamiques stochastiques stables\, pour lesquels tous les exposan ts de Lyapunov sont strictement négatifs\, ce qui signifie que toutes les trajectoires convergent in fine vers un attracteur ponctuel. Cependant\, si nous ajoutons du bruit dans les équations du mouvement\, contrairement à un étalement gaussien autour de l'attracteur\, nous retrouvons une di stribution en loi de puissance pour la séparation des trajectoires\, ind épendante du bruit additif. Nous interprétons l'exposant correspondant c omme une dimension fractale\, qui s'avère prendre des valeurs négatives. \n\nPlus spécifiquement\, nous avons étudié un modèle unidimensionnel décrivant la dynamique de particules inertielles dans un flot aléatoire. Nous exprimons la dynamique de séparation de trajectoires proches comme un processus de sédimentation dans un espace adapté. Nous présenterons des résultats issus de simulations numériques\, ainsi que des outils ana lytiques permettant de déterminer la dimension de corrélation. Indépend amment du modèle\, nous proposons une approche basée sur les grandes dé viations et pouvant être utilisée dans l'étude de systèmes intermitten ts.\n\n-----\n\nNegative fractal dimensions in random dynamical systems :\ n\nIn chaotic dynamical systems\, strange attractors have fractal structur es\, characterized by a (positive) dimension. In particular\, the correlat ion dimension is linked to the density of points in the phase space around a given trajectory. This density usually scales as a power-law in terms o f the separation of trajectories\, so that the correlation dimension is li nked to the exponent of the power-law.\n\nWe extended this notion to the c ase of stable stochastic dynamical systems for which all the Lyapunov expo nents are negative\, meaning that all trajectories converge to a point-lik e attractor with probability unity. Nevertheless\, in the presence of an a dditive noise\, instead of a gaussian distribution linked to the additive noise we retrieve a power-law distribution for the separation of trajector ies\, independent of the additive noise. We interpret the corresponding ex ponent as a fractal dimension\, which turns out to be negative.\n\nSpecifi cally\, we illustrate these notions with a simple one-dimensional model of colloidal particles in a randomly generated flow. We reformulate the dyna mics of close trajectories in terms of a sedimentation process in a suitab le space. Both numerical determinations and analytic tools to compute the correlation dimension will be presented. We propose a large deviation appr oach\, without reference to any specific model\, which can be applied to t he study of intermittent systems. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-504@lptms.universite-paris-saclay.fr DTSTART:20170531T110000Z DTEND:20170531T120000Z DTSTAMP:20170320T145957Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-thierry-bizebard/ SUMMARY:Physics-Biology interface seminar: Thierry Bizebard - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 31 Mai 17 11:00 DESCRIPTION:Ribosome assembly studied by single-molecule force measurements \nThierry Bizebard (IBPC\, Paris)\nRibosomes belong to the most complicate d structures in biology. Their assembly is a question of fundamental inter est\, but is still poorly understood. In vitro reconstitution studies have shown that the ribosome assembly process is highly cooperative and starts with the binding of a few ribosomal (r-) proteins to rRNA\, but how these early binders act is unknown. Our work focuses on the initial phase of th e assembly of the large subunit (50S) of the E. coli ribosome\, which invo lves 23S rRNA\, five r-proteins and a selection of assembly “helper” p roteins.\nOur force measurements on single RNA molecules have allowed us t o pinpoint several important properties of the early-binding r-proteins we have studied:\n- These proteins bind with high cooperativity to the rRNA (as would be expected to obtain a high yield of fully assembled and active ribosomes).\n- The r-proteins act as molecular clamps\, stabilising the R NA 3D structure.\n- As such\, they afford a strong mechanical and energeti cal stabilisation of the ribonucleoprotein structure (which is also probab ly necessary for optimum activity).\nIn the near future\, we intend to fur ther improve the potential of our single-molecule measurements by implemen ting combined force/fluorescence manipulations\, and apply this methodolog y to our study of the early phase of E. coli large ribosomal subunit assem bly.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-514@lptms.universite-paris-saclay.fr DTSTART:20170606T110000Z DTEND:20170606T120000Z DTSTAMP:20170531T082022Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ada-altieri-et-ines-rodriguez-arias/ SUMMARY:Séminaire du LPTMS: Ada Altieri et Inés Rodríguez-Arias - LPTMS\ , salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Juin 17 11:00 DESCRIPTION:The jamming paradigm: from computer science to field theory and beyond\nAda Altieri  (LPTMS\, Université Paris-Sud)\nA recent challengi ng problem concerns the study of glassy systems at low temperature. We pre sent a parallel derivation of an effective thermodynamic potential in two high-dimensional models: the negative  perceptron and its generalization to sphere systems. They both define continuous constrained satisfaction p roblems with a critical jamming transition characterized by the same expon ents. The disclosed method enables us to study the vibrational spectrum of soft modes and to deepen the diverging behavior of the stiffness coeffici ents. A pivotal feature emerging close to jamming is that the effective th ermodynamic potential has a subleading logarithmic contribution\, which tu rns out to be dominant in a suitable scaling limit.\nA detailed analysis o f higher-order corrections to the potential might also help in accounting for finite-dimensional systems and interpolating between different regimes .\nAnother interesting outcome concerns the extension of the jamming trans ition topic to generic Von Neumann problems\, especially focusing on ecosy stems in high dimension.\nRéf: Ada Altieri\, Silvio Franz &\; Giorgio Parisi\, The jamming transition in high dimension: an analytical study of the TAP equations and the effective thermodynamic potential\, J. Stat. M ech. (2016) 093301.\n\n\n\n\nA story of disorder\, interactions and a quan tum fridge inside a microwave oven\nInés Rodríguez-Arias (LPTMS\, Univer sité Paris-Sud)\nIn my presentation I will show two models for dynamic nu clear polarization (DNP)\, an extremely promising technique that enhances the nuclear spin polarization in order to improve the nuclear magnetic res onance (NMR) signal-to-noise ratio.\nWe have found this technique to repre sent a good scenario to check the ergodicity properties of the eigenstates of the system in a standard DNP protocol. The structure of the eigenstate s is indeed modified upon changing the strength of the dipolar interaction s between electrons keeping a constant disorder. Firstly\, I will present a spin model that shows a many-body localization (MBL) transition and that reproduces the so far unexplained results from the experiments. Secondly\ , I will compare this to an exactely solvable Anderson model\, which under goes an Anderson localization (AL) transition.\nRéfs:\n* Inés Rodríguez -Arias\, Markus Müller\, Alberto Rosso and Andrea De Luca\, An exactly so lvable model for Dynamic Nuclear polarization\, preprint cond-mat arXiv:17 03.05416.\n* Andrea De Luca\, Inés Rodríguez-Arias\, Markus Müller and Alberto Rosso\, Thermalization and many-body localization in systems under dynamic nuclear polarization\, Phys. Rev. B 94\, 014203 (2016)​. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-522@lptms.universite-paris-saclay.fr DTSTART:20170608T110000Z DTEND:20170608T120000Z DTSTAMP:20170601T102957Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-duncan-odell-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Duncan O'Dell *** séminaire exceptionnel ** * - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 8 Juin 17 11:00 DESCRIPTION:Quantum catastrophes\nDuncan O’Dell (McMaster University)\nCa tastrophe theory provides a unified description of a broad range of singul arities and defects in fields and has been applied extensively in optics. A key idea is that of scale: at large scales the catastrophe appears singu lar but at smaller scales it is smoothed\, e.g. by wave interference. In 2 004 Michael Berry and Mark Dennis suggested that waves might themselves di splay singularities which are only smoothed by the fundamental discretenes s of quantum field excitations (e.g. photons). In this talk I will give ex amples of such “quantum catastrophes” appearing in the dynamics of sim ple quantum systems such as a Josephson junction made from two BECs follow ing a quench.  I will emphasize that\, owing to the structural stability of catastrophes and their scaling properties\, quantum catastrophes repres ent a universal aspect of quantum dynamics.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-523@lptms.universite-paris-saclay.fr DTSTART:20170608T140000Z DTEND:20170608T140000Z DTSTAMP:20170602T113940Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-fast-lp tms-mark-hoefer/ SUMMARY:Séminaire FAST-LPTMS: Mark Hoefer - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 8 Juin 17 14:00 DESCRIPTION:The hydraulic analogy to superfluid-like dispersive hydrodynami cs\nMark Hoefer (Department of Applied Mathematics\, University of Colorad o\,  Boulder\, USA)\nThe classic "hydraulic analogy" between supercritica l shallow water flows and gas dynamics was leveraged in the early to mid 2 0th century as a means to model the flow patterns around wings with a rela tively simple water table. But this analogy breaks down when water wave di spersion is strong relative to dissipative effects as in oscillatory\, und ular bores. In this regime\, the more appropriate analogy is to dispersive hydrodynamic media such as superfluids and nonlinear optical diffractive or dispersive patterns\, where dispersive shock waves (DSWs)\, also called quantum and optical shock waves\, have been observed. In this talk\, the problem of steady pattern formation in supercritical\, shallow water flows will be examined theoretically and experimentally. Two new\, non-classica l types of oscillatory DSWs will be identified within the context of the f ifth order Kawahara equation resulting from a balance between capillarity and gravity at water depths on the order of 0.5 cm. Experiments with a sha llow water table demonstrate their physical existence and properties. The results presented have implications for dispersive hydrodynamic media with non-convex linear dispersion curvature such as ultracold atomic superflui ds and nonlinear fiber optics.\n\nVoir l'annonce du FAST: https://semmeca. limsi.fr/affiche/res17_15.html\n************************* ATTENTION ****** ********************** \nl'exposé est donné au FAST : accès\, cf. http ://www.fast.u-psud.fr/fr/plan\n ****************************************** ************************ CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-517@lptms.universite-paris-saclay.fr DTSTART:20170613T110000Z DTEND:20170613T120000Z DTSTAMP:20170427T120347Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-salvatore-manmana/ SUMMARY:Séminaire du LPTMS: Salvatore Manmana - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Juin 17 11:00 DESCRIPTION:Finite-temperature dynamics in low-dimensional quantum magnets\ nSalvatore Manmana (University of Göttingen\, Germany)\nQuantum magnetic materials are a fascinating research topic\, which  explores novel behavi or in quantum systems caused by strong  correlations. In my talk\, I will review basic properties of such strongly correlated quantum magnets. A pa rticular focus is given to  dynamical properties\, which reveal the eleme ntary excitations and their  properties. An interesting aspect here is th e effect of temperature.  This is discussed for one-dimensional systems. In particular\, the finite-temperature dynamics in the antiferromagnetic s pin-one chain is discussed\, which considerably is one of the most fundame ntal quantum many-body systems\, with symmetry protected topological order in the ground state. Increasing the temperature leads to additional struc tures  in the dynamical response functions\, which we propose to measure in experiments.\n\nReference :\n\n \nJonas Becker\, Thomas Köhler\, Alexa nder C. Tiegel\, Salvatore R. Manmana\, Stefan Wessel and Andreas Honecker \, Finite-temperature dynamics and thermal intra-band magnon scattering in Haldane spin-one chains\,  preprint cond-mat arXiv:1703.04652\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-491@lptms.universite-paris-saclay.fr DTSTART:20170614T110000Z DTEND:20170614T120000Z DTSTAMP:20170607T101830Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-ivo-sbalzarini/ SUMMARY:Physics-Biology interface seminar: Ivo Sbalzarini - LPTMS\, salle 2 01\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Juin 17 11:00 DESCRIPTION:Investigating embryogenesis using numerical simulations of biop hysics\nIvo Sbalzarini (Max Planck Institute of Molecular Cell Biology and Genetics\, Dresden\, Germany)\n\nAbstract:\n\nDevelopment and morphogenes is of tissues\, organs\, and embryos emerges from the collective self-orga nization of cells that communicate though chemical and mechanical signals. Decisions about growth\, division\, and migration are taken locally by ea ch cell based on the collective information. In this sense\, a developing tissue is akin to a massively parallel computer system\, where each cell o r processor computes robust local decisions\, integrating communication wi th other cells/processors. Mechanistically understanding and reprogramming this system is a grand challenge. Our vision is to develop a virtual comp uter model of a developing embryo\, incorporating the known biochemistry a nd biophysics into a computational model in 3D-space and time\, in order t o understand the information-processing aspects of development on an algor ithmic basis. While the “hardware” (proteins\, lipids\, etc.) and the “source code” (genome) are increasingly known\, we known virtually not hing about the algorithms that this code implements on this hardware. Usin g examples from our work\, I outline our roadmap toward a virtual embryo\, and highlight challenges along the way. These range from globally optimal approaches to image analysis\, to novel languages for parallel high-perfo rmance computing\, to virtual reality and real-time graphics for 3D micros copy and numerical simulations of biochemical and biomechanical models. Th is cooperative interdisciplinary effort contributes to all involved discip lines.\n\n\nBio:\n\nIvo Sbalzarini is the Chair of Scientific Computing fo r Systems Biology on the faculty of computer science of TU Dresden\, and d irector of the TUD-Department in the Center for Systems Biology Dresden. H e also is a permanent Senior Research Group Leader with the Max Planck Ins titute of Molecular Cell Biology and Genetics in Dresden. He graduated in Mechanical Engineering from ETH Zurich in 2002 (Willi Studer Award). He co mpleted his doctorate in computer science in 2006 at ETH Zurich (Chorafas Award\, Weizmann Institute of Science)\, where he formed a close collabora tion between biology and computer science. In 2006\, he was named Assistan t Professor for Computational Science in the Department of Computer Scienc e of ETH Zurich. In 2012\, Ivo and his group moved to Dresden\, where he b ecame one of the founding members of the new Max Planck Center for Systems Biology and the TU-Dresden Chair of Scientific Computing for Systems Biol ogy. He also serves as a co-leader of the biological systems path of the C enter for Advancing Electronics Dresden\, Dean of the International Max Pl anck Research School in Cell\, Developmental\, and Systems Biology\, and V ice-Dean of the Faculty of Computer Science.\n CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-524@lptms.universite-paris-saclay.fr DTSTART:20170616T110000Z DTEND:20170616T123000Z DTSTAMP:20170602T113645Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mark-hoefer-cours-1/ SUMMARY:Séminaire du LPTMS: Mark Hoefer (lecture n°1) - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Juin 17 11:00 DESCRIPTION:Lectures on Whitham Modulation Theory and Dispersive Hydrodynam ics (1)\nMark Hoefer (Department of Applied Mathematics\, University of Co lorado\,  Boulder\, USA)\nNonlinear wave modulation theory\, developed by G. B. Whitham over 50  years ago\, is a powerful mathematical tool to in vestigate dispersive  hydrodynamics.  Dispersive hydrodynamics encompass fluid and fluid-like  media in which nonlinear\, hydrodynamic phenomena (e.g.\, shock formation  and expansion waves) are influenced more promine ntly by wave dispersion  than by irreversible\, dissipative processes. Ex amples include  superfluids\, intense light propagation through a nonline ar medium\, and  the interface between two classical fluids.  A familiar feature of such  media includes the solitary wave or soliton\, whose wid th represents the  characteristic coherence length of the medium\, e.g.\, the so-called  healing length of a Bose-Einstein condensate.  Whitham t heory is used to study modulations of nonlinear waves on a scale much larg er than the\nmedium's coherence length.  It has been successfully used to describe  the most fundamental object in dispersive hydrodynamics\, a di spersive  shock wave.\n\nThese lectures will introduce the listener to th e basic theory of  Whitham with applications to several modern examples.  Mathematically\,  the Whitham modulation equations are a system of firs t order\,  quasi-linear partial differential equations.  Properties of t hese  hydrodynamic type systems such as (strict) hyperbolicity\, elliptic ity\,  genuine nonlinearity\, and simple wave solutions will be elucidate d with  a view toward understanding the physical implications of these ab stract  concepts.  Fundamental problems in dispersive hydrodynamics such as the  Riemann problem and the piston problem will be described. The th eory  will be sufficiently developed to describe a new type of hydrodynam ic  interaction where a soliton coherently interacts with a hydrodynamic   flow\, termed hydrodynamic soliton tunneling.\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-507@lptms.universite-paris-saclay.fr DTSTART:20170620T110000Z DTEND:20170620T120000Z DTSTAMP:20170613T153801Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexios-polychronakos-2/ SUMMARY:Séminaire du LPTMS: Alexios Polychronakos - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 20 Juin 17 11:00 DESCRIPTION:Duality\, Solitons and Hydrodynamics in Generalized Calogero Mo dels\nAlexios Polychronakos (The City College and Graduate Center of the C UNY\, New York)\nI will present a first-order formulation of the Calogero model in external potentials in terms of a generating function\, which sim plifies the derivation of its dual form. Solitons naturally appear in this formulation as particles of negative mass. Using this method I derive the dual form of Calogero particles in external quartic\, trigonometric and h yperbolic potentials\, which were known to be  integrable but had no know n dual formulation. I will also derive the fluid mechanical formulation o f these models and outline the corresponding fluid mechanical soliton solu tions.\n\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-525@lptms.universite-paris-saclay.fr DTSTART:20170623T110000Z DTEND:20170623T123000Z DTSTAMP:20170602T113709Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mark-hoefer-lecture-n2/ SUMMARY:Séminaire du LPTMS: Mark Hoefer (lecture n°2) - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 23 Juin 17 11:00 DESCRIPTION:Lectures on Whitham Modulation Theory and Dispersive Hydrodynam ics (2)\nMark Hoefer (Department of Applied Mathematics\, University of Co lorado\,  Boulder\, USA)\nNonlinear wave modulation theory\, developed by G. B. Whitham over 50  years ago\, is a powerful mathematical tool to in vestigate dispersive  hydrodynamics.  Dispersive hydrodynamics encompass fluid and fluid-like  media in which nonlinear\, hydrodynamic phenomena (e.g.\, shock formation  and expansion waves) are influenced more promine ntly by wave dispersion  than by irreversible\, dissipative processes. Ex amples include  superfluids\, intense light propagation through a nonline ar medium\, and  the interface between two classical fluids.  A familiar feature of such  media includes the solitary wave or soliton\, whose wid th represents the  characteristic coherence length of the medium\, e.g.\, the so-called  healing length of a Bose-Einstein condensate.  Whitham t heory is used to study modulations of nonlinear waves on a scale much larg er than the\nmedium's coherence length.  It has been successfully used to describe  the most fundamental object in dispersive hydrodynamics\, a di spersive  shock wave.\n\nThese lectures will introduce the listener to th e basic theory of  Whitham with applications to several modern examples.  Mathematically\,  the Whitham modulation equations are a system of firs t order\,  quasi-linear partial differential equations.  Properties of t hese  hydrodynamic type systems such as (strict) hyperbolicity\, elliptic ity\,  genuine nonlinearity\, and simple wave solutions will be elucidate d with  a view toward understanding the physical implications of these ab stract  concepts.  Fundamental problems in dispersive hydrodynamics such as the  Riemann problem and the piston problem will be described. The th eory  will be sufficiently developed to describe a new type of hydrodynam ic  interaction where a soliton coherently interacts with a hydrodynamic   flow\, termed hydrodynamic soliton tunneling. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-503@lptms.universite-paris-saclay.fr DTSTART:20170627T110000Z DTEND:20170627T120000Z DTSTAMP:20170619T165646Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexander-ossipov/ SUMMARY:Séminaire du LPTMS: Alexander Ossipov - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Juin 17 11:00 DESCRIPTION:Scattering approach to Anderson localisation\nAlexander Ossipov (School of Mathematical Sciences\, University of Nottingham\, UK)\nI will introduce a new approach to Anderson localisation problem\, which is base d on the scattering formalism. The first part of the talk will  review a derivation of some known results for the statistics of Wigner delay times and wavefunction amplitudes in the one-dimensional Anderson  model. Then I will explain how this method can be generalised to higher  dimensions. In particular\, the density of the Wigner delay times will be  derived fo r the two-dimensional Anderson model.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-519@lptms.universite-paris-saclay.fr DTSTART:20170628T140000Z DTEND:20170628T170000Z DTSTAMP:20170502T101714Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-aleksey-fedorov/ SUMMARY:Soutenance de thèse : Aleksey Fedorov - IPN-batiment 100\, Auditor iurm - 28 Juin 17 14:00 DESCRIPTION:Non-conventional many-body phases in ultracold dipolar systems\ nAleksey Fedorov\nThe problem of revealing and describing novel macroscopi c quantum states characterized by exotic and non-conventional properties h as the fundamental importance for modern physics. Such states offer fascin ating prospects for potential applications in quantum information processi ng\, quantum simulation\, and material research. In the present Thesis we develop a theory for describing non-conventional phases of ultracold dipol ar gases. The related systems of large-spin atoms\, polar molecules\, and dipolar excitons in semiconductors are actively studied in experiments. We put the main emphasis on revealing the role of the long-range character o f the dipole-dipole interaction. We consider the effect of rotonization fo r a 2D weakly interacting gas of tilted dipolar bosons in a homogeneous la yer\, and demonstrate that in contrast to the case of perpendicular dipole s\, in a wide range of tilting angles the condensate depletion remains sma ll even when the roton minimum is extremely close to zero. We predict the effect of rotonization for a weakly correlated Bose gas of dipolar exciton s in a semiconductor layer and calculate the stability diagram. According to our estimates\, the threshold of the roton instability for a bose-conde nsed exciton gas with the roton-maxon spectrum is achievable experimentall y in semiconductor layers. We then consider p-wave superfluids of identica l fermions in 2D lattices. The optical lattice potential manifests itself in an interplay between an increase in the density of states on the Fermi surface and the modification of the fermion-fermion interaction (scat- ter ing) amplitude. The density of states is enhanced due to an increase of th e effective mass of atoms. For short-range interacting atoms in deep latti ces the scattering amplitude is strongly reduced compared to free space du e to a small overlap of wavefunctions of fermions sitting in the neighbori ng lattice sites\, which suppresses the p-wave superfluidity. However\, we show that for a moderate lattice depth there is still a possibility to cr eate p-wave superfluids with sizable transition temperatures. For fermioni c polar molecules\, due to a long-range character of the dipole-dipole int eraction the effect of the suppression of the scattering amplitude is abse nt. It is shown that for microwave-dressed polar molecules a stable topolo gical p+ip superfluid may emerge in the 2D lattice at realistic temperatur es. Finally\, we discuss another interesting novel superfluid of fermionic polar molecules. It is expected in a bilayer system\, where dipoles are o riented perpendicularly to the layers and in opposite directions in differ ent layers. We demonstrate the emergence of interlayer superfluid pairing. In contrast to the already known s-wave interlayer superfluid\, when all dipoles are parallel to each other\, in our case the s-wave pairing is sup pressed and there can be p-wave or higher partial wave superfluids.\nDirec teurs de thèse: Georgy Shlyapnikov\nJury: Christophe Texier\, Mikhail Bar anov\, Paolo Pedri\, Andrey Varlamov CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-521@lptms.universite-paris-saclay.fr DTSTART:20170704T140000Z DTEND:20170704T150000Z DTSTAMP:20170702T151852Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thomas-barthel-2/ SUMMARY:Séminaire du LPTMS: Thomas Barthel - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 4 Juil 17 14:00 DESCRIPTION:*** ATTENTION: horaire inhabituel ->\; 14h ***\nEntanglement and computational complexity for 1D quantum systems at finite T\nThomas Ba rthel (Duke University\, USA)\nUsing the replica trick in 1+1 dimensional quantum field theory\, one can show that the cost for the classical simula tion of one-dimensional quantum many-body systems at finite temperatures g rows only polynomially with the inverse temperature and is system-size ind ependent - even for gapless systems. In particular\, I will show that the thermofield double state (TDS)\, a widely used purification of the equilib rium density operator\, has a faithful matrix product state (MPS) represen tation. The argument is based on the scaling behavior of Rényi entangleme nt entropies in the TDS. At finite temperatures\, they obey the area law. For gapless conformally invariant systems\, the Rényi entropies are found to grow only logarithmically with inverse temperature.\nThe field-theoret ical results are complemented by exact and quasi-exact numerical computati ons for integrable as well as non-integrable spin chains\, and the Bose-Hu bbard model. This allows us to compare actual matrix product truncation di mensions with upper bounds derived from Rényi entropies. Finally\, I will highlight some applications\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-528@lptms.universite-paris-saclay.fr DTSTART:20170706T110000Z DTEND:20170706T120000Z DTSTAMP:20170704T052130Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-vladimir-gritsev-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Vladimir Gritsev *** séminaire exceptionnel * ** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Juil 17 11:00 DESCRIPTION:Integrability and supersymmetry in quantum optics\nVladimir Gri tsev (University of Amsterdam)\nFirst I will give an overview of quantum i ntegrable models used in quantum optics.\nThen I will discuss some new met hods recently developed by us for solving quantum dynamics\nin various non linear models of quantum optics. Finally I am going to talk about supersym metry\nin quantum optics and spin-orbit coupled systems. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-530@lptms.universite-paris-saclay.fr DTSTART:20170905T110000Z DTEND:20170905T120000Z DTSTAMP:20170829T061359Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-raoul-santachiara/ SUMMARY:Séminaire du LPTMS: Raoul Santachiara - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 5 Sep 17 11:00 DESCRIPTION:Riemann-Hilbert problem in 2D Conformal Field Theory\nRaoul San tachiara (LPTMS\, Université Paris-Sud)\n \;\nThe Riemann-Hilbert pro blem asks whether the global properties (i.e. their the analytic continuat ion) of a space of holomorphic functions allows to determine uniquely the   linear ordinary complex differential equation (of Fuchsian type) of whi ch they are solutions.  The answer is positive for a class of  equations that are called rigid systems. We have recently observed that the rigid s ystems describe a class of fundamental equations that lie in the heart of the 2D conformal field theories. Moreover we used for the first time a pro cedure developed in the last decades for the solutions of rigid systems to provide new results in CFTs.  In this talk\, I will try to introduce the (beautiful) mathematics behind the Fuchsian systems\, and I will try to g ive you an idea of the reason why these equations are related to the confo rmal symmetry. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-529@lptms.universite-paris-saclay.fr DTSTART:20170912T110000Z DTEND:20170912T120000Z DTSTAMP:20170829T055033Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sergio-ciliberto/ SUMMARY:Séminaire du LPTMS: Sergio Ciliberto - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Sep 17 11:00 DESCRIPTION:\n\n\nThe Maxwell demon and Landuer's principle: from gedanken to real experiments\n\n\n\nSergio Ciliberto (Laboratoire de Physique\, ENS de Lyon)\n\n\n\n\nDuring this talk we will recall the connections between information and thermodynamics. We will then discuss a specific example o f the measure of the Landauer's bound. Rolf Landauer argued that the erasu re of information is a dissipative process . A minimal quantity of heat\, proportional to the thermal energy\, is necessarily produced when a classi cal bit of information is deleted. A direct consequence of this logically irreversible transformation is that the entropy of the environment increas es unavoidably by a finite amount. We experimentally show the existence of the Landauer bound in a generic model of a one-bit memory. Using a system of a single colloidal particle trapped in a modulated double-well potenti al\, we establish that the mean dissipated heat saturates at the Landauer bound in the limit of long erasure cycles. This result demonstrates the in timate link between information theory and thermodynamics. For a memory er asure procedure\, which is a logically irreversible operation\, a detailed Jarzynski Equality is verified\, retrieving the Landauer limit independen tly of the work done on the system.\n\nReferences :\n\n Experimental verif ication of Landauer’s principle linking information and thermodynamics\, A. Bérut\, A. Arakelyan\, A. Petrosyan\, S. Ciliberto\, R. Dillenschnei der\, E. Lutz\, Nature 483\, 187–189 (08 March 2012)\n Detailed Jarzynsk i Equality applied to a Logically Irreversible Procedure\, A. Bérut\, A. Petrosyan\, S. Ciliberto\, EPL 103\, 60002 (2013)\n Information: From Max well’s demon to Landauer’s eraser\, Eric Lutz\, Sergio Ciliberto\, Phy sics Today 68 (9)\, 30 (2015)\n\n\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-535@lptms.universite-paris-saclay.fr DTSTART:20170920T110000Z DTEND:20170920T120000Z DTSTAMP:20170905T102230Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-antonin-coutant/ SUMMARY:Séminaire du LPTMS: Antonin Coutant - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 20 Sep 17 11:00 DESCRIPTION:**** Attention: jour inhabituel  *****\nMimicking black holes in fluids\nAntonin Coutant (University of Nottingham\, UK)\nI will discuss the possibility to mimic black hole physics in fluid flows. The starting point is an analogy discovered by Unruh between the propagation of sound i n a flowing fluid and waves around a black hole. I will discuss the analog ue of the Hawking effect through which a black hole loses its mass\, and i ts recent experimental verifications. I will also present a recent water w ave experiment\, where we have observed the analogue of black hole superra diance\, that is\, the amplification of waves by extraction of angular mom entum from a rotating flow\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-532@lptms.universite-paris-saclay.fr DTSTART:20170925T100000Z DTEND:20170925T123000Z DTSTAMP:20170905T101517Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-stefano-spigler/ SUMMARY:Soutenance de thèse: Stefano Spigler - LPTMS-batiment 100\, salle des conseils - 25 Sep 17 10:00 DESCRIPTION:Avalanches in glassy systems\nStefano Spigler\nBeaucoup de syst èmes qui ont un certain degré de désordre ont des similarités dans leu r structure : le paysage énergétique est aléatoire et il a plusieurs mi nima locaux de l’énergie. Quand on ajoute une petite perturbation exter ne au système à basse température\, il est raisonnable d’attendre que la dynamique conduira le système d’un minimum à l’autre\, et ça do nne lieu à une réponse aléatoire et saccadée. Les sautes discontinus q ue l’on observe sont appelés avalanches\, et l’intérêt de ce travai l est le calcul de leur distribution. Un des résultats est en effet le d éveloppement d’un cadre pour calculer cette distribution dans des syst èmes en dimension infinie qui peuvent être décrits avec le replica symm etry breaking. Nous appliquons les résultats à l’un des modèles les p lus simples des verres structuraux\, c’est à dire les empilements dense s de sphères molles avec répulsion harmonique\, avec une déformation (s hear strain) du volume comme perturbation. Nous soutenons que\, quand la d éformation est suffisamment petite\, une portion de la distribution des a valanches devient une loi de puissance\, dont l’exposant peut être dire ctement lié au paramètre d’ordre de la brisure de symétrie de replica . Cet exposant est également lié à la distribution des forces de contac t (au moins entre certaines sphères)\, dont le comportement asymptotique on sait que ne dépend pas fortement de la dimension spatiale \; pour cett e raison nous comparons les prédictions de champ moyen en dimension infin ie avec des simulations du même système en dimension trois et\, remarqua blement\, on trouve un bon accord. Dans le reste de la thèse nous discuto ns aussi les similarités avec des travaux précédents et quelques consé quences que la distribution des avalanches donne sur les propriétés éla stiques de la matière granulaire dense.\nDirecteur de thèse: Silvio Fran z\nJury: Jean-Louis BARRAT\, Giulio BIROLI\, Chiara CAMMAROTA\, Giuseppe F OFFI\, Tommaso RIZZO\, Matthieu WYART CATEGORIES:seminars LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:1-527@lptms.universite-paris-saclay.fr DTSTART:20170929T150000Z DTEND:20170929T180000Z DTSTAMP:20170904T071903Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-thibault-congy/ SUMMARY:Soutenance de thèse: Thibault Congy - IPN-batiment 100\, Auditoriu rm - 29 Sep 17 15:00 DESCRIPTION:Fluctuations non-linéaires dans les gaz quantiques à deux com posantes\nThibault Congy\nCette thèse est dédiée à l'étude des fluctu ations non-linéaires dans les condensats de Bose-Einstein à deux composa ntes. Dans un régime de champ moyen\, la dynamique des deux espèces du c ondensat est régie par deux équations de Gross-Pitaevskii couplées et o n montre que le spectre des excitations se sépare en deux modes de propag ation distincts : un mode dit de densité correspondant au mouvement globa l des atomes à l'intérieur du condensat et un mode dit de polarisation c orrespondant au mouvement relatif entre les deux espèces constituant le c ondensat.\nCette séparation en une dynamique globale et une dynamique rel ative persiste en présence d'un couplage cohérent entre les deux espèce s\, et on présentera dans une première partie les équations gouvernant la propagation des excitations non-linéaires du mode de polarisation en p résence d'un couplage de Rabi. En particulier on analysera la stabilité modulationnelle de ce mode à l'aide de la méthode des échelles multiple s et on montrera que les excitations de polarisation\, au contraire des ex citations de densité\, souffrent d'une instabilité de Benjamin-Feir.\nDa ns une deuxième partie\, on présentera la dynamique de polarisation du c ondensat proche de la limite dite de Manakov. Plus particulièrement dans le cas où les coefficients d'interaction inter-et-intra espèces sont pro ches\, la dynamique de polarisation se révèle être régie par une équa tion de Landau-Lifshitz sans dissipation. Les équations de Landau-Lifshit z appartiennent à une hiérarchie d'équations intégrables (hiérarchie Ablowitz-Kaup-Newell-Segur) et on peut déterminer les solutions à une ph ase à l'aide de la méthode d'intégration "finite-gap". Profitant de l'i ntégrabilité du système\, on résoudra notamment le problème de Rieman n à l'aide de la théorie de modulation de Whitham et on montrera que les condensats à deux composantes peuvent propager des ondes de raréfaction ainsi que des ondes de choc dispersives.\nDirecteur de thèse: N. Pavloff \n\nJury: F. Chevy\, B. Gallet\, S. Gavrilyuk\, C. Josserand\, C. Nore\, F . Lagoutière CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-533@lptms.universite-paris-saclay.fr DTSTART:20171003T110000Z DTEND:20171003T120000Z DTSTAMP:20170927T102728Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-davide-squizzato/ SUMMARY:Séminaire du LPTMS: Davide Squizzato - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 3 Oct 17 11:00 DESCRIPTION:\nKPZ Physics in Exciton Polaritons Systems\n\nDavide Squizzato (LPMMC\, Grenoble)\nThe experimental demonstration of Bose-Einstein conde nsation of exciton polaritons gases in driven-dissipative conditions [1] h as given rise to several questions on the nature and the characterization of out-of-equilibrium bosonic systems under pump and dissipation. Such sys tems can be theoretically described by a generalised Gross-Pitaevskii equa tion (gGPE) in which complex coefficients and noise enrich the equilibrium picture. An analytical mapping between gGPE and the Kardar-Parisi-Zhang ( KPZ) equation has been demonstrated at long wavelength if fluctuations of the amplitude of the condensate are negligible with respect to the ones of the phase field. Hence\, one expects the long-distance properties of driv en-dissipative condensates to pertain to the KPZ universality class. A num erical verification of KPZ scaling was given in (1+1)dimensions [2]\; howe ver\, the experimental accessibility of the KPZ mapping is still under deb ate. In this work we use both Keldysh field-theoretical approach and numer ical simulations to investigate the effects of inhomogeneities typical of experimental set-ups and study their effects on the universal properties o f driven-dissipative polaritons condensates\; we furthermore look at the r eal-time statistics of the phase in both homogeneous and in-homogeneous ca se in order to better understand the nature of KPZ behaviour\, i.e. the ge ometrical sub-class to which it belongs to.\n\nReferences:\n\n [1] J. Kasp rzak et al.\, “Bose-Einstein condensation of exciton polaritons”\, Nat ure 443\, pp. 409–414\, Sep 2006.\n [2] L. He\, L. M. Sieberer\, E. Altm an\, and S. Diehl\, “Scaling properties of one-dimensional driven-dissip ative condensates”\, Phys. Rev. B 92\, 155307\, Oct 2015.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-531@lptms.universite-paris-saclay.fr DTSTART:20171006T140000Z DTEND:20171006T170000Z DTSTAMP:20170920T080320Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-maksim-sevelev/ SUMMARY:Soutenance de thèse: Maxime Sevelev - IPN-batiment 100\, Auditoriu rm - 6 Oct 17 14:00 DESCRIPTION:Phase diagram\, jamming and glass transitions in the non-convex perceptron\nMaxime Sevelev\nThis thesis treats the «spherical perceptron model»\, a simple exactly solvable model for glassy behavior and jamming suitably generalized to negative values of scalar product parameter κ. T he classical machine-learning problem of random pattern classification by the perceptron is a convex constraint satisfaction problem (CSP). Even whe n the «stability parameter» κ of the model becomes negative\, the probl em still makes sense and can be interpreted as the problem of particles on an N-dimensional sphere trying to avoid randomly placed obstacles. In thi s case\, the corresponding CSP is non-convex. This thesis studies the prob lem in detail in the non-convex domain. Systematic study is made possible by assigning to a constraint satisfaction problem its corresponding optimi zation version endowed with a Hamiltonian function (cost function) quantif ying the violations of the constraints\, as a function of the system's con figuration. The connection between random CSP and glassy phenomenology in physics is well known and has been explored in detail for models with disc rete variables. The presence of continuous variables in the (spherical) pe rceptron model enables us to unveil\, in random CSP\, the characteristic S AT/UNSAT transition where the system transits from the satisfiable regime (where the ground state has zero energy) to the unsatisfiable one (where t he ground state energy is positive). This phase transition can also be int erpreted as a jamming transition similar to the one that exhibit models wi th frictionless spheres. The simplicity of the considered model allows the exact determination of the zero temperature phase diagram as a function o f the control parameters: the density of obstacles and their size. In the present thesis\, the jamming transition thus identified is completely char acterized and several glass phases of stable and marginal character are st udied in detail.\nKeywords: spin glass\, phase transition\, disordered sys tem\, jamming\n\nDirecteur de thèse: S. Franz\n\nJury: R. Mulet\, F. Ricc i.tersenghi\, V. Lecomte\, M. Tarzia\, V. Terras\, C. Texier. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:1-545@lptms.universite-paris-saclay.fr DTSTART:20171010T110000Z DTEND:20171010T120000Z DTSTAMP:20171005T085924Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-vladimir-gritsev/ SUMMARY:Séminaire du LPTMS: Vladimir Gritsev - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Oct 17 11:00 DESCRIPTION:Integrable Floquet Dynamics\nVladimir Gritsev (University of Am sterdam)\nI will discuss several classes of integrable Floquet systems\, i .e. systems which do not exhibit chaotic behavior even under a time depend ent perturbation. The first class is associated with finite-dimensional Li e groups and infinite-dimensional generalization thereof. The second class is related to the row transfer matrices of the 2D statistical mechanics m odels. The third class of models\, called the "boost models"\, is construc ted as a periodic interchange of two Hamiltonians - one is the integrable lattice model Hamiltonian\, while the second is the boost operator. The la tter for known cases coincides with the entanglement Hamiltonian and is cl osely related to the corner transfer matrix of the corresponding 2D statis tical models. As an interesting application of the boost models I discuss a possibility of generating periodically oscillating states with the perio d different from that of the driving field. In particular\, one can realiz e an oscillating state by performing a static quench to a boost operator. We term this state a "Quantum Boost Clock". All analyzed setups can be rea dily realized experimentally\, for example in cod atoms. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-526@lptms.universite-paris-saclay.fr DTSTART:20171017T110000Z DTEND:20171017T120000Z DTSTAMP:20170918T111634Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thierry-jolicoeur/ SUMMARY:Séminaire du LPTMS: Thierry Jolicoeur - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 17 Oct 17 11:00 DESCRIPTION:Quantum coherence in bilayer graphene in the quantum Hall regim e\nThierry Jolicoeur (LPTMS\, Université Paris-Sud)\nBilayer graphene und er a magnetic field has a central octet of quasi-degenerate Landau levels due to spin\, valley\, and orbital degeneracies. This set of zero-energy L andau level is resolved into several incompressible states whose detailed nature is still elusive. A Hartree-Fock treatment of a realistic tight-bin ding four-band model can be used to understand the quantum ferromagnetism phenomena expected for integer fillings of the octet levels.  I will disc uss various phase diagrams as a function of applied bias and magnetic fiel d. In some corners of these diagrams are interesting phases with quantum c oherence involving valley or orbital degrees of freedom.\n\nReference:\n\n Angelika Knothe and Thierry Jolicoeur\, Phase diagram of a graphene bilay er in the zero-energy Landau level\, Phys. Rev. B 94\, 235149 (2016).\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-539@lptms.universite-paris-saclay.fr DTSTART:20171018T110000Z DTEND:20171018T120000Z DTSTAMP:20171005T121757Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-paul-francois/ SUMMARY:Physics-Biology interface seminar: Paul François - Amphi BLANDIN d u LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 18 Oct 17 11 :00 DESCRIPTION:Untangling the biological hairball of immune recognition networ ks\nPaul François (McGill University\, Canada)\n\nComplex mathematical mo dels of interaction networks are routinely used for prediction in systems biology. However\, it is difficult to reconcile network complexities with a formal understanding of their behavior. I will introduce several models of immune recognition by T cells and will show how a simple procedure can be used to reduce them to functional submodules\, using statistical mech anics of complex systems combined with a fitness-based approach inspired b y in silico evolution. Our procedure works by putting parameters or combin ation of parameters to some asymptotic limit\, while keeping (or slightly improving) the model performance\, and requires parameter symmetry breakin g for more complex models. An intractable model of immune recognition with close to a hundred individual transition rates is reduced to a simple two -parameter model\, and connected to the ``adaptive sorting" principle that we previously identified and experimentally validated. Our procedure extr acts three different mechanisms for early immune recognition\, and automat ically discovers similar functional modules in different models of the sam e process allowing for model classification and comparison. \n CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-543@lptms.universite-paris-saclay.fr DTSTART:20171019T140000Z DTEND:20171019T150000Z DTSTAMP:20171009T063036Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cecile-repellin/ SUMMARY:Séminaire du LPTMS: Cécile Repellin - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Oct 17 14:00 DESCRIPTION:!!!! jour et horaire inhabituels !!!!\n\nNumerical investigatio n of gapped edge states in fractional quantum Hall-superconductor heterost ructures\nCécile Repellin (MPI\, Dresden\, Allemagne)\nThe possibility of realizing anyons -- quasiparticles with fractional  exchange statistics -- is an exciting prospect in the field of  interacting topological phase s. Non-abelian anyons\, whose exchange is  characterized by a matrix rath er than a simple phase\, are of the most  exotic kind. They are highly so ught after as they could be used as  qubits for quantum computation intri nsically immune to decoherence. While non-abelian anyons are expected to a ppear in the fractional  quantum Hall effect\, engineering systems that p urposefully favor their  emergence might be a better strategy to probe th eir properties. Progress  in creating quantum devices with Majorana bound states represents an  important achievement in this direction. Realizing the even more elusive  parafermions\, which unlike Majoranas could suppo rt universal quantum  computation\, would be an exciting next step.\n\nPa rafermion states have been envisioned to occur in heterostructures  using fractional quantum Hall (FQH) states and superconductors. Existing  theo retical studies of these systems have been entirely based on  effective t heories of fractional quantum Hall edge states which cannot  offer any qu antitative analysis of competing energy scales\, correlation  lengths etc . To fill this gap\, we propose and implement a numerical  setup for stud ying edge states of FQH droplets with a superconducting  instability. Usi ng exact diagonalization\, we report the first  observation in a fully mi croscopic model of gapped FQH edge modes with  topological degrees of fre edom. The topological nature of these modes is  probed through fractional Josephson effect and flux insertion\, and  evidence the cooper pairing o f fractionalized quasiparticles.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-534@lptms.universite-paris-saclay.fr DTSTART:20171024T110000Z DTEND:20171024T120000Z DTSTAMP:20171017T125830Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mauricio-pato/ SUMMARY:Séminaire du LPTMS: Mauricio Pato - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 24 Oct 17 11:00 DESCRIPTION:Pseudo-Hermitian random matrix ensembles\nMauricio Pato (Univer sidade de São Paulo\, Brazil)\n\nIn my talk\, I will revise results obtai ned in an effort to construct ensemble of random matrices which are connec ted with their adjoint by a similarity transformation. Matrices satisfying this condition have eigenvalues real or complex conjugate and are called pseudo-Hermitian. This condition arose in studies of systems whose Hamilto nians are PT-symmetric invariant\, that is\, Hamiltonians which though not invariant under the time-reversl and the parity transformations performed isolatedly become invariant when these transformations are combined. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-554@lptms.universite-paris-saclay.fr DTSTART:20171031T110000Z DTEND:20171031T120000Z DTSTAMP:20171023T054304Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-martin-evans/ SUMMARY:Séminaire du LPTMS: Martin Evans - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 31 Oct 17 11:00 DESCRIPTION:Model of Antibiotic Action on Bacterial Growth\nMartin Evans (U niversity of Edinburgh\, UK)\nIn this talk I will describe a simple  mode l for the growth of a  bacterial population under the challenge of riboso me-targetting  antibiotics. I shall endeavour to motivate why statistical physics lends itself to the study of bacterial dynamics. The model I will    discuss is statistical physics-like in that it makes a coarse-grained description of the growth process\, reduced to three variables within the bacterial cell - the antibiotic concentration\, the concentration of ribo somes bound to antibiotics and the concentration of unbound ribosomes. Rem arkably the model can explain several observations concerning   antibiot ic action and bacterial growth rate. In particular the growth-dependent ba cterial susceptibility is controlled by a single\, "universal" parameter a nd the extreme behaviours correspond to the phenomenological classificatio n into bactericidal and bacteriostatic antibiotics. The predictions of the model are backed up by experimental studies. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-536@lptms.universite-paris-saclay.fr DTSTART:20171107T110000Z DTEND:20171107T121500Z DTSTAMP:20171103T141713Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-d-baillie/ SUMMARY:Séminaire du LPTMS: Danny Baillie - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 7 Nov 17 11:00 DESCRIPTION:Dipolar droplets\nDanny Baillie (University of Otago\, New Zeal and)\nExperiments with Bose-Einstein condensates of dysprosium [1] and erb ium [2] atoms have observed the formation of dilute quantum gas droplets t hat can preserve their form\, even in the absence of any external confinem ent [3]. These droplets are stabilized by Lee-Huang-Yang (LHY) quantum flu ctuation corrections to meanfield theory [4]. We discuss the regimes in wh ich such self-bound droplet states are stable [5]\, and examine the proper ties of their collective excitations. Notably we observe that the elongate d filament-shaped droplets act as a quasi-one-dimensional waveguide along which low angular momentum phonons propagate [6].\nReferences\n\n[1] H. Ka dau\, M. Schmitt\, M. Wenzel\, C. Wink\, T. Maier\, I. Ferrier-Barbut\, an d T. Pfau\, Nature 530\, 194 (2016).\n\n[2] L. Chomaz\, S. Baier\, D. Pett er\, M. J. Mark\, F. Wächtler\, L. Santos\, and F. Ferlaino\, Phys. Rev. X 6\, 041039 (2016).\n\n[3] M. Schmitt\, M. Wenzel\, F. Böttcher\, I. Fer rier-Barbut\, and T. Pfau\, Nature 539\, 259 (2016).\n\n[4] T. D. Lee\, K. Huang\, and C. N. Yang\, Phys. Rev. 106\, 1135 (1957).\n\n[5] D. Baillie\ , R. M. Wilson\, R. N. Bisset\, and P. B. Blakie\, Phys. Rev. A 94\, 02160 2(R) (2016).\n\n[6] D. Baillie\, R. M. Wilson\, and P. B. Blakie\, arXiv:1 703.07927. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-560@lptms.universite-paris-saclay.fr DTSTART:20171114T110000Z DTEND:20171114T120000Z DTSTAMP:20171105T194827Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giacomo-mazza/ SUMMARY:Séminaire du LPTMS: Giacomo Mazza - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 14 Nov 17 11:00 DESCRIPTION:Strong light-matter coupling: transient superconductivity in op tical stimulated systems and electronic properties inside optical cavities \nGiacomo Mazza (CPhT\, Ecole Polytechnique\, Université Paris-Saclay)\n\ nThe interaction between light and matter has been intensively used for pr obing the properties of condensed matter systems. In the last years\, this paradigm evolved and the light-matter interaction has become a tool for s trongly modify the systems properties and accessing states of matter that are not present (or hidden) in equilibrium conditions. In this talk I will discuss two different examples.\n\nIn the first case I will consider the optical stimulation of solids by means of strong light pulses. A series of recent experiments reported the observations of light-induced modificatio n of the electronic properties suggestive of the formation of transient su perconducting states. Remarkably these transient states extend far above t he equilibrium critical temperatures and appear in different compounds\, a s cuprates and organics superconductors (fullerides) [1\,2]. I will disc uss from the theoretical point of view possible realisations of such trans ient superconductivity in simplified models for correlated superconductors . In particular\, I will start from the general case of superconductivity induced by a strong attractive interaction [3] and then move the more spe cific case of fullerides [4]. \n\n\nAs a second example I will consider t he electronic properties of materials placed inside high-finesse optical c avities\, where the vacuum electromagnetic field strongly interact with a given electronic transition. I will discuss how the electronic properties are modified by the light-matter coupling and how the latter can be used t o tune the electronic transport properties.\n\n\n\n \;\nReferences:\n\ n\n [1] D. Fausti et al.\, Light-induced superconductivity in a stripe-ord ered cuprate\, Science 331\, 189 (2011)\n [2] M. Mitrano et al.\, Possible light-induced superconductivity in K3C60 at high temperature\, Nature 530 \, 461 (2016)\n [3] G. Mazza\, From sudden quench to adiabatic dynamics in the attractive Hubbard model\, arXiv:1708.01096 \n [4] G. Mazza and A. G eorges\, Nonequilibrium superconductivity in driven alkali-doped fulleride s\, Phys.Rev.B 96\, 064515 (2017).\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-540@lptms.universite-paris-saclay.fr DTSTART:20171115T110000Z DTEND:20171115T120000Z DTSTAMP:20171030T161108Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-felix-rico/ SUMMARY:Physics-Biology interface seminar: Felix Rico - Amphi BLANDIN du LP S de la Faculté des Sciences d’Orsay (Bâtiment 510) - 15 Nov 17 11:00 DESCRIPTION:Molecular to cellular mechanics probed by high-speed atomic for ce microscopy\nFelix Rico (Aix-Marseille Université)\n\nThe mechanical pr operties of individual proteins\, filaments\, and supramolecular assemblie s provide structural stability and mechanical flexibility to the living ce ll. Thus\, molecular understanding of the mechanics from the single molecu le to the whole cell is relevant to understand biological function. High-s peed atomic force microscopy (HS-AFM) is a unique technology that combines nanometric-imaging capabilities at video rate. In this talk\, I will pres ent our recent applications of HS-AFM to probe protein and cellular mechan ics. In the first part\, I will introduce the development of high-speed fo rce spectroscopy (HS-FS) to probe protein unfolding at the timescales of m olecular dynamics simulations (1). This provides a unique approach to acqu ire atomistic understanding of biomolecular processes based on experimenta l results. In the second part\, I will present our recent work on the adap tation of HS-AFM to probe the microrheology of living cells at high freque ncies (up to 100 kHz)\, revealing cytoskeletal dynamics (2). We show that the mechanical response at high frequencies depends on the actin filament tension and pathological state of the cell. Microrheology over a wide dyna mic range—up to the frequency characterizing the molecular components— provides a mechanistic understanding of cell mechanics.\n\n1. F. Rico\, L. Gonzalez\, I. Casuso\, M. Puig-Vidal\, S. Scheuring\, High-Speed Force Sp ectroscopy Unfolds Titin at the Velocity of Molecular Dynamics Simulations . Science 342\, 741 (2013).\n\n\n2. A. Rigato\, A. Miyagi\, S. Scheuring\, F. Rico\, High-frequency microrheology reveals cytoskeleton dynamics in l iving cells. Nat Phys 13\, 771 (2017).\n CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:1-561@lptms.universite-paris-saclay.fr DTSTART:20171115T140000Z DTEND:20171115T151500Z DTSTAMP:20171113T120758Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-natalia-menezes-silva-da-costa/ SUMMARY:Séminaire exceptionnel du LPTMS: Natalia Menezes Silva Da Costa - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Nov 17 1 4:00 DESCRIPTION:Quantum field theory in low-dimensional condensed-matter system s\nNatália Menezes Silva Da Costa (Utrecht University)\nIn this talk I wi ll present two examples of how quantum field theories may be applied to de scribe the long wavelength regime of condensed-matter systems.\n\nThe firs t example [1] concerns the study of electronic interactions on the boundar y of a two-dimensional time-reversal-invariant topological insulator. Whil e the bulk of this two-dimensional material is insulating\, the boundary e xhibits propagating modes that may be described in terms of a one-dimensio nal Dirac theory.  By assuming that there is an underlying electromagneti c theory mediating the e-e interaction on the edges\, and by employing a d imensional reduction procedure\, I will show that the effective one-dimens ional theory is a non-Fermi liquid\, known as the helical Luttinger liquid (HLL).  This HLL resembles a theory of free bosons\, however\, with a pa rameter in its kinematics that indicates the strength of the e-e interacti ons. Within the quantum-field theoretical formalism\, I will show that suc h parameter can be written in terms of the fine structure constant\, which allows one not only to predict its value but also to manipulate the natur e attractive/repulsive of the interaction.\n\nThe second example [2] conce rns the topological response of a fermionic model defined on the Lieb latt ice in presence of an electromagnetic field. The tight-binding model is bu ilt in terms of three species of spinless fermions and supports a topologi cal Varma phase due to the spontaneous breaking of time-reversal symmetry. In the low-energy regime\, the emergent effective Hamiltonian coincides w ith the so-called Duffin-Kemmer-Petiau (DKP) Hamiltonian\, which describes relativistic pseudospin-0 quasiparticles and goes beyond the commonly stu died spin-1/2 Dirac/Weyl paradigm. By considering a minimal coupling betwe en the DKP quasiparticles and an external Abelian gauge field\, I will pre sent both the Landau-level spectrum and the emergent Chern-Simons theory. The corresponding Hall conductivity reveals an atypical quantum Hall effec t\, which can be simulated in an artificial Lieb lattice.\n\n[1] N. Meneze s\, G. Palumbo and C. Morais Smith\, Sci. Rep. 7\, 14175 (2017).\n\n[2] N. Menezes\, C. Morais Smith and G. Palumbo\, arXiv:1710.07916 (2017). CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-562@lptms.universite-paris-saclay.fr DTSTART:20171121T110000Z DTEND:20171121T120000Z DTSTAMP:20171113T215650Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexios-polychronakos-3/ SUMMARY:Séminaire du LPTMS: Alexios Polychronakos - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 21 Nov 17 11:00 DESCRIPTION:The 2017 Physics Nobel prize: the observation of gravitational waves\n\nAlexios Polychronakos (The City College and Graduate Center of th e CUNY\, New York\, USA)\nA sweeping review of the history\, drama and exc itement behind the recent observation of gravitational waves will be prese nted\, including its human aspects\, theoretical and technical challenges\ , physics and engineering\, at a level appropriate for non-experts. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-551@lptms.universite-paris-saclay.fr DTSTART:20171128T110000Z DTEND:20171128T120000Z DTSTAMP:20171120T151651Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-spyros-sotiriadis/ SUMMARY:Séminaire du LPTMS: Spyros Sotiriadis - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 28 Nov 17 11:00 DESCRIPTION:Quantum transport after inhomogeneous quenches\n\nSpyros Sotiri adis (University of Ljubljana\, Slovenia)\n\nI will discuss quantum dynami cs and transport in systems that are initially split in two halves lying a t different temperature or particle density and abruptly connected. After such an inhomogeneous quench\, a Non-Equilibrium Steady State (NESS) typic ally forms in the thermodynamic and large time limit. I will demonstrate h ow the emergence of NESS can be derived from first principles\, starting f rom non-interacting lattice models in one dimension and considering the ef fects of different boundary conditions and of interacting defects. Next I will focus on a genuinely interacting integrable system\, the Lieb-Liniger gas\, for which it has been recently conjectured that Generalised Hydrody namics (GHD) emerges at large times. I will derive an exact determinant fo rmula for the NESS and show how certain predictions of the above conjectur e can be deduced from it.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-559@lptms.universite-paris-saclay.fr DTSTART:20171129T110000Z DTEND:20171129T120000Z DTSTAMP:20171121T105357Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-pascal-silberzan/ SUMMARY:Physics-Biology interface seminar: Pascal Silberzan - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 29 Nov 17 11:00 DESCRIPTION:Confining and releasing cell monolayers\nPascal Silberzan (Inst itut Curie\, Paris)\nCell monolayers routinely exhibit collective behavior s largely controlled by cell-cell interactions. In this context\, confinem ent and boundary conditions play an important role in the organization and dynamics of these cell assemblies. Interestingly\, many in vivo processes \, including morphogenesis or tumor maturation\, involve small populations of cells within a spatially restricted region.\nWe report experiments in which epithelial monolayers confined in circular disks exhibit low-frequen cy periodic radial displacement modes. When the boundary is removed\, cell s collectively migrate on the free surface. The essential characteristics of the collective dynamics in these two situations are well-accounted for by the same theoretical model in which cells are described as persistent r andom walkers which adapt their motion to that of their neighbors.\n\nIn c ontrast\, elongated fibroblasts that do not develop significant cell-cell adhesions self-organize until reaching a perfect nematic order upon confin ement in linear stripes. When the cells are confined within a disk\, the n umber and charge of the topological defects characteristic of nematics can be controlled\, emphasizing the role of friction in this active nematic s ystem.\n\nAfter days in culture\, the confined epithelia develop a tridime nsional structure in the form of a peripheral cell cord at the domain edge . Confinement by itself is therefore sufficient to induce morphogenetic-li ke processes including spontaneous collective pulsations\, global orientat ion and transition from 2D to 3D. \n CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-558@lptms.universite-paris-saclay.fr DTSTART:20171205T110000Z DTEND:20171205T120000Z DTSTAMP:20171128T102728Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cristiano-ciuti/ SUMMARY:Séminaire du LPTMS: Cristiano Ciuti - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 5 Déc 17 11:00 DESCRIPTION:Dissipative phase transitions in open quantum manybody systems\ nCristiano Ciuti (Laboratoire Matériaux et Phénomènes Quantiques\, Univ ersité Paris Diderot et CNRS)\nIn the first part of the talk\, I will int roduce the general  theoretical concepts behind the physics of dissipativ e phase  transitions in open quantum manybody systems\, with a particular   emphasis on driven-dissipative lattices. These systems can be  impleme nted using several platforms including superconducting quantum  circuits and semiconductor microcavity lattices. In the second part of the talk\, I will present recent theoretical  results about critical phenomena in the 2D dissipative XYZ Heisenberg  model and critical slowing down in the dr iven-dissipative Bose-Hubbard  model. Perspectives and challenges will be discussed.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-547@lptms.universite-paris-saclay.fr DTSTART:20171212T110000Z DTEND:20171212T120000Z DTSTAMP:20171201T134736Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-antoine-browaeys/ SUMMARY:Séminaire du LPTMS: Antoine Browaeys - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Déc 17 11:00 DESCRIPTION:Many-body physics with arrays of individual Rydberg atoms\nAnto ine Browaeys (Laboratoire Charles Fabry\, Institut d'Optique)\nThis talk w ill present our effort to control the interaction between cold Rydberg at oms in order to implement spin Hamiltonians that may be useful for quantu m simulation of condensed matter problems. In our experiment\, we trap in dividual atoms in two-dimensional arrays of optical tweezers separated by few micrometers and excite them to Rydberg states using lasers. We will present our demonstration of the coherent energy exchange between two Rydb erg atoms resulting from their dipole-dipole interaction\, and the imple mentation of the quantum Ising model in a system of 50 atoms with van der Waals Rydberg interaction. This demonstrates a new platform for quantum s imulation using neutral atoms complementary to the ones based on ions\,  magnetic atoms or dipolar molecules. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-548@lptms.universite-paris-saclay.fr DTSTART:20171213T110000Z DTEND:20171213T120000Z DTSTAMP:20171212T064213Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jan-brugues/ SUMMARY:Physics-Biology interface seminar: SEMINAR CANCELLED - Amphi BLANDI N du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 13 Déc 1 7 11:00 DESCRIPTION:SEMINAR CANCELLED.\nJan Brugués (MPI-CBG Dresden) CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-570@lptms.universite-paris-saclay.fr DTSTART:20171214T110000Z DTEND:20171214T121500Z DTSTAMP:20171214T070113Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-boris-svistunov/ SUMMARY:Séminaire exceptionnel du LPTMS: Boris Svistunov - LPTMS\, salle 2 01\, 2ème étage\, Bât 100\, Campus d'Orsay - 14 Déc 17 11:00 DESCRIPTION:The Halon: A Quasiparticle Featuring Critical Charge Fractional ization\nBoris Svistunov (University of Massachussetts Amherst)\nI will pr esent two quite different examples of a new impurity driven quantum critic ality associated with a sharply defined integer charge of a quasiparticle (polaron). On the approach to the critical point\, the charge distributio n splits into a fractionally charged core and a critically large halo carr ying the complementary charge. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-564@lptms.universite-paris-saclay.fr DTSTART:20171219T110000Z DTEND:20171219T120000Z DTSTAMP:20171207T103751Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-julien-cividini/ SUMMARY:Séminaire du LPTMS: Julien Cividini - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 19 Déc 17 11:00 DESCRIPTION:Driven tracer with absolute negative mobility\nJulien Cividini (Weizmann Institute\, Israël)\nInstances of negative mobility\, where a s ystem responds to a perturbation in a way opposite to naive expectation\, have been studied theoretically and experimentally in numerous nonequilibr ium systems. After reviewing part of the literature on the topic\, we will consider a simple one-dimensional lattice model of a driven tracer in bat h. We will show that  contrary to previous expectations\, Absolute Negati ve Mobility (ANM)\, whereby current is produced in a direction opposite to the drive\, occurs around an equilibrium state. We derive analytical pred ictions for the mobility in the linear response regime. The high density r egime will help us elucidate the mechanism leading to ANM. The lattice mod el can be seen as a toy model for hard Brownian discs in a narrow planar c hannel. Molecular dynamics studies show that the hard discs model exhibits Negative Differential Mobility (NDM)\, but no ANM. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-556@lptms.universite-paris-saclay.fr DTSTART:20180109T110000Z DTEND:20180109T120000Z DTSTAMP:20171222T155921Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicolas-cherroret/ SUMMARY:Séminaire du LPTMS: Nicolas Cherroret - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Jan 18 11:00 DESCRIPTION:Novel perspectives from Anderson localization of atomic matter waves\nNicolas Cherroret (Laboratoire Kastler-Brossel\, Université Pierre et Marie Curie)\n \;\n\nIn the last decades\, the field of atom optic s has allowed for accurate experimental investigations of quantum transpor t with cold atoms. In this context\, the physics of Anderson localization (AL) can today be finely studied\, using tunable atomic matter waves in we ll controlled optical random potentials.\nAfter briefly introducing the ma in concepts of atom optics in random optical potentials\, I will address t he problem of the out-of-equilibrium evolution of a non-interacting matter wave in a random potential. The discussion will be focused on two differe nt dynamical scenarios where unexpected manifestations of AL show up. Firs t\, I will discuss the spatial spreading of a narrow wave packet\, a situa tion where AL triggers a « mesoscopic echo » peak in the density distr ibution. This phenomenon has been observed experimentally with cold atoms only recently. In the second scenario\, I will consider the evolution of a plane matter wave in the random potential. In this case\, the interesting dynamics takes place in momentum space\, where AL manifests itself as a s urprising « coherent  forward scattering peak »\, twin of the well-kno wn coherent backscattering effect. I will conclude the talk with open ques tions on the role of atomic interactions. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-553@lptms.universite-paris-saclay.fr DTSTART:20180110T110000Z DTEND:20180110T120000Z DTSTAMP:20180104T204328Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-stephanie-bonneau/ SUMMARY:Physics-Biology interface seminar: Stéphanie Bonneau - Moyen Amphi \, Building 510\, Université Paris-Saclay Orsay - 10 Jan 18 11:00 DESCRIPTION:Controled oxidation in living systems\nStéphanie Bonneau (Labo ratoire Jean Perrin\, Paris)\nLiving systems produce energy by oxidizing c arbon : in aerobic organisms\, a major step of this oxidation is processed by the respiratory chain in mitochondria. Energy production involves oxid ation and subsequent ageing of the cellular materials. The control of thei r oxidative activity allows cells to remain far enough to the thermodynami c equilibrium and consequently the balance between respiration and ageing is a major regulation parameter of cell's fate. The key role of mitochondr ia in this phenomenon will be discussed.\nExperimentally\, the control of the cellular oxidation is performed by using chosen photosensitizers. Due to their macrocycle\, such molecules present very special photo-physical properties. Their light irradiation generates\, through their triplet stat e\, reactive oxygen species. The lifetime of these molecular species is ve ry short and their action is very localized. To specifically target photos ensitizers to one or the other cell compartments is thus the basis of thei r potential to modify and control the physiology of the cells. For example \, the photo-chemical internalization (PCI) of macromolecules into cells i s based on the photo-induced alteration of endosomal membranes - before th eir maturation in lysosomes - allowing the escape of the macromolecules\, free to reach its targets within cell. More extensive photo-induced change s\, in particular to the mitochondria\, lead to cell death by necrosis or apoptosis. This photo-induced cell death is basis of an anticancer therapy so-called PDT.\nFirst\, we focussed on the photo-induced modifications of the cellular trafficking. By combining measurements of local cytoplasmic viscosity and active trafficking\, we found that photodynamic effect induc ed a only slight increase in viscosity but a massive decrease in diffusion . These effects are the signature of a return to thermodynamic equilibrium of the system after photo-activation. Secondly\, to better apprehend such complex effects\, we turned to model systems. In particular\, we focused on photo-oxidation of membranes lipids\, that are important oxidative targ ets. We extensively studied their modifications under photo-oxidation. Our purpose is to demonstrate that the photo-induced permeabilization of the membranes is correlated with a deep physical stress\, which can be relaxed by various pathways\, depending on its lipids composition\, which is char acteristic of the targeted cellular compartment. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-537@lptms.universite-paris-saclay.fr DTSTART:20180116T110000Z DTEND:20180116T120000Z DTSTAMP:20180108T093044Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-remy-dubertrand-3/ SUMMARY:Séminaire du LPTMS: Rémy Dubertrand &\; Pierre Illien - LPTMS\ , salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Jan 18 11:00 DESCRIPTION:A semiclassical perspective to study quantum interacting partic les\nRémy Dubertrand (Université de Liège\, Belgique)\nQuantum chaos ha ve had a great success to describe various types of one-particle quantum s ystems in the semiclassical regime (e.g. large quantum numbers). I will de scribe how these techniques can be used to describe quantum systems of int eracting particles. For example I contributed to look at Bose Hubbard mode l and justify why the spectral statistics agrees with RMT for a certain re gime of the ratio between onsite interaction and hopping energies. I will discuss in a more general framework how fruitful a semiclassical approach can be to study such systems of interacting particles.\n\n\n\nEffect of cr owding and hydrodynamic interactions on the dynamics of fluctuating system s\nPierre Illien (EC2M laboratory\, ESPCI Paris)\nDescribing the interacti ons of a fluctuating object with its environment is an ubiquitous problem of statistical physics. I will first focus on the dynamics of a driven p article in a host medium which hinders its motion through crowding interac tions. Going beyond the usual effective descriptions of the environment of the active tracer\, we propose a lattice model which takes explicitly int o account the correlations between the dynamics of the tracer and the resp onse of the bath and for which we determine analytically exact and approxi mate solutions\, that reveal intrinsically nonlinear and nonequilibrium pr operties.\n\nI will then present recent results that reveal how the diffus ivity of enzymes can be enhanced when they are catalytically active. In o rder to identify the physical mechanisms at stake in this phenomenon\, we perform measurements on the endothermic and relatively slow enzyme aldolas e. We propose a new physical paradigm\, which reveals that the diffusion c oefficient of a model enzyme hydrodynamically coupled to its environment i ncreases significantly when undergoing changes in conformational fluctuati ons in a substrate concentration dependent manner\, and is independent of the overall turnover rate of the underlying enzymatic reaction. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-572@lptms.universite-paris-saclay.fr DTSTART:20180118T110000Z DTEND:20180118T120000Z DTSTAMP:20180110T145215Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrei-bernevig-seminaire-extraordinaire/ SUMMARY:Séminaire du LPTMS: Andrei Bernevig *** séminaire exceptionnel * ** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Jan 18 11:00 DESCRIPTION:Topological Quantum Chemistry\nAndrei Bernevig (Department of P hysics\,  Princeton University\, USA)\nThe past decade has seen tremendou s success in predicting and experimentally discovering distinct classes of topological insulators (TIs) and semimetals.  We review the field and we propose an electronic band theory that highlights the link between topolo gy and local chemical bonding\, and combines this with the conventional ba nd theory of electrons. Topological Quantum Chemistry is a description of the universal global properties of all possible band structures and materi als\, comprised of a graph theoretical description of momentum space and a dual group theoretical description in real space. We classify the possibl e band structures for all 230 crystal symmetry groups that arise from loca l atomic orbitals\, and show which are topologically nontrivial. We show h ow our topological band theory sheds new light on known TIs\, and demonstr ate the power of our method to predict a plethora of new TIs.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-544@lptms.universite-paris-saclay.fr DTSTART:20180123T110000Z DTEND:20180123T120000Z DTSTAMP:20171230T190333Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pierre-elie-larre-2/ SUMMARY:Séminaire du LPTMS: Pierre-Elie Larré &\; Clément Tauber - LP TMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 23 Jan 18 11: 00 DESCRIPTION:Quantum simulating many-body phenomena with propagating light\n Pierre-Elie Larré (Université de Cergy-Pontoise)\nWe consider the propag ation of a quantum light field in a cavityless nonlinear dielectric. In th is all-optical platform\, the space propagation of the field's envelope ma y be mapped onto the time evolution of a quantum fluid of interacting phot ons. The resulting many-body quantum system constitutes a particular class of quantum fluids of light and presently attracts a growing interest as a powerflul tool for quantum simulation. I will present recent theoretical and experimental progresses in this rapidly emerging research field\, incl uding investigations on superfluidity\, elementary excitations\, disorder\ , quantum quenches\, prethermalization\, thermalization\, and Bose-Einstei n condensation.\n\n\n\nBulk-edge correspondence for Floquet topological in sulators\nClément Tauber (ETH\, Zürich)\nFloquet topological insulators describe independent electrons on a lattice driven out of equilibrium by a time-periodic Hamiltonian\, beyond the usual adiabatic approximation. In dimension two such systems are  characterized by integer-valued topologic al indices associated to the  unitary propagator\, alternatively in the b ulk or at the edge of a  sample. In this talk I will give new definitions of the two indices\,  relying neither on translation invariance nor on a veraging\, and show  that they are equal. In particular weak disorder and defects are  intrinsically taken into account. Finally indices can be de fined when  two driven sample are placed next to one another either in sp ace or in  time\, and then shown to be equal. The edge index is interpret ed as a  quantized pumping occurring at the interface with an effective v acuum. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-552@lptms.universite-paris-saclay.fr DTSTART:20180124T110000Z DTEND:20180124T120000Z DTSTAMP:20171222T073721Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-shiladitya-banerjee/ SUMMARY:Physics-Biology interface seminar: Shiladitya Banerjee - Moyen Amph i\, Building 510\, Université Paris-Saclay Orsay - 24 Jan 18 11:00 DESCRIPTION:Adaptive division control in stressed bacterial cells\nShiladit ya Banerjee (UCL\, UK)\n\nControl of cell size is a fundamental adaptive t rait that underlies the coupling between cell growth and division. Cells p ossess the unique ability to adapt their size and shapes in response to en vironmental cues\, thereby translating extracellular information into deci sions to grow or divide. However\, the physical mechanisms mediating the r egulation of cell size and division timing remain poorly understood. In th is talk\, I will discuss our recent discovery of an adaptive model of cell size control in bacteria\, where the decision to divide is tightly regula ted by the spatial patterning of cell wall growth modes. Using a combinati on of stochastic mechanical modelling and single-cell experiments\, I will elucidate the implications of the size control model for cellular fitness adaptation under stress. In particular\, our results show that morphologi cal transformations provide fitness and survival advantages to bacteria un der sustained antibiotic treatment.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-563@lptms.universite-paris-saclay.fr DTSTART:20180130T110000Z DTEND:20180130T120000Z DTSTAMP:20180123T102119Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christopher-joyner/ SUMMARY:Séminaire du LPTMS: Christopher Joyner - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 30 Jan 18 11:00 DESCRIPTION:A random walk approach to linear statistics in random tournamen t ensembles\nChristopher Joyner (Queen Mary University of London\, UK)\nWe investigate the linear statistics of random matrices with purely imaginar y Bernoulli entries exhibit global correlations in terms of row sums. Thes e are related to ensembles of so-called random regular tournaments. Specif ically\, we construct a random walk within the space of these matrices and show the induced motion of the first k traces in a Chebyshev basis conver ges to a suitable Ornstein-Uhlenbeck process. Coupling this with Stein’s method allows us to compute the rate of convergence to a Gaussian distrib ution in the limit of large matrix dimension. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-542@lptms.universite-paris-saclay.fr DTSTART:20180206T110000Z DTEND:20180206T120000Z DTSTAMP:20180129T115631Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-beatriz-seoane-bartolome-3/ SUMMARY:Séminaire du LPTMS: Beatriz Seoane Bartolomé &\; Ulisse Ferrar i - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Fév 18 11:00 DESCRIPTION:Phase transitions in computer simulations : the Tethered Monte Carlo method\n\nBeatriz Seoane Bartolomé (LPT-ENS\, Paris)\nIn this talk\ , I will present a powerful Monte Carlo method that I developed during my PhD [1\,2] and extended recently [3]\, designed to efficiently study phase transitions at equilibrium. The principle is very simple\, by means of ex ternal constraints to the system\, we are able to avoid the traditional cr itical (exponential) slowing down associated to the second (first) order t ransition\, and thus reach much larger system sizes than with traditional methods. Furthermore\, the reconstruction of the constrained free energy i s much simpler than in other similar methods\, such as the famous Umbrella Sampling\, allowing us to both fix multiple constraints at the same time\ , and to extract magnitudes such as the inter-facial free energy with an u nusual high precision. In particular\, I will discuss the Tethered Monte C arlo strategy in the context of a toy model for crystalline porous media [ 3].\n[1] J. Stat. Phys. 144\, 554 (2011).\n[2] Phys. Rev. Lett. 108\, 1657 01 (2012).\n[3] The Journal of Chemical Physics 147 \, 084704 (2017).\n\n\ n\nStatistical Physics-inspired models of biological network: collective b ehavior in neuronal ensembles\nUlisse Ferrari (Institut de la Vision\, Ins erm &\; UPMC)\nIn both cortices and sensory systems\, information is re presented and transmitted through the correlated activity of large neurona l networks. Neurons\, in fact\, do not work independently: each of them dr ives the activity of the others\, thus working as a collective ensemble. M ethods borrowed from Statistical Physics and Machine Learning are powerful tools for characterizing the collective behavior of large systems and hen ce offer promising approaches to understand the activity of neuronal popul ations. In this talk I will show how the Maximum Entropy principle\, appli ed to cortical in-vivo recording\, allows for characterizing and comparing the population behavior during wakefulness and deep sleep. Then\, I will use hidden-layer models\, point processes and “experimental” linear re sponse theory to account for non-linear stimulus processing in sensory net works\, such as the retina. These approaches allow for constructing high p erforming models of the retinal population response to visual stimuli and thus for characterizing how a network of neurons can encode and transmit v isual information. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-546@lptms.universite-paris-saclay.fr DTSTART:20180207T110000Z DTEND:20180207T120000Z DTSTAMP:20180130T181628Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-pere-roca-cusachs/ SUMMARY:Physics-Biology interface seminar: Pere Roca-Cusachs - Amphi BLANDI N du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 7 Fév 18 11:00 DESCRIPTION:Sensing the matrix: transducing mechanical signals from integri ns to the nucleus.\nPere Roca-Cusachs (Institute for Bioengineering of Cat alonia\, Universitat de Barcelona\, Spain)\nCell proliferation and differe ntiation\, as well as key processes in development\, tumorigenesis\, and w ound healing\, are strongly determined by the properties of the extracellu lar matrix (ECM)\, including its mechanical rigidity and the density and d istribution of its ligands. In this talk\, I will explain how we combine m olecular biology\, biophysical measurements\, and theoretical modelling to understand the mechanisms by which cells sense and respond to matrix prop erties. I will discuss how the properties under force of integrin-ECM bond s\, and of the adaptor protein talin\, drive and regulate matrix sensing. I will further discuss how this sensing can be understood through a comput ational molecular clutch model\, which can quantitatively predict the role of integrins\, talin\, myosin\, and ECM receptors\, and their effect on c ell response. Finally\, I will analyze how signals triggered by rigidity a t cell-ECM adhesions are transmitted to the nucleus\, leading to the activ ation of the transcriptional regulator YAP. CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-565@lptms.universite-paris-saclay.fr DTSTART:20180213T110000Z DTEND:20180213T120000Z DTSTAMP:20180129T121506Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicola-bartolo/ SUMMARY:Séminaire du LPTMS: Nicola Bartolo &\; Mathieu Hemery - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Fév 18 11:00 DESCRIPTION:Exact results for non-equilibrium phase transitions\nNicola Bar tolo (Laboratoire Matériaux et Phénomènes Quantiques\, Université Pari s Diderot et CNRS)\nIn out-of-equilibrium systems\, the competition betwee n Hamiltonian evolution and dissipation can result in dissipative phase tr ansitions. We investigate this kind of phenomena in the steady state of a general class of driven-dissipative systems\, consisting of a nonlinear Ke rr resonator in the presence of both coherent (one-photon) and parametric (two-photon) driving and dissipation.\nWe analytically derive the exact st eady-state solution via the formalism of the complex P-representation. The exact solution applies to any photon density regime\, allowing to investi gate the thermodynamic limit of large photon densities. In this regime\, w e point out and characterise the emergence of dissipative phase transition s of both first and second order.\n\n\n\nφ-evo: from function to network\ nMathieu Hemery (McGill University\, Montréal\, Canada)\nMolecular networ ks are at the core of most cellular decisions\, but there architecture is often intricate and difficult to grasp. Starting from the putative functio n of a network and using an evolutionnary algorithm (EA) to explore the po ssible architectures seems however to gives good predictions. After a brie f introduction to EA and regulatory network\, I will present my own work w ith \\phievo: the lac-operon that show its validity and a logarithmic netw ork that highlight its possibilities. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-568@lptms.universite-paris-saclay.fr DTSTART:20180220T110000Z DTEND:20180220T113000Z DTSTAMP:20180215T095633Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-chikashi-arita/ SUMMARY:Séminaire du LPTMS: Chikashi Arita - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 20 Fév 18 11:00 DESCRIPTION:Variational calculation of diffusion coefficients in stochastic lattice gases\nChikashi Arita (Universität des Saarlandes\, Saarbrücken )\nDeriving macroscopic behaviors from microscopic dynamics of particles    is a fundamental problem. In stochastic lattice gases one tries to  de monstrate this hydrodynamic limit. The evolution of a stochastic   latti ce gas with symmetric hopping rules is described by a diffusion   equati on with density-dependent diffusion coefficient. In practice\,  even when the equilibrium properties of a lattice gas are analytically  known\, th e diffusion coefficient cannot be explicitly computed\, except  when a la ttice gas additionally satisfies the "gradient condition"\,  e.g. the dif fusion coefficients of the simple exclusion process and   non-interactin g random walks are exactly identical to their hopping  rates. We develop a procedure to obtain systematic analytical approximations for the diffusi on coefficient in non-gradient lattice  gases with known equilibrium. The method relies on a variational  formula found by Varadhan and Spohn. Res triction on test functions to  finite-dimensional sub-spaces allows one t o perform the minimization  and gives upper bounds for the diffusion coef ficient. We apply the   procedure to the following two models\; one-dime nsional generalized  exclusion processes\, where each site can accommodat e at most two   particles (2-GEPs) [1]\, and the Kob-Andersen (KA) model on the square  lattice\, which is classified into kinetically-constraine d gas [2]. The   prediction of the diffusion coefficient depends on the domain  ("shape") of test functions. The smallest shapes give approximati ons  which coincide with the mean-field theory\, but the larger shapes\, the   more precise upper bounds we obtain. For the 2-GEPs\, our analytic al  predictions provide upper bounds which are very close to simulation    results throughout the entire density range. For the KA model\, we also   find improved upper bounds when the density is small. By combining the    variational method with a perturbation approach\, we discuss the  as ymptotic behavior of the diffusion coefficient in the high density   lim it.\n\n [1] C. Arita\, P. L. Krapivsky and K. Mallick\, Variational calcul ation of transport coefficients in diffusive lattice gases\, Phys. Rev. E 95\, 032121 (2017)\n [2] C. Arita\, P. L. Krapivsky and K. Mallick\, Bulk diffusion in a kinetically constrained lattice gas\, preprint cond-mat arX iv:1711.10616\n\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-644@lptms.universite-paris-saclay.fr DTSTART:20180220T110000Z DTEND:20180220T120000Z DTSTAMP:20181126T132629Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sergej-moroz-2/ SUMMARY:Séminaire du LPTMS: Sergej Moroz - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 20 Fév 18 11:00 DESCRIPTION: CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-582@lptms.universite-paris-saclay.fr DTSTART:20180220T113000Z DTEND:20180220T120000Z DTSTAMP:20180215T095552Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandre-lazarescu-2/ SUMMARY:Séminaire du LPTMS: Alexandre Lazarescu - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 20 Fév 18 11:30 DESCRIPTION:On the hydrodynamic behaviour of interacting lattice gases far from equilibrium\nAlexandre Lazarescu (Centre de Physique Théorique\, Éc ole Polytechnique)\nLattice gases are a particularly rich playground to st udy the large scale emergent behaviour of microscopic models. A few things are known in general for models that are sufficiently close to equilibriu m (i.e. with rates close to detailed balance\, and where the dynamics is t ypically diffusive): in particular\, the local density of particles behave s autonomously in the macroscopic limit\, even at the level of large devia tions\, and the system can be described through a Langevin equation involv ing only a few quantities called transport coefficients. As demonstrated i n the previous talk\, obtaining those coefficients in practice can be quit e challenging\, but we can usually be confident that they exist.\n\nI will be talking about a situation that is quite different at first sight: syst ems far from equilibrium\, where the dynamics is propagative\, and where v ery little is known in general. The question is then whether one can hope to be able to describe those models with a similar hydrodynamic structure\ , or if that description breaks down (if\, for instance\, long-range corre lations become relevant). I will present recent results showing that\, for a broad class of 1D models with hard-core repulsion but also interactions and space-dependent rates\, the answer is yes and no: all those models ex hibit a dynamical phase transition between a hydrodynamic regime and a hig hly correlated one\, which can be related to the so-called "third order ph ase transitions". The methods involved are quite general and likely to be applicable to many more families of models.\n\n A. Lazarescu\, Generic Dyn amical Phase Transition in One-Dimensional Bulk-Driven Lattice Gases with Exclusion\, J. Phys. A: Math. Theor. 50\, 254004 (2017)\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-583@lptms.universite-paris-saclay.fr DTSTART:20180227T110000Z DTEND:20180227T113000Z DTSTAMP:20180215T095913Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrea-de-luca/ SUMMARY:Séminaire du LPTMS: Andrea de Luca - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 27 Fév 18 11:00 DESCRIPTION:Solution of a minimal model for many-body quantum chaos\nAndrea de Luca (Rudolf Peierls Centre for Theoretical Physics\, Oxford Universit y\, UK)\nI present a minimal model for quantum chaos in a spatially extend ed many-body system. It consists of a chain of sites with nearest-neighbou r coupling under Floquet time evolution. Quantum states at each site span a q-dimensional Hilbert space and time evolution for a pair of sites is ge nerated by a q2×q2 random unitary matrix. The Floquet operator is specifi ed by a quantum circuit\, in which each site is coupled to its neighbour o n one side during the first half of the evolution period\, and to its neig hbour on the other side during the second half of the period. I will intro duce a diagrammatic formalism useful to average the many-body dynamics ove r realisations of the random matrices. This approach leads to exact expres sions in the large-q limit and sheds light on the universality of random m atrices in many-body quantum systems and the ubiquitous entanglement growt h in out-of-equilibrium dynamics. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-584@lptms.universite-paris-saclay.fr DTSTART:20180227T113000Z DTEND:20180227T120000Z DTSTAMP:20180215T095919Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-laurent-de-forges-de-parny-2/ SUMMARY:Séminaire du LPTMS: Laurent de Forges de Parny - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 27 Fév 18 11:30 DESCRIPTION:Multicomponent Bose-Hubbard Model: Nematic Order in Spinor Cond ensates\nLaurent de Forges de Parny (Albert-Ludwigs University of Freiburg \, Germany)\nSince the seminal work of D. Jaksch et al. [1]\, the motivati on of considering bosonic mixtures has emerged from the promising perspect ives of observing coexisting quantum phases\, spin-dynamics\, and quantum magnetism. Recently\, ultracold bosons with effective spin degree of freed om allowed to engineer magnetic quantum phase transitions and non trivial magnetic phases\, e.g. the nematic order\, which breaks the spin-rotation symmetry without magnetic order [2].\n\nI will discuss the magnetic proper ties of strongly interacting spin-1 bosons in optical lattices. Employing a combined strategy based on exact numerical methods (quantum Monte Carlo simulations and exact diagonalization) and analytical calculations\, we ha ve derived the phase diagrams and characterized the phase transitions beyo nd the mean field description [3\,4]. Furthermore\, we have established th e low energy spectrum of the nematic superfluid phase and have confirmed a singlet-to-nematic phase transition inside the Mott insulator phase.\n\nR eferences:\n\n D. Jaksch\, C. Bruder\, J. I. Cirac\, C. W. Gardiner and P. Zoller\, Cold Bosonic Atoms in Optical Lattices\, Phys. Rev. Lett. 81\, 3 108 (1998)\n T. Zibold\, V. Corre\, C. Frapolli\, A. Invernizzi\, J. Dalib ard and F. Gerbier\, Spin-nematic order in antiferromagnetic spinor conden sates\, Phys. Rev. A 93\, 023614 (2016).\n L. de Forges de Parny\, F. Héb ert\, V. G. Rousseau\, and G. G. Batrouni\, Interacting spin-1 bosons in a two-dimensional optical lattice\, Phys. Rev. B 88\, 104509 (2013).\n Laur ent de Forges de Parny\, Hongyu Yang\, and Frédéric Mila\, Anderson Tow er of States and Nematic Order of Spin-1 Bosonic Atoms on a 2D Lattice\, P hys.Rev.Lett. 113\, 200402 (2014)\n\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-585@lptms.universite-paris-saclay.fr DTSTART:20180306T110000Z DTEND:20180306T113000Z DTSTAMP:20180221T170850Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-shuang-wu/ SUMMARY:Séminaire du LPTMS: Shuang Wu - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 6 Mar 18 11:00 DESCRIPTION:Thouless bandwidth formula in the Hofstadter model\nShuang Wu ( LPTMS\, Université Paris-Sud)\nI will show a method of D. J. Thouless to calculate the Hofstadter spectrum bandwidth in relation to the Catalan con stant. And I will present how we generalize Thouless bandwidth formula to its n-th moment and obtain a closed expression in terms of polygamma\, zet a and Euler numbers.\n\n Reference: S. Ouvry and S. Wu\, Thouless bandwidt h formula in the Hofstadter model\, J. Phys. A: Math. Theor. 50\, 495204 ( 2017)\n\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-586@lptms.universite-paris-saclay.fr DTSTART:20180306T113000Z DTEND:20180306T120000Z DTSTAMP:20180221T170903Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giulio-bertoli/ SUMMARY:Séminaire du LPTMS: Giulio Bertoli - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 6 Mar 18 11:30 DESCRIPTION:Finite temperature disordered bosons in two dimensions\nGiulio Bertoli (LPTMS\, Université Paris-Sud)\nIn this talk\, I will present a s tudy of the phase transitions in a two dimensional weakly interacting Bose gas in a random potential at finite temperatures. It is possible to ident ify superfluid\, normal fluid and insulator phases. The study of the effec t of interaction between particles on localization demonstrates that inter acting particles can undergo a many-body localization-delocalization trans ition\, that is the transition from insulator to fluid state. I will also discuss the influence of disorder on the BKT transition between superfluid and normal fluid\, in order to construct the phase diagram. At T=0 one ha s a tricritical point\, where the three phases coexist. It is shown that t he truncation of the energy distribution function at the trap barrier\, wh ich is a generic phenomenon in evaporative cooling of cold atoms\, limits the growth of the localization length\, so that the insulator phase is pre sent at any temperature.\n\n Reference: G. Bertoli\, V.P. Michal\, B.L. Al tshuler\, G.V. Shlyapnikov\, Finite temperature disordered bosons in two d imensions\, preprint cond-mat.dis-nn arXiv:1708.03628\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:1-557@lptms.universite-paris-saclay.fr DTSTART:20180307T110000Z DTEND:20180307T120000Z DTSTAMP:20171029T133639Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-pierre-sens/ SUMMARY:Physics-Biology interface seminar: Pierre Sens - Moyen Amphi\, Buil ding 510\, Université Paris-Saclay Orsay - 7 Mar 18 11:00 DESCRIPTION:Mechano-sensitive adhesion in cell spreading and crawling\nPier re Sens (Institut Curie\, Paris)\n\nCrawling cell motility is powered by a ctin polymerization and acto-myosin contraction. When moving over a flat a nd rigid substrate\, cells usually develop thin and broad protrusions at t heir front\, called lamellipodia\, where actin polymerisation generates a protrusive force pushing the front edge of the cell forward. The lamellipo dium displays interesting dynamics\, including normal and lateral waves\, possibly relevant to cell polarisation and the initiation of motion. I wil l discuss a stochastic model of mechano-sensitive cell adhesion\, and disc uss its relevance for symmetry breaking\, cell polarisation\, and motility . I will then discuss a generic model of micro-crawlers\, built as an exte nsion of low Reynolds number micro-swimmers\, that highlights the crucial role of mechano-sensitive adhesion for the active crawling of cells and bi omimetic objects.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-574@lptms.universite-paris-saclay.fr DTSTART:20180309T150000Z DTEND:20180309T160000Z DTSTAMP:20180110T145130Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandre-p-dos-santos-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Alexandre P. dos Santos *** séminaire excepti onnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Mar 18 15:00 DESCRIPTION:**** ATTENTION: horaire inhabituel !!! ****\nPressure between c harged polarizable surfaces\nAlexandre Pereira Dos Santos (Instituto de Fi sica\, Universidade Federal do Rio Grande do Sul\, Porto Alegre\, Brazil)\ nWe obtain phase diagrams and binodal curves for the repulsion/attraction between charged low dielectric/metallic surfaces in a salt-free environmen t. Punctual counterions are confined between the surfaces\, however\, they are not allowed to approach the surfaces nearer than a characteristic len gth which can model the ionic hydration. The polarization of the surfaces is considered with a recently introduced method based on periodic Green fu nctions. We show that the density profiles are strongly dependent on the d ielectric contrast in special for high electrostatic couplings. However\, the pressure curves and consequently the binodal curves and critical point s slightly change for different polarizable surfaces and hydration lengths . LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-577@lptms.universite-paris-saclay.fr DTSTART:20180313T110000Z DTEND:20180313T113000Z DTSTAMP:20180301T144427Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandre-nicolas-2/ SUMMARY:Séminaire du LPTMS: Alexandre Nicolas - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 13 Mar 18 11:00 DESCRIPTION:Bottleneck flows of pedestrians and grains\n\nAlexandre Nicolas (LPTMS\, Université Paris-Sud)\nSimple models from Statistical Physics c an be surprisingly useful to study practical problems that lie outside the traditional realm of Physics. I will illustrate this statement with two d istinct (yet related!) examples: granular flows through a constriction and competitive passages of pedestrians through a door.\n\nTo destroy clogs i n constricted granular flows\, vibrations are often applied to the hopper or silo\, but clogs do not yield instantly. Instead\, they exhibit an anom alously broad distribution of lifetimes. This elusive feature was recently captured within a model in which we likened the destruction of clogs to t hermally activated escapes from a set of energy traps\; the model also rep roduces other salient experimental observations [1]. Turning to the second example\, competitive pedestrian flows through a narrow door look very di sordered\, and yet they were found to present robust statistical features\ , such as anticorrelated time gaps between escapes and exponentially distr ibuted bursts of escapes. On the basis of simple models\, we have shown th at in fact these features emerge generically in constricted flows [2].\n\n [1] Alexandre Nicolas\, Ángel Garcimartín and Iker Zuriguel\, "A trap m odel for clogging and unclogging in granular hopper flows" (2017)\, prepri nt arxiv:1711.04455\n [2] Alexandre Nicolas and  Ioannis Touloupas\, Orig in of the correlations between exit times in pedestrian flows through a bo ttleneck\, J. Stat. Mech.: Theor. Exp. 2018(1)\, 013402.\n\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-590@lptms.universite-paris-saclay.fr DTSTART:20180313T113000Z DTEND:20180313T120000Z DTSTAMP:20180302T210155Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-izaak-neri/ SUMMARY:Séminaire du LPTMS: Izaak Neri - LPTMS\, salle 201\, 2ème étage\ , Bât 100\, Campus d'Orsay - 13 Mar 18 11:30 DESCRIPTION:Thermodynamic bounds on the statistics of first-passage times a nd extreme values of stochastic processes\nIzaak Neri (Max Planck Institut e for the Physics of Complex Systems\, Dresden\, Allemagne)\n \;\n\nSt ochastic thermodynamics generalizes concepts from thermodynamics\, and mak es them useful to study mesoscopic systems driven far from thermal equilib rium\, such as\, optically driven colloidal particles\, noisy processes in cell biology or microelectronic devices. In mesoscopic systems thermodyna mic observables -- such as\, entropy production\, heat and mesoscopic curr ents --\nare fluctuating quantities\, and stochastic thermodynamics charac terizes universal properties of these fluctuating quantities. Established results are the fluctuation relations and the thermodynamic uncertainty re lations\, which express universal properties of fluctuations of stochastic currents at a fixed time. In this talk I will present thermodynamic bound s for the statistics of first-passage times and extreme values of stochast ic currents\, which are fluctuating properties of trajectories of stochast ic currents. Some interesting results are: a bound for the mean first-pass age time of current variables in terms of the dissipation rate\, a fluctua tion theorem for first-passage times of entropy production\, and a univers al bound on the supremum statistics of the heat absorbed by a nonequilibri um system. These results will be illustrated on examples of physical proce sses\, such as\, the dynamics a molecular motor and charge transport in mi croelectronic devices.\n\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-580@lptms.universite-paris-saclay.fr DTSTART:20180315T110000Z DTEND:20180315T113000Z DTSTAMP:20180312T071457Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-samuel-belliard-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Samuel Belliard *** séminaire exceptionnel * ** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Mar 18 11:00 DESCRIPTION:Modified Bethe Ansatz for models without U(1) symmetry\nSamuel Belliard (IPhT\, CEA\, Saclay)\n\nI will present a modified version of the algebraic Bethe ansatz (MABA) that allows to characterize the eigenvalues and the eigenstates of spins chains without U(1) symmetry.  In the case of the XXX Heisenberg spins chain on the circle with a twisted boundary co ndition\, the Bethe vectors and associated eigenvalues will be constructed and the correlation function problem will be discussed. This method also works for the XXX and XXZ Heisenberg spins chains on the segment.\n\n\n\n\ n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-593@lptms.universite-paris-saclay.fr DTSTART:20180315T113000Z DTEND:20180315T120000Z DTSTAMP:20180307T201708Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-bertrand-lacroix-a-chez-toine-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Bertrand Lacroix-à-chez-Toine *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d 'Orsay - 15 Mar 18 11:30 DESCRIPTION:Extreme value statistics in a gas of 2D charged particles\nBert rand Lacroix-à-chez-Toine (LPTMS\, Université Paris-Sud)\n \;\n\nWe study a system of N charged particles in two dimensions with Coulomb logar ithmic repulsion and confined in an external symmetric potential. At the i nverse temperature of interest β = 2\, the positions of the charges form a 2D determinantal point process. In the case of a quadratic potential\, t here is a mapping between the positions of these charges and the eigenvalu es of complex Ginibre matrices. We focus on the extremal statistics of the positions of the charges and in particular we highlight\na new universal regime (with respect to a large class of confining potentials) which had b een overlooked before [1]. It allows to solve a puzzle of matching between the typical regime of fluctuations [2] and the large deviation regime [3] . Finally we also considered potentials that deviates from this universali ty class and computed the extremal statistics in these cases.\n\n \n[1] B. Lacroix-A-Chez-Toine\, A. Grabsch\, S. N. Majumdar\, G. Schehr\, Extremes of 2d Coulomb gas: universal intermediate deviation regime\, J. Stat. Mec h. P013203\, (2018).\n \n[2] B. Rider\, J. Phys. A 36(12)\, 3401 (2003).\n [3] F. D. Cunden\, F. Mezzadri\, P. Vivo\, J. Stat. Phys. 164(5)\, 1062-1 081 (2016).\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-569@lptms.universite-paris-saclay.fr DTSTART:20180320T110000Z DTEND:20180320T120000Z DTSTAMP:20180314T101921Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lev-truskinovsky/ SUMMARY:Séminaire du LPTMS: Lev Truskinovsky - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Mar 18 11:00 DESCRIPTION:Rigidity generation by nonthermal fluctuations and muscle contr action\nLev Truskinovsky (ESPCI\, Paris)\nActive stabilization in systems with zero or negative  stiffness is an essential element of a wide variet y of technological processes. We discuss a prototypical example of this  phenomenon in a  biological setting and show how active rigidity\, interp reted as a formation of a pseudo-well in the effective energy  landscape\ , can be generated in an over-damped stochastic system. We link the transi tion from negative to positive  rigidity with time correlations in the ad ditive noise\, and  show that subtle differences in the out-of-equilibriu m  driving may compromise the emergence of a pseudo-well. We apply our re sults to the description of  the power  stroke machinery in skeletal mus cles  which is behind their  remarkable  ability to take up an applied slack in a ms time  scale. Along the way we draw some interesting paralle ls between muscle  physiology and the theory of spin glasses. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-571@lptms.universite-paris-saclay.fr DTSTART:20180321T110000Z DTEND:20180321T120000Z DTSTAMP:20180307T124730Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-ulisse-ferrari/ SUMMARY:Physics-Biology interface seminar: Ulisse Ferrari - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 21 Mar 18 11:00 DESCRIPTION:Non-linear stimulus processing by the retina\nUlisse Ferrari (I nstitut de la Vision\, Paris)\nUnderstanding how sensory systems process i nformation is an open challenge. This is mostly because these systems are non-linear\, making it extremely difficult to model the relation between t he stimulus and the sensory response. In this talk I will discuss two stra tegies to tackle this problem and apply them to the retina.\nFirst\, we us e ex-vivo multi-electrode array experiments to record the retinal activity and directly model the ganglion cell response to complex stimuli\, such a s videos of moving objects. Here I will show that standard\, nearly-linear \, models are not enough and highly non-linear models are required. Then I will present the result of a closed-loop experiment where we adapted the stimulus on-line to investigate how the response changes when the visual s timulation is perturbed.\nWith this approach we could estimate the optimal performance of a neural decoder and show that the non-linear sensitivity of the retina is consistent with an efficient encoding of stimulus informa tion.\nReferences:\n-) U. Ferrari\, C. Gardella\, T. Mora\, O. Marre. eNeu ro\, vol. 4\, 6. 2017.\n-) S. Deny\, U. Ferrari\, P. Yger\, R. Caplette\, S. Picaud\, G. Tkacik\, O. Marre\, Nature Commun. 8 (1) 2017\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-587@lptms.universite-paris-saclay.fr DTSTART:20180322T110000Z DTEND:20180322T113000Z DTSTAMP:20180227T143423Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mario-collura-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Mario Collura *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 22 Mar 18 11:00 DESCRIPTION:Full counting statistics out of equilibrium: melting of antifer romagnetic order\nMario Collura (Oxford University\, UK)\nOne of the basic principles of quantum mechanics is the statistical nature of measurements of observables. The result of measurements is indeed described by a pro bability distribution\, and measuring the same observable  in identical  systems will give different outcomes in accordance with this distribution.   The full probability distribution carries very detailed information a bout the system and\, on top of expectation value\, encodes all fluctuatio ns of the system.  I will focus on the non-equilibrium dynamics of a full y polarised antiferromagnetic state under the unitary evolution induced by the XXZ Hamiltonian. It turns out that\, depending on the value of the in teractions\, the full probability distribution of the subsystem staggered magnetisation may retain informations about the original antiferromagnetic order\, thus acquiring a shape much different from a simple Gaussian dist ribution.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-589@lptms.universite-paris-saclay.fr DTSTART:20180322T113000Z DTEND:20180322T120000Z DTSTAMP:20180313T080307Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-simon-pigeon-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Simon Pigeon *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 22 Mar 18 11:30 DESCRIPTION:Vibrational assisted conduction in a molecular wire\nSimon Pige on (LKB\, UPMC\, Paris)\nI will present a detailed study of the conduction properties of a molecular wire where hopping processes between electroni c sites are coupled to a vibrational mode of the molecule. This descriptio n is inspired by the idea that physically the vibrational mode does not n eed to change the energetic structure of the electronic part but can just perturb the exchange taking place on this subsystem. It is shown that th e presence of the vibrational system can give rise to strong enhancement o f the wire conductivity. Moreover through the control of the vibrational properties (temperature and position) one can accurately control the elec tronic flux crossing the device. An increase of the temperature enhances t he conduction\, while the control of the equilibrium position of the osci llator can switch on and off the conduction.This work establishes how vibr ational coupled hopping affects the electronic properties of a molecular  wire. These crucial results pave the way to a better understanding and mor e complete description of electronic properties of these promising device s.\nRef:\n\n S. Pigeon\, L. Fusco\, G. De Chiara &\; M. Paternostro\, V ibrational assisted conduction in a molecular wire\, Quantum Science and T echnology 2\, 025006 (2017) \; arXiv:1612.01809\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-595@lptms.universite-paris-saclay.fr DTSTART:20180326T110000Z DTEND:20180326T121500Z DTSTAMP:20180321T101033Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/quantum-physics-j ournal-club-giovanni-martone/ SUMMARY:Quantum Physics Journal Club: Giovanni Martone - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 26 Mar 18 11:00 DESCRIPTION:Supersolids: a short overview\nGiovanni Italo Martone (LPTMS)\n   LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-578@lptms.universite-paris-saclay.fr DTSTART:20180329T110000Z DTEND:20180329T113000Z DTSTAMP:20180313T213416Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandru-petrescu-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Michele Filippone *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 29 M ar 18 11:00 DESCRIPTION:Controlled Parity Switch of Persistent Currents and Topological charge-pumping effects induced by bulk magnetic fluxes\n\nMichele Filippo ne (Université de Genève\, Suisse)\n\nWe investigate persistent currents for a fixed number of fermions in periodic quantum ladders threaded by Ah aronov-Bohm and transverse magnetic fluxes Φ and χ. We show that the cou pling between ladder legs provides a way to effectively change the ground- state fermion-number parity\, by varying χ. We demonstrate that varying χ by 2π (one flux quantum) leads to an apparent fermion-number parity sw itch. We find that persistent currents exhibit a robust 4π periodicity as a function of χ\, despite the fact that χ→χ+2π leads to modificatio ns of order 1/N of the energy spectrum\, where N is the number of sites in each ladder leg. We connect the parity switching effect to the quantum Ha ll regime in two-dimensional systems. We show that the parity switching ef fect is related to the parity of the number of filled Landau levels and th at it inherits strong robustness against disorder in the Harper-Hofstadter quantum Hall regime. Indeed\, we show that the 4π periodicity is a mesos copic manifestation of a novel type of fermionic pumping in topological sy stems\, complementary to Thouless' pump.  Focusing on the low-energy edge physics in the general framework of Chern-Simons theory\, we discuss this alternative type of pumping in the context of integer and fractional quan tum Hall systems. Our construction provides an intuitive setting to unders tand known effects and explore new ones. In particular\, we show that addi ng superconductivity to the picture allows us to recover the 4π Josephson effect of Majorana fermions and its generalizations to parafermions.  Th e parity-switching and the 4π periodicity effects are robust with respect to temperature and disorder and we outline potential physical realization s using Corbino disk geometries in solid state systems\, quantum ladders w ith cold atomic gases and\, for bosonic analogs of the effects\, photonic lattices.\n\n\nRef:\n\n Michele Filippone\, Charles-Edouard Bardyn\, Thier ry Giamarchi\, Controlled parity switch of persistent currents in quantum ladders\, preprint cond-mat.mes-hall arXiv:1710.02152\n\n\n\n\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-596@lptms.universite-paris-saclay.fr DTSTART:20180329T113000Z DTEND:20180329T120000Z DTSTAMP:20180316T084333Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandru-petrescu-seminaire-exceptionnel-2/ SUMMARY:Séminaire du LPTMS: Alexandru Petrescu *** séminaire exceptionnel *** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 29 M ar 18 11:30 DESCRIPTION:\n\n\nFluxon-based quantum simulation in circuit QED\n\n\n\nAle xandru Petrescu (Department of electrical engineering\, Princeton Universi ty\, USA)\n\n\n\n\nLong-lived fluxon excitations can be trapped inside a s uperinductor ring\, which can be realized with a long array of Josephson j unctions\, one of which offers the input/output path for the magnetic flux [1]. The superinductor ring can be separated into smaller loops by a peri odic sequence of Josephson junctions in the quantum regime\, thereby allow ing fluxons to tunnel between neighboring loops [2]. This model is dual to that of two-leg ladder bosons\, which have a rich phase diagram depending on flux and density [3–6]. By tuning the Josephson coupling\, and impli citly the tunneling probability amplitude of fluxons\, a wide class of 1D tight-binding lattice models may be implemented and populated with a stabl e number of fluxons. In this context\, fluxons are lattice bosons with rep ulsive interactions. We illustrate this quantum simulation platform by dis cussing the Su-Schrieffer-Heeger model in the 1-fluxon subspace\, which ho sts a symmetry-protected topological phase with fractionally charged bound states at the edges [7\,8]. This pair of localized edge states could be u sed to implement a superconducting qubit increasingly decoupled from decoh erence mechanisms.\n\n\n\n\n [1]  N. A. Masluk\, I. M. Pop\, A. Kamal\, Z. K. Minev\, and M. H. Devoret\, Phys. Rev. Lett. 109\, 137002 (2012).\n [2]  A. Petrescu\, H. E. Türeci\, A. V. Ustinov\, and I. M. Pop\, ArXiv e-prints (2017)\, arXiv:1712.08630 [cond-mat.mes-hall].\n [3]  E. Orign ac and T. Giamarchi\, Phys. Rev. B 64\, 144515 (2001).\n [4]  A. Petresc u and K. Le Hur\, Phys. Rev. Lett. 111\, 150601 (2013).\n [5]  M. Piraud \, F. Heidrich-Meisner\, I. P. McCulloch\, S. Greschner\, T. Vekua\, and U . Schollwöck\, Phys. Rev. B 91\, 140406 (2015).\n\n\n\n\n\n\n\n\n [6]  A. Petrescu\, M. Piraud\, G. Roux\, I. P. McCulloch\, and K. Le Hur\, Phys . Rev. B 96\, 014524(2017).\n [7]  R. Jackiw and C. Rebbi\, Phys. Rev. D 13\, 3398 (1976).\n [8]  W. P. Su\, J. R. Schrieffer\, and A. J. Heeger \, Phys. Rev. Lett. 42\, 1698 (1979).\n\n\n\n\n\n\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-573@lptms.universite-paris-saclay.fr DTSTART:20180403T110000Z DTEND:20180403T113000Z DTSTAMP:20180327T185228Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-raffaela-cabriolu/ SUMMARY:Séminaire du LPTMS: Raffaela Cabriolu - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 3 Avr 18 11:00 DESCRIPTION:Creep response of a soft glass\nRaffaela Cabriolu (Department o f Chemistry\, Norwegian University of Science and Technology\, Trondheim\, Norway)\nIn this work we discuss finite size effects in the fluidization process of dense amorphous mate-\nrials subjected to an external load. By means of molecular dynamics simulations we study the\nmechanical response of a densly packed 3D particle system to a sudden applied shear stress. In \norder to disentangle possible boundary effects from finite size effects\ , we use an unusual setup by\nimplementing a geometry-constraint protocol with periodic boundary conditions in all directions.\nWe show that this pr otocol is well controlled and that the long time fluidization process is t o a\ngreat extend independent of the details of the protocol parameters. T his procedure allows for a\nrobust study of finite size effects regarding the creep exponents and the fluidization process. The\nslow dynamics show a power-law creep with exponents that do not depend on the system size\nwh ereas the fluidisation time shows strong finite size effects\, that we can rationalize within a finite\nsize scaling relation.\n\n \; LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-597@lptms.universite-paris-saclay.fr DTSTART:20180403T113000Z DTEND:20180403T120000Z DTSTAMP:20180326T183827Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mehdi-bouzid/ SUMMARY:Séminaire du LPTMS: Mehdi Bouzid - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 3 Avr 18 11:30 DESCRIPTION:Athermal analogue of sheared colloidal suspensions\nMehdi Bouzi d (LPTMS\, Université Paris-Sud)\nSand-piles\, window glass\, tomato ketc hup\, are three materials that would not necessarily strike the larger pub lic for their similarities. However\, they take part of one of the most li ngering enigma of condensed matter physics as they are examples of fluids undergoing dynamical arrest and becoming solid in a way essentially differ ent from a thermodynamic phase transition. Such complex fluids\, developin g a yield-stress and becoming very hard solids (metallic or oxide glasses) or soft glassy materials (colloidal pastes\, granular packing\, polymer m elts ...)\, are of central importance in statistical physics\, material sc ience or chemical engineering. In this talk I will highlight an analogy be tween the rheology of Brownian and  non-Brownian  suspensions\, we show that these systems can be described by a Herschel-Bulkley law as soon as t he shear rate and shear stress  are respectively normalized by an energy scale and a microscopic time of reorganization\, which are both functions of the normal confinement stress. The pressure-controlled approach\, orig inally developed for granular flows\, reveals a striking physical analogy between the colloidal glass transition and the granular jamming transiti on. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-550@lptms.universite-paris-saclay.fr DTSTART:20180404T110000Z DTEND:20180404T120000Z DTSTAMP:20180326T122154Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-emmanuel-de-langre/ SUMMARY:Physics-Biology interface seminar: Emmanuel de Langre - Moyen Amphi \, Building 510\, Université Paris-Saclay Orsay - 4 Avr 18 11:00 DESCRIPTION:Plant vibration\, from wind flutter to phenotyping\nEmmanuel d e Langre (École polytechnique\, Palaiseau\, France)\n\nPlants are often very flexible objects. This results in motion under stimuli such as wind or currents\, but also hosts such as insects. Motion are known to influenc e plant development by thigmomorphogenesis. I will review methodologies and results from the past ten years\, aimed at quantifying and understan ding the vibration of plants\, or parts of plants\, from Arabidopsis Thali ana to large trees. I will focus on experimental techniques indoor and ou tdoor\, on simple models of motions\, and the role of the plant architect ure. The recent application to high throughput plant phenotyping by vibrat ions will also be presented. \n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-576@lptms.universite-paris-saclay.fr DTSTART:20180410T110000Z DTEND:20180410T113000Z DTSTAMP:20180326T112918Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-leonardo-mazza-2/ SUMMARY:Séminaire du LPTMS: Leonardo Mazza - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 10 Avr 18 11:00 DESCRIPTION:Majorana zero modes in one-dimensional Ytterbium quantum gases\ nLeonardo Mazza (Département de Physique\, ENS\, Paris)\nAfter their intr oduction in the context of the relativistic Dirac equation\, Majorana ferm ions have recently experienced a renewed interest for their relevance in t he description of topological superconducting models\, where they appear a s Majorana zero modes. In this talk I will investigate the possibility of realizing Majorana zero modes in cold-atom experiments\, and in particular I will argue that one-dimensional Ytterbium gases offer a natural experim ental playground for their experimental implementation.\n\nReference:\n\n [1] F. Iemini\, L. Mazza\, L. Fallani\, P. Zoller\, R. Fazio and M. Dalmo nte\, Majorana Quasiparticles Protected by ℤ2 Angular Momentum Conservat ion\, Phys.Rev.Lett. 118 200404 (2017)\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-598@lptms.universite-paris-saclay.fr DTSTART:20180410T113000Z DTEND:20180410T120000Z DTSTAMP:20180328T114202Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jacopo-de-nardis-2/ SUMMARY:Séminaire du LPTMS: Jacopo de Nardis - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 10 Avr 18 11:30 DESCRIPTION:Edge singularities and quasi-long-range order in non-equilibriu m steady states\nJacopo de Nardis (LPT-ENS\, Paris)\nI will present a theo retical study of exotic states of matter realized via the bi-partite quant um quench protocol\, where two many-body systems at different density or t emperatures are put in contact. I will mostly focus on the 1d interacting Bose gas and I will show how the non-equilibrium steady state emerging fro m the junction displays strong quantum correlations that are more typical of gapless ground states than thermal states in one spacial dimension. I w ill then show how by means of new form factors techniques we can provide a full characterization of the strong edge singularities which in principle could also be studied via universal field theory methods similar to non-l inear Luttinger liquids.\n\nRef:\n\n Jacopo De Nardis\, Miłosz Panfil\,  Edge singularities and quasi-long-range order in non-equilibrium steady states\, preprint cond-mat.quant-gas arXiv:1801.08079.\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-591@lptms.universite-paris-saclay.fr DTSTART:20180412T110000Z DTEND:20180412T113000Z DTSTAMP:20180326T074953Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-corrado-rainone-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Corrado Rainone *** séminaire exceptionnel ** * - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Avr 18 11:00 DESCRIPTION:Mechanical Failure in Amorphous Solids: Scale Free Spinodal Cri ticality\nCorrado Rainone (Dpt of Chemical and biological physics\, Weizma nn Institute of Science\, Israël)\nThe mechanical failure of amorphous me dia is a ubiquitous phenomenon from material engineering to geology. It ha s been noticed for a long time that the phenomenon is "scale-free"\, indic ating some type of criticality. In spite of attempts to invoke "Self-Organ ized Criticality"\, the physical origin of this criticality\, and also its universal nature\, being quite insensitive to the nature of microscopic i nteractions\, remained elusive. Recently we proposed that the precise natu re of this critical behavior is manifested by a spinodal point of a thermo dynamic phase transition. Moreover\, at the spinodal point there exists a divergent correlation length which is associated with the system-spanning instabilities (known also as shear bands) which are typical to the mechani cal yield. Demonstrating this requires the introduction of an "order param eter" that is suitable for distinguishing between disordered amorphous sys tems\, and an associated correlation function\, suitable for picking up th e growing correlation length. The theory\, the order parameter\, and the c orrelation functions used are universal in nature and can be applied to an y amorphous solid that undergoes mechanical yield. Critical exponents for the correlation length and the system size dependence are estimated. We co nclude with some perspectives and modelling ideas on the subject.\n\nRéf: \n\n Itamar Procaccia\, Corrado Rainone\, and Murari Singh\, Mechanical f ailure in amorphous solids: Scale-free spinodal criticality\, Phys. Rev. E 96\, 032907 (2017)\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-599@lptms.universite-paris-saclay.fr DTSTART:20180412T113000Z DTEND:20180412T120000Z DTSTAMP:20180321T213517Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gregoire-ithier-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Grégoire Ithier *** séminaire exceptionnel * ** - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 12 Avr 18 11:30 DESCRIPTION:Typicality and unconventional equilibrium states of an embedded quantum system.\nGrégoire Ithier (Royal Holloway\, London\, UK)\n\nIn re cent years\, the progress in quantum engineering has provided new tools fo r simulating the dynamics of truly isolated quantum systems. These systems \, made of trapped ions or cold atoms[1]\, can be prepared in a global pur e state and their level of isolation is such that they evolve unitarily ac cording to the Schrödinger equation. Surprisingly\, despite being at all times in a pure quantum state\, they display signatures of a local equilib ration which can be in strong disagreement with the predictions of statis tical physics [2]. These experimental facts are clearly questioning what k ind of statistical description is relevant for isolated many body quantum systems.\n\nIn this talk\, I will present our recent results on a theoreti cal model dedicated to this problem. This model considers a quantum system coupled to a large quantum environment\, and introduces  some randomness at the level of the interaction Hamiltonian. We then demonstrate that the system has a typical dynamics for several classes of random interactions and most importantly for arbitrary system\, environment\, and global initi al state [3]. In other words\, the microscopic structure of interaction Ha miltonians does not matter and reduced density matrices have a self-averag ing property. \n\nThese results have two important consequences: first th ey can explain the absence of sensitivity to microscopic details of proces ses like e.g. thermalization. Second they provide the rigorous ground for an averaging procedure over random interactions which can be used for anal ytical non perturbative calculations performed with full generality i.e. f or arbitrary system\, environment\, and initial state.\n\nWe apply this te chnique to calculate analytically the stationary state at long times of th e system and find a new thermodynamical ensemble more general than the mic rocanonical one [4]. \n \n\n [1] C. Gross and I. Bloch\, Quantum simula tions with ultracold atoms in optical lattices\, Science 357\, 6355\, pp. 995-1001  (2017)\n [2] M. Schreiber et al\, Observation of many-body loc alization of interacting fermions in a quasirandom optical lattice\, Scien ce 349\, 6250\, pp. 842-845 (2015)\n [3] G. Ithier and F. Benaych-Georges \, Dynamical typicality of embedded quantum systems\, Phys. Rev. A 96\, 01 2108 (2017)\n [4] G. Ithier\, S. Ascroft\, and F. Benaych-Georges\, Typic al equilibrium state of an embedded quantum system\, Phys. Rev. E 96\, 060 102(R) (2017) \n\n\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-604@lptms.universite-paris-saclay.fr DTSTART:20180419T110000Z DTEND:20180419T120000Z DTSTAMP:20180406T065933Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alfredo-ozorio-de-almeida-jour-inhabituel/ SUMMARY:Séminaire du LPTMS: Alfredo Ozorio de Almeida - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 19 Avr 18 11:00 DESCRIPTION:!!! Attention : jour inhabituel !!!\nTranslations and reflectio ns on the torus: Identities for discrete Wigner functions and transforms\n Alfredo Miguel Ozorio de Almeida (Centro Brasileiro de Pesquisas Fisicas\, Rio de Janeiro\, Brazil)\n\nA finite Hilbert space can be associated to a periodic phase space\, that is\, a torus. A finite subgroup of operators corresponding to reflections and translations on the torus form respective ly the basis for the discrete Weyl representation\, including the Wigner f unction\, and for its Fourier conjugate\, the chord representation. They a re invariant  under Clifford transformations and obey analogous product r ules to the continuous representations\, so allowing for the calculation o f expectations and correlations for observables. We here import new identi ties from the continuum for products of pure state Wigner functions and ch ord functions\, involving\, for instance the inverse phase space participa tion ratio and correlations of a state with its translation. Connections b etween products of Wigner functions and mixed (transition) Wigner function s also arise. Finally\, generalizations of translations and reflections to a doubled phase space connect the Weyl representation of the evolution op erator to the propagator of Wigner functions. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-579@lptms.universite-paris-saclay.fr DTSTART:20180424T110000Z DTEND:20180424T120000Z DTSTAMP:20180406T100233Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jose-lebreuilly/ SUMMARY:Séminaire du LPTMS: José Lebreuilly - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 24 Avr 18 11:00 DESCRIPTION:Stabilizing zero temperature quantum phases and incompressible states of light via non-Markovian reservoir engineering\nJosé Lebreuilly (Laboratoire Pierre Aigrain\, ENS\, Paris)\nWe study the possibility of st abilizing strongly correlated quantum fluids of light in driven-dissipativ e devices through novel non-Markovian reservoir engineering techniques. Th is approach allows to compensate losses and refill selectively the photoni c population so to sustain a desired steady-state. It relies in particular on the use of a frequency-dependent incoherent pump which can be implemen ted\, e.g.\, via embedded two-level systems maintained at a strong inversi on of population. As specific applications of these methods\, we discuss t he generation of a photonic Mott Insulator (MI). As a first step\, we pres ent the case of a narrow band emission spectrum and show how this allows f or the stabilization of MI states under the condition that the photonic st ates are relatively flat in energy. As soon as the photonic bandbwidth bec omes comparable to the emission linewidth\, important non-equilibrium sign atures and entropy generation appear\, and a novel dissipative phase trans ition from a Mott Insulating state toward a superfluid (SF) phase is unvei led. As a second step\, we present a more advanced configuration based on reservoirs with a broadband frequency distribution\, and we highlight the potential of this configuration for the quantum simulation of equilibrium quantum phases at zero temperature with tunable chemical potential. As a p roof of principle we establish the applicability of our scheme to the Bose -Hubbard model by confirming the presence of a perfect agreement with the ground-state predictions both in the MI and SF regions\, and more generall y in all parts of the parameter space. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-588@lptms.universite-paris-saclay.fr DTSTART:20180502T110000Z DTEND:20180502T120000Z DTSTAMP:20180501T192353Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-quan-li/ SUMMARY:Physics-Biology interface seminar: Quan Li - Laboratoire Aimé Cott on\, Salle Balmer (Batiment 505) - 2 Mai 18 11:00 DESCRIPTION:Nanodiamond based quantum sensors for biological applications\n Quan Li (Chinese University of Hong Kong\, China)\nSpecial location: Labor atoire Aimé Cotton\, Orsay\n\nNanodiamond (ND) with Nitrogen-vacancy (NV) centers serves as promising bio-sensor due to its excellent bio-compatibi lity\, high photo-stability\, and the long spin coherence time at room tem perature. However\, the complicated biological environment\, e.g. in a sin gle cell\, imposes stringent requirements on the sensor probes to be inter nalized. In this talk\, I will discuss the requirements on nanodiamond as intra-cellular sensor\, and the possible strategies that will enable vario us bio-sensing measurements. I will start with the understanding of nanodi amond-cell interfaces\, from anchoring of ND on the plasma membrane to the ir internalization\, and eventually to their intracellular trafficking. Ot her than the conventional three-dimensional trajectories tracking of the N D\, it is also possible to track their orientations (rotation)\, providing additional information of the intracellular environment. One problem with NV based bio-sensing is that the NV center is less sensitive to certain p arameters such as temperature and pressure\, and not at all response to ma ny other important biochemical parameters such as pH and non-magnetic biom olecules. I will also discuss possible schemes of constructing nanodiamond based hybrid sensors\, which lead to significantly enhanced sensitivity a nd/or potentially enable the measurement of various biochemical parameters using NV based quantum sensing.\n CATEGORIES:physbio,seminars LOCATION:Laboratoire Aimé Cotton\, Salle Balmer (Batiment 505)\, Batiment 505 Université Paris-Sud\, Orsay \, 91405\, France GEO:48.702613;2.182569 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=Batiment 505 Université Pa ris-Sud\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Laboratoire A imé Cotton\, Salle Balmer (Batiment 505):geo:48.702613,2.182569 END:VEVENT BEGIN:VEVENT UID:0-575@lptms.universite-paris-saclay.fr DTSTART:20180515T110000Z DTEND:20180515T120000Z DTSTAMP:20180507T072848Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jacopo-rocchi/ SUMMARY:Séminaire du LPTMS: Jacopo Rocchi - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 15 Mai 18 11:00 DESCRIPTION:Self-sustained clusters in spin glass models\nJacopo Rocchi (LP TMS\, Université Paris-Sud)\nWhile macroscopic properties of spin glasses have been thoroughly investigated\, their manifestation in the correspond ing microscopic configurations is much less understood. To identify the e merging microscopic structures with macroscopic phases at different temper atures\, we introduce the concept of self-sustained clusters (SSC). SSC are regions of the space where in-cluster induced fields dominate over th e field induced by out-cluster spins. We study their properties in the Is ing p-spin model with p=3 using replicas. The intuition gained using ful ly connected models is then used in the study of models defined on random graphs. A message-passing algorithm is developed to determine the probabil ity of individual spins to belong to SSC. Results for specific instances\, which compare the predicted SSC associations with the dynamical properti es of the spins\, are obtained from numerical simulations. This insight gi ves rise to a way to predict individual spin dynamics from a single snap shot of spin configurations. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-606@lptms.universite-paris-saclay.fr DTSTART:20180516T110000Z DTEND:20180516T120000Z DTSTAMP:20180504T090110Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-gervaise-mosser/ SUMMARY:Physics-Biology interface seminar: Gervaise Mosser - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 16 Mai 18 11:00 DESCRIPTION:Collagen and gelatin from sol to gel states for the synthesis o f biomaterials\nGervaise Mosser (Laboratoire de Chimie de la Matière Cond ensée\, Université Pierre et Marie Curie)\nCollagen type I\, the most ab undant protein of connective tissues (bones\, dermis\, tendons\, etc)\, is a macromolecular mesogen that can form lyotropic liquid-crystal phases. With this approach\, our team works on elaborating several biomimetic biom aterials. However\, the use of collagen can be hindered due to its price a nd the possibility to easily denature into gelatine and noticeably during sterilization processes. In this context\, we wanted to determine whether collagen could be partially replaced by gelatine without modification of t he overall hierarchical structure of the biomaterial. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-594@lptms.universite-paris-saclay.fr DTSTART:20180522T110000Z DTEND:20180522T120000Z DTSTAMP:20180509T075130Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marcel-filoche/ SUMMARY:Séminaire du LPTMS: Marcel Filoche - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 22 Mai 18 11:00 DESCRIPTION:Localization landscape and localization potential in disordered or complex structures\nMarcel Filoche (Laboratoire de Physique de la Mati ère Condensée\, Ecole Polytechnique)\nStanding waves in disordered or co mplex systems can be subject to a strange and intriguing phenomenon which has puzzled the physics and mathematical communities for more than 60 year s\, namely wave localization. This phenomenon consists of a concentration (or a focusing) of the wave energy in a very restricted sub-region of the entire domain. It has been evidenced experimentally in mechanics\, acousti cs and quantum physics. Determining the conditions for the onset of locali zation\, depending on the disorder amplitude\, the energy\, or the wave ty pe\, is the aim of many theoretical studies. We will present a theory that unifies different types of localization within a single mathematical fram ework [1]. To that end\, we will introduce the notion of "localization lan dscape"\, solution to an associated Dirichlet problem. Going further\, thi s will enable us to define an "effective localization potential"\, providi ng a new insight into the confinement of the waves in disordered media. Th is potential allows us to predict the localization region\, the energies o f the localized modes\, the density of states\, and the long range decay o f the wave functions. We will present experimental and numerical examples of this theory in mechanics\, in semiconductor physics\, and in molecular systems\, as well as theoretical perspectives with cold atom systems.\n\n[ 1] M. Filoche and S. Mayboroda\, Universal mechanism for Anderson and weak localization\,  PNAS 109\, 14761–14766 (2012). LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-592@lptms.universite-paris-saclay.fr DTSTART:20180529T110000Z DTEND:20180529T120000Z DTSTAMP:20180509T123828Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-shamashis-sengupta/ SUMMARY:Séminaire du LPTMS : Shamashis Sengupta - LPTMS\, salle 201\, 2èm e étage\, Bât 100\, Campus d'Orsay - 29 Mai 18 11:00 DESCRIPTION:Gate-tunable superconductivity in oxide heterostructures\nShama shis Sengupta (CSNSM\, Université Paris-Sud)\n \;\n\nThe realization of two-dimensional electronic gases (2DEGs) in oxide-based heterostructure s (e.g. LaAlO3/SrTiO3) has led to important discoveries about superconduct ivity in low dimensions. There have been reports of the observation of pai ring interactions without superconductivity (Cheng et al.\, Nature 521\, 1 96 (2015)) and density-of-states features resembling the pseudogap in cupr ates (Richter et al.\, Nature 502\, 528 (2013)). Consequently\, this 2DEG has emerged as a model system to study the physics of Cooper pair formatio n in two dimensions and to gain useful insights about complex problems\, e .g.\, the phase diagram of high temperature superconductors. In this talk\ , we will discuss about a new method developed in our group for realizing such superconducting systems in oxide heterostructures\, and the results o f experiments to characterize their properties. Due to the low carrier den sity\, it is possible to change it using a gate voltage following the prin ciple of a field-effect transistor. The superconducting critical parameter s (temperature and field) are tunable as a function of the gate voltage\, leading to a 'superconducting dome' in the phase diagram. The possibility of continuously varying the carrier density allows us to study different e quilibrium and non-equilibrium features characterizing the electronic phas es. Results of some recent experiments will be presented. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-549@lptms.universite-paris-saclay.fr DTSTART:20180530T110000Z DTEND:20180530T120000Z DTSTAMP:20180524T094648Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-david-bensimon/ SUMMARY:Physics-Biology interface seminar: David Bensimon - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 30 Mai 18 11:00 DESCRIPTION:Quantitative analysis of the somitogenetic wavefront\nDavid Ben simon (LPS-ENS\, Paris\, France)\n \;\nSomitogenesis is the process by which the anterio-posterior axis is segmented in all vertebrates thus def ining the coordinate system that will serve for positioning of the appendi ces and organs. This process of segmentation is due to the interaction bet ween a posterior moving wavefront of morphogens and a posterior located cl ock generating somites (segments) at regular times and places. The existen ce and characterization of the clock has been amply demonstrated. In this talk I will focus on the molecular network behind the wavefront. I will di scuss the wavefront response to various perturbations and compare our obse rvations with a model of this network. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-610@lptms.universite-paris-saclay.fr DTSTART:20180604T110000Z DTEND:20180604T120000Z DTSTAMP:20180529T050030Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/quantum-physics-j ournal-club-raoul-santachiara/ SUMMARY:Quantum Physics Journal Club: Raoul Santachiara - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 4 Juin 18 11:00 DESCRIPTION:Quantum mechanics in multi-connected space and the origin of ne w statistics in low dimensional system\nRaoul Santachiara (LPTMS\, Univers ité Paris-Sud)\nWe recall how to define the problem of N indinstinguishib le quantum particles and argue that the topology of the configuration spac e plays a crucial role. This observation\, that has been put on solid grou nds by Leinaas and Mirheim in the 1977\, has provided the theoretical fram ework for the existence of anyonic statistics in two dimensions. Moreover\ , it inspired the connection between the Conformal field theory and topolo gical phases in two dimensions: via this connection\, the occurence of non -Abelian anyons in the fractional quantum Hall effect has been suggested. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-609@lptms.universite-paris-saclay.fr DTSTART:20180605T110000Z DTEND:20180605T120000Z DTSTAMP:20180529T053815Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-serguey-andreev-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Serguey Andreev - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 5 Juin 18 11:00 DESCRIPTION:Effective interactions in a quantum Bose-Bose mixture\nSerguey Andreev\, ITMO University\, St. Petersburg\, Russia\nApplication of the me thods of Quantum Electrodynamics (QED) to a system of bosons at absolute z ero temperature put forward by Spartak Beliaev in 1958 has been one of the most powerful analytical methods in studies of Bose-Einstein condensates. The Beliaev theory provides a prescription of replacement of the actual m icroscopic interaction by an effective potential which can be used for per turbative expansion of the many-body Hamiltonian. Originally designed for one-component systems\, the method has recently been applied to binary Bos e mixtures in the context of supersolidity and stabilization of collapsing Bose-Einstein condensates by quantum fluctuations. The present work is ai med at investigation of legitimacy of extrapolation of the Beliaev prescri ption to two-component systems. We show that quantum scatterings of differ ent components\, which until now have been assumed independent\, can inter fere due to the Andreev-Bashkin entrainment effect. The effect manifests i tself in renormalization of the elementary excitations of the system. This result has escaped the earlier considerations based on the Fourier expans ion of small-amplitude oscillations of the order parameter. We explain how one can account for the effect by using a properly generalized Bogoliubov approach. In 3D the effect appears in the second order of the perturbatio n theory\, which makes possible using the concept of effective potential i n this case. The entrainment arises due to "dressing" of magnons with Bogo liubov phonon modes\, by analogy with the physics of Bose polaron. We expl oit this fruitful analogy to speculate on possible formation of a magnon c rystal in the strongly-interacting regime. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-608@lptms.universite-paris-saclay.fr DTSTART:20180607T110000Z DTEND:20180607T120000Z DTSTAMP:20180525T124915Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-eoin-quinn-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Eoin Quinn *** séminaire exceptionnel *** - L PTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 7 Juin 18 11 :00 DESCRIPTION:Splitting of electrons and violation of the Luttinger sum rule\ nEoin Quinn (University of Amsterdam\, The Netherlands)\nWe present a fram ework for organising the correlations of interacting electrons\, which all ows us to describe a regime of strongly correlated behaviour. We highlight two ways to characterise the electronic degree of freedom\, either by the canonical fermion algebra or by the graded Lie algebra su(2|2). The first underlies the Fermi liquid description of correlated matter\, and we iden tify a novel regime governed by the latter. We derive a systematic expansi on of the electronic correlations\, and compute the electronic spectral fu nction at the leading order. This reveals a splitting in two of the electr onic band\, a violation of the Luttinger sum rule\, and a Mott metal-insul ator transition.\n\nRéf:\n\n Eoin Quinn\, Splitting of electrons and vio lation of the Luttinger sum rule\, Phys. Rev. B 97\, 115134 (2018)\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-607@lptms.universite-paris-saclay.fr DTSTART:20180613T140000Z DTEND:20180613T150000Z DTSTAMP:20180605T053958Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-senthil-todadri/ SUMMARY:Séminaire du LPTMS: Senthil Todadri - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 13 Juin 18 14:00 DESCRIPTION:*** ATTENTION: horaire inhabituel ***\nDualities in condensed m atter physics\nSenthil Todadri (Massachusetts Institute of Technology\, Ca mbridge\, USA)\nThere has been much recent progress in unearthing and unde rstanding dualities of theories in 2 space dimensions. I will describe som e of this progress and their relevance to frontier problems in condensed m atter physics. I will specifically focus on a class of new dualities that generalize the familiar charge-vortex duality of bosons to theories that i nclude fermions. LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-611@lptms.universite-paris-saclay.fr DTSTART:20180618T110000Z DTEND:20180618T120000Z DTSTAMP:20180608T081018Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/quantum-physics-j ournal-club-maurizio-fagotti/ SUMMARY:Quantum Physics Journal Club: Maurizio Fagotti - LPTMS\, salle 201\ , 2ème étage\, Bât 100\, Campus d'Orsay - 18 Juin 18 11:00 DESCRIPTION:Lieb-Robinson Bounds\nMaurizio Fagotti (LPTMS\, Université Par is-Sud) LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-614@lptms.universite-paris-saclay.fr DTSTART:20180619T110000Z DTEND:20180619T120000Z DTSTAMP:20180614T071117Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-aurelien-decelle/ SUMMARY:Séminaire du LPTMS: Aurélien Decelle - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Juin 18 11:00 DESCRIPTION:Spectral learning of Restricted Boltzmann Machines\nAurélien D ecelle (Laboratoire de Recherche en Informatique\, Université Paris Sud)\ nIn this presentation I will expose our recent results on the Restricted B oltzman Machine (RBM). The RBM is a generative model very similar to the I sing model\, it is composed of both visible and hidden binary variables\,   and traditionally used in the context of machine learning. In this cont ext\, the goal is to infer the parameters of the RBM such that it reproduc es correctly a dataset's distribution. Although they have been widely used in computer science\, the phase\ndiagram of this model is not known preci sely in the context of learning. In particular\, it is not known how the p arameters influence the learning\, and what exactly is learned within the parameters of the model. After an introduction to some aspects of Machine learning\, I will expose our work\, showing how the SVD of the data govern s the first phase of the learning and how this decomposition helps to unde rstand the dynamics and the equilibrium properties of the model.\n\nRéf:\ n\n Aurélien Decelle\, Giancarlo Fissore and Cyril Furtlehner\, Spectral dynamics of learning in restricted Boltzmann machines\, EuroPhys. Lett. 1 19\, 60001 (2017)\n Aurélien Decelle\, Giancarlo Fissore and Cyril Furtl ehner\, Thermodynamics of Restricted Boltzmann Machines and related learni ng dynamics\, preprint cond-mat arXiv:1803.01960 (2018).\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-605@lptms.universite-paris-saclay.fr DTSTART:20180626T110000Z DTEND:20180626T120000Z DTSTAMP:20180529T053137Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-urna-basu/ SUMMARY:Séminaire du LPTMS: Urna Basu - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 26 Juin 18 11:00 DESCRIPTION:Active Brownian Motion in Two Dimensions\nUrna Basu (LPTMS\, Un iversité Paris-Sud)\nWe study the dynamics of a single active Brownian pa rticle in a two-dimensional harmonic trap. The active particle has an intr insic time scale set by the rotational diffusion. The harmonic trap also i nduces a relaxational time-scale. We show that the competition between the se two time scales leads to a nontrivial time evolution for the active Bro wnian particle. At short times a strongly anisotropic motion emerges leadi ng to anomalous persistence properties. At long-times\, the stationary pos ition distribution in the trap exhibits two different behaviours: a Gaussi an peak at the origin in the strongly passive limit and a delocalised ring away from the origin in the opposite strongly active limit. The predicted stationary behaviours in these limits are in agreement with recent experi mental observations.\n\nRéf:\n\n Urna Basu\, Satya N. Majumdar\, Alberto Rosso and Grégory Schehr\, Active Brownian Motion in Two Dimensions\, pr eprint cond-mat.stat-mech arXiv:1804.09027\n LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-601@lptms.universite-paris-saclay.fr DTSTART:20180627T110000Z DTEND:20180627T120000Z DTSTAMP:20180413T133715Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-knut-drescher/ SUMMARY:Physics-Biology interface seminar: Knut Drescher - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 27 Juin 18 11:00 DESCRIPTION:Bacterial collective behaviours\nKnut Drescher (Max Planck Inst itute for Terrestrial Microbiology\, Marburg\, Germany\nIn nature\, bacter ia often engage in a range of collective behaviors. In this presentation\, I will demonstrate how two bacterial behaviors\, swarming and biofilm for mation\, are related by physical interactions\, chemical signaling\, and d ynamical transitions. I will show how these collective behaviors arise fro m cell-cell interactions\, and the physiological state of individual cells . Furthermore\, I will introduce new experimental methods for investigatin g bacterial collective behaviors. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-600@lptms.universite-paris-saclay.fr DTSTART:20180702T140000Z DTEND:20180702T170000Z DTSTAMP:20180426T095559Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/these-aurelien-gr absch/ SUMMARY:Soutenance de thèse: Aurélien Grabsch - IPN-batiment 100\, Audito riurm - 2 Juil 18 14:00 DESCRIPTION:Soutenance de thèse :\nRandom matrix theory in statistical phy sics: quantum scattering and disordered systems\nby\n\nAurélien Grabsch\n  \;\nJury:\n\n Alexander Altland (University of Cologne\, Germany)\n Jean-Philippe Bouchaud (CFM\, Paris)\n David S. Dean (LOMA\, Université de Bordeaux)\n Yan V. Fyodorov (King's College London\, UK)\n Satya N. Majumdar (LPTMS\, Université Paris-Sud)\, directeur de thèse\n Cécile Monthus (IPhT\, CEA-Saclay)\n Christophe Texier (LPTMS\, Université Pari s-Sud)\, directeur de thèse\n\nAbstract:\nRandom matrix theory has applic ations in various fields: mathematics\, physics\, finance\, ... In physics \, the concept of random matrices has been used to study the electonic tra nsport in mesoscopic structures\, disordered systems\, quantum entanglemen t\, interface models in statistical physics\, cold atoms\, ... In this the sis\, we study coherent AC transport in a quantum dot\, properties of fluc tuating 1D interfaces on a substrate and topological properties of multich annel quantum wires.\nThe first part gives a general introduction to rando m matrices and to the main method used in this thesis: the Coulomb gas. Th is technique allows to study the distribution of observables which take th e form of linear statistics of the eigenvalues. These linear statistics re present many relevant physical observables\, in dif- ferent contexts. This method is then applied to study concrete examples in coherent transport a nd fluctuating interfaces in statistical physics.\nThe second part focuses on a model of disordered wires: the multichannel Dirac equation with a ra ndom mass. We present an extension of the powerful methods used for one di mensional systems to this quasi-1D situation\, and establish a link with a random matrix model. From this result\, we extract the density of states and the localisation properties of the system. Finally\, we show that this system exhibits a series of topological phase transitions (change of a qu antum number of topological nature\, without changing the symmetries)\, dr iven by the disorder. LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-612@lptms.universite-paris-saclay.fr DTSTART:20180709T110000Z DTEND:20180709T120000Z DTSTAMP:20180704T051731Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/quantum-physics-j ournal-club-bradraj-pandey/ SUMMARY:Quantum Physics Journal Club: Bradraj Pandey - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Juil 18 11:00 DESCRIPTION:Out-of-time-order correlators in quantum mechanics CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-616@lptms.universite-paris-saclay.fr DTSTART:20180710T110000Z DTEND:20180710T120000Z DTSTAMP:20180705T193021Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thorsten-emig/ SUMMARY:Séminaire du LPTMS: Thorsten Emig - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 10 Juil 18 11:00 DESCRIPTION:A Minimal Physiological Model for Human Running Performance\nTh orsten Emig (LPTMS\, Université Paris-Sud)\n \;\n\nMeasurements of ph ysiological variables during exercise and performance evaluations and pred ictions are important for a fundamental understanding of physiological pro cesses\, training and assessment of athletes\, and beyond sport in the stu dy of complex physiological response related to aging\, muscular structure and cardiovascular health. Models for human running performances of vario us complexities and underlying principles have been proposed\, often emplo ying a combination of data for world record performances and concepts that are not always based on simple principles of human physiology. We present a novel\, minimal model for human running performance that follows from a self-consistency relation for the time dependent power output during raci ng events. The model has a total of four parameters that are not fixed a p riori and characterize individual physiological profiles for a runner. The analytic approach presented here is the first to derive the observed loga rithmic scaling between world (and other) record running speeds and times from basic principles. Various female and male record performances (world\ , national) and also personal best performances of individual runners for distances from 800m and to the Marathon are excellently described by our m odel\, with mean absolute errors of (often much) less than 1%. Physiologic al parameters of our model\, as obtained from records and individual runne rs\, are consistent with existing laboratory measurements. The computed ma ximal power output that can be sustained for a given time describes well e xisting experimental data for the time to exhaustion dependence of suprama ximal oxygen consumption in the anaerobic regime. Our model is used to def ine and estimate endurance for both the aerobically and anaerobically domi nated performances. As an application of our model\, we derive personalize d training speeds for prescribed duration and intensity. Our findings coul d be a basis for plethora of further studies including assessment of perfo rmance dependence on age\, altitude\, muscular structure\, specialization of athlete\, racing strategies\, and optimal dosing of recreational exerci se. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-618@lptms.universite-paris-saclay.fr DTSTART:20180904T110000Z DTEND:20180904T120000Z DTSTAMP:20180828T062458Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-erik-aurell/ SUMMARY:Séminaire du LPTMS: Erik Aurell - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 4 Sep 18 11:00 DESCRIPTION:Continuous-time dynamic cavity for equilibrium and non-equilibr ium processes\nErik Aurell (KTH-Royal Institute of Technology\, Sweden)\nD ynamics on locally tree-like graphs can be described by marginals which sa tisfy equations known as dynamic cavity. These equations are for probabili ties of whole histories of single variables\, and therefore need further a pproximations or closure. I will present a closure for continuous-time pro cesses\, and show how it behaves for some standard models in disordered sy stems which are either in equilibrium\, or relaxing towards equilbrium. I will also discuss local search algorithms on K-satisfiability of the walks at type\, processes which do not satisfy detailed balance.\n\nThis is join t work over the last few years with Gino Del Ferraro\, Eduardo Dominguez\, David Machado and Roberto Mulet. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-613@lptms.universite-paris-saclay.fr DTSTART:20180907T093000Z DTEND:20180907T170000Z DTSTAMP:20180726T053915Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-kirill-plekhanov/ SUMMARY:Soutenance de thèse: Kirill Plekhanov - IPN-batiment 100\, Auditor iurm - 7 Sep 18 09:30 DESCRIPTION:Soutenance de thèse :\n\nTopological Floquet states\, artifici al gauge fields in strongly correlated quantum fluids\nby\nKirill Plekhano v\n\nJury :\n\nMark Oliver Goerbig (Université Paris-Sud - LPS)\n\nNathan Goldman (Université libre de Bruxelles)\n\nWalter Hofstetter (Goethe-Uni versitat Frankfurt)\n\nKaryn Le Hur (Ecole Polytechnique - CPHT) directeur de thèse\n\nTitus Neupert (University of Zurich)\n\nGuido Pupillo (Unive rsité de Strasbourg)\n\nNicolas Regnault (ENS - LPA)\n\nGuillaume Roux (U niversité Paris-Sud - LPTMS) directeur de thèse\n\n\nAbstract:\nIn this thesis we study the topological aspects of condensed matter physics\, that received a revolutionary development in the last decades. Topological sta tes of matter are protected against perturbations and disorder\, making th em very promising in the context of quantum information. The interplay bet ween topology and interactions in such systems is however far from being w ell understood\, while the experimental realization is challenging. Thus\, in this work we investigate such strongly correlated states of matter and explore new protocols to probe experimentally their properties. In order to do this\, we use various both analytical and numerical techniques.\nFir st\, we analyze the properties of an interacting bosonic version of the ce lebrated Haldane model – the model for the quantum anomalous Hall effect . We propose its quantum circuit implementation based on the application o f periodic time-dependent perturbations – Floquet engineering. Continuin g these ideas\, we study the interacting bosonic version of the Kane-Mele model – the first model of a topological insulator. This model has a ver y rich phase diagram with an emergence of an effective frustrated magnetic model and a variety of symmetry broken spin states in the strongly intera cting regime. Ultra-cold atoms or quantum circuits implementation of both Haldane and Kane-Mele bosonic models would allow for experimental probes o f the exotic states we observed.\nSecond\, in order to deepen the perspect ives of quantum circuit simulations of topological phases we analyze the s trong coupling limit of the Su-Schrieffer-Heeger model and we test new exp erimental probes of its topology associated with the Zak phase. We also wo rk on the out-of-equilibrium protocols to study bulk spectral properties o f quantum systems and quantum phase transitions using a purification schem e which could be implemented both numerically and experimentally.\n\n\n\nM ini-workshop\n\n13:30-14:00  Walter Hofstetter -- Johann Wolfgang Goethe- Universität\, Frankfurt / Main\, Germany http://www.goethe-university-fra nkfurt.de/66535594/AG-Hofstetter\n\n14:00-14:30 Titus Neupert -- Universi ty of Zürich\, Switzerland http://www.physik.uzh.ch/en/groups/neupert/tea m/neupert.html\n\n14:30-15:00 Nathan Goldman -- Université libre de Bruxe lles\, Belgium hhtps://www.nathan-goldman-physics.com\n\n15:00-15:30 Pause \n\n15:30-16:00 Guido Pupillo -- ISIS\, Université de Strasbourg https:/ /isis.unistra.fr/laboratoire-de-physique-quantique-guido-pupillo/\n\n16:00 -16:30 Nicolas Regnault -- LPA\, ENS http://www.lpa.ens.fr/spip.php?page=a nnuaire&\;Chercheurs=1&\;lang=fr\n\n16:30-17:00 Mark Oliver Goerbig -- LPS\, Université Paris-Sud https://www.equipes.lps.u-psud.fr/GOERBIG/ \n CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-620@lptms.universite-paris-saclay.fr DTSTART:20180911T110000Z DTEND:20180911T120000Z DTSTAMP:20180829T094716Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mihail-poplavskyi/ SUMMARY:Séminaire du LPTMS: Mihail Poplavskyi - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 11 Sep 18 11:00 DESCRIPTION:Pfaffian Point Processes and corresponding gap probabilities\nM ihail Poplavskyi (King’s College London\, Department of Mathematics)\nSt ochastic point processes are natural models of complex particle systems. I n this talk we discuss point processes with a special structure of correla tion functions\, called Pfaffian Point Processes (PPP). We then give sever al examples of PPP such as the Glauber dynamics of Ising spin model\, ense mbles of random matrices with orthogonal symmetry\, random Kac series\, et c. In the second part of the talk we present recent results on gap probabi lities for PPP and their applications to persistence probabilities for a c lass of stochastic models.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-626@lptms.universite-paris-saclay.fr DTSTART:20180918T110000Z DTEND:20180918T120000Z DTSTAMP:20180911T053650Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-guillaume-roux/ SUMMARY:Séminaire du LPTMS: Guillaume Roux - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 18 Sep 18 11:00 DESCRIPTION:Quantum purification spectroscopy\nGuillaume Roux (LPTMS\, Univ ersité Paris-Sud)\nWe discuss a protocol based on quenching a purified qu antum system that allows to capture bulk spectral features. It uses an inf inite temperature initial state and an interferometric strategy to access the Loschmidt amplitude\, from which the spectral features are retrieved v ia Fourier transform\, providing coarse-grained approximation at finite ti mes. It involves techniques available in current experimental setups for q uantum simulation\, at least for small systems. We illustrate possible app lications in testing the eigenstate thermalization hypothesis and the phys ics of many-body localization.\n\nReference:\n\n Bradraj Pandey\, Kirill Plekhanov and Guillaume Roux\, Quantum purification spectroscopy\, preprin t quant-ph arXiv:1802.04638.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-617@lptms.universite-paris-saclay.fr DTSTART:20180925T110000Z DTEND:20180925T120000Z DTSTAMP:20180912T185349Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-arthur-goetschy/ SUMMARY:Séminaire du LPTMS: Arthur Goetschy - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 25 Sep 18 11:00 DESCRIPTION:Optimizing energy transfer and dwell times in disordered system s: a statistical approach\nArthur Goetschy (Institut Langevin\, ESPCI)\n\n \nWhen a wave such as light propagates through a disordered system\, it is scattered many times in various directions before escaping. At first sigh t\, this process is well described by diffusion. However\, diffusion negle cts interferences\, making us believe that the information content of a wa ve is progressively lost through spreading. This picture is incorrect. In fact\, multiple scattering is a linear process that redistributes informat ion among many degrees of freedom which can nowadays be resolved and manip ulated.\nIn this talk\, we will give an overview of different strategies t o achieve original light transport properties in open disordered systems t hat deviate both from the diffusive picture and the Gaussian field model. First\, we will characterize the statistical properties of the transmissio n matrix to demonstrate large energy transfer or focusing through nominall y opaque media [1\, 2]. Then\, we will discuss how to achieve similar perf ormance in transmission by means of the reflection matrix only [3\, 4]. Fi nally\, we will characterize the distribution of scattering times\, in ord er to generate excitations with particularly short or long dwell times.\n\ nReferences:\n\n [1] A. Goetschy and A. D. Stone\, Filtering Random Matri ces: The Effect of Incomplete Channel Control in Multiple Scattering\, Phy s. Rev. Lett. 111\, 063901 (2013)\n [2] C. W. Hsu\, S. F. Liew\, A. Goets chy\, H. Cao\, and A. D. Stone\, Correlation-enhanced control of wave focu sing in disordered media\, Nature Phys. 13\, 497 (2017)\n [3] N. Fayard\, A. Goetschy\, R. Pierrat and R. Carminati\, Mutual Information between Re flected and Transmitted Speckle Images\, Phys. Rev. Lett. 120\, 073901 (20 18)\n [4] I. Starshynov\, A. M. Paniagua-Diaz\, N. Fayard\, A. Goetschy \, R. Pierrat\, R. Carminati and J. Bertolotti\, Non-Gaussian Correlations between Reflected and Transmitted Intensity Patterns Emerging from Opaque Disordered Media\, Phys. Rev. X 8\, 021041 (2018)\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-603@lptms.universite-paris-saclay.fr DTSTART:20180927T140000Z DTEND:20180927T170000Z DTSTAMP:20180910T065100Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-ines-rodriguez-arias/ SUMMARY:Soutenance de thèse: Ines Rodriguez-Arias - IPN-batiment 100\, Aud itoriurm - 27 Sep 18 14:00 DESCRIPTION:Soutenance de thèse:\nCollective behaviors in interacting spin systems\npar\n\nInès Rodriguez-Arias\nJury:\n\n Cécile Monthus\, IPhT\ , CEA-Saclay\, présidente\n Juan Garrahan\, University of Notthingham\, rapporteur\n Nicolas Laflorencie\, LPT Université Paul Sabatier\, rappor teur\n Cristiano Ciuti\, MPQ Université Paris Diderot\, examinateur\n G eoffrey Bodenhausen\, Département de Chimie\, ENS\, examinateur\n Andrea De Luca\, University of Oxford\, invité.\n Alberto Rosso\, LPTMS\, Univ ersité Paris-Sud\, directeur de thèse\n\nRésumé: Dynamic nuclear polar ization (DNP) is one of the most promising techniques towards a new genera tion of Magnetic Resonance Imaging (MRI). The idea is to use the Nuclear M agnetic Resonance (NMR) in other nuclei rather than the traditional hydrog en\, such as carbon. For the carbon signal to be detected\, one needs to e nhance its spin polarization. In thermal equilibrium — at low temperatur e and high magnetic field — electron spins are far more polarized than a ny system of nuclear spins\, which is due to their smaller mass. With the DNP technique we bring the system out-of- equilibrium irradiating it with microwaves. This triggers polarization transfer from the electron spins to the nuclear ones.\nDuring my Ph.D\, I have studied both analytically and numerically the competition between the dipolar interactions among electro n spins (which can be tuned experimentally) and the disorder naturally pre sent in the sample. I proposed two models to study DNP: a Heisenberg spin- chain and a system of free-fermions in the Anderson model. Two different r egimes were found :\n(I) For strongly interacting electron spins\, the out -of-equilibrium steady state displays an effective thermodynamic behavior characterised by a very low spin temperature.\n(II) In the weakly interact ing regime\, it is not possible to define a spin temperature\, and it is a ssociated to a many-body localized phase (or an Anderson-localized phase). \nMy research was focused on the properties of the two phases with respect to the performance of DNP\, and I found it to be optimal at the transitio n between the two. This is a very important result that has been verified by recent experiments carried in École Normale Supérieure de Paris. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-624@lptms.universite-paris-saclay.fr DTSTART:20181003T110000Z DTEND:20181003T120000Z DTSTAMP:20180925T101123Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-alexis-lomakin/ SUMMARY:Physics-Biology interface seminar: Alexis Lomakin - Amphi BLANDIN d u LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 3 Oct 18 11: 00 DESCRIPTION:How do cells measure their boundaries to tailor physiological r esponses?\nAlexis Lomakin (King's College London\, UK)\n\nMuch like modern day engineered devices\, cells in the human body are able to make precise measurements: intestinal epithelial cells monitor local cell densities to prevent hyperplasia\, neutrophils sample their microenvironment to comput e the fastest migratory route toward infection sites\, and epidermal stem cells use extracellular matrix occupancy to make cell fate decisions. What these examples illustrate is the sensitivity of complex cell behaviors to spatial and mechanical constraints\, known in quantitative sciences as bo undary conditions. Although the importance of boundary conditions in cell and tissue physiology is increasingly recognized\, it remains unclear how cells sample their boundaries to tailor specific behaviors to boundary con ditions. Here\, using biophysical tools to manipulate cell boundaries in a highly controlled\, quantitative manner\, we found that cells estimate ex ternally-imposed confinement using their largest and stiffest intracellula r component\, the nucleus. Cell confinement below a certain threshold defo rms the nucleus and expands its envelope area. Unbuffered against area exp ansion due to slow turnover of constituents\, the nuclear envelope becomes stretched. This in turn engages signaling via nuclear membrane stretch-se nsitive proteins to the actomyosin cortex\, activating contractility. The latter provides a motive force for the cell to squeeze through tight pores and constrictions in the extracellular matrix. Interestingly\, no increas e in cell contractility is observed when cells move through environmental confines that do not significantly deform the nucleus. Thus\, the nucleus acts as an internal ruler for environmental confinement size\, allowing ce lls to utilize energetically costly contractility on demand\, only when su rrounding space becomes restrictive. The advantage of the proposed mechani sm is that in contrast to the plasma membrane\, nuclear membranes do not p articipate in constitutive membrane trafficking\; their surface area thus fluctuates less. This intrinsic quiescence should privilege them to functi on as low-noise detectors\, to readily discriminate local environmental co nditions from internal traffic-induced cell area/tension fluctuations.\n CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-621@lptms.universite-paris-saclay.fr DTSTART:20181009T110000Z DTEND:20181009T120000Z DTSTAMP:20180903T103128Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pierre-ronceray/ SUMMARY:Séminaire du LPTMS: Pierre Ronceray - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 9 Oct 18 11:00 DESCRIPTION:Learning force fields from stochastic trajectories\nPierre Ronc eray (Princeton Center for Theoretical Science\, USA)\nFrom nanometer-scal e proteins to micron-scale colloidal particles\, particles in biological a nd soft matter systems undergo Brownian dynamics: their deterministic moti on due to external forces and interactions competes with the random diffus ion due to thermal noise. In the absence of forces\, all trajectories look alike: the key information characterizing the system's dynamics thus lies in its force field. However\, reconstructing the force field by inspectin g microscopy observations of the system's trajectory is a hard problem\, f or two reasons. First\, there needs to be enough information about the for ce available in the trajectory: the effect of the force field becomes appa rent only after a long enough observation time. Second\, one needs a pract ical method to extract that information and reconstruct the force field\, which is challenging for force fields with a spatial structure\, in partic ular in the presence of measurement noise. Here we address these two probl ems for steady-state Brownian trajectories. We first give a quantitative m eaning to the information contained in a trajectory\, and show how it limi ts force inference. We then propose a practical procedure to optimally use this information to reconstruct the force field by decomposing it into mo ments. Using simple model stochastic processes\, we demonstrate that our m ethod permits a quantitative evaluation of phase space forces and currents \, circulation\, and entropy production with a minimal amount of data. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-628@lptms.universite-paris-saclay.fr DTSTART:20181015T110000Z DTEND:20181015T120000Z DTSTAMP:20180914T054042Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/topological-trans ition-in-a-non-hermitian-quantum-walk/ SUMMARY:Quantum Journal Club: Leonardo Mazza - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 15 Oct 18 11:00 DESCRIPTION:Topological Transition in a Non-Hermitian Quantum Walk CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-625@lptms.universite-paris-saclay.fr DTSTART:20181017T110000Z DTEND:20181017T120000Z DTSTAMP:20181012T062142Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-pierre-ronceray/ SUMMARY:Physics-Biology interface seminar: Pierre Ronceray - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 17 Oct 18 1 1:00 DESCRIPTION:Cell contraction induces long-ranged stress stiffening in the e xtracellular matrix\nPierre Ronceray (Princeton University\, USA)\nAnimal cells in tissues are supported by biopolymer matrices\, which typically ex hibit highly nonlinear mechanical properties. While the linear elasticity of the matrix can significantly impact cell mechanics and functionality\, it remains largely unknown how cells\, in turn\, affect the nonlinear mech anics of their surrounding matrix. Here we show that living contractile ce lls are able to generate a massive stiffness gradient in three distinct 3D extracellular matrix model systems: collagen\, fibrin\, and Matrigel. We decipher this remarkable behavior by introducing Nonlinear Stress Inferenc e Microscopy (NSIM)\, a novel technique to infer stress fields in a 3D mat rix from nonlinear microrheology measurement with optical tweezers. Using NSIM and simulations\, we reveal a long-ranged propagation of cell-generat ed stresses resulting from local filament buckling. This slow decay of str ess gives rise to the large spatial extent of the observed cell-induced ma trix stiffness gradient\, which could form a mechanism for mechanical comm unication between cells. CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-622@lptms.universite-paris-saclay.fr DTSTART:20181023T110000Z DTEND:20181023T120000Z DTSTAMP:20180913T063151Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-valentina-ros/ SUMMARY:Séminaire du LPTMS: Valentina Ros - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 23 Oct 18 11:00 DESCRIPTION:Arrangement of local minima and phase transitions in the energy landscape of simple glassy models\nValentina Ros (IPhT\, CEA-Saclay)\nUnd erstanding the statistical properties of the stationary points of high-dim ensional\, random energy landscapes is a central problem in the physics of glassy systems\, as well as in interdisciplinary applications to computer science\, ecology and biology. In this talk\, I will discuss a framework to perform the computation of the quenched complexity of stationary points \, making use of a replicated version of the Kac-Rice formula. I will disc uss its application to simple models (the spiked tensor model and its gene ralizations) which capture the competition between a deterministic signal and stochastic noise\, and correspond to a spherical p-spin Hamiltonian en dowed with ferromagnetic multi-body interaction terms. I will describe the phase transitions that occur in the structure of the landscape when chang ing the signal-to-noise ratio\, and highlight the implications for the evo lution of local dynamics within the landscape.\n\nReference:\n\n Valentin a Ros\, Gerard Ben Arous\, Giulio Biroli and Chiara Cammarota\, Complex en ergy landscapes in spiked-tensor and simple glassy models: ruggedness\, ar rangements of local minima and phase transitions\, preprint cond-mat arXiv :1804.02686\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-629@lptms.universite-paris-saclay.fr DTSTART:20181029T110000Z DTEND:20181029T120000Z DTSTAMP:20180914T061741Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/quantum-journal-c lub-eoin-quinn/ SUMMARY:Quantum Journal Club: Eoin Quinn - LPTMS\, salle 201\, 2ème étage \, Bât 100\, Campus d'Orsay - 29 Oct 18 11:00 DESCRIPTION:Organising strong correlations: Schwinger-Shastry formalism CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-631@lptms.universite-paris-saclay.fr DTSTART:20181030T110000Z DTEND:20181030T120000Z DTSTAMP:20181023T142302Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alberto-biella/ SUMMARY:Séminaire du LPTMS: Alberto Biella - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 30 Oct 18 11:00 DESCRIPTION:Efficient stochastic unraveling of disordered open quantum syst ems\nAlberto Biella (Laboratoire Matériaux et Phénomènes Quantiques\, U niversité Paris Diderot)\nThe interplay of interaction\, dissipation and driving in open quantum systems can trigger transitions between nonequilib rium phases. Such behaviour can emerge in extended lattices\, in more then one spatial dimension\, when homogenous systems are considered. However\, in any realistic experimental realization\, disorder cannot be neglected.  In this work we develop a method to efficiently unravel the density matr ix of a generic disordered open quantum system exploiting stochastic traje ctories. We use it to study the effect of on-site disorder in the paradigm atic driven-dissipative Bose-Hubbard lattice in two dimensions. In particu lar\, we will focus on the role of the disorder when the system is driven across a first-order transition from the low- to the high-density phase. W e found that the disorder induces the formation of density domains which p rogressively smears the sharp transition leading to a crossover behaviour in the thermodynamic limit. We characterize this mechanism in terms of pho ton density and spatial correlation functions and we discuss how inhomogen eities affects the bistable dynamics of the system at the transition. Our results are relevant for state-of-the-art experiments in extended photonic lattices based on semiconductor microcavities and superconducting circuit s. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-639@lptms.universite-paris-saclay.fr DTSTART:20181107T110000Z DTEND:20181107T120000Z DTSTAMP:20181025T174853Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-willy-supatto/ SUMMARY:Physics-Biology interface seminar: Willy Supatto - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 7 Nov 18 11:0 0 DESCRIPTION:Live imaging of motile cilia to investigate left-right symmetry breaking in zebrafish embryos\nWilly Supatto (LOB\, École polytechnique) \nIn vertebrate embryos\, cilia-driven fluid flows are guiding left-right body symmetry breaking within the left-right organizer (LRO). To investiga te the generation and sensing of flows\, it is required to quantify cilia biophysical features in 3D and in vivo [1]. In the zebrafish embryo\, the LRO is called the Kupffer’s vesicle (KV) and is a spheroid shape cavity\ , which is covered with motile cilia distributed at its surface and orient ed in all directions of space. This transient structure varies in size and shape during development and from one embryo to the other. As a consequen ce\, the experimental investigation of cilia properties is challenging. It requires quantifying cilia features in vivo and in 3D and combining the d ata from different embryos to compare one embryo to the other and perform statistical analyses.To reach this goal\, we devised an experimental workf low combining live 3D imaging using multiphoton microscopy\, image process ing\, and data registration to quantify cilia biophysical features\, such as cilia density\, motility\, 3D orientation\, or length. We integrated su ch experimental features obtained in vivo into a fluid dynamics model and a multiscale physical study of flow generation and detection. This strateg y enabled us to demonstrate how cilia orientation pattern generates the as ymmetric flow within the KV [2]. In addition\, we could investigate the ph ysical limits of flow detection to clarify which mechanisms could be relia bly used for body axis symmetry breaking [2]. Finally\, we discovered the distribution of cilia orientation is asymmetric within the KV [3]. Importa ntly\, these results suggested that the asymmetric force detection could r esult from the cilium being sensitive to its own motion. Together\, this w ork sheds light on the complexity of left-right symmetry breaking and chir ality genesis in developing tissues.\n[1] From cilia hydrodynamics to zebr afish embryonic development. Supatto &\; Vermot\, Current Topics in Dev elopmental Biology 2011\n[2] Physical limits of flow sensing in the left-r ight organizer. Ferreira et al\, eLife 2017\n[3] Chiral cilia orientation in the left-right organizer. Ferreira et al\, Cell Reports\, in press CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-636@lptms.universite-paris-saclay.fr DTSTART:20181108T110000Z DTEND:20181108T120000Z DTSTAMP:20181023T055546Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-paola-ruggiero/ SUMMARY:Séminaire du LPTMS: Paola Ruggiero - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 8 Nov 18 11:00 DESCRIPTION:*** Attention : jour inhabituel ***\nConformal field theory on top of a breathing Tonks-Girardeau gas\nPaola Ruggiero (SISSA\, Trieste\, Italie)\nConformal field theory (CFT) has been extremely successful in des cribing universal effects in critical one-dimensional (1D) systems\, in si tuations in which the bulk is uniform. However\, in many experimental cont exts\, such as quantum gases in trapping potentials and in several out-of- equilibrium situations\, systems are strongly inhomogeneous. Recently it w as shown that the CFT methods can be extended to deal with such 1D situati ons [1\,2]: the system’s inhomogeneity gets reabsorbed in the parameters of the theory\, such as the metric\, resulting in a CFT in curved space. Here in particular we make use of CFT in curved spacetime to deal with the out-of-equilibrium situation generated by a frequency quench in a Tonks-G irardeau gas in a harmonic trap [3]. We show compatibility with known exac t result and use this new method to compute new quantities\, not explicitl y known by means of other methods\, such as the dynamical fermionic propag ator and the one particle density matrix at different times.\n\nRefs:\n\n [1] J. Dubail\, JM. Stéphan\, J. Viti &\; P. Calabrese\, Conformal f ield theory for inhomogeneous one-dimensional quantum systems: the example of non-interacting Fermi gases\, SciPost Phys. 2\, 002 (2017).\n [2] S. Murciano\, P. Ruggiero &\; P. Calabrese\, Entanglement and relative ent ropies for low-lying excited states in inhomogeneous one-dimensional quant um systems\, arXiv:1810.02287\n [3] P. Ruggiero\, Y. Brun &\; J. Dubai l\, To appear.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-615@lptms.universite-paris-saclay.fr DTSTART:20181113T110000Z DTEND:20181113T120000Z DTSTAMP:20181108T073131Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-herbert-spohn/ SUMMARY:Séminaire du LPTMS: Herbert Spohn - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 13 Nov 18 11:00 DESCRIPTION:Nonlinear fluctuating hydrodynamics for one-dimensional fluids\ nProfessor Herbert Spohn (Zentrum Mathematik\, München)\nFor one-dimensio nal fluids the conventional Landau-Lifshitz fluctuating hydrodynamics brea ks down. I discuss its nonlinear extension in the approximation of an anha rmonic chain\, in particular the dynamical phase diagram and self-similar shape functions. A recent novel development concerns the application of th e theory to nonintegrable classical spin chains.\n\n\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-638@lptms.universite-paris-saclay.fr DTSTART:20181115T110000Z DTEND:20181115T120000Z DTSTAMP:20181011T101828Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexios-polychronakos-seminaire-exceptionnel/ SUMMARY:Séminaire du LPTMS: Alexios Polychronakos *** séminaire exception nel *** - LPTMS-batiment 100\, salle des conseils - 15 Nov 18 11:00 DESCRIPTION:!!!! ATTENTION : LIEU INHABITUEL (salle des conseils de l'IPN) !!!!\n\n100 Years of Feynman and 30 without him: reminiscences from his la st year\nAlexios P. Polychronakos (The City College and Graduate Center of the CUNY\, New York)\n2018 marks the 100th anniversary of the birth and 3 0 years since the passing of Richard Feynman\, a brilliantly creative phys icist and a legendary personality in science and society at large. During the last year of his life at Caltech Feynman became fascinated by integrab le models\, his involvement and enthusiasm inspiring and motivating both e xperts and novices in the field. I will attempt to give a glimpse into Fey nman's thinking and personality through the lens of personal memories and mementos from that last year.\n\n \; CATEGORIES:seminars LOCATION:LPTMS-batiment 100\, salle des conseils\, 15 Rue Georges Clemencea u\, Orsay\, France GEO:48.698200;2.181770 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS-batiment 100\, salle des conseils:geo:48.698200,2.181770 END:VEVENT BEGIN:VEVENT UID:0-623@lptms.universite-paris-saclay.fr DTSTART:20181120T110000Z DTEND:20181120T120000Z DTSTAMP:20181010T121206Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-emmanuel-trizac/ SUMMARY:Séminaire du LPTMS: Emmanuel Trizac - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 20 Nov 18 11:00 DESCRIPTION:When random walkers help solving intriguing integrals\nEmmanuel Trizac (LPTMS\, Université Paris-Sud)\nWe will discuss the properties of a family of integrals involving the cardinal sine fuction\, first studied by Borwein &\; Borwein. The aim is to provide a physicist's perspectiv e onto a curious change of behaviour occurring within this family\, notice d when benchmarking computer algebra packages\, and initially attributed t o a bug. A number of non-trivial generalizations will be obtained. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-633@lptms.universite-paris-saclay.fr DTSTART:20181121T110000Z DTEND:20181121T120000Z DTSTAMP:20181115T071904Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jan-brugues-2/ SUMMARY:Physics-Biology interface seminar: Jan Brugues - Amphi BLANDIN du L PS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 21 Nov 18 11:00 DESCRIPTION:How to set the proper size and shape of metaphase spindles\nJan Brugues (MPI Dresden\, Germany)\nRegulation of size and growth is a funda mental problem in biology. A prominent example is the formation of the mit otic spindle\, where protein concentration gradients around chromosomes ar e thought to regulate spindle growth by controlling microtubule nucleation . Previous evidence suggests that microtubules nucleate throughout the spi ndle structure. However\, the mechanisms underlying microtubule nucleation and its spatial regulation are still unclear. In the first part of the ta lk I will present an assay based on laser ablation to directly probe micro tubule nucleation events in Xenopus laevis egg extracts. Combining this me thod with theory and quantitative microscopy\, we show that the size of a spindle is controlled by autocatalytic growth of microtubules\, driven by microtubule-stimulated microtubule nucleation. The autocatalytic activity of this nucleation system is spatially regulated by the limiting amounts o f active microtubule nucleators\, which decrease with distance from the ch romosomes. This mechanism provides an upper limit to spindle size even whe n resources are not limiting. Once the necessary amounts of microtubules a re created\, the activities of motors lead to the proper shape and archite cture of spindles. In the second part of the talk I will discuss the origi n of motor-mediated stress in spindles. CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-637@lptms.universite-paris-saclay.fr DTSTART:20181122T143000Z DTEND:20181122T170000Z DTSTAMP:20181009T132025Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-shuang-wu/ SUMMARY:Soutenance de thèse: Shuang Wu - IPN-batiment 100\, Auditoriurm - 22 Nov 18 14:30 DESCRIPTION:Soutenance de thèse:\nAlgebraic area distribution of two dimen sional random walks and the Hofstadter model\npar\n\nShuang Wu\nJury:\n\n Rapporteur: Sergei Matveenko (Landau Institute for Theoretical Physics\, Moscow\, Russia)\n Rapporteur: Alexios Polychronakos  (The City College of New York\, USA)\n Examinateur: Angel Alastuey (Laboratoire de Physique \, ENS Lyon)\n Examinateur: Vincent Pasquier (IPhT\, CEA Saclay)\n Exami natrice: Didina Serban (IPhT\, CEA Saclay)\n Invité: Olivier Giraud (LPT MS\, Université Paris-Sud)\n Directeur de thèse: Stéphane Ouvry (LPTMS \, Université Paris-Sud)\n\nRésumé:\nThis thesis is about the Hofstadte r model\, i.e\, a single electron moving on a two-dimensional lattice coup led to a perpendicular homogeneous magnetic field. Its spectrum is one of the famous fractals in quantum mechanics\, known as the Hofstadter's butte rfly. There are two main subjects in this thesis: the first is the study o f the deep connection between the Hofstadter model and the distribution of the algebraic area enclosed by two-dimensional random walks. The second f ocuses on the distinctive features of the Hofstadter's butterfly and the s tudy of the bandwidth of the spectrum. We found an exact expression for th e trace of the Hofstadter Hamiltonian in terms of the Kreft coefficients\, and for the higher moments of the bandwidth. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-642@lptms.universite-paris-saclay.fr DTSTART:20181126T110000Z DTEND:20181126T120000Z DTSTAMP:20181121T103902Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/quantum-journal-c lub-christophe-texier/ SUMMARY:Quantum Journal Club: Christophe Texier - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 26 Nov 18 11:00 DESCRIPTION:Correlations of occupation numbers in the canonical ensemble \n Christophe Texier (LPTMS\, Université Paris-Sud)\nThe connection between the statistical physics of non-interaction indistinguishable particles in quantum mechanics and the theory of symmetric functions will be reviewed. Then\, I will study the $p$-point correlation function $\\overline{n_1\\cd ots n_p}$ of occupation numbers in the canonical ensemble \; in the grand canonical ensemble\, they are trivially obtained from the independence of individual quantum states\, however the constraint on the number of partic les makes the problem non trivial in the canonical ensemble. I will show s everal representations of these correlation functions. I will illustrate t he main formulae by revisiting the problem of Bose-Einstein condensation i n a 1D harmonic trap in the canonical ensemble\, for which we have obtaine d several analytical results. In particular\, in the temperature regime do minated by quantum correlations\, the distribution of the ground state occ upancy is shown to be a truncated Gumbel law.\n\nRef: Olivier Giraud\, Aur élien Grabsch &\; Christophe Texier\, Correlations of occupation numbe rs in the canonical ensemble and application to BEC in a 1D harmonic trap\ , Phys. Rev. A 97\, 053615 (2018). CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-619@lptms.universite-paris-saclay.fr DTSTART:20181127T110000Z DTEND:20181127T120000Z DTSTAMP:20181121T103926Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandre-krajenbrink/ SUMMARY:Séminaire du LPTMS: Alexandre Krajenbrink - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 27 Nov 18 11:00 DESCRIPTION:Linear statistics and pushed Coulomb-gas at the soft edge of ra ndom matrices : four paths to large deviations\nAlexandre Krajenbrink (LPT -ENS\, Paris)\nIn this talk\, I will consider the classical problem of lin ear statistics in random matrix theory. This amounts to study the distribu tion of the sum of a certain function of the matrix eigenvalues. Varying t his function\, this problem can describe fluctuations of conductance\, sho t noise\, Renyi entropy\, center of mass of interfaces\, particle number …\nThis problem has been extensively studied for the bulk of the eigenva lues (macroscopic linear statistics) where interesting phase transitions h ave been unveiled but not so much at the edge of the spectrum (microscopic linear statistics) on which I will focus.\nIn particular\, I will introdu ce four methods to solve this problem\, show their equivalence and I will discuss the physical applications of these results (large deviations of th e solution of the Kardar-Parisi-Zhang equation\, existence of phase transi tions with continuously varying exponent and possible experimental realiza tion of this setup with non-intersecting Brownian interfaces).\nReference :\n\n Alexandre Krajenbrink &\; Pierre Le Doussal\, Linear statistics and pushed Coulomb gas at the edge of beta random matrices: four paths to large deviations\, preprint arXiv:1811.00509\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-627@lptms.universite-paris-saclay.fr DTSTART:20181204T110000Z DTEND:20181204T120000Z DTSTAMP:20181204T124706Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lucile-julien/ SUMMARY:Séminaire du LPTMS: Lucile Julien - IPN-batiment 100\, Auditoriurm - 4 Déc 18 11:00 DESCRIPTION:La révision du système international d'unités\nLucile Julien (Laboratoire Kastler-Brossel\, UPMC\, Paris)\nPrésentation en pdf\nArtic le de Pierre Cladé et Lucile Julien\, "Les mesures atomiques de haute pr écision. Un outil privilégié pour tester l’électrodynamique quantiqu e"\, Reflets de la Physique 59\, sept. 2018\nLe SI\, système internationa l d’unités\, né en 1960\, est l’héritier du système métrique et d u système MKSA. Il est fondé sur 7 unités de base\, dont les définitio ns peuvent changer lorsque les besoins des utilisateurs le rendent nécess aire. Ainsi\, le mètre a été redéfini en 1983 en fixant la valeur num érique de la vitesse de la lumière dans le vide.\nLa 26ème Conférence Générale des Poids et Mesures\, qui s'est réunie du 13 au 16 novembre\, a décidé de la même façon de redéfinir le kilogramme\, l’ampère\, la mole et le kelvin en fixant les valeurs de quatre constantes de la phy sique.\nAprès une présentation historique du SI\, je présenterai les mo tivations de sa révision actuelle\, les travaux qui l’ont rendue possib le et la façon dont elle est réalisée.\n\n \;\n!!!! ATTENTION : LIE U INHABITUEL (Auditorium Irène Joliot Curie) !!!!\n**** l'exposé sera en français ****\n CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-632@lptms.universite-paris-saclay.fr DTSTART:20181205T110000Z DTEND:20181205T120000Z DTSTAMP:20181203T125711Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-ana-jesus-garcia-saez/ SUMMARY:Physics-Biology interface seminar: Ana-Jesus Garcia-Saez - Moyen Am phi\, Building 510\, Université Paris-Saclay Orsay - 5 Déc 18 11:00 DESCRIPTION:Single molecule analysis of mitochondrial permeabilization in a poptosis\nAna-Jesus Garcia-Saez (MPI Tübingen\, Germany)\nBax and Bak are key regulators of apoptosis and mediate the permeabilization of the outer mitocondrial membrane that leads to cytochrome and Smac release. Although it is widely accepted that Bax and Bak function and molecular mechanism l argely overlap\, there is limited evidence how Bak works. In previous stud ies\, we have used single molecule microscopy to characterize the oligomer ization of Bax in the membrane and its organization at the nanoscale in th e mitochondria of apoptotic cells. We now extended these approaches to Bak and identified key structural differences between the two proteins that m ay have functional implications. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-630@lptms.universite-paris-saclay.fr DTSTART:20181211T110000Z DTEND:20181211T120000Z DTSTAMP:20181113T213822Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christophe-mora/ SUMMARY:Séminaire du LPTMS: Christophe Mora - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 11 Déc 18 11:00 DESCRIPTION:Parafermions and symmetry-enriched Majorana fermions in one-dim ensional fermionic models\nChristophe Mora (Laboratoire Pierre Aigrain\, E NS\, Paris)\nStabilizing and manipulating exotic emergent quasiparticles i s one of the main goal of modern condensed matter physics. The quest for o bserving Majorana fermions and their non-Abelian braiding statistics in su perconducting nanostructures is currently attracting a lot of attention\, with fascinating prospects in fault-tolerant quantum computation. Paraferm ions are the simplest generalization of Majorana fermions: they show non-A belian fractional statistics and are typically associated with topological phases. We will discuss the possibility of harboring these exotic excitat ions in genuinely one-dimensional electronic platforms. We focus on a spec ific model of fermions in one dimension with a generalized ZN multiplet pa iring extending the standard and so-called Kitaev chain model. Using a com bination of analytical techniques\, we find an interesting topological pha se intertwined with spontaneous symmetry breaking. Each symmetry-breaking sector is shown to possess a pair of boundary Majorana fermions encoding a topological character. A careful study of the quantum anomaly through pum ping in the system finally reveals that parafermions exist in one dimensio n but only as non-local operators.\n\nReferences:\n\n Fernando Iemini\, C hristophe Mora &\; Leonardo Mazza\, Topological phases of parafermions: a model with exactly-solvable ground states\, Phys. Rev. Lett. 118\, 1704 02 (2017)\n Leonardo Mazza\, Fernando Iemini\, Marcello Dalmonte &\; C hristophe Mora\, Poor man's parafermions in a lattice model with even mult iplet pairing\, preprint cond-mat arXiv:1801.08548.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-648@lptms.universite-paris-saclay.fr DTSTART:20181218T110000Z DTEND:20181218T120000Z DTSTAMP:20181207T111312Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christophe-texier-2/ SUMMARY:Séminaire du LPTMS: Christophe Texier - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Déc 18 11:00 DESCRIPTION:Counting the equilibria of a directed polymer in a random mediu m and Anderson localisation\nChristophe Texier (LPTMS\, Université Paris- Sud)\nI will discuss a new connection between two different problems: the counting of equilibria of a directed polymer in a random medium (DPRM) and the problem of Anderson localisation for the 1D Schrödinger equation. Us ing the Kac-Rice formula\, it is possible to express the mean number of eq uilibria of a DPRM in terms of functional determinants. In the one-dimensi onal situation\, these functional determinants can be calculated thanks to the Gelfand-Yaglom method\, showing that the mean number of equilibria of the DPRM growth exponentially with the length of the polymer\, with a rat e controlled by the generalized Lyapunov exponent (GLE) of the localisatio n problem (cumulant generating function of the log of the wave function). The GLE is solution of a spectral problem studied by combining numerical a pproaches and WKB-like approximation. Furthermore\, the formalism can be e xtended in order to obtain the number of equilibria at fixed energy\, prov iding the (annealed) distribution of the energy density of the line over t he equilibria.\n\nReference:\n\n Yan V. Fyodorov\, Pierre Le Doussal\, Al berto Rosso and Christophe Texier\, Exponential number of equilibria and d epinning threshold for a directed polymer in a random potential\, Annals o f Physics 397\, 1-64 (2018)\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-635@lptms.universite-paris-saclay.fr DTSTART:20181219T110000Z DTEND:20181219T120000Z DTSTAMP:20181214T201310Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-karim-benzerara/ SUMMARY:Physics-Biology interface seminar: Karim Benzerara - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 19 Déc 18 11:00 DESCRIPTION:Seminar cancelled: rescheduled for March 13th\nKarim Benzerara (Sorbonne Universités\, Paris) CATEGORIES:physbio,seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-643@lptms.universite-paris-saclay.fr DTSTART:20190115T110000Z DTEND:20190115T120000Z DTSTAMP:20181204T143924Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-fabio-franchini/ SUMMARY:Séminaire du LPTMS: Fabio Franchini - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 15 Jan 19 11:00 DESCRIPTION:Spontaneous Ergodicity Breaking in Invariant Matrix Models\nFab io Franchini (Institut Ruđer Bošković\, Zagreb\, Croatia)\nWe reconside r the study of the eigenvectors of a random matrix\, to better understand the relation between localization and eigenvalue statistics. Traditionally \, the requirement of base invariance has lead to the conclusion that inva riant models describe only extended (conductive) systems. We show that dev iations of the eigenvalue statistics from the Wigner-Dyson universality re flects itself on the eigenvector distribution. In particular\, gaps in the eigenvalue density spontaneously break the U(N) symmetry to a smaller one \, hence rendering the system not anymore ergodic. Models with log-normal weights\, recently considered also in string theory models such as ABJM th eories\, show a critical eigenvalue distribution which would indicate a cr itical breaking of the U(N) symmetry\, supposedly resulting into a multi-f ractal eigenvector statistics. These results pave the way to the explorati on of localization problems using random matrices via the study of new cla sses of observables and potentially to novel\, interdisciplinary\, applica tions of matrix models. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-634@lptms.universite-paris-saclay.fr DTSTART:20190116T110000Z DTEND:20190116T120000Z DTSTAMP:20181130T204701Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-philippe-marcq/ SUMMARY:Physics-Biology interface seminar: Philippe Marcq - LPTMS\, salle 2 01\, 2ème étage\, Bât 100\, Campus d'Orsay - 16 Jan 19 11:00 DESCRIPTION:From cells to tissue: A continuum model of epithelial mechanics \nPhilippe Marcq (Institut Curie\, Paris)\nSPECIAL LOCATION\nA continuum m odel of epithelial tissue mechanics is formulated using cellular-level mec hanical ingredients and cell morphogenetic processes\, including cellular shape changes and cellular rearrangements. This model incorporates stress and deformation tensors\, which can be compared with experimental data. F ocusing on the interplay between cell shape changes and cell rearrangement s\, we elucidate dynamical behavior underlying passive relaxation\, active contraction-elongation\, and tissue shear flow. Extensions of the model a llow to incorporate additional ingredients\, such as cell division\, cell death\, and cell motility. CATEGORIES:physbio,seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-641@lptms.universite-paris-saclay.fr DTSTART:20190122T110000Z DTEND:20190122T120000Z DTSTAMP:20190115T115007Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gatien-verley/ SUMMARY:Séminaire du LPTMS: Gatien Verley - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 22 Jan 19 11:00 DESCRIPTION:Non-equilibrium conductance -- Assembly of energy converter\nGa tien Verley (LPT\, Bât. 210\, Université Paris-Sud)\nStochastic thermody namic is the appropriated theory to study small non-equilibrium systems mo deled by Markov processes. These systems are driven by several heat reserv oirs (or work sources) and are crossed by strong energy currents. In this framework and for stationary Markov jump processes\, I will introduce the concept of non-equilibrium conductance matrix that connects energy current s and thermodynamic forces\, as Onsager matrices do for close-to-equilibri um systems. I will discuss the Thermodynamic Uncertainty Relations (TUR) t hat generalizes far from equilibrium the fluctuations-dissipation theorem. A central result is that current covariances are bounded from below by th e conductance matrix (Loewner partial order). In the close to equilibrium limit\, this TUR saturates restoring the fluctuations-dissipation theorem. \nNon-equilibrium conductance matrices are also convenient to study energy converters and power efficiency trade-off. In the second part\, I will de scribe an energy converter made of many small interacting elementary machi nes. This energy converter has many original features that I found inspiri ng for understanding the physics of non-equilibrium systems :\n- emergent strong coupling in the mean-field treatment (as evidenced by the non-equil ibrium conductance matrix)\,\n- collective enhancement of efficiency and p ower\,\n- dynamical phase transition and emergent ergodicity breaking (non -convex large deviation functions for currents)\n- non-typical efficiency fluctuations CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-647@lptms.universite-paris-saclay.fr DTSTART:20190130T110000Z DTEND:20190130T120000Z DTSTAMP:20190115T104017Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-mathilde-badoual/ SUMMARY:Physics-Biology interface seminar: Mathilde Badoual - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 30 Jan 19 11:00 DESCRIPTION:Modeling evolution of brain tumors \nMathilde Badoual (IMNC\, U . Paris-Sud)\nDiffuse low-grade gliomas are slowly-growing tumors. After t ens of years\, they transform inexorably into more aggressive forms\, jeop ardizing the patient’s life. Mathematical modeling could help clinicians to have a better understanding of the natural history of these tumors and their response to treatments. \nWe present here different models of these tumors: the first one is discrete and describes the appearance of the fir st glioma cells and the genesis of a tumor. The second model is continuous and consists in a partial differential equation that describes the evolut ion of the cell density. This model can describe the natural evolution of gliomas and their response to treatments such as radiotherapy. The discret e and the continuous models are designed to be close to the biological rea lity. The results are quantitatively compared with either biological data or clinical data\, at the cellular level (histological samples) and at the organ level (clinical imaging\, such as MRI scans). CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-646@lptms.universite-paris-saclay.fr DTSTART:20190205T143000Z DTEND:20190205T173000Z DTSTAMP:20190124T073511Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-de-giulio-bertoli/ SUMMARY:Soutenance de thèse: Giulio Bertoli - IPN-batiment 100\, Auditoriu rm - 5 Fév 19 14:30 DESCRIPTION:Soutenance de thèse:\nMany-body localization of two-dimensiona l disordered bosons\npar\n\nGiulio Bertoli\nJury:\n\n Rapporteur : Anna M inguzzi (LPMMC\, Grenoble)\n Rapporteur : Vladimir Yudson (Russian Quantu m Center\, Moscow)\n Examinateur : Vladimir Kravtsov (ICTP\, Trieste)\n Examinateur : Nicolas Pavloff (LPTMS\, Orsay)\n Directeur de thèse : Geo rgy Shlyapnikov (LPTMS\, Orsay)\n\nRésumé:\nThe study of the interplay b etween localization and interactions in disordered quantum systems led to the discovery of the interesting physics of many-body localization (MBL). This remarkable phenomenon provides a generic mechanism for the breaking o f ergodicity in quantum isolated systems\, and has stimulated several ques tions such as the possibility of a finite-temperature fluid-insulator tran sition. At the same time\, the domain of ultracold interacting atoms is a rapidly growing field in the physics of disordered quantum systems.\nIn th is Thesis\, we study many-body localization in the context of two-dimensio nal disordered ultracold bosons. After reviewing some importance concepts\ , we present a study of the phase diagram of a two-dimensional weakly inte racting Bose gas in a random potential at finite temperatures. The system undergoes two finite-temperature transitions: the MBL transition from norm al fluid to insulator and the Berezinskii-Kosterlitz-Thouless transition f rom algebraic superfluid to normal fluid. At T=0\, we show the existence o f a tricritical point where the three phases coexist. We also discuss the influence of the truncation of the energy distribution function at the tra p barrier\, a generic phenomenon for ultracold atoms. The truncation limit s the growth of the localization length with energy and\, in contrast to t he thermodynamic limit\, the insulator phase is present at any temperature . Finally\, we conclude by discussing the stability of the insulating phas e with respect to highly energetic particles in systems defined on a conti nuum. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-649@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190212T110000 DTEND;TZID=Europe/Paris:20190212T120000 DTSTAMP:20190207T080117Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marie-farge/ SUMMARY:Séminaire du LPTMS: Marie Farge - IPN-batiment 100\, Auditoriurm - 12 Fév 19 11:00 DESCRIPTION:Comment faire évoluer le système de publication académique e n faisant passer l'intérêt des chercheurs devant celui des maisons d'éd ition?\nMarie Farge (CNRS-INSMI et ENS Paris)\nLa publication des résulta ts de la recherche se fait encore aujourd'hui selon un modèle hérité de l'imprimerie\, où les revues académiques appartiennent aux maisons d'é dition et où les chercheurs\, ou leur institution\, doivent payer pour li re les articles\, voire même pour publier. Ce modèle est inadapté à l' ère de l'édition électronique et du Web et le préserver tel quel est c ontre-productif pour l'avancement de la recherche. Il est important que le s chercheurs proposent de nouveaux modèles mieux adaptés à leurs besoin s. Nous donnerons différents exemples d'outils développés par les cherc heurs pour les chercheurs\, dont les plateformes http://dissem.in et https ://www.centre-mersenne.org/.\nhttp://openscience.ens.fr/MARIE_FARGE\nhttps ://hal.archives-ouvertes.fr/hal-01503303\nhttps://hal.archives-ouvertes.fr /hal-01503304\nhttps://hal.archives-ouvertes.fr/hal-01503306\nhttps://hal. archives-ouvertes.fr/hal-01503287\nhttps://zenodo.org/record/1227093\n____ __________________________________________________________________________ __\nMarie Farge est Directrice de Recherche au CNRS. Elle est rattachée à l'Institut National des Mathématiques et de leurs interactions (INSMI) et affectée au Laboratoire de Météorologie Dynamique (LMD) de l'ENS-Pa ris. Ses domaines de recherche sont la dynamique non linéaire\, la turbul ence et l'analyse harmonique\, en particulier la transformée en ondelette s. Elle a rédigé en 2011 l'avis du COMETS (Comité d'Ethique du CNRS) su r les relations entre les chercheurs et les maisons d'édition et a partic ipé en 2012 au lancement du mouvement The cost of knowledge. En 2015 elle a co-fondé le Comité pour l'Accessibilité aux Publications en Sciences and Humanités (CAPSH) qui développe la plate-forme http://dissem.in pou r aider les chercheurs à mettre leurs articles en accès ouvert. Elle est membre du conseil de l'Academia Europaea depuis 2013 et du conseil scient ifique du Centre Mersenne créé en 2018\, https://www.centre-mersenne.org /.\nhttp://openscience.ens.fr/MARIE_FARGE\nhttp://wavelets.ens.fr   dans   'Publications' CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-658@lptms.universite-paris-saclay.fr DTSTART:20190213T110000Z DTEND:20190213T120000Z DTSTAMP:20190203T212314Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-andela-saric/ SUMMARY:Physics-Biology interface seminar: Andela Saric - Moyen Amphi\, Bui lding 510\, Université Paris-Saclay Orsay - 13 Fév 19 11:00 DESCRIPTION:Sensing and creating mechanical forces by protein assembly\nAnd ela Saric (University College London\, UK)\nResponding to mechanical cues and producing mechanical forces is central to survival and adaptation of a ll organisms. To do so\, cells dynamically organise a large number of memb rane proteins into functional nanoscale structures. Due to their multiscal e nature\, such processes are challenging to resolve with current experime ntal techniques and are too complex for detailed molecular simulations. Co arse-grained computer simulations\, rooted in statistical mechanics and so ft-matter physics\, can be of great value in determining how functional pr otein nanostructures operate. Here I will discuss cooperative gating of me chanosensitive membrane channels\, and the production of mechanical forces by elastic filaments adsorbed on membranes\, using minimal coarse-grained models. I will provide quantitative predictions for cooperative action of bacterial mechanosensitive channels\, from molecular to cellular scales. I will propose how geometrical transitions of ESCRT-III filaments can remo del and sever membranes of various shapes and topologies\, creating membra ne cones\, tubes\, buds\, and dividing tubular and spherical membranes. Be yond their biological context\, our findings can also guide the design of artificial structures that mechanically sculpt cells and sense mechanical forces at the nanoscale.\n\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-653@lptms.universite-paris-saclay.fr DTSTART:20190219T110000Z DTEND:20190219T120000Z DTSTAMP:20190215T115835Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-isabelle-bouchoule/ SUMMARY:Séminaire du LPTMS: Isabelle Bouchoule - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Fév 19 11:00 DESCRIPTION:Generalised hydrodynamics on an atom chip\nIsabelle Bouchoule ( Institut d'Optique)\nDescribing the out-of-equilibrium dynamics of many-bo dy quantum systems is a priori a tremendously difficult task. However\, a recent theoretical development provides an ab-initio description of the lo ng wavelength dynamics of 1D integrable quantum systems\, the so-called Ge neralised Hydrodynamics (GHD). In contrast to conventional hydrodynamics\, GHD does not assume that gas is locally described by the Gibbs ensemble b ut it keeps track of all conserved quantities of the integrable system. In cold atom experiments\, 1D bosonic gases are realised\, which are well de scribed by the famous integrable Lieb-Liniger model. Cold atom experiments thus offer an ideal platform to test GHD.\n\nWe use the atom-chip experim ent of LCF\, where 1D gases of 87Rb are realized\, to test experimentally GHD. Starting from a cold atomic cloud at thermal equilibrium\, dynamics i s generated by a sudden quench of the longitudinal potential. The measured time evolution of the density profiles are in excellent agreement with pr edictions from GHD. We also compare our data with predictions from the con ventional hydrodynamics method\, which assumes locally a thermal equilibri um described by a Gibbs ensemble. Except for the special case of harmonic potentials\, we find that conventional hydrodynamics completely fails to r eproduce our data. Hydrodynamics even predicts the development of sharp st ructures leading to a chock phenomena\, such a phenomena being absent in t he data and in the GHD description.\n\n \; CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-654@lptms.universite-paris-saclay.fr DTSTART:20190219T110000Z DTEND:20190219T120000Z DTSTAMP:20190116T155849Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-fernando-luis-barroso-da-silva/ SUMMARY:Physics-Biology interface seminar: Fernando Luis Barroso Da Silva - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 19 Fév 19 11:00 DESCRIPTION:Developing and applying fast constant pH methods in biological systems: From biomaterials to virus\nFernando Luis Barroso Da Silva (Unive rsity of São Paulo\, Brazil)\nSPECIAL TIME & DATE\npH is a key parameter for biological and technological processes. Different numerical schemes we re developed during the last years for such simulations ranging from Poiss on-Boltzmann approaches to explicit solvent based methods. Ideally\, the p roton equilibria should correctly describe the experimental system without hampering the calculation time. A fast proton titration scheme (FPTS)\, r ooted in the Kirkwood model of impenetrable spheres\, where salt is treate d at the Debye-Huckel level\, was specially developed for proteins and nuc leic acids. This method has now been coupled with OPEP5 force field for co nstant pH molecular dynamics simulations. A benchmark study will be presen ted. Despite our approximations\, both the robustness and its ability to p roper describe the system physics by these numerical methods can be confir med. FPTS was also applied to quantify protein stability and biomolecular interactions. In this talk\, I will present results for some protein syste ms with importance in different applied fields from biomaterials to public health. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-650@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190226T110000 DTEND;TZID=Europe/Paris:20190226T120000 DTSTAMP:20190214T084519Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-patrick-azaria/ SUMMARY:Séminaire du LPTMS: Patrick Azaria - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 26 Fév 19 11:00 DESCRIPTION:Topological States in Massless One-dimensional Fermionic System s\nPatrick Azaria (LPTMC-Sorbonne Universités)\n\n\nTopological states ar e characterized by the unique exponentially localized excitations they hos t at their ends in an open geometry. The topological protections of these systems relies on the bulk of these systems being gapped. This is the case in one-dimensional systems for superconductors proximity coupled to a bul k superconductor. However in a purely one-dimensional system\, where super conductivity arises from intrinsic charge conserving attractive interactio ns\, the bulk of the system remains gapless due to large quantum fluctuati ons of the phase. One may then naturally question the existence of such to pological phases in the presence of massless bulk excitations. Indeed\, sy stems of spinless fermions with either attractive or repulsive interaction s are described by a Luttinger liquid and are topologically trivial: they display quasi-long range dominant superconducting or 2kF charge density wa ve instabilities without exponentially localized modes at their ends. In t his talk I shall show that in coupled chains\, or in interacting multi-fla vor fermionic systems\, topological states with non trivial end modes may exist provided there is enough symmetry protection. This includes systems with tendency toward superconducting order as well as the more seemingly i nnocuous situations of coupled density waves with repulsive interactions. In the particular case with N=3 flavors\, I shall argue that a non trivial topological superconducting phase\, corresponding to the gapless analogue of the Haldane phase in spin-1 chains\, as well as non trivial chiral gap less spin density waves phases hosting Z3 parafermionic edge modes may be stabilized.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-651@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190312T110000 DTEND;TZID=Europe/Paris:20190312T120000 DTSTAMP:20190227T185200Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-serge-dmitrieff/ SUMMARY:séminaire du LPTMS: Serge Dmitrieff - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 12 Mar 19 11:00 DESCRIPTION:Simple elasticity problems inspired by biology\nSerge Dmitrieff (Institut Jacques Monod)\nBiological cells are physical elements under in ternal and external mechanical constraints. For instance\, cell need to op pose exterior stress to maintain their shapes\, and overcome large interna l drag forces to transport cargo. I will discuss about the role of semi-fl exible polymers called microtubules in these processes.\n\nWe will see tha t we can use simple physical notions from elasticity to address these prob lems : the maintenance the shape of blood cells can be understood as the b uckling of a visco-elastic bundle in confinement\, while some examples of intracellular transport to the cell center appears akin to Newton's first theorem\, albeit with elastic forces. Even minimal formulations of these p roblems are deceivingly simple\, and yield interesting new physics\, such as the metastability of disc-like cells\, and unexpected scaling laws for centering forces. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-652@lptms.universite-paris-saclay.fr DTSTART:20190313T110000Z DTEND:20190313T120000Z DTSTAMP:20181214T201230Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-karim-benzerara-2/ SUMMARY:Physics-Biology interface seminar: Karim Benzerara - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 13 Mar 19 11:00 DESCRIPTION:Formation of intracellular amorphous carbonates by bacteria\nKa rim Benzerara (Sorbonne Universités\, Paris)\n\nLiving cells can sustain out-of-equilibrium states in a given environment by consuming free energy. The formation of some intracellular mineral phases provides some example s of this. Here I will review some of the work we have performed in the la st years to describe and understand how some cyanobacteria\, which are abu ndant photosynthesizing bacteria appeared several billions years ago at th e surface of the Earth\, manage to form intracellular amorphous carbonates . I will show the environmental conditions under which they catalyze this process\, detail the methodologies (including cryo-TEM and spectroscopies) we used to characterize these phases and finally address the involved (bi o)molecular mechanisms. The question of the selective advantage(s) provide d by this process\, if any\, will be asked. The implications for basic and applied research will also be addressed. Overall\, this talk should convi nce you that a highly interdisciplinary work is crucially needed to global ly understand this intracellular biomineralization process.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-668@lptms.universite-paris-saclay.fr DTSTART:20190318T110000Z DTEND:20190318T120000Z DTSTAMP:20190312T114948Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-manas-kulkarni/ SUMMARY:Séminaire exceptionnel du LPTMS: Manas Kulkarni - LPTMS\, salle 20 1\, 2ème étage\, Bât 100\, Campus d'Orsay - 18 Mar 19 11:00 DESCRIPTION:Duality in a model integrable even in a box-like confinement: M ulti-soliton solutions and field theory\nManas Kulkarni (International Cen tre for Theoretical Sciences\, Bengaluru)\n\nModels that remain integrable even in confining potentials are extremely rare and almost non-existent. Here\, we consider the Hyperbolic Calogero (HC) model which remains integr able even in confining potentials (which has box-like shapes). We present a first-order formulation of the HC model in external confining potential. Using the rich property of duality\, we find multi-soliton solutions of t his confined integrable model. We demonstrate the dynamics of these multi- soliton solutions via brute-force numerical simulations. We study the phys ics of soliton collisions and quenching using numerical simulations. We ha ve examined the motion of dual variables and found an analytic expression for the time period in a certain limit. We give the field description of t his model and find analytical solutions for background (absence of soliton s) in the large-N limit (which has the form of a table-top). Analytical ex pressions of soliton solutions have been obtained in the absence of confin ing potential. Our work is of importance to understand general features of trapped interacting particles that remain integrable and can be of releva nce to the collective behaviour of trapped cold atomic gases. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-645@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190319T110000 DTEND;TZID=Europe/Paris:20190319T120000 DTSTAMP:20190301T101023Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sergej-moroz-3/ SUMMARY:Séminaire du LPTMS: Sergej Moroz - LPTMS\, salle 201\, 2ème étag e\, Bât 100\, Campus d'Orsay - 19 Mar 19 11:00 DESCRIPTION:Low-energy physics of a superfluid vortex lattice\nDr. Sergej M oroz (TU Munich)\nSuperfluidity is one of the most intriguing quantum phen omena that emerges at temperatures close to absolute zero. Vortices with q uantized circulation are the hallmark of superfluidity and are created und er external rotation. If the number of vortices is much smaller than the n umber of particles\, vortices arrange themselves in a triangular lattice t hat exhibits intriguing collective dynamics. Quantum vortex crystals in su perfluids and superconductors have been one of the exciting avenues of res earch for many decades. In this talk I will introduce an effective field t heory built from low-energy degrees of freedom which captures universal pr operties of vortex lattices in bosonic superfluids. I will present our res ults for current and stress tensor Hall responses and will provide some ar guments that the Hall viscosity of a quantum vortex crystal vanishes at ze ro frequency and momentum. In the end of the talk\, I will describe new di rections that we are currently exploring using this effective field theory . CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-669@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190320T110000 DTEND;TZID=Europe/Paris:20190320T120000 DTSTAMP:20190315T150859Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-hugo-vanneuville/ SUMMARY:Séminaire exceptionnel du LPTMS : Hugo Vanneuville - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Mar 19 11:00 DESCRIPTION:Level set percolation for Gaussian fields\nHugo Vanneuville (Un iversity of Lyon)\nIn this talk\, we consider a random smooth Gaussian fun ction from the\nplane to \\R and\, given a level u\, we colour the points where the\nfunction is larger than u in black and the points where the fun ction\nis less than u in white. By relying on the recent work by V. Beffar a\nand D. Gayet\, we study the percolation properties of this random\ncolo uring and we try to compare it with Bernoulli percolation (in\nparticular by proposing a mathematical study of the Harris criterion).\nOur work is m otivated by the work by E. Bogomolny and C. Schmit in the\ncase of random planar waves. Joint w. S. Muirhead and A. Rivera. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-659@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190326T110000 DTEND;TZID=Europe/Paris:20190326T120000 DTSTAMP:20190318T135815Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-naomi-oppenheimer/ SUMMARY:Séminaire du LPTMS: Naomi Oppenheimer - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 26 Mar 19 11:00 DESCRIPTION:Membrane Hydrodynamics and Their Role on Protein Interactions\n Prof. Naomi Oppenheimer (Flatiron Institute\, USA)\nSince the 1970s vast r esearch has been devoted to studying the equilibrium properties of membran es as elastic surfaces. Much less attention has been given to their in-pla ne dynamics\, which is crucial for protein function. In this talk\, I will describe the basics of membrane hydrodynamics and give a few implications of the results. From a coarse-grained perspective\, the membrane could be considered as a quasi-two-dimensional (Q2D) colloidal suspension\, where the lipids play the role of the molecular fluid\, and the proteins play th e role of particle inclusions. We will see a couple of implications of mem brane hydrodynamics: (1) Hindrance of chemical reactions taking place in a membrane\, (2) Fluid mediated self-assembly of ATP synthase proteins in a membrane\, or of artificial rotating colloids in a soap film. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-667@lptms.universite-paris-saclay.fr DTSTART:20190327T110000Z DTEND:20190327T120000Z DTSTAMP:20190314T063845Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-daria-bonazzi/ SUMMARY:Physics-Biology interface seminar: Daria Bonazzi - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 27 Mar 19 11:00 DESCRIPTION:Bacterial aggregates of Neisseria meningitidis flow inside bloo d vessels like a honey-like viscous liquid\nDaria Bonazzi (Institut Pasteu r\, Paris)\nDuring human meningococcal infections\, bacteria accumulate an d finally fill up blood vessels\, causing severe diseases such as septicae mia and meningitis. However\, the mechanisms governing formation of bacter ial aggregates and their impact on infection remained elusive. In this mul tidisciplinary work we unravel that aggregates of Neisseria meningitidis b ehave as a viscous liquid similar to honey. This is due to type-IV pili\, long adhesive filaments which are constantly extending and retracting at t he bacterial surface. By these means\, bacteria can find each other and tr ansiently come into contact. Aggregation is therefore based on an intermit tent process of attraction between bacteria\, and gives rise to a new type of active material. Importantly\, the unique physical properties of menin gococcal aggregates allow them to gradually adapt to the complex geometry of the vascular network. As a consequence\, these physical properties are essential for the progression of infection. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-657@lptms.universite-paris-saclay.fr DTSTART:20190402T110000Z DTEND:20190402T123000Z DTSTAMP:20190323T140524Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kris-van-houcke/ SUMMARY:Séminaire du LPTMS: Kris Van Houcke - LPTMS\, salle 201\, 2ème é tage\, Bât 100\, Campus d'Orsay - 2 Avr 19 11:00 DESCRIPTION:Summation of diagrammatic series for a strongly correlated ferm ionic theory with zero convergence radius\nKris Van Houcke (École Normale Supérieure\, Paris)\nIn this talk I will mainly focus on the unitary Fer mi gas (spin 1/2 fermions with contact interactions in 3D\, which describe s cold atomic gases at a Feshbach resonance) in the normal phase. Thanks t o a diagrammatic Monte Carlo algorithm\, we accurately sample all skeleton \ndiagrams (built on dressed single-particle and pair propagators) up to o rder nine [1]. The diagrammatic series is divergent and there is no small parameter so that a resummation method is needed. We compute the large-ord er asymptotics of the diagrammatic series\, based on a functional integral representation of the skeleton series and the saddle-point\nmethod. We sh ow that the radius of convergence is actually zero\, but the series is sti ll resummable\, by a generalised conformal-Borel transformation that incor porates the large-order asymptotics [2]. This yields new high-precision da ta\, not only for the equation of state\, but also for Tan's contact coeff icient and for the momentum distribution [3].\nI will also highlight some recent developments in (determinant) diagrammatic Monte Carlo and present new high-precision data for the Fermi polaron\, which is a single impurity atom immersed in a Fermi sea.\n\nReferences:\n\n[1] K. Van Houcke\, F. We rner\, T. Ohgoe\, N. V. Prokof'ev\, and B. V. Svistunov\, "Diagrammatic Mo nte Carlo algorithm for the resonant Fermi gas"\, Phys. Rev. B 99\, 035140 (2019).\n[2] R. Rossi\, T. Ohgoe\, K. Van Houcke\, F. Werner\, "Resummati on of diagrammatic series with zero convergence radius for strongly correl ated fermions"\, Phys. Rev. Lett. 121\, 130405 (2018)\n[3] R. Rossi\, T. O hgoe\, E. Kozik\, N. Prokof'ev\, B. Svistunov\, K. Van Houcke\, F. Werner\ , "Contact and momentum distribution of the unitary Fermi gas"\, Phys. Rev . Lett. 121\, 130406 (2018) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-666@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190409T110000 DTEND;TZID=Europe/Paris:20190409T120000 DTSTAMP:20190329T115104Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mathilde-badoual/ SUMMARY:séminaire du LPTMS: Mathilde Badoual and Christophe Deroulers - LP TMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Avr 19 11:0 0 DESCRIPTION:How modelling and statistical physics can contribute to underst and brain tumors?\nMathilde Badoual and Christophe Deroulers (IMNC)\nDiffu se low-grade gliomas are slowly-growing tumors. After tens of years\, they transform inexorably into more aggressive forms\, jeopardizing the patien t’s life.\nIn our team\, we combine mathematical modelling\, statistical physics and image analysis\, in order to have a better understanding of t he natural history of these tumors and their response to treatments.\nWe p resent here two projects:\nWe will start with the effect of radiotherapy o n gliomas. We developed a mathematical model that describes the evolution of cell density in gliomas and their response to treatments such as radiot herapy. We will show how biological data and clinical data were used to de sign and validate the model\, and we will discuss the results of the model .\nThe second part of the talk will be about the collective behaviour of p recursor cells that are suspected to be at the origin of gliomas. In their "normal state"\, these cells proliferate and die in order to maintain a c onstant cell density all over the adult brain (homeostasis). We modelled t hese phenomena with a cellular automaton and we will show that in the case s of almost uniform conditions\, we observe oscillations\, but in the case of non-uniform conditions\, we observe intriguing phenomena such as propa gating waves\, spiral waves\, large transient oscillations\, and even popu lation extinction. We will also show how the appearance of an abnormal cel l can lead to the appearance of a glioma. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-640@lptms.universite-paris-saclay.fr DTSTART:20190410T110000Z DTEND:20190410T120000Z DTSTAMP:20190408T144230Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-stefan-karpitschka/ SUMMARY:Physics-Biology interface seminar: Stefan Karpitschka - Moyen Amphi \, Building 510\, Université Paris-Saclay Orsay - 10 Avr 19 11:00 DESCRIPTION:SEMINAR CANCELLED\nStefan Karpitschka (MPI Göttingen) CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-672@lptms.universite-paris-saclay.fr DTSTART:20190415T100000Z DTEND:20190415T110000Z DTSTAMP:20190412T110841Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-deni s-ullmo/ SUMMARY:Journal Club: Denis Ullmo - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 15 Avr 19 10:00 DESCRIPTION:Semiclassical expectation value for an out of equilibrium syste m\nDenis Ullmo (LPTMS/Institut Pascal) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-671@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190416T110000 DTEND;TZID=Europe/Paris:20190416T120000 DTSTAMP:20190404T130008Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gregory-astrakharchik/ SUMMARY:Séminaire du LPTMS: Gregory Astrakharchik - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 16 Avr 19 11:00 DESCRIPTION:Andreev-Bashkin Effect in quantum gases\nGregory Astrakharchik (UPC\, Barcelona)\nWe study a mixture of two superfluids with density–de nsity and current–current (Andreev–Bashkin) interspecies interactions. The Andreev–Bashkin coupling gives rise to a dissipationless drag (or e ntrainment) between the two superfluids. Within the quantum hydrodynamics approximation\, we study the relations between speeds of sound\, susceptib ilities and static structure factors\, in a generic model in which the den sity and spin dynamics decouple. Due to translational invariance\, the den sity channel does not feel the drag. The spin channel\, instead\, does not satisfy the usual Bijl–Feynman relation\, since the f-sum rule is not e xhausted by the spin phonons. The very same effect on one dimensional Bose mixtures and their Luttinger liquid description is analysed within pertur bation theory. Using diffusion quantum Monte Carlo simulations of a system of dipolar gases in a double layer configuration\, we confirm the general results. Given the recent advances in measuring the counterflow instabili ty\, we also study the effect of the entrainment on the dynamical stabilit y of a superfluid mixture with non-zero relative velocity. We quantify the non-dissipative drag effect\, resulting from the Andreev-Bashkin current- current interaction between the two components of the gas\, and we show th at in the regime of strong coupling it causes a significant suppression of the spin-wave velocity.\n\n[1] L. Parisi\, G. E. Astrakharchik\, and S. G iorgini\,\nSpin Dynamics and Andreev-Bashkin Effect in Mixtures of One-Dim ensional Bose Gases\,\nPhys. Rev. Lett. 121\, 025302 (2018)\n\n[2] Jacopo Nespolo\, Grigori E. Astrakharchik\, Alessio Recati\,\nAndreev-Bashkin eff ect in superfluid cold gases mixture\,\nNew J. Phys. 19\, 125005 (2017) CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-660@lptms.universite-paris-saclay.fr DTSTART:20190507T110000Z DTEND:20190507T120000Z DTSTAMP:20190430T092805Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jeremie-bouttier/ SUMMARY:Séminaire du LPTMS: Jérémie Bouttier - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 7 Mai 19 11:00 DESCRIPTION:\n\nLast passage percolation\, Schur processes and free fermion s\nJérémie Bouttier (IPhT-Saclay and ENS Lyon)\nWe consider the model of (directed 2D) last passage percolation (LPP)\, defined as follows. To eve ry site of Z^2 we assign a nonnegative random number called weight. To eve ry directed (north-east) path in Z^2\, we assign a weight equal to the sum of of the weights of the sites that it visits. If x\,y are two sites such that y is north-east of x\, we define the LPP time L(x\,y) as the maximal weight of a directed path from x to y.\n\nIn his seminal paper arXiv:math /9903134 [math.CO]\, Johansson considered the situation where the weights are all independent and drawn according to the same geometric or exponenti al distribution. This case is\nintimately connected with the Totally Asymm etric Simple Exclusion Process (TASEP) and the so-called Corner Growth Mod el. He proved that the fluctuations of L(x\,y)\, when |y-x| gets large\, a re asymptotically governed by the Tracy-Widom GUE distribution.\n\nSeveral variants have been considered. In particular\, Baik and Rains considered the situation where the weight array has symmetries\, for instance a refle ction symmetry along the main diagonal i-j=0. This is\nequivalent to consi dering LPP in the half-plane i-j≥0. They have shown that the asymptotic fluctuations of L(x\,y)\, for x and y close to the main diagonal\, are now governed by the Tracy-Widom GOE or GSE\ndistribution.\n\nWhat allows to o btain such precise results is that\, in these models\, there exists an exa ct formula for the distribution of L(x\,y) in the form of a Fredholm deter minant or pfaffian. Such property holds for the more general class of Schu r processes\, which may be studied using free fermions.\n\nAfter reviewing these results\, I will discuss Schur processes with periodic and free bou ndary conditions. In the LPP picture\, this corresponds to imposing some p eriodicity/symmetry properties on the weight array. We will see that\, in suitable asymptotic regimes\, the fluctuations of the LPP time are governe d by nontrivial deformations of the Tracy-Widom distributions.\n\nThis tal k is based on joint work with Dan Betea\, Peter Nejjar and Mirjana Vuleti ć.\n CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-664@lptms.universite-paris-saclay.fr DTSTART:20190514T110000Z DTEND:20190514T120000Z DTSTAMP:20190507T101651Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thibault-congy/ SUMMARY:Séminaire du LPTMS: Thibault Congy - LPTMS\, salle 201\, 2ème ét age\, Bât 100\, Campus d'Orsay - 14 Mai 19 11:00 DESCRIPTION:Wave-mean flow interactions in dispersive hydrodynamics\nThibau lt Congy (Department of Mathematics\, Physics and Electrical Engineering\, Northumbria University\, Newcastle upon Tyne\, UK)\nThe interaction of wa ves with a mean flow is a fundamental and longstanding problem in fluid me chanics. The key to the study of such an interaction is the scale separati on\, whereby the length and time scales of the waves are much shorter than those of the mean flow. The wave-mean flow interaction has been extensive ly studied for the cases when the mean flow is prescribed externally—as a stationary or time-dependent current (a "potential barrier").\n\nIn this talk\, I will describe a new type of the wave-mean flow interactions wher eby a short-scale linear wave is incident on a evolving large-scale nonlin ear dispersive hydrodynamic state: a rarefaction wave or a dispersive shoc k wave (DSW). Modulation equations are derived for the coupling between th e wavepacket and the mean flow in the nonlinear dispersive hydrodynamic st ate. These equations admit particular classes of solutions that describe t he transmission or trapping of the linear wave by an unsteady hydrodynamic state. Two adiabatic invariants of motion are identified in both cases th at determine the transmission\, trapping conditions and show that wavepack ets incident upon smooth expansion waves or compressive\, rapidly oscillat ing DSWs exhibit so-called hydrodynamic reciprocity.\n\nThe developed theo ry is general and can be applied to a broad class of nonlinear dispersive wave equations in various physical contexts including nonlinear optics and cold atom physics. The Korteweg-de Vries equation will be considered as a concrete example. This is joint work with Gennady El and Mark Hoefer\, an d the talk is based on Ref. [1].\n\n[1] T. Congy\, G. A. El and M. A. Hoef er\, Interaction of linear modulated waves with unsteady dispersive hydrod ynamic states\, arXiv:1812.06593. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-670@lptms.universite-paris-saclay.fr DTSTART:20190520T110000Z DTEND:20190520T120000Z DTSTAMP:20190514T123020Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-maxime-dupont/ SUMMARY:Séminaire exceptionnel du LPTMS: Maxime Dupont - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 20 Mai 19 11:00 DESCRIPTION:Dynamics in quantum magnets\nMaxime Dupont (UC Berkeley)\nTheor etically challenging\, the understanding of the dynamical response in quan tum magnets is of great interest\, in particular for both inelastic neutro n scattering (INS) and nuclear magnetic resonance (NMR) experiments. In th is talk\, I will address this question for quasi-one-dimensional quantum m agnets\, e.g.\, weakly coupled spin chains for which many compounds are av ailable in nature. In this class of systems\, the dimensional crossover be tween a three-dimensional ordered regime at low temperature towards one-di mensional physics at higher temperature is a nontrivial issue\, notably di fficult concerning dynamical properties. I will present a comprehensive th eoretical study based on both analytical calculations and numerical simula tions which allows us to describe the full temperature crossover for the N MR relaxation rate 1/T1\, from one-dimensional Tomonaga-Luttinger liquid p hysics to the three-dimensional ordered regime\, as a function of intercha in couplings. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-665@lptms.universite-paris-saclay.fr DTSTART:20190521T110000Z DTEND:20190521T120000Z DTSTAMP:20190509T112009Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cecile-appert-rolland/ SUMMARY:Séminaire du LPTMS: Cécile Appert-Rolland - LPTMS\, salle 201\, 2 ème étage\, Bât 100\, Campus d'Orsay - 21 Mai 19 11:00 DESCRIPTION:Experiment driven models for pedestrians and crowds\nCécile Ap pert-Rolland (LPT - U-Psud Orsay)\nThe growing interest for crowd modeling has led to the development of various types of models\, in part inspired by fluid mechanics.\nHowever we are still lacking full knowledge of pedest rian behavior throughout all the scales (from individuals to crowds\, from low to high densities\, etc).\nIn this seminar I will show how experiment s can be used to develop or improve microscopic or macroscopic models. Sev eral series of experiments will be reported.\nSome\, performed in Rennes\, deal with interactions at low and moderate densities (PEDIGREE and PEDINT ERACT Project) while other ones\, performed in Orsay and in Argentina (PER CEFOULE Project)\, have provided intriguing observations of high density c rowds that question current models.\nIn another perspective\, models can b e useful to scan the mechanisms responsible for\, for example\, pattern fo rmation occurring at the crossing of perpendicular pedestrian flows. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-673@lptms.universite-paris-saclay.fr DTSTART:20190522T110000Z DTEND:20190522T120000Z DTSTAMP:20190514T134946Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-pierre-henri-puech/ SUMMARY:Physics-Biology interface seminar: Pierre-Henri Puech - Moyen Amphi \, Building 510\, Université Paris-Saclay Orsay - 22 Mai 19 11:00 DESCRIPTION:Some aspects of immune cells mechanobiology: activation of T ly mphocytes and parasite phagocytosis by macrophages\nPierre-Henri Puech (Ad hesion and Inflammation Lab - Aix-Marseille Universités)\nSurface protein s of cells which are implicated in cell recognition and adhesion are also subjected to forces\, since the interactions with their partner is often o ccuring at the interface between two cells. The study of the roles of phys ical cues\, such as forces\, substrate mechanics and dynamics has lead to the emergence of mechanobiology. One idea is to dissect how these physical cues "help" the cells to read and interpret\, sometimes react to\, bioche mical messages\, a process known as mechanotransduction.\n\nIn this semina r\, we will present why and how forces and mechanics are thought to be key regulators of immune cell recognition using our work using two biological models:\n\n the crucial step of T cell activation which leads to an effi cient immune response\n the phagocytic response of macrophages to the par asite Toxoplasma Gondii\, responsible of toxoplasmosis.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-677@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190523T110000 DTEND;TZID=Europe/Paris:20190523T120000 DTSTAMP:20190517T084219Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-anthony-mays/ SUMMARY:Séminaire exceptionnel du LPTMS: Anthony Mays - LPTMS\, salle 201 \, 2ème étage\, Bât 100\, Campus d'Orsay - 23 Mai 19 11:00 DESCRIPTION:Determinantal polynomials\, vortices and random matrices: an ex ercise in experimental mathematical physics\nAnthony Mays (University of M elbourne)\nInspired by the interpretation of eigenvalues of random matrice s as a gas of interacting particles we develop a toy model of vortex or pa rticle dynamics using determinantal polynomials of random matrices. By int roducing quaternionic structures we generate vortex/anti-vortex systems\, and from studying the phase surface of the associated wavefunction\, we id entify topological rules governing the creation and annihilation of the vo rtices. We also discuss an interpretation of annihilation events in terms of quaternionic states CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-663@lptms.universite-paris-saclay.fr DTSTART:20190528T110000Z DTEND:20190528T120000Z DTSTAMP:20190508T080308Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-zhan-shi/ SUMMARY:Séminaire du LPTMS: Zhan Shi - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 28 Mai 19 11:00 DESCRIPTION:The Derrida-Retaux conjecture\nZhan Shi (Labo. de Probabilités \, Statistique et Modélisation\, Paris VI)\nI am going to present element ary discussions on the Derrida-Retaux conjecture concerning the free energ y of some max-type recursive systems. Ongoing work with Xinxing Chen (Shan ghai)\, Victor Dagard (ENS)\, Bernard Derrida (Collège de France)\, Yueyu n Hu (Paris Nord)\, Mikhail Lifshits (St. Petersburg). CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-675@lptms.universite-paris-saclay.fr DTSTART:20190604T143000Z DTEND:20190604T170000Z DTSTAMP:20190507T105521Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-bertrand-lacroix-a-chez-toine-2/ SUMMARY:Soutenance de thèse: Bertrand Lacroix-à-chez-Toine - IPN-batiment 100\, Auditoriurm - 4 Juin 19 14:30 DESCRIPTION:Soutenance de thèse:\nExtreme value statistics of strongly cor related systems: fermions\, random matrices and random walks\npar\nBertran d Lacroix-à-chez-Toine\n \;\n\nJury:\n\n-Djalil Chafaï (CEREMADE\, U niversité Paris-Dauphine)\n\n-Andrea Gambassi (Scuola Internazionale Supe riore di Studi Avanzati\, Italy)\n\n-Jean-Marc Luck (IPhT\, CEA Saclay)\n\ n-Satya N. Majumdar (LPTMS\, Université Paris-Sud)\n\n-Grégory Schehr (L PTMS\, Université Paris-Sud)\, directeur de thèse\n\n-Christophe Texier (LPTMS\, Université Paris-Sud)\n\n-Patrizia Vignolo (INPHYNI\, Universit é de Nice-Sophia Antipolis)\n\n-Pierpaolo Vivo (King’s College London\, UK)\n\n \;\n\nRésumé:\nPredicting the occurrence of extreme events is a crucial issue in many contexts\, ranging from meteorology to finance. For independent and identically distributed (i.i.d.) random variables\, t hree universality classes were identified (Gumbel\, Fréchet and Weibull) for the distribution of the maximum. While modelling disordered systems by i.i.d. random variables has been successful with Derrida's random energy model\, this hypothesis fail for many physical systems which display stron g correlations. In this thesis\, we study three physically relevant models of strongly correlated random variables: trapped fermions\, random matric es and random walks.\nIn the first part\, we show several exact mappings b etween the ground state of a trapped Fermi gas and ensembles of random mat rix theory. The Fermi gas is inhomogeneous in the trapping potential and i n particular there is a finite edge beyond which its density vanishes. Goi ng beyond standard semi-classical techniques (such as local density approx imation)\, we develop a precise description of the spatial statistics clos e to the edge. This description holds for a large universality class of ha rd edge potentials. We apply these results to compute the statistics of th e position of the fermion the farthest away from the centre of the trap\, the number of fermions in a given domain (full counting statistics) and th e related bipartite entanglement entropy. Our analysis also provides solut ions to open problems of extreme value statistics in random matrix theory. We obtain for instance a complete description of the fluctuations of the largest eigenvalue in the complex Ginibre ensemble.\nIn the second part of the thesis\, we study extreme value questions for random walks. We consid er the gap statistics\, which requires to take explicitly into account the discreteness of the process. This question cannot be solved using the con vergence of the process to its continuous counterpart\, the Brownian motio n. We obtain explicit analytical results for the gap statistics of the wal k with a Laplace distribution of jumps and provide numerical evidence sugg esting the universality of these results. CATEGORIES:seminars LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay \, France GEO:48.698196;2.181773 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm: geo:48.698196,2.181773 END:VEVENT BEGIN:VEVENT UID:0-656@lptms.universite-paris-saclay.fr DTSTART:20190605T110000Z DTEND:20190605T120000Z DTSTAMP:20190129T201005Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-matthew-turner/ SUMMARY:Physics-Biology interface seminar: Matthew Turner - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 5 Juin 19 11:00 DESCRIPTION:Intelligence\, a recipe\nMatthew Turner (Warwick University\, U K)\nWe study information-processing (artificial)\, or “intelligent” (l iving)\, agents. These agents seek maximal control of their environment vi a future state maximisation (FSM)\, a principle that we argue may relate t o intelligent behaviour more generally. Here we study moving\, re-oreintab le agents that seek to maximise their space of accessible (visual) environ ments\, out to some time horizon. The action of each agent is (re)establis hed by exhaustive enumeration of its future decision tree at each time ste p - each agent chooses the branch of its tree leading from the present to the richest future state space. Remarkably\, cohesive swarm-like motion em erges that is similar to that observed in animal systems\, such as bird fl ocks. We develop heuristics that mimic computationally intensive FSM but t hat could also operate in real time under animal cognition. Finally\, we s how that iterative application of these heuristics as the model for the be haviour of others\, when determining the dynamics of self under full FSM\, can lead to a form of closure for the problem. I will argue that this off ers a philosophically attractive\, bottom-up mechanism for the emergence o f swarming. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-679@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190607T110000 DTEND;TZID=Europe/Paris:20190607T120000 DTSTAMP:20190529T150147Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnelle-du-lptms-leo-radzihovsky/ SUMMARY:Séminaire exceptionnelle du LPTMS: Leo Radzihovsky - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 7 Juin 19 11:00 DESCRIPTION:Fracton-elasticity duality\nLeo Radzihovsky (University of Colo rado\, Boulder)\nI will discuss a recent discovery that elasticity theory of a two-dimensional crystal is dual to a fracton tensor gauge theory\, pr oviding a concrete realization of the fracton phenomenon. The disclination s and dislocations respectively map onto charges and dipoles of the tensor gauge theory. The fractionalized mobility of fractons matches the constra ined dynamics of lattice defects. This duality leads to predictions for fr actonic phases and phase transitions\, such as the counterparts to the com mensurate crystal\, supersolid\, hexatic\, and isotropic fluid phases of t he elasticity theory. Extensions of this duality to generalized elasticity theories provide a route to discovery of new fracton models. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-662@lptms.universite-paris-saclay.fr DTSTART:20190611T110000Z DTEND:20190611T120000Z DTSTAMP:20190524T102801Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lenart-zadnik/ SUMMARY:Séminaire du LPTMS: Lenart Zadnik - LPTMS\, salle 201\, 2ème éta ge\, Bât 100\, Campus d'Orsay - 11 Juin 19 11:00 DESCRIPTION:Inhomogeneous matrix product ansatz and exact solutions for str ongly boundary driven spin chains\nLenart Zadnik (University of Ljubljana) \nI will present a novel inhomogeneous Lax structure and demonstrate the e xact solvability of a dissipatively boundary driven XYZ spin-1/2 chain in the limit of strong dissipation. I will describe the explicit inhomogeneou s matrix product ansatz for the nonequilibrium steady state of the problem . The constituent matrices of this ansatz satisfy a simple set of linear r ecurrence relations. Although they can be embedded into an infinite-dimens ional auxiliary space\, they cannot be simultaneously put into a tridiagon al form\, not even in the case of axially symmetric (XXZ) bulk interaction s and general nonlongitudinal boundary dissipation. The results are expect ed to have further fundamental applications for the construction of nonloc al integrals of motion for the open XYZ model with arbitrary boundary fiel ds. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-678@lptms.universite-paris-saclay.fr DTSTART:20190619T110000Z DTEND:20190619T120000Z DTSTAMP:20190527T162158Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-stephanie-mangenot-aurelie-bertin/ SUMMARY:Physics-Biology interface seminar: Stéphanie Mangenot &\; Auré lie Bertin - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 19 Juin 19 11:00 DESCRIPTION:Membrane reshaping induced by Curvature sensitive Septin filame nts: A story of paired filaments told by a pair of Orsay alumni\nStéphani e Mangenot &\; Aurélie Bertin (Institut Curie\, Paris)\nSeptins are cy toskeletal proteins that assemble into a variety of supramolecular organiz ations from paired filaments to bundles\, ring like structures or gauzes o f orthogonal filaments [1‐3]. Septins are bound to the inner plasma memb rane through specific interactions with phosphoinositides [1\,4]. Septins are essential for cell division\, participate in the formation of diffusio n barrier and might be involved in membrane deformation and rigidity. Thro ughout cell division\, septins undertake major rearrangements. Septin fila ments are first aligned toward the mother‐daughter cell axis and then ro tate to be circumferential around the constriction site.\n\nWe have shown that septins arrange differently on positive or negative curvatures using Scanning Electron Microscopy on micro‐patterned PDMS periodic undulated substrates. Besides\, this curvature preference is closely related to the ability of septins to reshape and deform membranes. Indeed\, bound to Gian t unilamellar Vesicles (GUVs)\, septins induce striking deformations with regular spikes and hollow micrometric deformations at the surface of lipos omes\, as visualized by fluorescence microscopy. Smaller vesicles (LUVs of 100‐300 nm in diameter)\, highly positively curved\, are flattened by S eptin filaments into “pancake”like objects as shown in 3D by cryo‐el ectron tomography. With the resolution of cryo‐EM and sub‐tomogram ave raging we visualize both the septin filaments and the deformed vesicles. W e propose a simple model where the filamentous properties of septins contr ol their curvature sensitivity and thus impose their orientation in situ [ 5].\n\n[1] A. Bertin\, et al. (2010)\, Phosphatydinositol 4\,5 biphosphate promotes budding yeast septin filament assembly and organization\, J. Mol . Biol.\, 404(4)\, 711‐31.\n[2] G. Garcia et al. (2011)\, The regulatory budding yeast septin Shs1 promotes ring and gauze formation in a phosphor ylation dependent manner.\, J. Cell. Biol.\, 195(6)\, 993‐1004.\n[3] A.B ertin\, et al. (2008)\, Saccharomyces Cerevisiae septins: supramolecular o rganization of heterooligomers and the mechanism of filament assembly\, Pr oc.Natl. Acac. Sci USA\, 105\, 8274‐8279\n[4] Beber A et al.\,Septin‐b ased readout of PI(4\,5)P2 incorporation into membranes of giant unilamell ar vesicles. (2018) Cytoskeleton. doi: 10.1002/cm.21480\n[5] A. Beber et a l. (2019)\, Membrane reshaping by micrometric curvature sensitive septin f ilaments\, Nat. Commun.\, 10\, 420.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-680@lptms.universite-paris-saclay.fr DTSTART:20190701T131500Z DTEND:20190701T180000Z DTSTAMP:20190628T035714Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/modern-trends-in- closed-and-open-quantum-systems/ SUMMARY:Modern trends in closed and open quantum systems - - 1 Juil 19 13: 15 DESCRIPTION:A welcome workshop for Davide Rossini (Università di Pisa and LPTMS\, Orsay)\nMonday\, July 1 2019\n\nUniversité Paris Diderot - Bâtim ent Condorcet\, 4th floor\, Salle Luc Valentin (454A)\n\nFree participatio n\n\nProgram:\n\n13h15 - Welcome coffee break\n\n13h45 - Davide Rossini (U niv. Pisa &\; LPTMS)\nDiscrete time crystal in a finite chain of Rydber g atoms without disorder \n\n14h30 - Cristiano Ciuti (MPQ)\nQuantum caviti es: from vacuum manipulation to photon simulation of quantum materials\n\n 15h00 - Guillaume Roux (LPTMS)\nTrapped interacting Rydberg atoms : cat st ates\, thermometry and quantum transitions\n\n15h30 - Coffee break\n\n16h0 0 - Marco Schirò (IPHT &\; Collège de France)\nFluctuations Effects i n Driven-Dissipative Quantum Systems\n\n16h30 - Fabrice Gerbier (LKB &\ ; Collège de France)\nAnomalous momentum diffusion of strongly interactin g bosons in optical lattices\n\n17h00 - Christophe Mora (LPENS)\nTopology and strong correlation in twisted bilayer graphene\n\n17h30 - Maurizio Fag otti (LPTMS)\nThe spectrum of the time averaged state in a quantum spin la ttice system\n\nOrganizers: Leonardo Mazza (LPTMS) and Alberto Biella (MPQ ) CATEGORIES:seminars END:VEVENT BEGIN:VEVENT UID:0-661@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190910T110000 DTEND;TZID=Europe/Paris:20190910T120000 DTSTAMP:20190828T194552Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-yacine-ikhlef/ SUMMARY:Séminaire du LPTMS: Yacine Ikhlef - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Sep 19 11:00 DESCRIPTION:Three-point functions in the fully packed loop model on the hon eycomb lattice\nDr. Yacine Ikhlef (LPTHE)\nThe Fully-Packed Loop (FPL) mod el on the honeycomb lattice is a critical model of non-intersecting polygo ns covering the full lattice\, and was introduced by Reshetikhin in 1991. Using the two-component Coulomb-Gas approach of Kondev\, de Gier and Nienh uis (1996)\, we argue that the scaling limit consists of two degrees of fr eedom: a field governed by the imaginary Liouville action\, and a free bos on. We introduce a family of three-point correlation functions which probe the imaginary Liouville component\, and we use transfer-matrix numerical diagonalisation to compute finite-size estimates. We obtain good agreement with our analytical predictions for the universal amplitudes and spatial dependence of these\ncorrelation functions. Finally we conjecture that thi s relation between non-intersecting loop models and the imaginary Liouvill e theory is in fact quite generic. We give numerical evidence that this re lation indeed holds for various loop models. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-687@lptms.universite-paris-saclay.fr DTSTART:20190911T113000Z DTEND:20190911T123000Z DTSTAMP:20190628T050958Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-wolfgang-keil/ SUMMARY:Physics-Biology interface seminar: Wolfgang Keil - Amphi de l'Insti tut Curie\, bâtiment 111 - 11 Sep 19 11:30 DESCRIPTION:Using microfluidics for quantitative studies of post-embryonic development in C. elegans\nWolfgang Keil (Institut Curie\, Paris)\nSpecial location and time\; seminar hosted by Carsten Janke\n\nThe development of most metazoans can be divided in an early phase of embryogenesis and a su bsequent phase of post-embryonic development. Developmental dynamics durin g the post-embryonic phase are generally much slower and often controlled by very different molecular mechanisms that\, e.g.\, ensure tissue synchro ny and integrate metabolic queues. However\, obtaining long-term in-vivo q uantitative imaging data post-embryonically with good statistical and cell ular resolution has been highly challenging because animals must be allowe d to grow\, feed\, and move in order to properly develop after embryogenes is. In this talk\, I will discuss our recent progress in overcoming these challenges in the model organism C. elegans\, using microfluidics technolo gy. I will then outline two of our recent studies\, in which quantitative in-vivo imaging data of post-embryonic development allows novel insights i nto mechanisms of cell-fate acquisition and the regulation of oscillatory gene expression in C. elegans.\n CATEGORIES:physbio,seminars LOCATION:Amphi de l'Institut Curie\, bâtiment 111\, 111\, Rue Jean-Dominiq ue Cassini\, Bures-sur-Yvette\, 91440\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=111\, Rue Jean-Dominique Ca ssini\, Bures-sur-Yvette\, 91440\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi de l'Institut Curie\, bâtiment 111:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-702@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20190912T110000 DTEND;TZID=Europe/Paris:20190912T120000 DTSTAMP:20190909T121553Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onel-du-lptms-daniel-cabra/ SUMMARY:Séminaire exceptionnel du LPTMS: Daniel Cabra - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Sep 19 11:00 DESCRIPTION:Daniel Cabra (Universidad Nacional de La Plata\, Argentina)\n\n Multiferroics: magneto-electric coupling through phonons\n\nWe propose a m icroscopic magneto-electric model in which the coupling between spins and electric dipoles is mediated by lattice distortions. The magnetic sector i s described by a spin S=1/2 Heisenberg model coupled directly to the latti ce via a standard spin-Peierls term and indirectly to the electric dipole variables via the distortion of the surrounding electronic clouds. Electri c dipoles are described by Ising variables for simplicity. We show that th e effective magneto-electric coupling which arises due to the interconnect ing lattice deformations is quite efficient in one-dimensional arrays. Mor e precisely\, we show using bosonization and extensive DMRG numerical simu lations that increasing the magnetic field above the spin Peierls gap\, a massive polarization switch-off occurs due to the proliferation of soliton pairs. We also analyze the effect of an external electric field E when th e magnetic system is in a gapped (plateau) phase and show that the magneti zation can be electrically switched between clearly distinct values. More general quasi-one-dimensional models and two-dimensional systems are also discussed. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-701@lptms.universite-paris-saclay.fr DTSTART:20190916T110000Z DTEND:20190916T120000Z DTSTAMP:20190905T093241Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-serg uei-brazovskii-2/ SUMMARY:Journal club: Serguei Brazovskii - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Sep 19 11:00 DESCRIPTION:When the intuition betrays or saves: messages from the 1d world \n\n\nAbstract : Series of two lectures with four excursions\n\nTheory of (quasi) one-dimensional electronic systems attracts us thanks to its speci al facilities but also because of some specific curiosities. In these excu rsions we shall meet some examples of not quite expected relations\, diffi culties and even mistakes which one can pickup from the half-a-century his tory of this field.\nFirst excursion will descend to the contradictory sto ry of Luttinger liquid with its curiosities in historical \, personal and linguistic aspects. It will also introduce the once unattended role of so called chiral or Schwinger anomalies.\nSecond excursion will meet the chir al anomalies as they appear already in simplest\, MF or BCS types\, models particularly at finite temperatures when normal excitations are present. The resulting effective Ginzburg-Landau theory will prove to be quite diff erent from what is commonly expected.\nThird excursion will undermine the common belief of the spin-charge separation which is seemingly endorsed by the bosonization and exact solutions. Actually\, spin excitations must ca rry the electric current as it takes place for free fermions. The resoluti on comes from correct definition of current carrying states and current op erators taking into account the band curvature.\nForth excursion will lead to the early days when 1D models were studies to understand the phase dia gram of real quasi-1D systems. We will see that\, unlike the common belief s\, the 1D (g-ological) phase diagram based upon diverging power-law susce ptibilities\, does not want at all to reproduce itself when electrons acqu ire a bandwidth in interchain directions. The system falls to the Fermi-li quid regime unless the “imaginary gaps” appear from external symmetry lowering due to the crystal field of the magnetic field.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-682@lptms.universite-paris-saclay.fr DTSTART:20190917T110000Z DTEND:20190917T120000Z DTSTAMP:20190907T134854Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-zorana-zeravcic-espci/ SUMMARY:Séminaire du LPTMS: Zorana Zeravcic (ESPCI) - Salle des séminaire s du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Sep 19 11:00 DESCRIPTION:Towards Living Matter with Colloidal Particles \nZorana Zeravci c (ESPCI)\n\nBiological systems inspire a new paradigm for material synthe sis\, aiming to design materials that emulate living systems. Colloidal pa rticles endowed with specific interactions provide a particularly promisin g approach for realizing this vision. In this talk I will focus on a set o f colloidal spheres with specific\, time-dependent interactions\, and demo nstrate that the interactions can be programmed so that three fundamental properties of living materials are realized: The ability to spontaneously assemble complex structures\; the ability to self-replicate\; and the abil ity to perform complex and coordinated reactions that enable transformatio ns impossible to realize if a single structure acted alone.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-688@lptms.universite-paris-saclay.fr DTSTART:20190918T110000Z DTEND:20190918T120000Z DTSTAMP:20190903T100730Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnelle-du-lptms-elia-macaluso-universita-di-trento/ SUMMARY:Séminaire exceptionnel du LPTMS: Elia Macaluso - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 18 Sep 19 11:00 DESCRIPTION:Charge and statistics of lattice quasiholes from density measur ements\nElia Macaluso (Università di Trento\, Italy)\nIn the last decades \, the lattice counterparts of the fractional quantum Hall effect have att racted strong attention. These systems\, generally known as fractional Che rn insulators (FCIs)\, support elementary bulk excitations carrying fracti onal charge and anyonic statistics.\nIn this context\, I will first introd uce the FCI state at filling ν = 1/2 described by the bosonic Harper-Hofs tadter model with hard-core interactions. Then\, I will show how the aform entioned bulk excitations can be studied by means of a Tree Tensor Network (TTN) technique and\, in particular\, how the TTN ansatz for the many-bod y state allows us to study relatively large samples (up to N=18 particles on a 16x16 lattice)\, with the experimentally relevant open boundary condi tions. Finally\, I will explain how\, not only the fractional charge\, but also the anyonic statistics of the FCI excitations can be obtained throug h simple density measurements. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-700@lptms.universite-paris-saclay.fr DTSTART:20190923T110000Z DTEND:20190923T120000Z DTSTAMP:20190909T093001Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journal-club-serg uei-brazovskii/ SUMMARY:Journal club: Serguei Brazovskii - LPS\, salle de réunion\, deuxi ème étage - 23 Sep 19 11:00 DESCRIPTION:When the intuition betrays or saves: messages from the 1d world \n\n\nAbstract : Series of two lectures with four excursions\n\nTheory of (quasi) one-dimensional electronic systems attracts us thanks to its speci al facilities but also because of some specific curiosities. In these excu rsions we shall meet some examples of not quite expected relations\, diffi culties and even mistakes which one can pickup from the half-a-century his tory of this field.\nFirst excursion will descend to the contradictory sto ry of Luttinger liquid with its curiosities in historical \, personal and linguistic aspects. It will also introduce the once unattended role of so called chiral or Schwinger anomalies.\nSecond excursion will meet the chir al anomalies as they appear already in simplest\, MF or BCS types\, models particularly at finite temperatures when normal excitations are present. The resulting effective Ginzburg-Landau theory will prove to be quite diff erent from what is commonly expected.\nThird excursion will undermine the common belief of the spin-charge separation which is seemingly endorsed by the bosonization and exact solutions. Actually\, spin excitations must ca rry the electric current as it takes place for free fermions. The resoluti on comes from correct definition of current carrying states and current op erators taking into account the band curvature.\nForth excursion will lead to the early days when 1D models were studies to understand the phase dia gram of real quasi-1D systems. We will see that\, unlike the common belief s\, the 1D (g-ological) phase diagram based upon diverging power-law susce ptibilities\, does not want at all to reproduce itself when electrons acqu ire a bandwidth in interchain directions. The system falls to the Fermi-li quid regime unless the “imaginary gaps” appear from external symmetry lowering due to the crystal field of the magnetic field.\n\n CATEGORIES:seminars LOCATION:LPS\, salle de réunion\, deuxième étage\, 1 rue Nicolas Appert\ , Bâtiment 510\, Orsay\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=1 rue Nicolas Appert\, Bât iment 510\, Orsay\, France;X-APPLE-RADIUS=100;X-TITLE=LPS\, salle de réun ion\, deuxième étage:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-683@lptms.universite-paris-saclay.fr DTSTART:20190924T110000Z DTEND:20190924T120000Z DTSTAMP:20190917T102918Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marco-schiro/ SUMMARY:Séminaire du LPTMS: Marco Schirò - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Sep 19 11:00 DESCRIPTION:Defying Quantum Thermalization through Interactions and Disorde r: From Many Body Localization to Quantum Glassiness\nMarco Schirò (IPHT and Collège de France)\nGeneric interacting quantum many body systems are expected to reach thermal equilibrium when isolated from their environmen t and let evolve under their own quantum dynamics. Exceptions to this para digm can emerge in presence of quenched random disorder\, due to many body localization (MBL) or quantum glassiness. Those two robust scenarios for ergodicity breaking have recently attracted considerable interest both fro m a purely theoretical viewpoint and for their implications on the robustn ess of future quantum technologies.\nIn this talk I will study the quantum dynamics of two prototype models for MBL and quantum glassy systems.\nI w ill first introduce a theoretical framework based on flow equations to stu dy the properties MBL systems\, in particular the emergence of localised i ntegral of motions\, and their dynamics. Then I will consider a mean field model of a quantum glass and I will study its isolated dynamics after a q uantum quench. I will show that\, contrary to the conventional wisdom base d on thermodynamics\, quantum fluctuations and non equilibrium effects res ult in an enhanced glassiness and ageing behavior. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-674@lptms.universite-paris-saclay.fr DTSTART:20190925T140000Z DTEND:20190925T150000Z DTSTAMP:20190919T061256Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-carine-douarche/ SUMMARY:Physics-Biology interface seminar: Carine Douarche - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 25 Sep 19 14:00 DESCRIPTION:Collective motion in bacterial suspensions\nCarine Douarche (Un iversité Paris-Sud)\nWarning: special seminar time.\nSuspending highly mo tile Escherichia coli in a liquid lowers the viscosity of the solution at low shear rate. At higher cell concentrations\, a regime of near zero visc osity can be reached. In this work\, we investigate the system-size depend ence of the rheological response of an E. coli suspension as a function of shear rate and bacteria concentration using a low-shear Couette rheometer . Additionally\, we image the suspensions in a cone-plate rheo-imaging set up allowing direct visualisation of the collective organisation under shea r. We find the flow becomes banded and viscosity decreases to near zero at a bacterial concentration close to where collective motion appears in abs ence of flow.\nIndeed\, dense suspensions of swimming bacteria display rem arkable collective motion\, i.e. local bacterial ordering associated with a characteristic correlation length\, reminiscent of turbulent flow behavi our. Using video microscopy over large fields of view (up to 3 mm x 4 mm)\ , and particle image velocimetry\, we calculate the spatial correlation of the velocity vectors and extract a characteristic length scale. At suffic iently high bacterial concentrations\, we find this length to be proportio nal to the smallest system size. However\, the absence of saturation towar ds large system-sizes suggests there is no intrinsic length-scale in these dense populations of such ‘pusher-like’ swimmers. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-684@lptms.universite-paris-saclay.fr DTSTART:20191001T110000Z DTEND:20191001T120000Z DTSTAMP:20190922T221850Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-werner-krauth-lpens/ SUMMARY:Séminaire du LPTMS: Werner Krauth (LPENS) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 1 Oct 19 11:00 DESCRIPTION:Fast irreversible Markov chains in statistical physics\nWerner Krauth (LPENS)\nThe Monte Carlo method is an outstanding computational too l in science. Since its origins\, it has relied on the detailed-balance co ndition (that is\, the absence of flows in equilibrium) to map general com putational problems onto equilibrium-statistical-physics systems.\n\nIrrev ersible Markov chains violate the detailed-balance condition. They realize the equilibrium Boltzmann distribution as a steady state with non-vanishi ng flows. For one-dimensional particle models we have proven rigorously th at local algorithms reach equilibrium on much faster time scales than the reversible algorithms that satisfy detailed balance. The event-chain Monte Carlo algorithm (ECMC) generalizes these irreversible Markov chains to hi gher dimensions. It relies on a factorized Metropolis filter which is base d on a consensus rule rather than on an energy criterion.\n\nAs applicatio ns I will discuss the solution of the famous two-dimensional melting prob lem for hard disks and related systems\, where we showed\, using ECMC\, that hard disks melt neither following the Kosterlitz-Thouless-Halperin-Ne lson-Young prescription nor the alternative first-order liquid-solid scena rio. I will also present the use of ECMC for the general classical all-ato m N-body problem. Here\, the Boltzmann distribution exp(-beta E) is sample d (without any discretization or truncation error) but the potential energ y E remains unknown. This is of great interest in the Coulomb problem\, wh ere E or its derivatives\, the forces\, are hard to compute. Our recent Je LLyFysh open-source Python application implements ECMC for models from har d spheres to three-dimensional water systems. I will finish by discussing its features\, that closely mirror the mathematical formulation of ECMC\, and by presenting its future challenges. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-693@lptms.universite-paris-saclay.fr DTSTART:20191008T110000Z DTEND:20191008T120000Z DTSTAMP:20191002T085529Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sylvain-nascimbene-lkb/ SUMMARY:Séminaire du LPTMS: Sylvain Nascimbène (LKB) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Oct 19 11:00 DESCRIPTION:Synthetic quantum Hall system with ultracold Dysprosium atoms\n Sylvain Nascimbène (LKB)\nA quantum Hall system is characterized by the q uantization of its Hall conductance\, and its robustness with respect to m aterial imperfections. In solid states devices disorder induces strong inh omogeneities in the Hall current distribution\, making the connection with simple disorder-free models challenging. In this talk I will present the realization of a synthetic quantum Hall system using ultracold atoms of Dy sprosium\, in which a synthetic dimension is encoded in the electronic spi n J=8. Dynamics in this dimension is induced by laser-induced spin couplin gs\, and the Doppler effect occuring in these processes leads to a spin-or bit coupling\, interpreted as an artificial magnetic field. We show that o ur system reproduces several characteristic features of Landau levels. We observe a clear distinction between bulk states -- with inhibited motion d ue to limited energy dispersion -- and edge modes\, free to move in one di rection only. We also probe the system excitations\, via the measurement o f cyclotron and skipping orbits. We finally probe the Hall response of the system\, and make the connection to topological properties of the lowest energy band. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-703@lptms.universite-paris-saclay.fr DTSTART:20191009T110000Z DTEND:20191009T120000Z DTSTAMP:20190923T195317Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/156514/ SUMMARY:Physics-Biology interface seminar: Aurore Loisy - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Oct 19 11:00 DESCRIPTION:Active fluids under confinement: spontaneous flow and negative viscosity\nAurore Loisy (School of Mathematics\, University of Bristol)\nS eminar hosted by Harold Auradou\nIt has been known for a long time that ad ding motile bacteria to a liquid lowers the viscosity of the mixture. But only recently came the experimental evidence that this phenomenon can cont inue until a zero viscosity is reached (Lopez\, Gachelin\, Douarche\, Aura dou\, & Clément\, Phys. Rev. Lett. 115\, 028301 (2015)). An even more int riguing result in this experiment was the (single) data point located belo w the zero-viscosity threshold. So\, how is it possible to observe a stead y state with a negative viscosity? In this talk I will use a simple model of an active liquid and propose an explanation to this peculiar phenomenon .\nTime permitting\, I will then consider a drop of active liquid (a minim al model for the actomyosin cytoskeleton) and show how the same physics al lows this drop to propel itself on a substrate without the need to exert a ny traction locally on the surface. This mode of self-propulsion\, which d oes not rely on adhesion\, may be relevant to cell motility in crowded env ironments. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-685@lptms.universite-paris-saclay.fr DTSTART:20191015T110000Z DTEND:20191015T120000Z DTSTAMP:20191003T064103Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jerome-martin-iap/ SUMMARY:Séminaire du LPTMS: Jérôme Martin (IAP) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 Oct 19 11:00 DESCRIPTION:Cosmic Inflation and Quantum Mechanics\nJérôme Martin (IAP)\n One of the most important insight of modern Cosmology is that galaxies are of quantum-mechanical origin. According to the theory of inflation\, they are indeed nothing but quantum fluctuations\namplified by gravitational i nstability and stretched to cosmological distances by cosmic expansion. In this talk\, I describe this mechanism and discuss the implications for pr imordial cosmology but also for\nfoundational issues in Quantum Mechanics. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-709@lptms.universite-paris-saclay.fr DTSTART:20191017T110000Z DTEND:20191017T120000Z DTSTAMP:20191006T162135Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-martin-evans-univ-of-edinburgh/ SUMMARY:Séminaire exceptionnel du LPTMS: Martin Evans (Univ. of Edinburgh) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 1 7 Oct 19 11:00 DESCRIPTION:Active Interface Equations\nMartin Evans (Univ. of Edinburgh)\n In this work we consider the role of active inclusions in a growing interf ace\, for example membrane binding proteins which catalyse growth in the p lasma membrane of eukaryotic cells. The interface is thus rendered active and is described by two coupled fields: the height field of the interface and the density of the inclusions. The equations generalise to active inte rface growth the Kardar Parisi Zhang equation\, which describes nonequilib rium growth and also represents many other systems driven out of out of eq uilibrium. In our model inclusions gravitate towards minima of the height field and then catalyse growth which generates interface waves. This leads to complex kinematic waves and pattern formation and the proteins are abl e to surf the waves they create. The interface width displays a novel supe rposition of scaling and sustained oscillations distinct from KPZ physics. \n\nReference: F. Cagnetta\, M. R. Evans and D Marenduzzo\, Phys. Rev. Let t. 120\, 258001 (2018) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-710@lptms.universite-paris-saclay.fr DTSTART:20191022T110000Z DTEND:20191022T120000Z DTSTAMP:20191009T123920Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-denis-boyer-unam-mexico/ SUMMARY:Séminaire du LPTMS: Denis Boyer (UNAM\, Mexico) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 22 Oct 19 11:00 DESCRIPTION:Random walks on networks with stochastic resetting\nDenis Boyer (UNAM\, Mexico)\nResetting a stochastic process from time to time to the initial state can represent an efficient search strategy for locating a hi dden target. This fact finds applications in statistical physics\, compute r science\, enzymatic reactions or foraging ecology. Random walks on gener al networks and subject to resetting have not been studied\, despite their relevance to epidemic spreading\, searching on the web or human mobility\ , among others. We develop an extension to an arbitrary network topology o f the diffusion problem with stochastic resetting. Our formalism applies t o finite undirected networks and is implemented from the spectral properti es of the random walk without resetting. We show that resetting can allow a faster exploration of many network architectures such as rings\, Cayley trees\, random networks and complex networks\, highlighting the importance of the choice of the starting/resetting node. The small-world effect and the presence of communities\, two properties of many real world etworks\, strongly affects exploration strategies based on resetting. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-686@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20191105T110000 DTEND;TZID=Europe/Paris:20191105T120000 DTSTAMP:20191017T122829Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-igor-ferrier-barbut/ SUMMARY:Séminaire du LPTMS: Igor Ferrier-Barbut - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 5 Nov 19 11:00 DESCRIPTION:Light scattering by cold atomic arrays\, towards quantum simula tion of dissipative many-body physics\nIgor Ferrier-Barbut (LCF\, Institut d’Optique)\n\nSingle atom trapping using tightly focused optical tweeze rs has emerged as a new versatile experimental platform. Optical holograph ic techniques allow to engineer 1\, 2 or 3D ensembles of atoms in vacuum\, that have an almost arbitrary geometry and are nearly free of defects. Ty pically\, these techniques are combined with an excitation of the atoms to Rydberg states\, that allow to engineer an interaction between the indivi dual atoms\, realizing quantum simulators for quantum many-body physics. I n this presentation I will focus on our progress to study dissipative quan tum many-body systems in such platforms. For this we use light-induced res onant dipole-dipole interactions between two-level atoms\, which contain b oth a conservative and dissipative part. We will present first experiments where we were able to increase the effect of such interactions\, and pros pects to reach the strongly interacting regime.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-676@lptms.universite-paris-saclay.fr DTSTART:20191106T110000Z DTEND:20191106T120000Z DTSTAMP:20191027T155153Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-heiko-rieger/ SUMMARY:Physics-Biology interface seminar: Heiko Rieger - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 6 Nov 19 11:00 DESCRIPTION:Biophysics of Killing – Theory and Experiment\nHeiko Rieger ( Saarland University)\nCytotoxic T lymphocytes and natural killer cells are the main cytotoxic killer cells of the human body to eliminate pathogen-i nfected or tumorigenic cells. Various processes are involved in a successf ul killing event: activation of the killer cell\, migration and search for the target\, formation of a synapse and polarization upon contact with th e target\, transport of cytotoxic agents towards the synapse\, and finally elimination of the target via necrosis or apoptosis. In this talk I will review various biophysical aspects of killing that were studied in collabo ration with experimental groups from biology and medicine. Topics include the analysis of search strategies of migrating killer cells\; the mechanis tic understanding of the molecular motor driven cytoskeleton rotation towa rds the synapse during polarization\; the efficiency of the spatial organi zation of the cytoskeleton for search problems occurring in intra-cellular cargo transport\; and the stochastic analysis of different killing strate gies via inducing necrosis or apoptosis.\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-695@lptms.universite-paris-saclay.fr DTSTART:20191112T110000Z DTEND:20191112T120000Z DTSTAMP:20191022T203956Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-erdal-oguz-tel-aviv-university/ SUMMARY:Séminaire du LPTMS: Erdal Oguz (Tel Aviv University) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Nov 19 11:00 DESCRIPTION:Hyperuniformity of quasicrystals and related structures\nErdal Oguz (Tel Aviv University)\nDensity fluctuations in many-body systems are of fundamental importance throughout various scientific disciplines. Hyper uniform systems\, which include crystals and quasicrystals\, have density fluctuations that are anomalously suppressed at long wavelengths compared to the fluctuations in typical disordered point distributions such as in i deal gases and liquids.\nIn this talk\, I will provide the first rigorous hyperuniformity analysis of quasicrystals and related points sets\, and it s consequences. Most importantly\, we reveal that one-dimensional quasicry stals obtained by the cut-and-project method fall into two distinct classe s with respect to their large-scale density fluctuations. This distinction provides a new classification scheme of quasicrystalline systems. Further more\, our results suggest that these two classes exhibit distinct physica l properties\; for instance\, by employing a tight-binding model\, we disc over that wave localization in each class displays a qualitatively differe nt behavior. \n\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-691@lptms.universite-paris-saclay.fr DTSTART:20191115T143000Z DTEND:20191115T173000Z DTSTAMP:20191113T130158Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-ivan-palaia/ SUMMARY:Soutenance de thèse: Ivan Palaia - Petit amphi\, bâtiment Pascal n° 530 - 15 Nov 19 14:30 DESCRIPTION:Charged systems in\, out of\, and driven to equilibrium: from n anocapacitors to cement\nPar\n\nIvan Palaia\n \;\n\nJury:\n\nRudolf Po dgornik\, Chinese Academy of Sciences\, rapporteur\n\nRené van Roij\, Utr echt University\, rapporteur\n\nEmanuela del Gado\, Georgetown University\ , examinatrice\n\nPatrick Guenoun\, CEA Saclay / CNRS\, examinateur\n\nMan oel Manghi\, Université de Toulouse / CNRS\, examinateur\n\nBenjamin Rote nberg\, Sorbonne Université / CNRS\, examinateur\n\nEmmanuel Trizac\, Uni versité Paris-Sud / CNRS\, directeur de thèse\n\nRésumé :\n\nMost syst ems in soft matter are immersed in solutions with charged species: some ca n be described by mean-field theories\, others require more sophisticated techniques. In this thesis defense we focus on two such systems.\n\nFirstl y\, we analyze the relaxation dynamics of a nanocapacitor within the mean- field approach. We study relaxation times in the linear and nonlinear regi me and characterize the behavior of the system as a function of salt densi ty and applied voltage. The problem of designing a smart applied potential \, to drive the system from an initial to a chosen final equilibrium state \, is also tackled.\n\nWe then discuss the physics of ionic correlations i n charged systems\, with particular focus on the phenomenon of like-charge attraction. We show the relevance of the strong coupling theory\, that we apply to the nanoscopic constituents of cement. We demonstrate that the s trong cohesion force of cement may be explained by a “dry water” pictu re\, in excellent agreement with molecular dynamics simulations\, thereby filling a gap in our understanding of the most used synthetic material in the world.\n CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-698@lptms.universite-paris-saclay.fr DTSTART:20191119T110000Z DTEND:20191119T120000Z DTSTAMP:20191013T052855Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christine-proust/ SUMMARY:Séminaire du LPTMS: Christine Proust - LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 19 Nov 19 11:00 DESCRIPTION:Mathématiques en Mésopotamie\, un panorama général et une a ttention particulière portée sur l'arithmétique des nombres flottants\n Christine Proust (CNRS - Université Paris-Diderot - SPHERE)\nCe séminair e s’appuie sur une collection de tablettes d’argile écrites il y a 40 00 ans dans les écoles de scribes de Mésopotamie. À première vue\, ce sont des exercices très simples\, de contenu mathématique élémentaire\ , et de ce fait\, ces modestes écrits n’ont guère attiré l’attentio n des historiens des mathématiques. Pourtant\, à y regarder de plus prè s\, cette simplicité se révèle trompeuse. Le sentiment de familiarité résulte essentiellement d’une projection sur le passé de conceptions p rofondément ancrées lors de nos propres apprentissages précoces. Une ob servation attentive des tablettes scolaires révèle des différences subt iles entre les conceptions anciennes et nos idées modernes sur ce que nou s appelons les nombres\, les quantités\, les unités\, la mesure\, les gr andeurs\, l’ordre\, la divisibilité\, etc. Les efforts pédagogiques de s maı̂tres scribes laissent percevoir un univers numérique tout à fait original\, doté de règles qui lui sont propres\, et permettant le déve loppement d’algorithmes de calcul puissants. CATEGORIES:seminars LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 Rue Georges Clemenceau\, Orsay\, 91405\, France GEO:48.698185;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768 END:VEVENT BEGIN:VEVENT UID:0-689@lptms.universite-paris-saclay.fr DTSTART:20191120T133000Z DTEND:20191120T143000Z DTSTAMP:20191019T202921Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-tuomas-knowles/ SUMMARY:Physics-Biology interface seminar: Tuomas Knowles - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Nov 19 13:30 DESCRIPTION:Probing proteins in small volumes\nTuomas Knowles (Cambridge Un iversity\, UK)\nWarning: special time\nThis talk outlines our efforts on e xploring experimental strategies to provide a new window into protein self -assembly that are enabled by operation in small volumes. We have shown th at microconfinement achieved through droplet microfluidics allows the isol ation of single nucleation events in protein aggregation and thus to study a rare event as single molecule resolution. Using this strategy we have a lso been able to develop an understanding of how aberrant misfolded protei n states are transmitted from one molecule to another through time and spa ce. More recently we have exploited measurements of mass transport through fluid streams under laminar flow conditions to generate a platform for pr obing protein-protein interactions under fully native conditions. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-690@lptms.universite-paris-saclay.fr DTSTART:20191121T143000Z DTEND:20191121T170000Z DTSTAMP:20191024T123711Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-luca-barberi/ SUMMARY:Soutenance de thèse: Luca Barberi - Petit amphi\, bâtiment Pascal n° 530 - 21 Nov 19 14:30 DESCRIPTION:Soutenance de thèse:\nInferring forces from geometry in biolog y\npar\n\nLuca Barberi\n \;\n\nJury:\n\nRudolf Podgornik\, University of Ljubljana (Slovenia) and Chinese Academy of Sciences (Beijing\, China)\ n\nAnđela Šarić\, University College London (United Kingdom)\n\nClémen t Campillo\, Université d'Évry Val d'Essonne (France)\n\nAntonio De Simo ne\, Scuola Internazionale Superiore di Studi Avanzati (Trieste\, Italy)\n \nAurélien Roux\, Université de Genève (Suisse)\n\nPierre Sens\, Instit ut Curie (Paris\, France)\n\nMartin Lenz\, CNRS and Université Paris-Sud (France)\n\n \;\n\nRésumé :\n\nInter-molecular forces on which we ha ve poor prior knowledge are often essential for the stability and evolutio n of biological assemblies. In this thesis\, we focus on two such forces t hat are critically involved in the deformation of either biopolymers or me mbranes. We infer these forces by reconciling the geometry of such deforma tion with simple mechanical models.\n\nIn the first part of the thesis\, w e consider the attractive force between DNA molecules mediated by multival ent cations. This attraction is required to compensate DNA bending rigidit y when packaging large quantities of DNA in comparatively small environmen ts\, such as the nuclei of sperm cells. In vitro\, multivalent cations dri ve DNA condensation into dense toroidal bundles. Geometrical data on DNA t oroidal bundles give access to the competition between inter-helical attra ction and DNA bending rigidity. From these data\, we infer inter-helical f orces and argue that the toroid curvature weakens the adhesion between DNA molecules.\n\nIn the second part of the thesis\, we turn to the binding f orce of a membrane remodeling protein complex\, ESCRT-III\, to cellular me mbranes. ESCRT-III proteins assemble into membrane-remodeling polymers dur ing many cellular processes\, ranging from HIV budding to cytokinesis. The mechanism by which ESCRT-III polymers deform membranes is still unclear. In vitro\, ESCRT-III polymers can reshape spherical membrane vesicles into helical tubes. We argue that helical tubes result from the peculiar posit ioning of membrane-binding sites on the surface of ESCRT-III polymers. Fur thermore\, we infer the binding force between ESCRT-III and membrane from the geometry of helical tubes.\n\n \; CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-713@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20191126T110000 DTEND;TZID=Europe/Paris:20191126T120000 DTSTAMP:20191115T152118Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandra-sheremet/ SUMMARY:Séminaire du LPTMS: Alexandra Sheremet - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Nov 19 11:00 DESCRIPTION:Light-matter interface based on collective and cooperative effe cts\nAlexandra Sheremet (Institut Langevin\, ESPCI)\n\nUnderstanding and c ontrol of light-matter interactions have been central to the development o f modern physics. A promising approach for study of such interactions is b ased on ensemble of neutral atoms. Manipulations with density and spatial organization of atoms in a system can bring fascinating results\, which ar e interesting for quantum information applications. For example\, reducing average distance between atoms up to resonant wavelength induces dipole-d ipole interaction and results in cooperative effects. These effects in spa tially dense atomic ensembles can modify optical properties of the system. Moreover\, spatial organization of atoms in ordered arrays and optical la ttices causes a manifestation of collective effects. In such systems\, lon g-range spatial order brings dramatic consequences for the light propagati on.\n\nCollective and cooperative effects manifistable in an atomic ensemb le could provide essential enhancement of the coupling strength between th e light and atomic systems. Moreover\, recent experimental advances in the trapping technique have made it possible to create 1D\, 2D or 3D spatiall y ordered atomic configurations\, where the collective effects play a very important role. In addition\, the interaction between light and atoms can be enhanced by trapping atoms in the vicinity of a nanoscale waveguide du e to strong confinement of the light.\n\nIn this talk\, I will discuss lig ht propagation in an atomic ensemble where average distance between atoms is comparable with the resonant wavelength. I will consider the light prop agation in both free space and trapped near a nanofiber surface atomic ens embles. The light scattering in such dense atomic configuration is describ ed in terms of microscopic approach based on the standard scattering matri x and resolvent operator formalism. We show theoretically and experimental ly that spatially dense atomic ensembles allow obtaining effective light-m atter interface and reliable light storage with essentially fewer atoms th an it can be achieved in dilute gases. Furthermore\, we show that the pres ence of an optical nanofiber modifies the character of atomic interaction and results in long-range dipole-dipole coupling between atoms not only vi a the free space\, but also through the waveguide mode. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-707@lptms.universite-paris-saclay.fr DTSTART:20191204T110000Z DTEND:20191204T120000Z DTSTAMP:20191129T132550Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-matthias-merkel/ SUMMARY:Physics-Biology interface seminar: Matthias Merkel - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Déc 19 11:00 DESCRIPTION:A new approach unifies mechanical rigidity in cell-based tissue models and biopolymer networks\nMatthias Merkel (Turing Center for Living Systems\, Marseille)\nUnderstanding how mechanical properties of biologic al tissues arise from collective cellular behavior is vital for understand ing the mechanisms that guide embryonic development\, cancer growth\, and wound healing. With my group\, I am studying several questions of collecti ve effects and self-organization in biological tissue. Recently\, a new ty pe of rigidity transition was discovered in a family of cell-based models for 2D and 3D tissues. Here I discuss these transitions and show that they are an instance of a much more general class of transitions\, which appea r when introducing geometric incompatibility into so-called under-constrai ned systems. This kind of transition also provides an important limiting c ase to understand stiffening in fiber network models\, which are used to d escribe biopolymer networks like collagen. We show that all of these model s exhibit generic elastic behavior close to the transition\, which is larg ely independent of the microscopic structure and the disorder in the syste m. We obtain analytic expressions for the relevant elastic properties and numerically verify our findings by simulations of under-constrained spring networks as well as 2D and 3D vertex models for dense biological tissues. Several of our predictions are parameter-free\, and we thus expect them t o be general hallmarks for geometric-incompatibility-induced stiffening in under-constrained materials. Hence\, they provide quantitative experiment al tests for whether stiffening in a given material is due to this effect or not. Finally\, I will briefly discuss another project of current intere st in my group\, where we will explore conditions for robust self-organize d oriented deformation of biological tissue. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-722@lptms.universite-paris-saclay.fr DTSTART:20191210T110000Z DTEND:20191210T120000Z DTSTAMP:20191122T100841Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-aurelien-grabsch/ SUMMARY:Séminaire du LPTMS: Aurélien Grabsch - Salle des séminaires du F AST et du LPTMS\, bâtiment Pascal n°530 - 10 Déc 19 11:00 DESCRIPTION:Electrical detection of non-Abelian statistics in topological s uperconductors\nAurélien Grabsch (Leiden University)\n\nTopological super conductors can support quasiparticle excitations which present unusual exc hange statistics\, called non-Abelian anyons. They correspond to midgap st ates localized in the core of a vortex or bound to the end of a nanowire. However\, their unusual statistics cannot be easily demonstrated as they a re immobile\, and one should rely on indirect methods. Here\, we propose a real space alternative which relies on the chiral motion along the edges of a topological superconductor. We present an approach which allows to in ject on demand so-called edge vortices\, which are pi-phase domain walls w hich propagate along the chiral edge channels\, and possess non-Abelian st atistics. We show that the signatures of this unusual exchange statistics can be detected in an electrical measurement.\n\nReferences:\n\nElectrical detection of the Majorana fusion rule for chiral edge vortices in a topol ogical superconductor\nC.W.J Beenakker\, A. Grabsch\, Y. Herasymenko\nSciP ost Phys. 6\, 022 (2019)\n\nTime-resolved electrical detection of chiral e dge vortex braiding\nI. Adagideli\, F. Hassler\, A. Grabsch\, M. Pacholski \, C.W.J. Beenakker\narXiv:1907.02422\n\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-694@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20191217T110000 DTEND;TZID=Europe/Paris:20191217T120000 DTSTAMP:20191211T103635Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-leticia-tarruell/ SUMMARY:Seminaire du LPTMS: Leticia Tarruell - Salle des séminaires du FAS T et du LPTMS\, bâtiment Pascal n°530 - 17 Déc 19 11:00 DESCRIPTION:Solitons and droplets in two-component Bose-Einstein condensate s\nLeticia Tarruell (ICFO-The Institute of Photonic Sciences\, Castelldefe ls)\n\nSelf-bound states appear in contexts as diverse as solitary waves i n channels\, optical solitons in non-linear media and liquid droplets. The ir binding results from a balance between attractive forces\, which tend t o make the system collapse\, and repulsive ones\, which stabilize it to a finite size. This talk will present experiments on three different types o f self-bound states existing in two-component Bose-Einstein condensates.\n \nIn the first series of experiments\, we study dilute quantum liquid drop lets: macroscopic clusters of ultra-cold atoms that are eight orders of ma gnitude more dilute than liquid Helium\, but have similar liquid-like prop erties. In particular\, they remain self-trapped in the absence of externa l confinement due to the compensation of attractive mean-field forces and an effective repulsion stemming from quantum fluctuations [1]. We experime ntally observe such droplets in a mixture of potassium Bose-Einstein conde nsates with repulsive intrastate and attractive interstate interactions [2 ]\, and study their relation with more conventional bright solitons [3]. \ n\nAs a second step\, we consider instead a system where each atom is plac ed in a coherent superposition of these two internal states. We measure th e elastic and inelastic properties of the gas\, and show that they can be flexibly controlled via the parameters of the coupling field [4\,5]. In th e attractive regime\, we exploit this method to form bright solitons forme d by dressed-state atoms\, and to create bright soliton trains. \n\nFinall y\, we explore the situation where the coupling field imparts a momentum k ick to the atoms\, breaking Galilean invariance and creating an artificial vector potential. For potassium condensates\, the intrastate interactions have very different values and this synthetic gauge field becomes density -dependent [6]. We show that our system implements a one-dimensional Chern -Simons gauge theory that contains a chiral current term\, and experimenta lly observe the stabilization of chiral bright solitons.\n\n[1] D. S. Petr ov\, Phys. Rev. Lett. 115\, 155302 (2015)\n[2] C. R. Cabrera et al.\, Scie nce 359\, 301 (2018)\n[3] P. Cheiney et al.\, Phys. Rev. Lett. 120\, 13530 1 (2018)\n[4] C. P. Search and P. R. Berman\, Phys. Rev. A 63\, 043612 (20 01)\n[5] D. S. Petrov\, Phys. Rev. Lett. 112\, 103201 (2014)\n[6] M. J. Ed monds et al.\, Phys. Rev. Lett. 110\, 085301 (2013) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-714@lptms.universite-paris-saclay.fr DTSTART:20200107T110000Z DTEND:20200107T120000Z DTSTAMP:20200105T162225Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-fernando-iemini-universidade-federal-fluminense/ SUMMARY:Séminaire du LPTMS: Fernando Iemini (Universidade Federal Fluminen se) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Jan 20 11:00 DESCRIPTION:Boundary time crystals\nFernando Iemini (Universidade Federal F luminense)\n\nSpontaneous symmetry breaking is a cornerstone of physics an d occurs at all energy scales\, in cosmology and high-energy physics as we ll as in condensed matter. Breaking space translation symmetry for example gives rise to crystals\, while superfluids and ferromagnets are manifesta tions or the spontaneous breaking of gauge or rotational invariance\, resp ectively. Amongst all possible complex situations that were considered and experimentally verified so far breaking the time-translation symmetry\, g enerating a "time-crystal"\, had not received attention. The possible exis tence of time crystals\, first addressed by Wilczek in 2013\, prompted an intense discussion.\n\nIn this seminar we will discuss about this new phas e of matter\, and present our recent results predicting a novel form of ti me-translation symmetry breaking: continuous Boundary Time Crystals (BTCs) . In the BTC phase\, symmetry breaking appears in a (macroscopic) fraction of the system. Moreover\, a BTC breaks the continuous time-translation sy mmetry\, i.e. the system self-organises in a time periodic pattern with a period which only depends on its coupling constants. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-715@lptms.universite-paris-saclay.fr DTSTART:20200114T110000Z DTEND:20200114T120000Z DTSTAMP:20200111T144518Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-martial-mazars-lpt-u-psud/ SUMMARY:Séminaire du LPTMS: Martial Mazars (LPT U-PSUD) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Jan 20 11:00 DESCRIPTION:Topological defects and the melting in two dimensions\nMartial Mazars (LPT U-PSUD)\n\nTopological defects have a preponderant role in the physics of (quasi) two-dimensional systems. One of the first applications is the description of the XY model by Kosterlitz and Thouless in the 1970 s\; this theoretical description of the XY model made possible in the 1980 s to formulate a theory for the fusion in two dimensions\, the KTHNY theor y (Kosterlitz - Thouless - Halperin - Nelson - Young). In KTHNY\, the tran sition from the solid phase to the liquid phase occurs with an intermediat e phase\, the hexatic phase\, and each of the transitions: solid / hexatic and hexatic / liquid is of the KT type.\nThe microscopic mechanisms in KT HNY leading to phase transitions are dissociations of clusters of topologi cal defects: the dissociation of dislocation pairs into free dislocations (solid / hexatic) and the dissociation of dislocations into free disclinat ions (hexatic / liquid). This description of the two-dimensional fusion is in competition with a first-order transition between solid and liquid\, w ithout hexatic phase.\nThe existence of an intermediate hexatic phase for simple systems in two dimensions remained hypothetical until the mid-2000s when it was observed in experiments on superparamagnetic colloids confine d to a water-air interface (Keim\, Maret 2007). This observation reinforce s the relevance of KTHNY. Then\, with computer simulations of hard disks ( Krauth - 2011) and in colloidal systems (Thorneywork\, Dullens - 2017)\, t he hexatic / liquid transition is found to be first order\, in contradicti on with KTHNY.\nIn this seminar\, we show that the mechanisms of dissociat ion of the KTHNY topological clusters are responsible for the solid / hexa tic and hexatic / liquid transitions\, and that\, by a statistical analysi s of the topological clusters\, the KTHNY theory is compatible with a firs t order transition for the hexatic / liquid.\n\nReferences : \n- P. Keim\, G. Maret and H.H. von Grünberg\, 2007\, Phys. Rev. E.\, 75\, 031402.\n- E.P. Bernard\, W. Krauth\, 2011\, Phys. Rev. Lett.\, 107\, 155704.\n- A. L . Thorneywork\, J. L. Abbott\, D. G. A. L. Aarts and R. P. A. Dullens\, 20 17\, Phys. Rev. Lett.\, 118\, 158001.\n\nThe results presented in this sem inar have been published in :\n- M. Mazars\, 2015\, EPL\, 110\, 26003. \n- M. Mazars and R. Salazar\, 2019\, EPL\, 126\, 56002. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-711@lptms.universite-paris-saclay.fr DTSTART:20200115T110000Z DTEND:20200115T120000Z DTSTAMP:20191014T193906Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-ronald-melki/ SUMMARY:Physics-Biology interface seminar: Ronald Melki - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 Jan 20 11:00 DESCRIPTION:Prion-like propagation of alpha-synuclein assemblies in synucle inopathies\, similarities with Tau in Tauopathies\nRonald Melki (Institut François Jacob\, CEA &\; CNRS)\nThe aggregation of proteins within the central nervous system is deleterious and associated to neurodegenerative disorders. The aggregation of the proteins alpha-synuclein and Tau are as sociated to synucleinopathies\, in particular Parkinson's disease\, and ta uopathies\, among which Alzheimer’s disease\, respectively. How alpha-sy nuclein and Tau aggregates\, how those aggregates traffic between cells\, amplify by recruiting endogenous monomeric alpha-synuclein or Tau and caus e distinct synucleinopathies or tauopathies is unclear.\n\nI will explain the molecular events that lead to alpha-synuclein or Tau aggregation. I wi ll show that alpha-synuclein and Tau aggregates bind to neurons cell membr anes and explain the cellular consequences of binding. The similarities an d differences between alpha-synuclein and Tau will be highlighted. I will explain how alpha-synuclein and Tau aggregates penetrate the cells and get transported. Finally\, I will describe how the structure of the fibrillar polymorphs alpha-synuclein and Tau aggregation yield distinct diseases.\n \nReferences:\n\nBrundin P et al. (2010) Nat Rev Mol Cell Biol. 11:301-7.\ nBousset L et al. (2013) Nat Commun. 4:2575.\nPeelaerts W et al. (2015) Na ture 522:340-4.\nShrivastava AN et al. (2015) EMBO J. 34:2408-23.\nBrahic M et al. (2016) Acta Neuropathol. 131:539-48.\nMakky A et al. (2016) Sci R ep. 6:37970.\nFlavin W et al. (2017) Acta Neuropathol. 134:629-653.\nShriv astava AN et al. (2017) Neuron 95:33-50.\nMelki R (2018) Neurobiol Dis. 10 9:201-208.\nGribaudo S et al. (2019) Stem Cell Reports. 12:230-244.\nShriv astava AN et al. (2019) EMBO J. 38. pii: e99871.\nFenyi A et al.\, (2019) Neurobiol Dis 129:38-43.\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-717@lptms.universite-paris-saclay.fr DTSTART:20200121T110000Z DTEND:20200121T120000Z DTSTAMP:20191220T085605Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-baruch-meerson/ SUMMARY:Séminaire du LPTMS: Baruch Meerson - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Jan 20 11:00 DESCRIPTION:Geometrical optics of constrained Brownian motion: three short stories\nBaruch Meerson (Racah Institute of Physics\, Hebrew University of Jerusalem)\n\nThe optimal fluctuation method — essentially geometrical optics — gives a deep insight into large deviations of Brownian motion\, and it achieves this purpose by simple means. Here we illustrate these points by telling three short stories about Brownian motions\, ``pushed" i nto a large-deviation regime by constraints.\n\nStory 1 deals with a long- time survival of a Brownian particle in 1 + 1 dimension against absorption by a wall which advances according to a power law xw(t)~ t&gamma\;\, wher e &gamma\; > 1/2. We also calculate the large deviation function (LDF) of the particle position at an earlier time\, conditional on the survival by a later time.\n\nStory 2 addresses a stretched Brownian motion above an a bsorbing obstacle in the plane. We compute the short-time LDF of the posit ion of the surviving Brownian particle at an intermediate point.\n\nIn sto ry 3 we compute the short-time LDF of the winding angle of a Brownian par ticle wandering around a reflecting disk in the plane.\n\nIn all three sto ries we uncover singularities of the LDFs which can be interpreted as dyna mical phase transitions and which have a simple geometric origin. We also use the small-deviation limit of the geometrical optics to reconstruct the distribution of typical fluctuations. We argue that\, in stories 1 and 2\ , this is the Ferrari–Spohn distribution.\n\nThe talk is based on a rece nt paper by B. Meerson and N. R. Smith\, J. Phys. A: Math. Theor. 52\, 415 001 (2019). CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-718@lptms.universite-paris-saclay.fr DTSTART:20200128T110000Z DTEND:20200128T120000Z DTSTAMP:20200111T144612Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giulio-biroli-lpens/ SUMMARY:Séminaire du LPTMS: Giulio Biroli (LPENS) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 28 Jan 20 11:00 DESCRIPTION:Multiple Equilibria\, Aging Dynamics and Chaos in Large Interac ting Ecosystems\nGiulio Biroli (LPENS)\n\nI will focus on Lotka-Volterra e quations\, which provide a general model to study large assemblies of stro ngly interacting degrees of freedom in many different fields: biology\, ec onomy and in particular ecology. I will present our analysis of the genera lised Lotka-Volterra model of an ecological community formed by a large nu mber of species and focus in particular on two different phases that emerg e: when interactions are symmetric we find a regime\, akin to the spin-gla ss phase of random magnets\, characterized by an exponential number of mul tiple equilibria\, all poised at the edge of stability. For non-symmetric interactions\, this phase is replaced by a chaotic one or a dynamical agin g regime depending on the presence of immigration from the mainland. Final ly\, I will consider spatially coupled communities and show that migration between them plays a key role in enhancing chaos and diversity of the eco system. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-721@lptms.universite-paris-saclay.fr DTSTART:20200129T110000Z DTEND:20200129T120000Z DTSTAMP:20200106T154445Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-stephane-vassilopoulos-2/ SUMMARY:Physics-Biology interface seminar: Stéphane Vassilopoulos - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Jan 20 11:00 DESCRIPTION:Native membrane visualization by meta-replica electron microsco py\nStéphane Vassilopoulos (Sorbonne Université)\nIn cell biology\, part icular Importance is given to developing new methods of sample preparation that will achieve a more natural appearance of samples in the microscope. To accomplish this\, scientists have developed the metal-replica electron microscopy (EM) technique directly on unroofed cultured cells. This parti cular EM technique permits visualization of the inner side of cell membran es and their components with an extremely high resolution using transmissi on EM. Metal-replicas have profoundly shaped our understanding of the func tional morphology of the cell and used to capture several different cellul ar processes including remodeling of cytoskeletons\, membrane trafficking\ , cell-to-cell contacts and formation of extracellular matrices. During th is presentation\, I will outline the history of this particular EM techniq ue and describe different methodologies and key applications in cell biolo gy with a particular emphasis on visualization of actin filament networks at the cell cortex.\n\nSelected publications:\n\nVassilopoulos S*\, Gibaud S\, Jimenez A\, Caillol G\, Leterrier C. Ultrastructure of the axonal per iodic scaffold reveals a braid-like organization of actin rings. Nat Commu n. 2019 Dec 20\;10(1):5803.\nFerrari R*\, Martin G\, Tagit O\, Guichard A\ , Cambi A\, Voituriez R\, Vassilopoulos S*\, Chavrier P*. MT1-MMP directs force-producing proteolytic contacts that drive tumor cell invasion. Nat C ommun. 2019 Oct 25\;10(1):4886.\n\nFranck A\, Lainé J\, Moulay G\, Lemerl e E\, Trichet M\, Gentil C\, Benkhelifa-Ziyyat S\, Lacène E\, Bui MT\, Br ochier G\, Guicheney P\, Romero N\, Bitoun M\, Vassilopoulos S*. Clathrin plaques and associated actin anchor intermediate filaments in skeletal mus cle. Mol Biol Cell. 2019 Mar 1\;30(5):579-590.\nRandrianarison-Huetz V\, P apaefthymiou A\, Herledan G\, Noviello C\, Faradova U\, Collard L\, Pincin i A\, Schol E\, Decaux JF\, Maire P\, Vassilopoulos S\, Sotiropoulos A. Sr f controls satellite cell fusion through the maintenance of actin architec ture. J Cell Biol. 2018 Feb 5\;217(2):685-700.\n\nElkhatib N\, Bresteau E\ , Baschieri F\, Rioja AL\, van Niel G\, Vassilopoulos S\, Montagnac G. Tub ular clathrin/AP-2 lattices pinch collagen fibers to support 3D cell migra tion. Science. 2017 Jun 16\;356(6343).\n\nVassilopoulos S*\, Gentil C\, La iné J\, Buclez PO\, Franck A\, Ferry A\, Précigout G\, Roth R\, Heuser J E\, Brodsky FM\, Garcia L\, Bonne G\, Voit T\, Piétri-Rouxel F\, Bitoun M . Actin scaffolding by clathrin heavy chain is required for skeletal muscl e sarcomere organization. J Cell Biol. 2014 May 12\;205(3):377-93. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-725@lptms.universite-paris-saclay.fr DTSTART:20200204T110000Z DTEND:20200204T120000Z DTSTAMP:20200128T113624Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-eugenio-valdano-ucla/ SUMMARY:Séminaire du LPTMS: Eugenio Valdano (UCLA) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Fév 20 11:00 DESCRIPTION:Predicting epidemic risk from contact and mobility data\nEugeni o Valdano (UCLA)\n\nThe vulnerability of a host population to a specific d isease measures how likely pathogen introduction will lead to an epidemic outbreak\, and how hard it is to contain or eliminate an ongoing one. Pred icting vulnerability is thus key to designing risk-reduction strategies th at limit disease burden on public health and economic development. To do t hat\, highly-resolved data tracking contacts and mobility of the host popu lation need to integrate into detailed models of disease dynamics. This re presents a twofold challenge. Firstly\, we need theoretical frameworks tha t turn data feeds into predictors of epidemic risk\, and can identify whic h of the structural features of the host population drive its vulnerabilit y. Secondly\, we need new ways to access\, analyze\, and share the relevan t contact and mobility data: a necessary step to make our predictions real istic and reliable. In my talk\, I will address both issues. I will show h ow to analytically derive the conditions that discriminate between epidemi c regime and quick pathogen extinction\, by representing diseases spreadin g on empirically measured contacts as dynamical processes on time-evolving complex networks. The analytical core of this theory leads to a broad ran ge of applications. At the same time\, its data-driven nature prompts cont ext-specific predictions that can inform policymaking\, as I will show in two case studies: reorganizing nurse scheduling to reduce the risk of spre ad of healthcare-associated infections\; linking the features of livestock trade movements to the spatial spread of cattle diseases. The latter appl ication is also an example of how limited access and incomplete data colle ction represent a big hurdle to predictive vulnerability analysis. To over come this\, I will present a collaborative platform for analyzing and comp aring trade networks coming from several European countries. Using a bring code to the data approach\, our platform surmounts the strict regulations preventing data sharing\, and builds an algorithm that predicts vulnerabi lity even in situations when limited data on cattle trade are available. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-729@lptms.universite-paris-saclay.fr DTSTART:20200206T110000Z DTEND:20200206T120000Z DTSTAMP:20200129T135420Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/francesco-sciorti no-uni-roma-la-sapienza/ SUMMARY:Séminaire exceptionnel du LPTMS: Francesco Sciortino (Uni Roma La Sapienza) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n °530 - 6 Fév 20 11:00 DESCRIPTION:Patchy DNA-made nanoparticles\nFrancesco Sciortino (Uni Roma La Sapienza)\nDNA oligomers can nowadays be assembled to produce a large var iety of nanometric constructs\, via a cascade of self-assembly processes\, each one guided by the length of complementary sequences of distinct DNA strands. In the lecture I will show that it is possible to build bulk quan tities of DNA-made nanoparticles that closely match idealized colloids\, t ransferring modern in-paper and in-silico intuitions into experimental rea lizations. I will show how unconventional collective behaviors\, recently explored theoretically and numerically\, can indeed be reproduced in the l ab. Specifically I will discuss:\n\n how to exploit limited valence inter actions to suppress phase separation\, enhancing the stability of the equi librium gel phase\;\n how to exploit competing interactions to generate a material that is fluid both at high and at low temperatures and a solid-l ike disordered open network structure in between and\n how to exploit bon d-swap dynamics to create an all-DNA vitrimer.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-726@lptms.universite-paris-saclay.fr DTSTART:20200224T143000Z DTEND:20200224T143000Z DTSTAMP:20200212T125817Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-thibault-bonnemain/ SUMMARY:Soutenance de thèse: Thibault Bonnemain - LPTM\, Université Cergy Pontoise - 24 Fév 20 14:30 DESCRIPTION:Quadratic Mean Field Games with Negative Coordination\npar\n\nT hibault Bonnemain\nJury:\n\nCécile APPERT-ROLLAND\, Univeristé Paris-Sac lay\, examinatrice\n\nThierry GOBRON\, Université Cergy-Pontoise\, direct eur de thèse\n\nOlivier GUEANT\, Université Paris 1 Panthéon-Sorbonne\, examinateur\n\nMax-Olivier HONGLER\, EPFL\, rapporteur\n\nJean-Pierre NAD AL\, École Normale Supérieure\, examinateur\n\nFilippo SANTAMBROGIO\, Un iversité Claude Bernard - Lyon 1\, rapporteur\n\nDenis ULLMO\, Univerist é Paris-Saclay\, co-directeur de thèse\n\nResumé:\n\nMean Field Games p rovide a powerful theoretical framework to deal with stochastic optimizati on problems involving a large number of coupled subsystems. They can find application in several fields\, be it finance\, economy\, sociology\, engi neering ... However\, this theory is rather recent and still poses many ch allenges. Its constitutive equations\, for example\, are difficult to anal yse and the set of behaviours they highlight are ill-understood. While the large majority of contributions to this discipline come from mathematicia ns\, economists or engineering scientists\, physicist have only marginally be involved in it. In this thesis I try and start bridging the gap betwee n Physics and Mean Field Games through the study of a specific class of mo dels dubbed "quadratic". CATEGORIES:seminars LOCATION:LPTM\, Université Cergy Pontoise\, 2 avenue Adolphe Chauvin\, Pon toise\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=2 avenue Adolphe Chauvin\, Pontoise\, France;X-APPLE-RADIUS=100;X-TITLE=LPTM\, Université Cergy Pont oise:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-732@lptms.universite-paris-saclay.fr DTSTART:20200225T143000Z DTEND:20200225T143000Z DTSTAMP:20200212T124941Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-samuel-cazayus-claverie/ SUMMARY:Soutenance de thèse: Samuel Cazayus-Claverie - Petit amphi\, bâti ment Pascal n° 530 - 25 Fév 20 14:30 DESCRIPTION:Effect of residual stress on the elasticity of fiber networks\n par\n\nSamuel Cazayus-Claverie\n \;\n\nJury:\n\nAnaël Lemaître - rap porteur \n\nChaouqi Misbah - rapporteur \n\nGiuseppe Foffi - examinateur \ n\nCécile Leduc - examinatrice \n\nMartin Lenz - directeur de thèse \n\n Raphaël Voituriez - examinateur\n\nResumé:\n\nCells are the basic units of all living organisms. Eukaryotic cells are stuctured on top of a scaffo ld of fibers ranging from stiff microtubules to semiflexible actin : the c ytoskeleton. As such the cytoskeleton is involved into a broad family of p rocesses of translocation and deformation of cells\, it is also responsibl e for cells mechanical stiffness. The actin filaments into cytoskeleton ca n be cross-linked into bundles built of as much as 30 parallel filaments\, but filaments can get bound at a finite angle also. These processes are i n competition during network’s self-assembly and result in strong residu al stresses. In this thesis\, we study the effect of these residual stress es on the elasticity of fiber networks in 2 dimensions of space. We develo p an original method to compute stress on the boundaries of a network and its\nelastic moduli. We find that residual stress induces a  stiffening i n the infinitesimal response of the network. Residual stress also affects the non linear response of the network : we find that it makes the network unstable under compression\, and that they control the onset of non linea r response to shear.\n\n \; CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-706@lptms.universite-paris-saclay.fr DTSTART:20200226T110000Z DTEND:20200226T120000Z DTSTAMP:20200226T081205Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-anne-virginie-salsac/ SUMMARY:Physics-Biology interface seminar: Anne-Virginie Salsac - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Fév 20 11 :00 DESCRIPTION:SEMINAR CANCELLED\nAnne-Virginie Salsac (Université de Technol ogie de Compiègne) CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-716@lptms.universite-paris-saclay.fr DTSTART:20200303T110000Z DTEND:20200303T120000Z DTSTAMP:20200225T112828Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jacopo-de-nardis-ghent-university/ SUMMARY:Séminaire du LPTMS: Jacopo De Nardis (Ghent University) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 3 Mar 20 11: 00 DESCRIPTION:Universalities of transport in quantum and classical chains: fr om diffusion to KPZ dynamics\nJacopo De Nardis (Ghent University)\n\nFindi ng a theoretical framework to explain how phenomenological transport laws on macroscopic scales emerge from microscopic deterministic dynamics poses one of the most significant challenges of condensed matter and statistica l physics. Recently there has been a flood of new numerical and analytical results in the transport theory of quantum and classical many-body1D Hami ltonian systems\, both integrable and not. I will provide a general framew ork to understand the main classes of transport observed: diffusion\, supe r-diffusion and logarithmic corrections to diffusion. I will review how di ffusive spreading is generically present in integrable chains and how KPZ dynamics emerges in both integrable and non-integrable rotationally invari ant magnets. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-730@lptms.universite-paris-saclay.fr DTSTART:20200310T110000Z DTEND:20200310T120000Z DTSTAMP:20200302T003638Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/muhittin-mungan-u ni-bonn/ SUMMARY:Séminaire du LPTMS: Muhittin Mungan (Uni Bonn) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Mar 20 11:00 DESCRIPTION:Driving with maps or: Finding your way in the glassy landscape of an amorphous solid\nMuhittin Mungan\, University of Bonn\n\nThe energy landscape of sheared amorphous solids\, even when probed under athermal an d quasistatic (AQS) conditions\, reveals rich features\, such as a transit ion from brittle to ductile response and yielding. In this talk I will arg ue that a natural (and rigorous) way of representing this AQS response is via "maps"\, i.e. state transition graphs. This opens the way for understa nding dynamical features in terms of the topological structure of the unde rlying transition graph. Moreover\, such graphs can be readily extracted f rom simulations of sheared amorphous solids.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-720@lptms.universite-paris-saclay.fr DTSTART:20200311T110000Z DTEND:20200311T120000Z DTSTAMP:20200304T151459Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-davy-martin/ SUMMARY:Physics-Biology interface seminar: Davy Martin - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 11 Mar 20 11:00 DESCRIPTION:Prion replication and structural diversification mechanisms\nDa vy Martin (INRA Jouy-en-Josas)\nPrions are proteinaceous infectious agents responsible for a range of neurodegenerative diseases in animals and huma ns. Prion particles are assemblies formed from a misfolded\, β-sheet rich \, aggregation-prone isoform (PrPSc) of the host-encoded cellular prion pr otein (PrPC). Prions replicate by recruiting and converting PrPC into PrPS c. PrPSc is a pleiomorphic protein as different conformations can dictate different disease phenotypes in the same host species. This is the basis o f the strain phenomenon in prion diseases. Moreover\, recent experimental evidence suggests further structural heterogeneity in PrPSc assemblies wit hin specific prion populations and strains. Still\, this diversity is rath er seen as a size continuum of assemblies with the same core structure\, w hile analysis of the available experimental data points to the existence o f structurally distinct arrangements. The atomic structure of PrPSc has no t been elucidated so far\, making the underlying mechanistical processes o f emergence and coevolution of structurally distinct assemblies difficult to understood. Here\, we will present our latest experimental results and replication model providing mechanistic insights into prion structural div ersification\, a key determinant for prion adaptation and toxicity. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-719@lptms.universite-paris-saclay.fr DTSTART:20200317T110000Z DTEND:20200317T120000Z DTSTAMP:20200314T074530Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexandre-solon/ SUMMARY:CANCELLED -- Séminaire du LPTMS: Alexandre Solon (LPTMC) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Mar 20 1 1:00 DESCRIPTION:Pressure and forces for active matter\nAlexandre Solon (LPTMC)\ n\nActive matter\, composed of self-propelling entities\, is found across scales in nature\, from cellular tissues to animal groups. Such systems\, as well as engineered active materials\, exhibit many types of collective behaviors and unusual mechanical properties. In this talk\, I will focus o n different aspects of the interactions between active fluids and boundari es or passive objects\, and show that they lead to intriguing effects\, sp ecific to active systems. In particular\, I will discuss the absence of eq uation of state for the pressure of active fluids\, the instability of a f ilament in an active bath\, long-range\ninteractions mediated by an active fluid and the localization of active particles in a random potential. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-736@lptms.universite-paris-saclay.fr DTSTART:20200323T110000Z DTEND:20200323T120000Z DTSTAMP:20200314T074551Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-joachim-krug-uni-cologne/ SUMMARY:CANCELLED -- Séminaire exceptionnel du LPTMS: Joachim Krug (Uni Co logne) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°5 30 - 23 Mar 20 11:00 DESCRIPTION:Fisher's geometric model and spin glasses\nJoachim Krug (Uni Co logne)\n\nFisher's geometric model describes biological fitness landscapes by combining a linear map from the discrete space of genotype sequences o f length L to an n-dimensional Euclidean phenotype space with a nonlinear\ , single-peaked phenotype-fitness map. Recent work has shown that the inte rplay between the genotypic and phenotypic levels gives rise to a range of different landscape topographies that can be characterised by the number of local fitness maxima. I will present new results for the distribution o f the number of maxima. The typical scale of the number of maxima is deriv ed for general n\, and the full scaled probability density and two point c orrelation function of maxima are determined for the one-dimensional case. The model is closely related to the anti-ferromagnetic Hopfield model wit h n random continuous pattern vectors\, and most results carry over to thi s setting. The talk is based on joint work with Sungmin Hwang and Su-Chan Park. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-723@lptms.universite-paris-saclay.fr DTSTART:20200324T110000Z DTEND:20200324T120000Z DTSTAMP:20200318T125650Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-julien-tailleur-2/ SUMMARY:Séminaire du LPTMS: Julien Tailleur (MSC - Diderot) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Mar 20 11:00 DESCRIPTION:Collective behaviors of active particles in and out of equilibr ium\nJulien Tailleur (MSC - Université Paris-Diderot)\n\nActive matter de scribes systems in which individual units dissipate energy to exert forces on their environment. Dissipation and injection of energy are then discon nected at the microscopic scale\, driving the system strongly out of equil ibrium. This leads to phenomenology markedly different from that of equili brium physics\, such as the emergence of dense phases in the absence of co hesive attractive forces. Nevertheless\, for a large class of systems\, no n-trivial mappings exist between active and passive dynamics. In this talk \, I will review the existing work on motility-induced phase separation an d discuss its relationship with equilibrium physics. I will then show how a large class of tactic active matter models admit an exact mapping onto e quilibrium dynamics at the fluctuating hydrodynamic level.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-728@lptms.universite-paris-saclay.fr DTSTART:20200325T110000Z DTEND:20200325T120000Z DTSTAMP:20200317T205532Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-marion-jasnin/ SUMMARY:Physics-Biology interface seminar: Marion Jasnin - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 25 Mar 20 11:00 DESCRIPTION:SEMINAR CANCELLED\nMarion Jasnin (MPI for Biochemistry\, Martin sried\, Germany) CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-724@lptms.universite-paris-saclay.fr DTSTART:20200331T110000Z DTEND:20200331T120000Z DTSTAMP:20200329T164127Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-charlie-duclut-mpi-pks-dresden/ SUMMARY:Séminaire du LPTMS: Charlie Duclut (MPI PKS Dresden) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 31 Mar 20 11:00 DESCRIPTION:Quorum effects in assemblies of chemotactic cells\nCharlie Ducl ut (MPI PKS Dresden)\n\nZOOM MEETING ID: 908 161 299 - PASSWORD: 026475 -- \n\nTo self-organise into complex structures such as tissues and organs\, individual cells need to interact. A generic mechanism for this interacti on is a chemical signalling. The ability of an individual cell to follow a gradient of chemicals is called chemotaxis. Starting from a microscopic d escription of chemotactic cells\, I will present a coarse-graining procedu re to describe an assembly of such particles. This system exhibits a phase transition that I will then study using a dynamical renormalisation group approach. This analysis indicates the crucial role of a polarity-based ch emotactic interaction\, usually overlooked in phenomenological approaches. Finally\, I will discuss an emergent symmetry of the model that allows us to compute scaling exponents exactly. In particular\, we deduce a superdi ffusive behavior of the particles in all physical dimensions. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-737@lptms.universite-paris-saclay.fr DTSTART:20200421T110000Z DTEND:20200421T120000Z DTSTAMP:20200416T084655Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cecile-sykes-institut-curie/ SUMMARY:Séminaire du LPTMS: Cécile Sykes (Institut Curie) - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Avr 20 11:00 DESCRIPTION:Active deformation of the cell membrane through actin assembly\ , and how we may infer nucleus deformation\nCécile Sykes (Institut Curie) \n\nZOOM MEETING ID: 919 2003 3856 - PASSWORD: 041219 -- \n\nIn all cell f unctions\, a common observation is that cytoskeleton assembly correlates w ith membrane deformation based on active forces. The exact role\, in parti cular\, of the actin cytoskeleton in cell membrane deformation\, with push ing or pulling forces\, is what we address both experimentally and theoret ically. We conceive stripped-down experimental systems that reproduce cell ular behaviours in simplified conditions: cytoskeleton dynamics are reprod uced on liposome membranes. Actin polymerization through the growth of a b ranched actin network is able to initiate membrane tubules and spikes by p ushing or pulling\, and mimics cellular deformations. By changing experime ntally membrane tension and the structural details of the cytoskeleton arc hitecture\, we displace the system within a phase diagram where inward or outward deformations are favoured [1]. Moreover\, shells of branched actin networks grown around liposomes display buckling and wrinkling under osmo tic deflation\, thereby confirming their elastic properties. The time duri ng which we let the network grow around liposomes allows us to vary the sh ell thickness\, and to specify the length scale of buckling versus wrinkli ng [2]. Our results illustrate the generic mechanism of buckling and wrink ling found in various systems spanning from pollen grains to the developme nt of the gut or the brain.\n\nInspired by actin forces exerted on membran es and organelles\, we address now how the nucleus\, which is the most rig id cell organelle\, is deformed by the actin cytoskeleton during cell tran slocation. When cells move through narrow spaces that are smaller than the ir nuclei\, we find that proteins of the nuclear membrane\, such as nespri ns\, accumulate at the nucleus front and pull the nucleus forward [3]. We want to address in the future how we could characterize this active proces s and infer its molecular details.\n\nReferences:\n[1] Simon et al.\, Natu re Physics (2019)\n[2] Kusters et al.\, Soft Matter (2019)\n[3] Davidson e t al.\, in revision CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-738@lptms.universite-paris-saclay.fr DTSTART:20200428T110000Z DTEND:20200428T120000Z DTSTAMP:20200416T084736Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-matthieu-mangeat/ SUMMARY:CANCELLED -- Séminaire du LPTMS: Matthieu Mangeat - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 28 Avr 20 11:00 DESCRIPTION:TBA CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-731@lptms.universite-paris-saclay.fr DTSTART:20200519T110000Z DTEND:20200519T120000Z DTSTAMP:20200514T071046Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marco-picco-lpthe/ SUMMARY:CANCELLED Séminaire du LPTMS: Marco PICCO (LPTHE) CANCELLED - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Mai 2 0 11:00 DESCRIPTION:TBA CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-739@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20200602T110000 DTEND;TZID=Europe/Paris:20200602T110000 DTSTAMP:20200519T085359Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lenka-zdeborova/ SUMMARY:Séminaire du LPTMS : Lenka Zdeborova POSTPONED - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Juin 20 11:00 DESCRIPTION:POSTPONED\nLenka Zdeborova (IPT\, Gif-sur-Yvette)\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-741@lptms.universite-paris-saclay.fr DTSTART:20200602T110000Z DTEND:20200602T120000Z DTSTAMP:20200526T223422Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-claudio-benzoni-tu-muenchen/ SUMMARY:Séminaire du LPTMS: Claudio Benzoni (TU Muenchen) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Juin 20 11:00 DESCRIPTION:Rayleigh edge waves in two-dimensional chiral crystals\nClaudio Benzoni (Technische Universitaet Muenchen)\n\nMeeting ID: 940 9301 2897 - - Password: 464951\n \nWe investigate\, within the framework of linear ela sticity theory\, edge Rayleigh waves of a two-dimensional elastic solid wh ich breaks time-reversal and parity symmetries due to the Coriolis-Lorentz force. We find that the direction of propagation of the Rayleigh modes is determined not only by the sign of the magnetic field but also by the Poi sson ratio of the elastic system. We discover three qualitatively differen t regions distinguished by the chirality of the low-frequency edge waves a nd study their universal properties. To illustrate the Rayleigh edge-waves in real time we have carried out finite-difference simulations of the mod el.\n\nhttps://arxiv.org/abs/2004.09517\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-733@lptms.universite-paris-saclay.fr DTSTART:20200609T110000Z DTEND:20200609T120000Z DTSTAMP:20200526T222502Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sandro-stringari-uni-trento/ SUMMARY:POSTPONED: Séminaire du LPTMS: Sandro Stringari (Uni Trento) - Sal le des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Juin 20 11:00 DESCRIPTION:TBA CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-743@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20200707T150000 DTEND;TZID=Europe/Paris:20200707T160000 DTSTAMP:20200703T151633Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ricard-alert-zenon/ SUMMARY:Séminaire du LPTMS : Ricard Alert Zenon - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Juil 20 15:00 DESCRIPTION:Topological Defects\, Turbulence\, and Phase Separation\nRicard Alert Zenon (Princeton)\n\nZOOM Meeting ID: 929 5958 3836\nPassword: 8135 01 \n\nActive fluids display striking collective phenomena not possible in passive fluids. Examples include spontaneous flows powered by microscopic constituents\, and phase separation in the absence of attractive interact ions. In this talk\, I will discuss three aspects of the physics of active fluids\, connected with experiments in both biological and artificial sof t matter systems. First\, I will show that dense colonies of the rod-shape d motile bacterium Myxococcus xanthus form active liquid crystals. I will show that topological defects of the cell alignment field induce flows tha t lead to the formation of new cell layers\, which triggers the developmen t of multicellular structures called fruiting bodies. Second\, I will disc uss chaotic flows in active liquid crystals. I will show that\, as in clas sic turbulence\, the statistical properties of these active flows at low R eynolds number are described by universal scaling laws. Unlike classic tur bulence\, however\, this type of active turbulence requires no energy tran sfer across scales. Finally\, I will present a new mechanism of liquid-gas phase separation in active fluids. I will show that\, in addition to repu lsive forces that oppose phase separation\, artificial self-propelled Janu s colloids experience torques that reorient particle motion toward high-de nsity regions\, providing a novel route to phase separation. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-742@lptms.universite-paris-saclay.fr DTSTART:20200910T140000Z DTEND:20200910T163000Z DTSTAMP:20200902T095329Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-mathieu-isoard/ SUMMARY:Soutenance de thèse: Mathieu Isoard - Grand amphi\, bâtiment Pasc al n° 530 - 10 Sep 20 14:00 DESCRIPTION:Theoretical study of quantum correlations and nonlinear fluctua tions in quantum gases\npar\n\nMathieu Isoard\n \;\n\nJury:\n\nMatteo Conforti\, Université Lille\, rapporteur\n\nPatrik Öhberg\, Heriot-Watt University\, rapporteur\n\nÉlisabeth Giacobino\, CNRS\, examinatrice\n\nS andro Stringari\, University of Trento\, examinateur\n\nChris Westbrook\, Institut d’Optique\, examinateur\n\nNicolas Pavloff\, Université Paris- Saclay/CNRS \, directeur de thèse\n\n \;\n\nResumé\n\nThis thesis is dedicated to the study of nonlinear-driven phenomena in two quantum gases which bear important similarities: Bose-Einstein condensates of ultracold atomic vapors and paraxial nonlinear laser beam.\n\nThese systems can be described within a hydrodynamic framework which make it possible to invest igate their short and long time propagation by means of mathematical metho ds developed by Riemann and Whitham. In particular\, we study the formatio n and the propagation of dispersive shock waves which arise after a wave b reaking event. We obtain a kind of a weak shock theory\, from which we can extract a quantitative description of experimentally relevant parameters\ , such as the velocity of the solitonic edge of the shock or the contrast of its fringes.\n\n\n\n\n\nIn a second part\, we study sonic analogues of black holes. In a Bose-Einstein condensate\, it is possible to implement a stationary configuration with a current flowing from a subsonic region to a supersonic one. This mimics a black hole\, since sonic excitations cann ot escape the supersonic region. Besides\, quantizing the phonon field lea ds to a sonic analogue of Hawking radiation. In this thesis\, we have show n that a correct account of zero modes is essential for an accurate descri ption of the Hawking process\, and results in a excellent comparison with recent experimental datas. In addition\, we characterize the entanglement shared among quantum excitations and show that they exhibit tripartite ent anglement.\n\n\n\n\n CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-746@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20200929T110000 DTEND;TZID=Europe/Paris:20200929T120000 DTSTAMP:20200922T053935Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ilya-galanov/ SUMMARY:Séminaire du LPTMS : Ilya Galanov - Grand amphi\, bâtiment Pascal n° 530 - 29 Sep 20 11:00 DESCRIPTION:On Self-Assembly of Aperiodic Tilings\nIlya Galanov (Laboratoir e d’Informatique de Paris Nord - Université Paris 13)\n\nSeminar taking place at Batiment Pascal with ZOOM streaming.\n\nZOOM Meeting ID: 973 982 7 8038\nPassword: 742352\n\nSelf-assembly is the process in which the comp onents of a system\, whether molecules\, polymers\, or macroscopic particl es\, are organized into ordered structures as a result of local interactio ns between the components themselves\, without exterior guidance. This tal k is devoted to the self-assembly of aperiodic tilings. Aperiodic tilings serve as a mathematical model for quasicrystals - crystals that do not hav e any translational symmetry. Because of the specific atomic arrangement o f these crystals\, the question of how they grow still remains open. Our a im is to develop a growth algorithm for a particular class of aperiodic ti lings - octagonal tilings of finite type. In order to mimic the growth of real-world quasicrystals\, we demand the algorithm be local: the tiles mus t be added one by one\, using only the local information\, and no data mus t be stored between the steps. Simulations strongly support the evidence t hat this algorithm grows aperiodic tilings\, up to an unavoidable but negl ectable proportion of missing tiles. CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-749@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201006T110000 DTEND;TZID=Europe/Paris:20201006T120000 DTSTAMP:20201003T144223Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lenart-zadnik-2/ SUMMARY:Séminaire du LPTMS : Lenart Zadnik - Grand amphi\, bâtiment Pasca l n° 530 - 6 Oct 20 11:00 DESCRIPTION:Large-anisotropy limit of Heisenberg antiferromagnet: Towards d escription of pre-relaxation phenomena\nLenart Zadnik (LPTMS)\n\nSeminar t aking place at Batiment Pascal with ZOOM streaming.\n\nZOOM Meeting ID: 95 9 1349 7684\nPassword: 878617 \n\nThe recent decade has witnessed several breakthroughs in the description of relaxation of local observables in qua ntum many-body systems prepared far from equilibrium. In contrast\, the ti me evolution on intermediate time scales that precede relaxation towards t he stationary state has remained much less explored. Strong coupling expan sions offer a good starting point for investigation of such problems\, sin ce they provide a natural time scale\, on which the pre-relaxation can occ ur. We will discuss the effective Hamiltonian that generates time evolutio n of states on intermediate time scales in the large-anisotropy limit of H eisenberg spin-1/2 chain. Such an effective Hamiltonian describes a simple Bethe-Ansatz-solvable model with local interactions. Starting from a micr oscopic picture of the dynamics\, I will explain the ballistic-scale hydro dynamic theory describing the time evolution after a quench\, in which two halves of the system\, thermalised at different temperatures\, are abrupt ly joined. CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-745@lptms.universite-paris-saclay.fr DTSTART:20201015T143000Z DTEND:20201015T173000Z DTSTAMP:20201008T142231Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-sebastian-grijalva/ SUMMARY:Soutenance de thèse: Sebastian GRIJALVA - Grand amphi\, bâtiment Pascal n° 530 - 15 Oct 20 14:30 DESCRIPTION:Boundary effects in Quantum Spin Chains and Finite-Size Effects in the Toroidal Correlated Percolation model\npar\n\nSebastian Grijalva\n Jury:\n\nChristian Hagendorf\, Université catholique de Louvain\, examina teur\n\nJacopo De Nardis\, ENS\, invité\n\nNikolai Kitanine\, Institut de Mathématiques de Bourgogne\, examinateur\n\nKarol Kozlowski\, ENS de Lyo n\, rapporteur\n\nVincent Pasquier\, IPhT\, examinateur\n\nPierre Pujol\, Université Paul Sabatier\, rapporteur\n\nRaoul Santachiara\, LPTMS\, Univ ersité Paris Saclay\, co-directeur de thèse\n\nVéronique Terras\, LPTMS \, Université Paris Saclay\, directrice de thèse\n\n \;\n\nRésumé: \nThis thesis is divided in two parts: The first one presents a 2D statist ical model of correlated percolation on a toroidal lattice. We present a p rotocol to construct long-range correlated surfaces based on fractional Ga ussian surfaces and then we relate the level sets to a family of correlate d percolation models. The emerging clusters are then numerically studied\, and we test their conformal symmetry by verifying that their finite-size corrections follow the predictions of Conformal Field Theory. We also prov ide numerical details to produce the results.\nThe second part studies the  quantum integrable XXZ spin-1/2 chain with open boundary conditions for even and odd number of sites. We concentrate in the anti-ferromagnetic reg ime and use the Algebraic Bethe Ansatz to determine the ground state confi gurations that arise in terms of the boundary fields. We find the conditio ns of existence of quasi-degenerate ground states separated by a gap to th e rest of the spectrum. We calculate the boundary magnetization at zero te mperature and find that it depends on the field at the opposite edge even in the semi-infinite chain limit. We finally calculate the time auto- corr elation function at the boundary and show that in the even-size case it is finite for the long-time limit as a result of the quasi-degeneracy.\n\n\n \nZOOM Meeting ID: 962 2604 2868\nPassword: 708393 CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-744@lptms.universite-paris-saclay.fr DTSTART:20201020T140000Z DTEND:20201020T170000Z DTSTAMP:20201019T082433Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-nina-javerzat/ SUMMARY:Soutenance de thèse: Nina Javerzat - Grand amphi\, bâtiment Pasca l n° 530 - 20 Oct 20 14:00 DESCRIPTION:New conformal bootstrap solutions and percolation models on the torus\npar\n\nNina Javerzat\nJury:\n\nBertrand Duplantier\, IPhT\, examin ateur\n\nMalte Henkel\, LPCT\, Université de Lorraine\, rapporteur\n\nEve liina Peltola\, University of Bonn\, examinatrice\n\nMarco Picco\, LPTHE\, examinateur\n\nSilvain Ribaud\, IPhT\, examinateur\n\nRaoul Santachiara\, LPTMS\, Université Paris Saclay\, directeur de thèse\n\nErik Tonni\, SI SSA\, rapporteur\n\nJacopo Viti\, Istituto Nazionale di Fisica Nucleare\, examinateur\n\n \;\n\nRésumé:\n\nThe geometric properties of critica l phenomena have generated an increasing interest in theoretical physics a nd mathematics over the last thirty years. Percolation-type systems are a paradigm of such geometric phenomena\, their phase transition being charac terised by the behaviour of non-local degrees of freedom: the percolation clusters. At criticality\, these clusters are examples of random objects w ith a conformally invariant measure. Even in the simplest model\, uncorrel ated percolation\, important universal properties remain out of reach\, i n particular the connectivity properties −the probabilities that points are connected by clusters.\n\n\nIn two dimensions\, the presence of confor mal symmetry has especially important implications\, which can be exploite d to obtain a complete determination of the universality classes. We will present results on the universal properties of two families of long-range correlated percolation models\, obtained using a conformal bootstrap appro ach and the study of the clusters connectivities on a torus topology.\n\n\ nThe first family is the random cluster Q− state Potts model\, whose con formal field theory is not yet −albeit almost\, fully solved today. We t est conjectures on this conformal field theory by computing the finite siz e effects induced on the connectivities by the torus topology\, and compar ing with numerical measurements.\n\n\nThe second family is obtained from t he excursion sets of fractional Gaussian surfaces. We use conformal field theory predictions on the torus cluster connectivities\, together with num erical simulations\, to establish the conformal invariance of these system s\, and obtain the first features of this new conformal field theory.\n\nZ oom meeting\n\nID de réunion : 968 8791 8326\nCode secret : 666675 CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-754@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201027T110000 DTEND;TZID=Europe/Paris:20201027T120000 DTSTAMP:20201022T120509Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicolas-levernier/ SUMMARY:Séminaire du LPTMS : Nicolas Levernier (IUSTI) - Grand amphi\, bâ timent Pascal n° 530 - 27 Oct 20 11:00 DESCRIPTION:Nicolas Levernier (IUSTI Aix-Marseille Université)\nFirst-pass age time of non markovian random walks\n\nSeminar in presence @LPTMS with ZOOM streaming -- \nZOOM Meeting ID: 973 9548 5969 -- Password: 396890 --\ n\nIn this talk\, I will present part of the results I got during my PhD\, and part of those obtained during my first postdoc\n\nI) The computation of the encounter time of particles is a key question in many contexts\, as this time quantifies the reactivity rate for diffusion-limited processes. In the case of markovian random walks\, such as brownian motion\, some an alytic results can be obtained. But in the case of non-markovian processes \, much fewer results do exist\, although "non-markov is the rule and mark ov is the exception" (Van Kampen). In this talk I will present a formalism we have developed to deal with non-markovian gaussian random walks and sh ow its application to Fractional Brownian Motion\, a paradigmatic example of highly-correlated process. If time allows\, I will briefly present how aging of the dynamics can deeply modify the encounter time statistics.\n\n II) In the second part of my talk\, I will briefly present results I got d uring my first postdoc. I will show how chaotic motion can arise in an ext ended active gel layer\, typically describing cortical cytoskeleton\, wher e polymerization and contraction due to molecular motors are combined. Thi s result questions the usual description of the cortex as a thin layer\, a s such a description cannot describe this instability. I will also briefly present recent experimental evidences of this predicted phenomenon.\n CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-747@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201103T110000 DTEND;TZID=Europe/Paris:20201103T120000 DTSTAMP:20201030T121541Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jerome-beugnon-lkb/ SUMMARY:Séminaire du LPTMS : Jérôme Beugnon (LKB) - Grand amphi\, bâtim ent Pascal n° 530 - 3 Nov 20 11:00 DESCRIPTION:Scale-invariant dynamics of a planar Bose gas : dynamical symme try\, solitons and breathers.\nJérôme Beugnon (LKB)\n\nOnline seminar -- - ZOOM Meeting ID: 913 5556 5450 -- Password: 966156 --\n\n\nLow temperatu re quasi-2D Bose gases feature an approximate scale invariance. I will di scuss several consequences of this scale-invariance on the equilibrium and dynamics of the gas and illustrate them through experiments with box-trap ped ultracold atoms. I will first present experimental signatures of the S O(2\,1) dynamical symmetry. In a two-component gas\, I will report the obs ervation of two-dimensional scale-invariant solitons\, the so-called Towne s solitons. Finally\, I will show the surprising existence of breathers th at might be related to the scale-invariance of the gas. CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-735@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201110T110000 DTEND;TZID=Europe/Paris:20201110T110000 DTSTAMP:20201102T100049Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-david-zwicker/ SUMMARY:Séminaire du LPTMS : David Zwicker (MPI DS Goettingen) - - 10 Nov 20 11:00 DESCRIPTION:Controlling phase separation in biological cells\nDavid Zwicker (Max Planck Institute for Dynamics and Self-Organization\, Göttingen)\n\ nOnline seminar --- Zoom Meeting ID: 944 4358 5604 --- Passcode: 322346 -- -\n\n\nPhase separation has emerged as an essential concept for the spatia l organization inside cells. In particular\, phase separation explains how droplets can form spontaneously to create subcellular compartments. Howev er\, traditional theories of phase separation cannot explain how cells cou ld control these droplets. To unveil part of this mystery\, I will present two different mechanisms used by cells in this talk. I will first discuss chemical reactions that influence the physical properties of droplet comp onents. Driving such reactions by exploiting the non-equilibrium environme nt of biological cells can stabilize multiple droplets and control their s ize. I will then focus on the elastic properties surrounding droplets\, e. g.\, provided by the cytoskeleton. I will show that stiffness gradients\, which are present in heterogeneous environments like cells\, can influence the positioning of droplets and thus determine their overall arrangement. These two examples demonstrate that heterogeneous\, living cells can regu late the size\, number\, and position of their droplets. Moreover\, simila r mechanisms may allow controlling droplets in technical applications in t he future.\n CATEGORIES:seminars END:VEVENT BEGIN:VEVENT UID:0-748@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201117T110000 DTEND;TZID=Europe/Paris:20201117T120000 DTSTAMP:20201112T115439Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thierry-lahaye/ SUMMARY:Séminaire du LPTMS : Thierry Lahaye (LCF) - LPTMS (100% online sem inar) - 17 Nov 20 11:00 DESCRIPTION:Tunable arrays of single Rydberg atoms for quantum simulation o f spin models\nThierry Lahaye (Institut d'Optique - LCF)\n\nOnline seminar --- Zoom Meeting ID: 927 0748 7986 -- Passcode: 865632 --\n\n\nOver the l ast years\, a novel platform for quantum simulation of spin Hamiltonians\, using arrays of single atoms held in optical tweezers and excited to Rydb erg levels to make them interact\, has emerged. In this seminar\, I'll exp lain how we can now create arrays of up to 200 individually-controlled ato ms with almost arbitrary geometries in 1\,2 and even 3 dimensions\, and il lustrate the quantum simulation of Ising and XY spin Hamiltonians on a var iety of recent experiments performed in our lab. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-750@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201124T110000 DTEND;TZID=Europe/Paris:20201124T120000 DTSTAMP:20201118T225104Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mikhail-zvonarev/ SUMMARY:Séminaire du LPTMS : Mikhail Zvonarev (LPTMS) - LPTMS (100% online seminar) - 24 Nov 20 11:00 DESCRIPTION:Mobile impurity in a quantum fluid\nMikhail Zvonarev (LPTMS)\n\ nOnline seminar --- ZOOM Meeting ID: 994 9374 5810 -- Password: 467383 --\ n\nI am planning to discuss several recent findings (theoretical and exper imental) in the dynamics of an impurity particle injected into a quantum l iquid:\n\n(i) The momentum distribution of the impurity in one dimension s ubject to a constant external force exhibits characteristic Bragg reflecti ons at the edge of an emergent Brillouin zone. As a consequence\, the impu rity exhibits periodic dynamics that is interpreted as Bloch oscillations\ , which arise even though the quantum liquid is translationally invariant. \n\n(ii) The impurity injected into a one-dimensional liquid with some ini tial momentum sheds only a part of it to the background gas\, and forms a correlated state that no longer decays in time\; furthermore\, if the init ial momentum is large enough\, the impurity undergoes long-lived oscillati ons. The value of the impurity's velocity at infinite time lies between ze ro and the speed of sound in the gas\, and is determined by the injection protocol. This way\, the impurity's frictionless motion is a dynamically e mergent phenomenon whose description goes beyond accounting for the kinema tic constraints of Landau's approach to superfluidity.\n\n(iii) The impuri ty traveling through a weakly interacting three-dimensional Bose-Einstein condensate (BEC) of ultra-cold atoms shows a phase transition in the groun d state and far-from-equilibrium properties of the system as a function of the impurity's velocity. Above a critical initial velocity\, the impurity 's final velocity reaches a fundamental kinematic boundary\, the BEC's spe ed of sound. For weak and intermediate impurity-BEC interactions\, the cri tical line is determined by the effective mass of the polaron. This quantu m transition can be interpreted as a dynamical Cherenkov effect\; the impu rity-BEC interaction causes the dynamics of the system to appear as if the bare impurity is propagating through a BEC whose speed of sound is altere d by an effective refractive index. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-752@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201201T110000 DTEND;TZID=Europe/Paris:20201201T120000 DTSTAMP:20201123T231544Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thibaud-maimbourg-lptms/ SUMMARY:Séminaire du LPTMS : Thibaud Maimbourg (LPTMS) - LPTMS (100% onlin e seminar) - 1 Déc 20 11:00 DESCRIPTION:Bath-induced Zeno localization in driven many-body quantum syst ems\nThibaud Maimbourg (LPTMS)\n\nOnline seminar --- ZOOM Meeting ID: 979 6114 1696 --- Password: 105367 --- \n\n\nIn this talk I will first discu ss the main conditions for a many-body quantum system to reach a thermal s tationary state. I will then focus on the mechanism by which\, relaxing on e of these conditions\, the system in contact with a bath of spatially-loc alized vibrational modes can fail to reach such a state. As a realistic il lustration\, I shall consider a quantum interacting spin system subject to an external drive\, serving as a model for dynamic nuclear polarization ( DNP) protocols. Those protocols\, besides their concrete applications\, re present an experimental platform to investigate ergodicity of the stationa ry state. Even when the isolated system is ergodic\, a sufficiently strong coupling to the bath may break ergodicity\, due to many-body quantum Zeno effect. In the DNP context\, this result provides an explanation of the b reakdown of the so-called "thermal mixing" regime (effective equilibrium)\ , experimentally observed above 4 – 5 Kelvin.\n\nRef.: arXiv:2009.11784. Joint work with D. M. Basko\, M. Holzmann (LPMMC Grenoble)\, A. Rosso (LP TMS). CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-751@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201208T110000 DTEND;TZID=Europe/Paris:20201208T120000 DTSTAMP:20201126T145015Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gwendall-feve-lpens/ SUMMARY:Séminaire du LPTMS : Gwendal Fève (LPENS) - LPTMS (100% online se minar) - 8 Déc 20 11:00 DESCRIPTION:Fractional statistics of anyons in a mesoscopic collider\nGwend al Fève (LPENS)\n\nOnline seminar --- ZOOM Meeting ID: 929 5714 7926 -- P assword: 084622 --\n\n\nIn three-dimensional space\, elementary particles are divided between fermions and bosons according to the properties of sym metry of the wave function describing the state of the system when two par ticles are exchanged. When exchanging two fermions\, the wave function acq uires a phase pi. On the other hand\, in the case of bosons\, this phase i s zero. This difference leads to deeply distinct collective behaviors betw een fermions\, which tend to exclude themselves\, and bosons which tend to bunch together. The situation is different in two-dimensional systems whi ch can host exotic quasiparticles\, called anyons\, which obey intermediat e quantum statistics characterized by a phase varying between 0 and pi [1\ ,2].\n\nFor example in the fractional quantum Hall regime\, obtained by ap plying a strong magnetic field perpendicular to a two-dimensional electron gas\, elementary excitations carry a fractional charge [3\,4] and have be en predicted to obey fractional statistics [1\,2] with an exchange phase p i/m (where m is an odd integer). I will present how fractional statistics of anyons can be demonstrated in this system by implementing and studying anyon collisions at a beam-splitter [5]. The collisions are first studied in the low magnetic field regime\, where the elementary excitations are el ectrons which obey the usual fermionic statistics. It leads to the observa tion of an antibunching effect in an electron collision: electrons systema tically exit in two different arms of the beam-splitter. The observed resu lt is completely different in the fractional quantum Hall regime. Fraction al statistics lead to a suppression of the antibunching effect and quasipa rticles tend to bunch together in larger packets of charge in a single out put of the splitter. This effect leads to the observation of negative corr elations of the current fluctuations [5] in perfect agreement with recent theoretical predictions [6].\n\n\n[1] B. I. Halperin\, Phys. Rev. Lett. 52 \, 1583–1586 (1984).\n[2] D. Arovas\, J. R. Schrieffer\, F. Wilczek\, Ph ys. Rev. Lett. 53\, 722–723 (1984).\n[3] R. de Picciotto et al.\, Nature 389\, 162–164 (1997). \n[4] L. Saminadayar\, D. C. Glattli\, Y. Jin\, B . Etienne\, Phys. Rev. Lett. 79\, 2526–2529 (1997)\n[5] H. Bartolomei\, M. Kumar et al. Science 368\, 173-177 (2020).\n[6] B. Rosenow\, I. P. Levk ivskyi\, B. I. Halperin\, Phys. Rev. Lett. 116\, 156802 (2016).\n\n\n\n\n\ n\n CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-758@lptms.universite-paris-saclay.fr DTSTART:20201214T140000Z DTEND:20201214T170000Z DTSTAMP:20201120T140621Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-hao-pei/ SUMMARY:Soutenance de thèse: Hao Pei - LPTMS (100% online seminar) - 14 D éc 20 14:00 DESCRIPTION:Separation of Variables and Correlation Functions of Quantum In tegrable Systems\npar\n\nHao Pei\nOnline defense - Zoom Meeting ID: 971 06 60 6090 - Password: 379764\nJury:\n\nChristian Hagendorf\, Université c atholique de Louvain\, examinateur\n\nNikolai Kitanine\, Université de B ourgogne\, examinateur\n\nKarol Kozlowski\, CNRS\, ENS de Lyon\, rapport eur\n\nVincent Pasquier\, CEA Saclay\, Université Paris Saclay\, examina teur\n\nEric Ragoucy\, CNRS\, Université Savoie Mont Blanc\, rapporteur \n\nVéronique Terras\, Université Paris-Saclay\, directrice de thèse\n \nResumé:\nThe aim of this thesis is to develop an approach for computing correlation functions of quantum integrable lattice models within the qua ntum version of the Separation of Variables (SoV) method. SoV is a powerfu l method which applies to a wide range of quantum integrable models with v arious boundary conditions. Yet\, the problem of computing correlation fun ctions within this framework is still widely open. Here\, we more precisel y consider two simple models solvable by SoV: the XXX and XXZ Heisenberg c hains of spins 1/2\, with anti-periodic boundary conditions\, or more gene rally quasi-periodic boundary conditions with a non-diagonal twist. We fir st review their solution by SoV\, which present some similarities but also crucial differences. Then we study the scalar products of separate states \, a class of states that notably contains all the eigenstates of the mode l. We explain how to obtain convenient determinant representations for the se scalar products. We also explain how to generalize these determinant re presentations in the case of form factors\, i.e. of matrix elements of the local operators in the basis of eigenstates. These form factors are of pa rticular interest for the computation of correlation functions since all c orrelation functions can be obtained as a sum over form factors. Finally\, we consider more general elementary building blocks for the correlation f unctions\, and explain how to recover\, in the thermodynamic limit of the model\, the multiple integral representations that were previously obtaine d from the consideration of the periodic models by algebraic Bethe Ansatz. \n \; CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-753@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20201215T110000 DTEND;TZID=Europe/Paris:20201215T120000 DTSTAMP:20210106T133342Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ilya-galanov-2/ SUMMARY:Séminaire du LPTMS : Ilya Galanov - Grand amphi\, bâtiment Pascal n° 530 - 15 Déc 20 11:00 DESCRIPTION:On Self-Assembly of Aperiodic Tilings\nIlya Galanov (Laboratoir e d’Informatique de Paris Nord - Université Paris 13)\n\nOnline seminar --- ZOOM Meeting ID: 956 4238 1538 --- Password: Ask L. Mazza and D. Petr ov\n\n\nSelf-assembly is the process in which the components of a system\, whether molecules\, polymers\, or macroscopic particles\, are organized i nto ordered structures as a result of local interactions between the compo nents themselves\, without exterior guidance. This talk is devoted to the self-assembly of aperiodic tilings. Aperiodic tilings serve as a mathemati cal model for quasicrystals - crystals that do not have any translational symmetry. Because of the specific atomic arrangement of these crystals\, t he question of how they grow still remains open. Our aim is to develop a g rowth algorithm for a particular class of aperiodic tilings - octagonal ti lings of finite type. In order to mimic the growth of real-world quasicrys tals\, we demand the algorithm be local: the tiles must be added one by on e\, using only the local information\, and no data must be stored between the steps. Simulations strongly support the evidence that this algorithm g rows aperiodic tilings\, up to an unavoidable but neglectable proportion o f missing tiles. CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-755@lptms.universite-paris-saclay.fr DTSTART:20201217T143000Z DTEND:20201217T160000Z DTSTAMP:20201130T150331Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-antonio-sclocchi/ SUMMARY:Soutenance de thèse: Antonio Sclocchi - LPTMS (100% online seminar ) - 17 Déc 20 14:30 DESCRIPTION:A new critical phase in jammed models: jamming is even cooler t han before\npar\n\nAntonio Sclocchi\n \;\nOnline defense – Zoom Meet ing ID: 940 6511 8835 – Password: 520321\nJury:\nJean-Louis Barrat\, Uni versité Grenoble-Alpes\, examinateur\nGiuseppe Foffi\, Université Paris- Saclay\, examinateur\nSilvio Franz\, LPTMS\, directeur de thèse\nLuca Leu zzi\, Consiglio Nazionale delle Ricerch\, rapporteur\nAndrea Liu\, Univers ity of Pennsylvania\, examinatrice\nMarkus Müller\, Paul Scherrer Institu t\, rapporteur\nPierfrancesco Urbani\, CNRS\, CEA Saclay\, examinateur\nMa tthieu Wyart\, École Polytechnique Fédérale de Lausanne\, examinateur\n Resumé:\n\n\nOver the last two decades\, an intensive stream of research has characterized the jamming transition\, a zero-temperature critical poi nt of systems with short-range repulsive interactions. Many of its propert ies are independent of spatial dimensionality\, with mean-field scalings b eing valid even for two-dimensional systems.\nIn this thesis\, we extend t his critical behavior from the jamming transition point to an entire jamme d phase. This is obtained by using a short-range linear repulsive interact ion potential for soft spheres and for a related mean-field model\, i.e. t he perceptron.We show that the non-differentiable point in the pairwise in teraction potential produces a network of tangent spheres (a “contact ne twork”) at every density beyond the jamming transition. The contact netw orks characterizing the minima of the system are isostatic\, critically se lf-organized and marginally stable.\nIn the first part\, we study the jamm ed phase of the perceptron\, both numerically and theoretically using tech niques developed for mean-field glassy systems. We show the presence of a critical phase and we develop a zero-temperature scaling theory which esta blishes its universality class.Therefore\, we use numerical simulations to study the soft spheres case in two and three dimensions and we point out the presence of the critical jammed phase also in finite dimensions.\nIn t he second part\, we define a compression protocol for the perceptron that allows us to study the avalanche dynamics in the critical phase. We show t hat the avalanche sizes are scale-free power law distributed with divergen t first moment and we characterize the finite-size scalings. Our numerical results are robustly consistent with the mean-field theory.\nThis work sh ows the existence of a new critical phase in finite dimensions whose unive rsality is strongly connected to the class of jamming universality. This o pens new perspectives to study marginally stable glasses and their related energy landscapes.\n\n CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-756@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210112T140000 DTEND;TZID=Europe/Paris:20210112T150000 DTSTAMP:20210106T133051Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andreas-mayer-princeton/ SUMMARY:Séminaire du LPTMS : Andreas Mayer (Princeton) - LPTMS (100% onlin e seminar) - 12 Jan 21 14:00 DESCRIPTION:A Langevin approach to the dynamics of the human immune system\ nAndreas Mayer (Princeton)\n\nOnline seminar --- Zoom Meeting ID: 951 1138 2280 -- Passcode: Ask L. Mazza or D. Petrov --\n\n\nNote the unusual time !\n\n\nNew sequencing techniques put studying populations with a very larg e number of distinct species within reach. As the number of species increa ses\, so does the number of interactions between species and with the envi ronment. Statistical physics provides a framework to adapt ecological theo ry to this new setting: key phenomena can be captured by replacing interac tions with effective stochastic forces. In my talk\, I will present how we have applied this Langevin approach to study the dynamics of adaptive imm unity. We propose a theory for the emergence and maintenance of an observe d power-law scaling in the sizes of different immune cell populations. Rem arkably\, linking our theory to snapshots of immune composition at differe nt ages we demonstrate that exposures in infancy leave a lifelong imprint with implications for pathogen defense and autoimmunity.\n\n CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-759@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210119T110000 DTEND;TZID=Europe/Paris:20210119T120000 DTSTAMP:20210106T132701Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-valentina-ros-lptms/ SUMMARY:Séminaire du LPTMS : Valentina Ros (LPTMS) - LPTMS (100% online se minar) - 19 Jan 21 11:00 DESCRIPTION:High-dimensional random landscapes: statistics of critical poin ts and dynamical instantons\nValentina Ros (LPTMS)\n\nOnline seminar --- Z OOM Meeting ID: 919 8494 7729 -- Password: Ask L. Mazza and D. Petrov --\n \n\nHigh-dimensional random functionals emerge ubiquitously when modeling complex systems: for example as energy landscapes in physics\, fitness lan dscapes in biology\, or more recently loss landscapes in machine learning. They are typically very non-convex: their optimization with stochastic dy namics is highly non-trivial due to the abundance of local minima that tra p the dynamics for very large times. In this talk\, I will focus on random functionals with Gaussian statistics and discuss simple activated process es\, in which the system jumps between trapping local minima passing throu gh the saddles (or transition states) connecting them. In particular\, I w ill discuss how to use random matrix theory to gain information on the dis tribution and reciprocal arrangement of the local minima and saddles in co nfiguration space\, and how to exploit this information to build dynamical instantons describing the activated jumps. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-757@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210126T110000 DTEND;TZID=Europe/Paris:20210126T120000 DTSTAMP:20210114T090533Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-matthieu-mangeat-saarland-university/ SUMMARY:Séminaire du LPTMS : Matthieu Mangeat (Saarland University) - LPTM S (100% online seminar) - 26 Jan 21 11:00 DESCRIPTION:Flocking and reorientation transition in the q-state active Pot ts model\nMatthieu Mangeat (Saarland University)\n\nOnline seminar --- Zoo m Meeting ID: 947 5714 7410 -- Passcode: Ask L. Mazza or D. Petrov --\n\n\ nWe study the q-state active Potts model (APM) on a two-dimensional lattic e in which active particles have q internal states corresponding to the q directions of motion. A local alignment rule inspired by the ferromagnetic q-state Potts model and self-propulsion via biased diffusion according to the internal particle states leads to a collective motion at high densiti es and low noise. We formulate a coarse-grained hydrodynamic theory with w hich we compute the phase diagram of the APM and explore the flocking dyna mics in the region\, in which the high-density (polar liquid) phase coexis ts with the low-density (gas) phase and forms a fluctuating band of cohere ntly moving particles. As a function of the particle self-propulsion veloc ity\, a novel reorientation transition of the phase-separated profiles fro m transversal to longitudinal band motion is found\, which is absent in th e Vicsek model [1] and the active Ising model [2]. The origin of this reor ientation transition is revealed by a stability analysis : for large veloc ities the transverse diffusion constant approaches zero and then stabilize s longitudinal band motion. Computer simulations corroborate the analytica l predictions of the flocking and reorientation\ntransitions and validate the phase diagrams of the APM [3].\n\n[1] T. Vicsek\, A. Czirok\, E. Ben-J acob\, I. Cohen\, and O. Shochet\, Phys. Rev. Lett. 75\, 1226 (1995).\n[2] A. P. Solon and J. Tailleur\, Phys. Rev. Lett. 111\, 078101 (2013) \; Phy s. Rev. E 92\, 042119 (2015).\n[3] S. Chatterjee\, M. Mangeat\, R. Paul\, and H. Rieger\, EPL 130\, 66001 (2020) \; M. Mangeat\, S. Chatterjee\, R. Paul\, and H. Rieger\, Phys. Rev. E 102\, 042601 (2020).\n\n\n\n\n CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-761@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210202T110000 DTEND;TZID=Europe/Paris:20210202T120000 DTSTAMP:20210105T221421Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-phlam-lille/ SUMMARY:Séminaire du LPTMS : Pierre Suret (PhLAM - Lille) - LPTMS (100% on line seminar) - 2 Fév 21 11:00 DESCRIPTION:Integrable turbulence and soliton gas: experiments and theoreti cal approaches\nPierre Suret (PhLAM - Lille)\n\nOnline seminar --- Zoom Me eting ID: 996 1840 3246 -- Passcode: Ask L. Mazza or D. Petrov --\n\n\nExa ctly integrable partial differential equations (PDEs) such as the Korteweg -de-Vries (KdV) or the one-dimensional nonlinear Schrödinger equation (1D NLSE) can be studied in the framework of the Inverse Scattering Transform (IST). Integrable PDEs exhibit an infinite hierarchy of invariants that pr event the development of "standard" Wave Turbulence and energy cascade. De spite the existence of the IST technique\, there is no general theory desc ribing of the propagation of random waves in integrable systems such as 1D NLSE. For this reason\, Integrable Turbulence\, which deals with random fi elds\, has been recently introduced as a completely "new chapter of turbul ence theory" by V.E. Zakharov\, one of the creators both of the wave turbu lence theory and of the IST [1].\n\nSoliton gas (SG) is one example of int egrable turbulence. The concept of SG as a large ensemble of solitons rand omly distributed on an infinite line and elastically interacting with each other originates from the work of Zakharov [2]\, who introduced the kinet ic equation for a nonequilibrium diluted gas of weakly interacting soliton s of the KdV equation. Zakharov’s kinetic equation has been generalized to the case of a dense SG in Ref. [3].\n\nOptical fibers and 1D water tank s are very favorable experimental platforms for the investigation of integ rable turbulence and soliton gas (described by the focusing 1DNLSE). In th is talk\, I will present our recent experimental results obtained both in optical fibers and water tanks [4-6]. In the second part of my talk\, by u sing the famous example of the modulation instability\, I will show that S G is a promising model to describe the statistical properties of integrabl e turbulence. The spontaneous modulation instability (MI) also named “no ise-induced MI” arises when a plane wave is perturbed by noise in 1DNLSE . We will show that the long-term evolution of MI can be described by a ca refully designed SG [7].\n\n[1] V. E. Zakharov\, Stud. Appl. Math. 122\, 2 19 (2009)\n[2] V. E. Zakharov\, Sov. Phys. JETP 33\, 538 (1971)\n[3] G. El \, Phys. Lett. A 311\, 374 (2003)\n[4] A. Tikan\, S. Bielawski\, C. Szwaj\ , S. Randoux\, and P. Suret\, Nature Photonics 12\, 228 (2018)\n[5] A. E. Kraych\, D. Agafontsev\, S. Randoux\, and P. Suret\, Phys. Rev. Lett. 123\ , 093902 (2019).\n[6] P Suret et al. Phys. Rev. Lett. 125\, 264101 (2020)\ n[7] A Gelash\, D Agafontsev\, V Zakharov\, G El\, S Randoux\, P Suret\, P hys. Rev. Lett 123\, 234102 (2019)\n\n\n\n CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-760@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210209T110000 DTEND;TZID=Europe/Paris:20210209T120000 DTSTAMP:20210128T221038Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alberto-biella-lptms/ SUMMARY:Séminaire du LPTMS : Alberto Biella (LPTMS) - LPTMS (100% online s eminar) - 9 Fév 21 11:00 DESCRIPTION:Measurement-induced entanglement phase transitions and the Quan tum Zeno Effect\nAlberto Biella (LPTMS)\n\nOnline seminar --- ZOOM Meeting ID: 918 3216 1661 -- Password: Ask L. Mazza or D. Petrov --\n\nIt is well known that by repeatedly measuring a quantum system it is possible to com pletely freeze its dynamics into a well defined state\, a signature of the Quantum Zeno Effect. In my talk I will discuss how\, for a many-body syst em evolving under competing unitary evolution and variable-strength measur ements\, the onset of the Zeno effect takes the form of a sharp phase tran sition [1]. Using the Quantum Ising chain with continuous monitoring of t he transverse magnetization as paradigmatic example\, we show that for wea k measurements the entanglement produced by the unitary dynamics remains p rotected\, while only above a certain threshold the system is sharply brou ght into an uncorrelated Zeno subspace. Furthermore\, we show that this tr ansition is invisible to the average dynamics\, but encoded in the rare fl uctuations of the stochastic measurement process. Finally we trace an intr iguing connection between the onset of the Zeno effect and the subradiance transition of the associated non-Hermitian Hamiltonian.\n\n[1] AB\, M. Sc hirò\, arXiv:2011.11620 CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-762@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210302T110000 DTEND;TZID=Europe/Paris:20210302T120000 DTSTAMP:20210223T100014Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-francesca-pietracaprina-trinity-college-dublin/ SUMMARY:Séminaire du LPTMS : Francesca Pietracaprina (Trinity College Dubl in) - LPTMS (100% online seminar) - 2 Mar 21 11:00 DESCRIPTION:Many-Body Localization in 2D and constrained models\nFrancesca Pietracaprina (Trinity College Dublin)\n\nOnline seminar --- ZOOM Meeting ID: 955 7840 0964 -- Password: ask L. Mazza and D. Petrov --\n\nMany-body localization is a way to break ergodicity\, thermalization and transport i n disordered and quasiperiodic interacting quantum systems. The existence of a many-body localization transition in 2D systems is an open question t hat is being addressed experimentally\, theoretically and numerically. In this talk\, I will show some recent numerical results for a model whose fe atures make it especially accessible to exact diagonalization. We numerica lly study the possibility of many-body localization transition in a constr ained system: a disordered quantum dimer model on the honeycomb lattice. B y using the peculiar constraints of this model and state-of-the-art exact diagonalization and time evolution methods\, we probe large two-dimensiona l systems of up to N=108 sites.\n\nF Pietracaprina and F Alet\, SciPost Ph ys. 10\, 044 (2021)\nC Chiaracane\, F Pietracaprina\, A Purkayastha and J Goold\, arXiv:2101.01111 [cond-mat.dis-nn] (2021) CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-763@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210309T110000 DTEND;TZID=Europe/Paris:20210309T120000 DTSTAMP:20210223T173106Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-blagoje-oblak-sorbonne-universite/ SUMMARY:Séminaire du LPTMS : Blagoje Oblak (Sorbonne Université) - LPTMS (100% online seminar) - 9 Mar 21 11:00 DESCRIPTION:Berry Phases and Drift in the KdV Equation\nBlagoje Oblak (Sorb onne Université)\n\nOnline seminar --- ZOOM Meeting ID: 952 7571 4537 -- Password: ask L. Mazza and D. Petrov --\n\nI consider a model of fluid mot ion closely related to the Korteweg-de Vries equation that governs shallow water waves. Upon reformulating this model as a geodesic in an infinite-d imensional group\, the fluid's drift velocity can be recast as an ergodic rotation number. The latter is sensitive to Berry phases\, inspired by con formal field theory and gravity\, that are produced by adiabatic deformati ons. Along the way\, I show that the topology of coadjoint orbits of wave profiles affects drift in a dramatic manner: orbits that are not homotopic to a point yield quantized rotation numbers. These arguments rely on the general structure of Euler equations\, suggesting the existence of other a pplications of infinite-dimensional geometry to nonlinear waves. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-769@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210316T110000 DTEND;TZID=Europe/Paris:20210316T120000 DTSTAMP:20210311T081105Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-benoit-vermersch-upmmc-grenoble/ SUMMARY:Séminaire du LPTMS : Benoît Vermersch (LPMMC Grenoble) - LPTMS (1 00% online seminar) - 16 Mar 21 11:00 DESCRIPTION:Probing mixed-state\, symmetry-resolved\, entanglement with ran domized measurements\nBenoît Vermersch (LPMMC Grenoble)\nOnline seminar - -- ZOOM Meeting ID: 970 5162 7987 -- Password: ask L. Mazza and D. Petrov --\n\nRecently\, protocols based on statistical correlations of randomized measurements have been introduced to probe entanglement in synthetic quan tum systems. This includes protocols to access Renyi entropies\, many-body state fidelities\, out-of-time-ordered correlators (OTOCs) and topologica l invariants\, etc. In this seminar\, I will first give a tutorial introdu ction to randomized measurements. Then\, I will present our protocol for d etecting and quantifying mixed-state entanglement in the framework of the positive-partial-transpose condition (PPT). Finally\, I will discuss symme try-resolved entanglement in synthetic quantum systems\, and present a uni versal mechanism of purification and entanglement creation of many-body qu antum states. In all parts of my talk\, I will show experimental results o btained in the Innsbruck's trapped ion quantum simulator. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-765@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210323T110000 DTEND;TZID=Europe/Paris:20210323T120000 DTSTAMP:20210304T231732Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-valerio-sorichetti-lptms/ SUMMARY:Séminaire du LPTMS : Valerio Sorichetti (LPTMS) - LPTMS (100% onli ne seminar) - 23 Mar 21 11:00 DESCRIPTION:Nonequilibrium simulation of cytoskeletal proteins: assembly\, bundling and gelation\nValerio Sorichetti (LPTMS)\n\nOnline seminar --- ZO OM Meeting ID: 996 5227 7025 -- Password: ask L. Mazza and D. Petrov --\n\ nThe cytoskeleton of living cells is a dynamical network with an extremely rich behavior: it maintains the shape of the cell\, gives it resistance t o deformation\, allows it to deform and migrate and provides the structure necessary for intracellular transport. In order to gain a better understa nding of the biological role of the cytoskeleton\, it is fundamental to un derstand how it assembles\, how it remodels itself and which factors deter mines its structure.\n\nThe competition between filament bundling and elon gation is one of the key factors in determining the structure and mechanic al properties of the cytoskeleton. In order to capture this out-of-equilib rium process\, we simulate a system of "patchy" monomers which can bind ir reversibly to each other to form long filaments.\n\nWe first consider mono mers which interact via a simple isotropic excluded volume interaction in addition to the patchy interaction. We study the assembly kinetics of the filaments\, finding that the mean filament length increases linearly with time\, and give a theoretical interpretation of this finding.\n\nSuccessiv ely\, we allow the monomers to stick reversibly to each other via isotropi c short-ranged interactions. We show that this simple model leads to a ver y rich range of different behaviors\, giving rise to filaments\, bundles\, and complex bundle networks\, depending on the thermodynamic parameters c onsidered CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-766@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210330T110000 DTEND;TZID=Europe/Paris:20210330T120000 DTSTAMP:20210319T140244Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mert-terzi-lptms/ SUMMARY:Séminaire du LPTMS : Mert Terzi (LPTMS) - LPTMS (100% online semin ar) - 30 Mar 21 11:00 DESCRIPTION:Collective deformation modes promote fibrous self-assembly in p rotein-like particles\nMert Terzi (LPTMS)\n\nOnline seminar --- ZOOM Meeti ng ID: 996 6280 8820 -- Password: ask L. Mazza and D. Petrov --\n\nSelf-as sembly is a crucial and ubiquitous process for biological systems\, in whi ch the building blocks spontaneously organize into larger complexes. If th e building blocks fit each other\, self-assembly leads to space filling ag gregates. However\, in the case of misfitting particles\, the resulting ag gregates may have limiting sizes. When the misfitting particles are deform able\, elastic energy builds up during the assembly. The energy cost of el astic deformation competes with a surface tension which drives the particl es into assembly. In the regime in which these two energies are comparable \, particles can assemble into self-limiting structures. The relationship between characteristics of the individual particles and the resulting aggr egates is not well understood. Through numerical simulations and elastic c oarse-graining we show that this relationship is dominated by collective a ggregate deformation modes in a broad class of soft particles. We identify two characteristics of particles predictive of the overall aggregate stru cture. When individual particles have soft deformation modes\, these modes collectively control the size of self-limiting aggregates and lead to lar ge-scale structures. The second characteristics is incompressibility which favors anisotropic\, and hence fibrous aggregates. Finally\, we discuss t he implications of our results to fiber formation in protein aggregation. \n\n CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-764@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210413T110000 DTEND;TZID=Europe/Paris:20210413T120000 DTSTAMP:20210330T112942Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-laura-foini-ipht-cea/ SUMMARY:Séminaire du LPTMS : Laura Foini (IPhT - CEA) - LPTMS (100% online seminar) - 13 Avr 21 11:00 DESCRIPTION:Quenches in initially coupled Luttinger liquids\nLaura Foini (I PhT - CEA)\n\nOnline seminar --- ZOOM Meeting ID: 969 0061 5152 -- Passwor d: ask L. Mazza and D. Petrov --\n\nWe study the quantum quench in two cou pled\, and generically different\, Luttinger liquids\, after that the coup ling between the two systems is removed. To solve the problem we exploit t he factorization of the initial state in terms of a massive and massless m ode which emerges in the low energy limit\, and we encode the non-equilibr ium dynamics in a proper rescaling of the time. With this the solution of the problem can be derived in terms of the known solutions for single Lutt inger liquids and\, in particular\, can rely on techniques exploiting conf ormal invariance. The emergent dynamics is characterized by a sequence of regimes and depending on the observable\, the contribution from the massiv e or from the massless mode can be the dominant one\, giving rise to expon ential or power-law decay in space-time\, respectively. \nWhile the approa ch can be relevant in a larger set of problems\, I will discuss the applic ation to two tunnel coupled tubes in cold atomic experiments\, discussing the complex thermalization properties of the system. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-767@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210504T110000 DTEND;TZID=Europe/Paris:20210504T120000 DTSTAMP:20210422T075133Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giulia-pisegna/ SUMMARY:Séminaire du LPTMS : Giulia Pisegna (University of Rome La Sapien za) - LPTMS (100% online seminar) - 4 Mai 21 11:00 DESCRIPTION:Dynamical Renormalization Group Approach to the Collective Beha vior of Swarms\nGiulia Pisegna (University of Rome La Sapienza)\n\nOnline seminar --- Zoom Meeting ID: 951 4623 4806 -- Passcode: ask L. Mazza and D . Petrov --\n\nWe study the critical behavior of a model with nondissipati ve couplings aimed at describing the collective behavior of natural swarms \, using the dynamical renormalization group under a fixed-network approxi mation. At one loop\, we find a crossover between an unstable fixed point\ , characterized by a dynamical critical exponent z=d/2\, and a stable fixe d point with z=2\, a result we confirm through numerical simulations. The crossover is regulated by a length scale given by the ratio between the tr ansport coefficient and the effective friction\, so that in finite-size bi ological systems with low dissipation\, dynamics is ruled by the unstable fixed point. In three dimensions this mechanism gives z=3/2\, a value sign ificantly closer to the experimental window\, 1.0≤z≤1.3\, than the val ue z≈2 numerically found in fully dissipative models\, either at or off equilibrium. This result indicates that nondissipative dynamical couplings are necessary to develop a theory of natural swarms fully consistent with experiments. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-768@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210511T110000 DTEND;TZID=Europe/Paris:20210511T120000 DTSTAMP:20210428T190406Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-antoine-fruleux/ SUMMARY:Séminaire du LPTMS : Antoine Fruleux (Ecole Polytechnique) - LPTMS (100% online seminar) - 11 Mai 21 11:00 DESCRIPTION:Fluctuations in biological tissues\nAntoine Fruleux (École Pol ytechnique\, LadHyX)\nBiophysics — Modeling &\; Data analysis — Mor phogenesis\n\nOnline seminar --- Zoom Meeting ID: 991 9867 1888 -- Passcod e: ask L. Mazza and D. Petrov --\n\n[caption id="" align="aligncenter" wid th="640"] Figure 1: Cell growth is heterogeneous in space and time. Exampl e of a sepal (green organ that protects a flower before it opens) from the model plant Arabidopsis thaliana. The colour scale corresponds to growth rates (high in red\, low in blue).[/caption]\n\nThe two hands of most huma ns almost superimpose. Similarly\, flowers of an individual plant have\nsi milar shapes and sizes. This is in striking contrast with growth and defor mation of cells during\norgan morphogenesis\, which feature considerable v ariations in space and in time\, raising the question\nof how organs and o rganisms reach well-defined size and shape. In order to link cell and orga n scales\,\nI built a stochastic hydrodynamic model of growing tissue with fibre-like structural elements that may\naccount for the plant cell wall or animal cytoskeleton or extracellular matrix [1]. The model gave two\nim portant predictions. First\, fluctuations occurring at cellular scale exhi bit long-range correlations.\nSecond\, the response of fibres to growth-in duced mechanical stress may enhance or buffer cellular\nvariability of gro wth\, making it possible to modulate the robustness of morphogenesis.\nI w ill present in more details these results as well as a mathematical tool I defined to analyze signal\nin tissues: the Cellular Fourier Transform (CF T) [2]. It is suited to those signals which can only be\ndefined at a cell ular scale\, or which are smoothed out of their sub-cellular variations\, and it allows\nto overcome the constrains met when studying biological tis sue\, foams\, granular materials or other\ngeometrically disordered materi als. I will introduce the method and explain how it reveals the physical\n mechanisms setting spatial heterogeneity in growing tissues.\nReferences\n [1] Antoine Fruleux and Arezki Boudaoud. Modulation of tissue growth heter ogeneity by responses\nto mechanical stress. Proceedings of the National A cademy of Sciences\, 116(6):1940–1945\, 2019.\n[2] Antoine Fruleux and A rezki Boudaoud. Cellular fourier analysis for geometrically disordered\nma terials. Physical Review Research\, 3(2):023036\, 2021. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-770@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210518T110000 DTEND;TZID=Europe/Paris:20210518T120000 DTSTAMP:20210506T110419Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-orazio-scarlatella-college-de-france/ SUMMARY:Séminaire du LPTMS : Orazio Scarlatella (Collège de France) - LPT MS (100% online seminar) - 18 Mai 21 11:00 DESCRIPTION:Dynamical Mean-Field Theory for Markovian Open Quantum Many-Bod y Systems\nOrazio Scarlatella (Collège de France)\n\nOnline seminar --- Z oom Meeting ID: 962 2949 3343 -- Passcode: ask L. Mazza and D. Petrov --\n \nMarkovian quantum many body systems describe a number of experimental pl atforms relevant for quantum simulations. Their theoretical understanding is hampered by the exponential scaling of their Hilbert space and by their intrinsic nonequilibrium nature\, limiting the applicability of many trad itional approaches. In this talk I will present an extension of the nonequ ilibrium Dynamical Mean Field Theory (DMFT) to bosonic Markovian open quan tum systems. Within DMFT\, a Lindblad master equation describing a lattice of dissipative particles is mapped onto an impurity problem describing a single site of the lattice coupled to a self-consistent environment\, whic h for bosons accounts for fluctuations beyond Gutzwiller mean-field theory due to the finite lattice connectivity. I will present a non-perturbative approach to solve this impurity problem\, which is tailored for Markovian open quantum systems. As a first application of this DMFT approach\, I wi ll discuss the steady-state of a driven-dissipative Bose-Hubbard model wit h two-body losses and incoherent pump. I will show that this model feature s a normal phase at small hopping and a phase transition towards a non-equ ilibrium superfluid. Remarkably\, this transition occurs as a finite-frequ ency instability\, leading to an oscillating in time order parameter. Then \, I will show that DMFT captures hopping-induced dissipative processes\, completely missed in Gutzwiller mean-field theory\, which crucially determ ine the properties of the normal phase\, including the suppression of loca l gain and the emergence of a stationary quantum-Zeno regime. I will also argue that these processes compete with coherent hopping processes to dete rmine the phase transition towards the superfluid phase\, leading to a lar ge extension of the normal phase due to finite-connectivity. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-771@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210525T110000 DTEND;TZID=Europe/Paris:20210525T120000 DTSTAMP:20210520T081339Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marko-medenjak-lpens/ SUMMARY:Séminaire du LPTMS : Marko Medenjak (LPENS) - LPTMS (100% online s eminar) - 25 Mai 21 11:00 DESCRIPTION:Bounds on time translation symmetry breaking \nMarko Medenjak ( LPENS)\n\nOnline seminar --- Zoom Meeting ID: 951 9908 9593 -- Passcode: a sk L. Mazza and D. Petrov --\n\nAbstract: Isolated systems consisting of m any interacting particles are generally\nassumed to relax to a stationary state\, whose macroscopic properties are\ndescribed by the laws of thermod ynamics and statistical physics. In this\nseminar we will explore whether quantum systems can avoid relaxation and\nif stationarity itself can be un stable\, meaning that even the slightest\ndisturbance of the thermal state leads to perpetually changing physical\nproperties. Analogous behaviour w as experimentally observed in driven\nquantum systems (Floquet time crysta ls)\, in which the response of the\nsystem does not follow the period of t he driving. We will show that time\ntranslation symmetry breaking is possi ble even in perfectly isolated\nquantum systems without any driving\, and provide rigorous bounds on it\nin terms of dynamical symmetries. Finally\, we will see how time\ntranslation symmetry breaking occurs in the Heisenb erg XXZ spin chain\,\nand show that its properties are a no-where continuo us (fractal)\nfunction of the system parameters.\n\n[1] M. Medenjak\, B. B uča\, and D. Jaksch\, Phys. Rev. B 102\, 041117(R) (2020).\n[2] M. Medenj ak\, T. Prosen\, and L. Zadnik\, SciPost Phys. 9\, 3 (2020). CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-772@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210601T110000 DTEND;TZID=Europe/Paris:20210601T120000 DTSTAMP:20210531T104638Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-samjay-ramassamy-ipht/ SUMMARY:Séminaire du LPTMS : Sanjay Ramassamy (IPHT) - LPTMS (100% online seminar) - 1 Juin 21 11:00 DESCRIPTION:Barak-Erdös graphs and the infinite-bin model\nSanjay Ramassam y (IPHT)\n\nOnline seminar --- Zoom Meeting ID: 916 6984 4150 -- Passcode: ask L. Mazza and D. Petrov !! NEW PASSWORD !! --\n\n\nBarak-Erdös graphs are the directed acyclic version of Erdös-Rényi random graphs : the ver tex set is {1\,...\,n} and for each i CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-778@lptms.universite-paris-saclay.fr DTSTART:20210730T100000Z DTEND:20210730T130000Z DTSTAMP:20210715T141407Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-nadia-milazzo/ SUMMARY:Soutenance de thèse: Nadia Milazzo - LPTMS (100% online seminar) - 30 Juil 21 10:00 DESCRIPTION:Optimal measurement strategies for quantum state and quantum ch annel estimation\npar\n\nNadia Milazzo\nAbstract:\nThe rapid advance of qu antum information technology requires precise control and manipulation of quantum systems\; in particular\, it is essential to certify that quantum processors truly work quantum mechanically\, in order to validate experime nts and their results. The problem of certification of quantum states and devices is a demanding one\, thus many attempts have been put forward to f ind ways of efficiently testing their basic functionalities\, such as thei r entanglement properties. The aim of the present thesis is to find optima l strategies for the estimation and characterization of quantum states and channels\, with a special focus on entanglement correlations.\nWe conside r in particular the certification of entanglement across a given partition of a multi-qubit system\, when only partial information about the corresp onding quantum state is available. We also discuss the problem of separabi lity of quantum channels in terms of the Choi matrix representation\, and we shall mention some preliminary results about quantum functional testing based on Bayesian adaptive strategies. As a separate issue\, we also high light the relevance of quantum information in the context of analogue grav ity.\nJury:\nProf. Otfried Gühne: Department Physik\, Universität Siegen (rapporteur)\nProf. Jens Siewert: Dpto. de Química-Física Facultad de C iencia y Tecnología\, Universidad del País Vasco\, UPV/EHU (rapporteur)\ nProfesseure d'université Rosa Tualle Brouri: Institut d'Optique Graduate School - Université Paris Saclay\nProf. Daniel Braun: Institut für Theo retische Physik\, Universität Tübingen\nProf. Igor Lesanovsky: Institut für Theoretische Physik\, Universität Tübingen\nDr. Olivier Giraud\, CN RS - Université Paris Saclay\n\nLocation: Institut für Theoretische Phys ik\, Universität Tübingen\, Room H33\nZoom link: https://zoom.us/j/93476 93638 CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-775@lptms.universite-paris-saclay.fr DTSTART:20210906T140000Z DTEND:20210906T140000Z DTSTAMP:20210726T073031Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-alexandre-pricoupenko/ SUMMARY:Soutenance de thèse : Alexandre Pricoupenko - Grand amphi\, bâtim ent Pascal n° 530 - 6 Sep 21 14:00 DESCRIPTION:Beyond-mean-field effects in ultracold gases\npar\n\nAlexandre Pricoupenko\nUltracold gases are well controllable quantum systems that ar e described by a set of few parameters. The idea to look at systems with p artially attractive and repulsive forces\, fine-tuned to an approximate ov erall cancellation of the mean-field term\, provide an interesting platfor m for studying various beyond-mean-field phenomena\, remarkable recent exa mples being quantum droplets and dipolar supersolids. In this thesis\, we take a step towards understanding the phase diagram of the 1D Bose-Bose mi xture with attractive interspecies and repulsive intraspecies contact inte ractions. We address the one-dimensional three-body problem with two- and three-body interactions that we solve analytically. Then\, we develop the perturbation theory for systems with a weak two-body potential interaction \, where the attractive and repulsive parts compensate each other. We calc ulate in every dimension the leading nonpairwise contribution\, which repr esents an effective three-body interaction. We apply this result particula rly to tilted dipoles in quasi-low-dimensional geometries. Interestingly\, we show the consistency of this few-body perturbative approach with the B ogoliubov one.\n \;\n\nJury :\n\nFrédéric Chevy\, LKB ENS\, Paris\, examinateur\n\nMario Gattobigio\, INPHYNI\, Nice\, rapporteur\n\nDenis Lac roix\, IJCLab\, Orsay\, examinateur\n\nDmitry Petrov\, LPTMS\, Orsay\, dir ecteur de thèse\n\nLuis Santos\, Leibniz Universität Hannover\, rapporte ur\n\nLeticia Tarruel\, ICFO\, Barcelona\, examinatrice CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-782@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210914T110000 DTEND;TZID=Europe/Paris:20210914T120000 DTSTAMP:20210908T124715Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-isabelle-bouchoule-lcf/ SUMMARY:Séminaire du LPTMS : Isabelle Bouchoule (LCF) - Petit amphi\, bât iment Pascal n° 530 - 14 Sep 21 11:00 DESCRIPTION:Effect of losses in correlated quantum gases\nIsabelle Bouchoul e (Laboratoire Charles Fabry)\nHybrid seminar: onsite + zoom (ID:932 9180 1483\, PW:cuTj9X).\n\nI propose\, during this seminar\, to make a review o f different results we obtained in the last years\, both theoretical and e xperimental\, concerning the effect of losses in quantum gases.\n\nLosses are always present in cold atoms experiments. However in presence of corre lations between atoms\, evaluating their effect is a difficult theoretical problem which is mainly unexplored. This is illustrated by our recent wor k on the effect of losses on a gas with contact interactions: if one makes the usual assumption that the environment involved in the loss process ha s a vanishing correlation time\, which is the assumption that leads to the famous Lindblad equation used so far to describe losses in the context of cold atoms\, then we show that the energy increase rate in the gas diverg es in dimensions larger than 1. The description of losses requires either taking into account the finite correlation time of the reservoir\, or taki ng into account the finite interaction range between atoms.\n\nIn dimensio n 1\, such a divergence is absent and for short enough correlation time of the reservoir\, losses are well described by the Lindblad equation\, even in the presence of contact interactions. We have investigated the effect of losses in the Lieb-Liniger model of 1D bosons with contact interaction. We assume slow losses so that the gas has time to relax at any time. In c ontrast to chaotic systems which relax towards a thermal state parameteriz ed by 2 quantities\, the particle density and the energy density\, the loc al properties of the Lieb-Liniger model after relaxation are parameterized by a whole function\, the rapidity distribution. We have computed the evo lution of the rapidity distribution in presence losses\, thus characterizi ng entirely the effect  of slow losses. We observe that losses bring the system to a non-thermal state\, and we show that a manifestation of the no n-thermal nature of the state is the breakdown of the popular Tan's relati on. \n\nIn the particular case when the gas lies into the quasi-condensat e regime\, we computed the effect of losses within the Bogoliubov descript ion of the gas. Experimentally\, our measurements\, which concern long wav e-length collective modes\, are in agreement with those theoretical predic tions. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-773@lptms.universite-paris-saclay.fr DTSTART;VALUE=DATE:20210916 DTEND;VALUE=DATE:20210917 DTSTAMP:20210913T122427Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journee-des-labor atoires-ffj/ SUMMARY:Journée des laboratoires FFJ - - 16 Sep 21 00:00 DESCRIPTION:Annonce J-FFJ 16 sept 2021 CATEGORIES:seminars END:VEVENT BEGIN:VEVENT UID:0-783@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210921T110000 DTEND;TZID=Europe/Paris:20210921T120000 DTSTAMP:20210917T121412Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pierfrancesco-urbani-ipht-2/ SUMMARY:Séminaire du LPTMS : Pierfrancesco Urbani (IPHT) - Petit amphi\, b âtiment Pascal n° 530 - 21 Sep 21 11:00 DESCRIPTION:Marginal stability in soft anharmonic mean field spin glasses\n Pierfrancesco Urbani (Institut de Physique Théorique)\nOnsite blackboard talk + zoom (zoom ID:995 6963 5229\, pw: M6Z5ib).\n\nI will consider sim ple mean field spin glasses of real degrees of freedom subjected to anharm onic quartic potential and study the glass phase. I will show how this ph ase realizes marginal stability through soft\, pseudogapped\, non-linear e xcitations. I will also discuss how these findings provide a new scenario for the longstanding problem of the spin glass transition in a field and w hy this is important for the physics of low temperature amorphous solids. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-777@lptms.universite-paris-saclay.fr DTSTART:20211004T133000Z DTEND:20211004T173000Z DTSTAMP:20210930T130136Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-hugo-le-roy/ SUMMARY:Soutenance de thèse : Hugo Le Roy - Petit amphi\, bâtiment Pascal n° 530 - 4 Oct 21 13:30 DESCRIPTION:Elasticity of self assembling bio-materials\npar\n\nHugo Le Roy \nHybrid PhD defense: onsite + zoom (https://cnrs.zoom.us/j/95416861091?pw d=NlhHOW9BWXM2aDN4UmJSSktpYTZmQT09  Meeting ID: 954 1686 1091 - For pwd\, please contact martin.lenz@universite-paris-saclay.fr)\nSelf organization is crucial for the wealth of living systems\, both at the molecular and c ellular level. To correctly achieve their role a tight control over the sh ape and structure of protein for instance\, is required. Any mistake can l ead to various disease like Alzheimer\, where proteins aggregate into fibr ous structures. On a larger scale\, cells need to probe the mechanical res ponse of their environment -the extra cellular matrix- and to adapt their own rigidity to collectively orientate. In this thesis\, we are looking a two different models. In the first part\, we study protein aggregation bey ond the microscopical details. By considering elastic assembling particles \, we are able to derive generic law and understand the very persistent fo rmation of fibers. In the second part\, we model the dynamical response of a fashionable class of hydrogels for their bio-compatibility. Material en gineers are now able to synthesize materials with more and more subtle beh avior\, although understanding certain emergent properties -such as non-ex ponential relaxation- can be a major challenge. We design a simple model f or the dynamical response of hydrogels connected by large multivalent cros slinkers. We are able to account for experimental results\,and rationalize their origin.\nJury :\n\nThibaut Divoux\, Laboratoire de Physique ENS Lyo n\, examinateur\n\nGreg Grason\, Univ. of Massachusetts Amherst\, rapporte ur\n\nMartin Lenz\, LPTMS\, directeur de thèse\n\nEmmanuel Trizac\, LPTMS \, examinateur\n\nEmanuela Zaccarelli\, Univ. La Sapienza\, rapportrice\n\ nZorana Zeravcic\, Laboratoire Gulliver ESPCI\, examinatrice CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-796@lptms.universite-paris-saclay.fr DTSTART:20211005T110000Z DTEND:20211005T123000Z DTSTAMP:20211004T120311Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mikhail-zvonarev-2/ SUMMARY:Séminaire du LPTMS: Mikhail Zvonarev - Salle des séminaires du FA ST et du LPTMS\, bâtiment Pascal n°530 - 5 Oct 21 11:00 DESCRIPTION:Spin-charge separation for hardcore fermions in one dimension\n Mikhail Zvonarev (LPTMS)\nOnsite + zoom seminar\n\nMeeting ID: 985 7618 93 84\nPasscode: AAs1jh\nLink: https://cnrs.zoom.us/j/98576189384?pwd=djN5OVo zR3pwNGFQWjY1VDlEN2I4QT09\nThe hardcore constraint permits no more than on e fermion per lattice site. Such a system is\, eventually\, strongly inter acting\, and has no small parameter expansion. I will discuss how spin and charge dynamics factorize at the level of correlation functions. The prob lem has a long history\, and I will show a trick\, eventually reducing the complete solution to a few elementary algebraic manipulations. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-776@lptms.universite-paris-saclay.fr DTSTART:20211008T093000Z DTEND:20211008T114500Z DTSTAMP:20211008T081540Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/fete-de-la-scienc e-2021/ SUMMARY:Fête de la Science 2021 - Salle des séminaires du FAST et du LPTM S\, bâtiment Pascal n°530 - 8 Oct 21 09:30 DESCRIPTION: CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-786@lptms.universite-paris-saclay.fr DTSTART:20211013T110000Z DTEND:20211013T120000Z DTSTAMP:20211005T164704Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-cecile-leduc/ SUMMARY:Physics-Biology interface seminar: Cécile Leduc - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Oct 21 11:00 DESCRIPTION:Structure and assembly of single intermediate filaments\nCécil e Leduc (Institut Jacques Monod)\nIntermediate filaments (IF) are involved in key cellular functions including polarization\, migration\, and protec tion against large deformations. These functions are related to their rema rkable ability to extend without breaking\, a capacity that should be dete rmined by the molecular organization of subunits within filaments. However \, this structure-mechanics relationship remains poorly understood at the molecular level. Here\, using super-resolution microscopy (SRM)\, we show that vimentin filaments exhibit a ~49 nm axial repeat both in cells and in vitro. As unit-length-filaments (ULFs) precursors were measured at ~59 nm \, this demonstrates a partial overlap of ULFs during filament assembly. U sing an SRM-compatible stretching device\, we also provide evidence that t he extensibility of vimentin is due to the unfolding of its subunits and n ot to their sliding\, thus establishing a direct link between the structur al organization and its mechanical properties. Overall\, our results pave the way for future studies of IF assembly\, mechanical and structural prop erties in cells. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-793@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211019T110000 DTEND;TZID=Europe/Paris:20211019T120000 DTSTAMP:20211010T162837Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-camille-aron-lpens/ SUMMARY:Séminaire du LPTMS : Camille Aron (LPENS) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Oct 21 11:00 DESCRIPTION:Non-analytic non-equilibrium field theory\nCamille Aron (Labora toire de Physique de l'Ecole Normale Supérieure)\nOnsite seminar + zoom ( ID: 981 7596 6473\, Passcode: fCjZ6d)\n\nThe Landau-Ginzburg theory is a c ornerstone of modern physics that unifies the various equilibrium phase tr ansitions of matter in a common framework. The free energy\, functional of the order parameter\, is built on simple principles: locality\, symmetry\ , stability\, and analyticity. It is still unclear when and how such a uni fied principle-based approach can be extended to non-equilibrium phase tra nsitions.\n\nIn this talk\, I will present the recent theoretical efforts to address the non-equilibrium phase transition which occurs during the re sistive switching (RS) of a variety of correlated oxides: their resistivit y suddenly drops by several orders of magnitude when subject to a finite v oltage bias.\n\nThe particular case of RS will lead me to propose to aband on the principle of analyticity of the Landau potential away from thermal equilibrium. This more general question will be addressed in the simpler c ontext of non-equilibrium versions of the Ising model. I will show how the usual φ^4 potential can be deformed by non-analytic operators of intrins ic non-equilibrium nature and use the renormalization group to discuss the ir low-energy relevance. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-788@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211026T110000 DTEND;TZID=Europe/Paris:20211026T120000 DTSTAMP:20211013T105934Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sara-murciano-sissa-1/ SUMMARY:Séminaire du LPTMS : Sara Murciano (SISSA) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Oct 21 11:00 DESCRIPTION:Symmetry-resolved entanglement and negativity in systems with U (1) symmetry\nSara Murciano (International School for Advanced Studies)\nO nsite seminar + zoom (ID: 948 1788 3604\,  Passcode: B3McPy).\n\nSymmetri es are a pillar of modern physics and an evergreen research topic is the c haracterisation of how the presence of a symmetry influences the propertie s of a physical system. I will present an analysis of the entanglement ent ropies and negativities related to different symmetry sectors of systems w ith an internal U(1) symmetry. The entanglement entropy admits a decomposi tion according to its total preserved charge thanks to the block diagonal form of the density matrix. Despite this structure becomes nontrivial afte r the operation of partial transposition on the density matrix\, it has be en shown that negativity admits a resolution in terms of the charge imbala nce between two subsystems. I will focus on the resolution of entanglement and negativity for free Dirac fields in two spacetime dimensions at finit e temperature and size. To this end\, I use a geometrical construction in terms of an Aharonov-Bohm-like flux inserted in the Riemann surface defini ng the entanglement. The main interesting finding is that both entanglemen t entropy and negativity are equally distributed among the different symme try sectors at leading order.\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-787@lptms.universite-paris-saclay.fr DTSTART:20211027T110000Z DTEND:20211027T120000Z DTSTAMP:20211004T092208Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-renaud-poincloux/ SUMMARY:Physics-Biology interface seminar: Renaud Poincloux - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 27 Oct 21 11:00 DESCRIPTION:Elasticity of dense actin networks produces nanonewton protrusi ve forces at macrophage podosomes\nRenaud Poincloux (IPBS\, Toulouse)\nAct in filaments assemble into force-generating systems that play pivotal role s in diverse cellular functions\, including cell motility\, adhesion\, con tractility and division. Thermodynamics and in vitro experiments showed th at the polymerization of single actin filaments generates forces in the 1- 10 pN range. How networks of crosslinked actin filaments\, individually ge nerating piconewton forces\, are able to produce forces reaching tens of n anonewtons remains unclear. We used in situ cryo-electron tomography to un veil how the nanoscale architecture of macrophage podosomes enables basal membrane protrusion. We show that the sum of the actin polymerization forc es at the membrane is not sufficient to explain the protrusive forces gene rated by podosomes. Quantitative analysis of podosome organization demonst rates that the core is composed of a dense network of bent actin filaments storing elastic energy. Theoretical modelling of the network as a spring- loaded elastic material reveals that it exerts forces of up to tens of nan onewtons\, similar to those evaluated experimentally. Thus\, taking into a ccount not only the interface with the membrane but also the bulk of the n etwork is crucial to understand force generation by actin machineries. Our integrative approach sheds light on the elastic behavior of dense actin n etworks and opens new avenues to understand force production inside cells. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-794@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211109T110000 DTEND;TZID=Europe/Paris:20211109T120000 DTSTAMP:20211109T094922Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-juliane-klamser-espci/ SUMMARY:Séminaire du LPTMS : Juliane Klamser (ESPCI) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Nov 21 11:00 DESCRIPTION:Monte Carlo descriptions of active matter and their continuous- time limits\nJuliane Klamser (École supérieure de physique et de chimie industrielles)\nOnsite seminar + zoom (Meeting ID: 984 8271 3951\, Passco de: dX3f5t\, link: https://cnrs.zoom.us/j/98482713951?pwd=L1AyQUtzeEFEMWRi c3pBV2NrWUFRUT09)\n\nCoauthors : Olivier Dauchot\, Julien Tailleur\nThe ph ysics of active matter is determined by the non-equilibrium dynamics of th e constituent particles. While constructing a non-equilibrium Monte Carlo (MC) dynamics for active matter is straightforward\, the question remains to what extent this discrete-time dynamics faithfully captures real-world/ continuous-time active systems. We focus on a kinetic MC version for the s implest kind of active matter: persistently moving\, non-polar\, interacti ng particles. On the multi-particle level\, the MC dynamics captures not o nly Motility-induced phase separation [1] but also features a non-equilibr ium extension of the celebrated two-dimensional melting [2]. We show [3]\, however\, that the continuous-time limit of existing MC dynamics[1\,2] is ill-defined\, leading to the vanishing of trademark behaviours of active matter such as the motility-induced phase separation\, ratchet effects\, a s well as to a diverging mechanical pressure. We show [3] how mixing passi ve/uncorrelated moves with active/time-correlated ones regularises this be haviour\, leading to a well-defined continuous-time limit. We propose new active kinetic MC algorithms whose continuous-time limits are the Langevin descriptions of the work-horse active-matter models\, namely Active-Ornst ein Uhlenbeck\, Active Brownian\, and Run-and-Tumbles particles.\n\nRefere nces:\n[1] D. Levis and L. Berthier\, Phys. Rev. E 89 (2014)\, 062301\n[2] J. U. Klamser\, S. C. Kapfer and W. Krauth\, Nat Commun 9 (2018) 5045\n[3 ] J. U. Klamser\, O. Dauchot and J. Tailleur\, Phys. Rev. Lett. 127 (2021 )\, 150602 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-798@lptms.universite-paris-saclay.fr DTSTART:20211110T110000Z DTEND:20211110T120000Z DTSTAMP:20211014T164329Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-yves-gaudin/ SUMMARY:Physics-Biology interface seminar: Yves Gaudin - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Nov 21 11:00 DESCRIPTION:Interactions between viral factories and cellular innate immuni ty\, a story of liquid biocondensates\nYves Gaudin (I2BC)\nReplication of Mononegavirales (MNV) occurs in viral factories which form inclusions in t he host-cell cytoplasm. For rabies virus (RABV)\, those inclusions are cal led Negri Bodies (NBs). NBs have characteristics similar to those of liqui d organelles: they are spherical\, they fuse to form larger structures\, a nd they disappear upon hypotonic shock. Their liquid phase was confirmed b y FRAP experiments. Live-cell imaging indicates that viral nucleocapsids a re ejected from NBs and transported along microtubules to form either new virions or secondary viral factories. \nWe developed several minimal syste ms (both cellular and acellular) allowing the formation of biomolecular co ndensates recapitulating NBs properties. Those minimal systems established RABV phosphoprotein (P) as the main regulator of the liquid liquid phase separation (LLPS) and identified structural elements of RABV nucleoprotein and P that are key in this process. Formation of liquid viral factories b y LLPS has been extended to other MNV. This is a paradigm change in the fi eld of MNV replication that invites us to revisit the interplay between vi ral factories and innate cellular immunity.\nAs an example\, we previously demonstrated that stress granules\, which are also liquid biomolecular co ndensates containing microbes-associated-molecular-patterns recognition re ceptors acting as sensors of RNA virus replication\, come into close conta ct with NBs\, exchange material with them\, but do not fully mix their con tent. We have now extended those observations to other components of the c ellular pathway leading to interferon production demonstrating a key role of viral and cellular biomolecular condensates in innate immunity. \n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-784@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211116T110000 DTEND;TZID=Europe/Paris:20211116T120000 DTSTAMP:20211103T160830Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cristiano-ciuti-mpq/ SUMMARY:Séminaire du LPTMS : Cristiano Ciuti (MPQ) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Nov 21 11:00 DESCRIPTION:Cavity-mediated effects in disordered quantum Hall systems\nCri stiano Ciuti (laboratoire Matériaux et Phénomènes Quantiques)\nOnsite s eminar + zoom (ID: 961 6880 9559\, PW: h2LNDE).\n\nThe manipulation of mat ter by giant vacuum fields in electromagnetic resonators is an emergent to pic in physics and chemistry [1].  In this seminar\, we will see how the cavity vacuum fluctuations affect  the physics of disordered quantum Hall systems [2]. In particular\, we will show how\, in the presence of electr onic disorder\, the cavity can mediate long-range electron hopping via the exchange of a virtual photon\, involving both edge and bulk states. Such an effect produces a breakdown of the topological protection of the intege r quantum Hall effect as demonstrated in recent transport experiments [3]. \n\n[1] F. J. Garcia-Vidal\, C. Ciuti\, T. W. Ebbesen\, Manipulating matte r by strong coupling to vacuum fields\, Science 373\,178 (2021).\n\n[2] C. Ciuti\, Cavity-mediated electron hopping in disordered quantum Hall syste ms\, Phys. Rev. B 104\, 155307 (2021).\n\n[3] F. Appugliese\, J. Enkner\, G. L. Paravicini-Bagliani\, M. Beck\, C. Reichl\, W. Wegscheider\, G. Scal ari\, C. Ciuti\, J. Faist\, Breakdown of the topological protection by cav ity vacuum fields in the integer quantum Hall effect\, preprint arXiv:2107 .14145 (2021)\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-774@lptms.universite-paris-saclay.fr DTSTART:20211117T143000Z DTEND:20211117T143000Z DTSTAMP:20211103T081842Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-lucas-varela-alvarez/ SUMMARY:Soutenance de thèse : Lucas Varela Alvarez - Petit amphi\, bâtime nt Pascal n° 530 - 17 Nov 21 14:30 DESCRIPTION:Systèmes coulombiens en une et deux dimensions : résultats ex acts\npar\n\nLucas Varela Alvarez\n \;\nSoft matter often features cha rged units which interact through Coulomb forces\, the treatment of which is difficult due to their long-range nature. This thesis gives results for three many-body systems where every long-range interaction is included\, without approximations. First\, we study exact results for a one-dimension al electroneutral salt-free suspension made of two fixed colloids and N ne utralizing mobile counterions\, with dielectric jumps at the colloids’ p osition. This includes the partition function\, density profile and pressu re. We find that for any N counterions system there may be like-charge att raction\, unlike when the dielectric is homogeneous in which case N must b e even. Secondly\, we consider the previous system out of equilibrium with in a homogeneous dielectric space\, as a model for the dynamics of two ele ctrical double- layers. Using a combination of exact calculations where po ssible and Brownian dynamics simulations\, we compute the relaxation time towards equilibrium (τ). The parity of N leads to distinctly different dy namics: for N even\, thermal effects are detrimental to relaxation\, incre asing τ\, while they accelerate relaxation for N odd. In the two 1D syste ms we show that in the limit N→∞ at fixed colloid’s charge\, the mea n-field prediction is recovered. Finally\, we analyse exactly the short-di stance effective potential between two “guest” charges immersed in a t wo-dimensional two-component charge-asymmetric plasma composed of positive ly (q1 = +1) and negatively (q2 = −1/2) charged point particles. The res ult is valid in the collapse-free regime\, where the Coulombic coupling (d imensionless inverse temperature) β <\; 4. At high Coulombic coupling β >\; 2\, this model features like-charge attraction.\n \;\n\nJury :\n\nJulien Barré\, Institut Denis Poisson\, rapporteur\n\nAlonso Botero\ , Universidad de Los Andes\, examinateur\n\nAlexei Chepelianskii\, LPS\, e xaminateur\n\nDavid Dean\, LOMA\, rapporteur\n\nBérengère Dubrulle\, SPE C\, examinatrice\n\nYan Levin\, Universidade Federal do Rio Grande do Sul\ , examinateur\n\nGabriel Téllez\, Universidad de Los Andes\, directeur de thèse\n\nEmmanuel Trizac\, LPTMS\, directeur de thèse CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-780@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211123T110000 DTEND;TZID=Europe/Paris:20211123T120000 DTSTAMP:20211117T114530Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-melanie-lebental/ SUMMARY:Seminaire du LPTMS : Mélanie Lebental (LUMIN) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 23 Nov 21 11:00 DESCRIPTION:Quantum chaos and geodesics: towards non-euclidean photonics\nM élanie Lebental (LUMIN)\nOnsite seminar + zoom (Meeting ID: 984 4152 4540 \, Passcode: p5WA0A).\n\nQuantum chaos is a research field dedicated to s emiclassical physics [1\,2]\, i.e. the relationship\nbetween a quantum sys tem and its classical counterpart. The predictions are investigated in\nan y wave system\, namely quantum\, acoustics\, microwaves\, optics\,… Micr olasers are a good platform to implement the predictions of quantum chaos. Reciprocally\, semi-classical physics provides efficient theoretical tool s to optimize photonic devices\, in particular the "trace formula" which d escribes the spectrum as a sum over periodic classical trajectories. I wil l review some of these results [3] and discuss on-going works on bifurcati on theory and the corresponding microlaser experiments.\n\nRecently it bec ame possible to fabricate three-dimensionnal (3D) microlasers with high op tical\nquality by direct laser writing [4]\, in particular curved surface- like microlasers\, leading to\nthe emerging domain of non-Euclidean photon ics. Actually\, the shortest path between\ntwo points within a curved surf ace is not the straight line anymore\, but is called a "geodesic".\nThe co rresponding trace formula should then be a sum over periodic geodesics. We checked this hypothesis with Möbius strip microlasers and provided exper imental and numerical evidences that the laser modes were indeed located a long periodic geodesics [5].\n\n[1] M. Brack and R. K. Bhaduri\, Semiclass ical physics\, Addison-Wesley Publishing Company (1997).\n\n[2] H.-J. Stö ckmann\, Quantum chaos\, an introduction\, Cambridge University Press (199 9).\n\n[3] A. Pascal\, A. Pascal\, S. Bittner\, B. Dietz\, A. Trabattoni\, C. Ulysse\, M. Romanelli\,\nM. Brunel\, J. Zyss\, and M. Lebental\,\nWave s and rays in plano-concave laser cavities\, Part II: a semiclassical appr oach\,\nEuropean Journal of Physics\, vol. 38\, 034011 (2017).\n\n[4] M. A . Guidry\, Y. Song\, C. Lafargue\, R. Sobczyk\, D. Decanini\, S. Bittner\, B. Dietz\,\nL. Huang\, J. Zyss\, A. Grigis\, and M. Lebental\,\nThree-dim ensional micro-billiard lasers: The square pyramid\,\nEurophysics Letters\ , vol. 126\, 64004 (2019).\n\n[5] Yalei Song\, Y. Monceaux\, S. Bittner\, Kimhong Chao\, H. M. Reynoso de la Cruz\,\nC. Lafargue\, D. Decanini\, B. Dietz\, J. Zyss\, A. Grigis\, X. Checoury\, and M. Lebental\,\nMöbius Str ip Microlasers: A Testbed for Non-Euclidean Photonics\nPhys. Rev. Lett. vo l. 127\, 203901 (2021). CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-800@lptms.universite-paris-saclay.fr DTSTART:20211124T110000Z DTEND:20211124T120000Z DTSTAMP:20211117T140337Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-diane-laure-pages/ SUMMARY:Physics-Biology interface seminar: Diane-Laure Pagès - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Nov 21 11:00 DESCRIPTION:Collective amoeboid migration of cancer cell clusters by polari sed jiggling\nDiane-Laure Pagès (Institut Gustave Roussy)\nWinner of the PhysBio2021 best short talk award\n\n\nMigration is a key step in many bio logical processes\, including the metastatic progression of cancers which accounts for most patient’s deaths. As far as we know\, cell locomotion occurs through three distinct mechanisms. In a few words\, single cells ca n migrate via two modes\, mesenchymal (adhesive\, traction-based) or amoeb oid (non-adhesive\, propulsion-based). Cell cohorts are generally led by p rotrusive leaders\, towing the collective through adhesion to the substrat e.\n\nWe have been able to demonstrate the existence of an undescribed mod e of collective migration. We study tumour cell clusters’ migration\, tr ansformed and non-transformed\, in non-adherent microfabricated channels. This collective migration is independent of focal-adhesions and traction b ut is dependent on integrin-mediated friction to the substrate. Moreover\, cell clusters display an actomyosin cortex that is polarised to the rear of clusters\, proportionally to migration speed. Inhibiting ROCK and myosi n activity decreases migration\, while optogenetic activation of RhoA dict ates directionality\, demonstrating that this migration relies on actomyos in contractility [2]. However\, such migration is not driven by a sustaine d cell or myosin flow. Instead\, we observed fluctuating cell and myosin d isplacements that are correlated with clusters’ speed. We then demonstra te analytically that\, together with friction with the substrate and myosi n polarisation\, this behaviour leads to migration. Our results suggest th at cell clusters can use a unique mode of collective migration\, based on “polarised jiggling”\, that may explain the metastatic potential of th ese tumour intermediates. We call this new mode of migration “collective amoeboid migration”\, by analogy with single cell amoeboid migration.\n \n1. Zajac\, O. et al. Tumour spheres with inverted polarity drive the for mation of peritoneal metastases in patients with hypermethylated colorecta l carcinomas. Nat. Cell Biol. 1 (2018). doi:10.1038/s41556-017-0027-6\n\n2 . Pagès\, D.-L. et al. Cell clusters adopt a collective amoeboid mode of migration in confined non-adhesive environments. bioRxiv 2020.05.28.106203 (2020) doi:10.1101/2020.05.28.106203.\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-792@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211130T110000 DTEND;TZID=Europe/Paris:20211130T120000 DTSTAMP:20211128T145232Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrea-de-luca-lptm-4/ SUMMARY:Séminaire du LPTMS : Andrea De Luca (LPTM) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 30 Nov 21 11:00 DESCRIPTION:Universal out-of-equilibrium dynamics of 1D noisy critical quan tum systems\nAndrea de Luca (Laboratoire de Physique Théorique et Modéli sation)\n** ZOOM SEMINAR**  (ID: 965 3800 3966\, Pw: Y8TBFQ).\nWe consid er critical one dimensional quantum systems initially prepared in their gr oundstate and perturbed by a smooth noise coupled to the energy density. B y using conformal field theory\, we deduce a universal description of the out-of-equilibrium dynamics. In particular\, the full time-dependent dist ribution of any 2-pt chiral correlation function can be obtained from solv ing two coupled ordinary stochastic differential equations. In contrast wi th the general expectation of heating\, we demonstrate that the system rea ches a non-trivial and universal stationary state characterized by broad d istributions. As an example\, we analyse the local energy density: while i ts first moment diverges exponentially fast in time\, the stationary distr ibution\, which we derive analytically\, is symmetric around a negative me dian and exhibits a fat tail with 3/2 decay exponent. We obtain a similar result for the entanglement entropy production associated to a given inte rval of size l. The corresponding stationary distribution has a 3/2 right tail for all l\, and converges to a one-sided Levy stable for large l.\nOu r results are benchmarked via analytical and numerical calculations for a chain of non-interacting spinless fermions with excellent agreement. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-797@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211207T110000 DTEND;TZID=Europe/Paris:20211207T120000 DTSTAMP:20211201T155202Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-denis-ullmo-lptms/ SUMMARY:Séminaire du LPTMS : Denis Ullmo (LPTMS) - Petit amphi\, bâtiment Pascal n° 530 - 7 Déc 21 11:00 DESCRIPTION:A Mean Field Game description of pedestrian dynamic\nDenis Ullm o (Laboratoire de Physique Théorique et Modèles Statistiques)\nOnsite se minar + zoom (ID: 962 4404 9550\, PW: 9thN9E).\n\nIn this talk\, I will c onsider the dynamics of crowds at the "operational" level\, which correspo nds to the relatively short time and length scale associated for instance with a single obstacle.  Comparing various model predictions with experim ental data\, I will show that\, contrarily to what is usually assumed in s uch context\, it is necessary to take into account the fact that pedestria n have the capacity to "anticipate" to reproduce even the qualitative prop erties of the experimental data.  Models based on a analogy with granular materials therefore fails drastically\, and even modern models of crowds dynamics including short term (ie up to the next collision) anticipation a re unable to reproduce the essential feature of the experiments.\n\nFurthe rmore\, I will show that a very simple model based on Mean Field Game\, th at can be analyzed through a very elegant connection with the non-linear S chrödinger equation\, is able (actually by construction) to take into acc ount the effects of anticipation of the pedestrians\, and reproduce nicely the important features of the experiment. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-799@lptms.universite-paris-saclay.fr DTSTART:20211208T110000Z DTEND:20211208T120000Z DTSTAMP:20211201T130220Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-raphael-voituriez/ SUMMARY:Physics-Biology interface seminar: Raphaël Voituriez - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Déc 21 11:00 DESCRIPTION:Quantifying memory effects in random search processes\nRaphaël Voituriez (Laboratoire Jean Perrin)\nA general question that arises in ra ndom walk theory is the quantification of space exploration by a random wa lker. A key observable is provided by the first-passage time\, which quan tifies the kinetics of general target search problems\, and as such has a broad range of applications from diffusion limited reactions at the molecu lar scale\, to immune cells patrolling tissues to find antigens\, or large r scale organisms looking for ressources.\n\nI will present asymptotic res ults which enable the determination of the first-passage time statistics to a target site for a wide range of random processes\, and show how these results generalize to non Markovian processes\, which are needed to mod el non Brownian\, complex searchers with memory skills. I will discuss how these results can be used to assess the optimality of general random sear ch processes. An explicit example of cellular system where long range memo ry effects emerge will be given. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-785@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20211214T110000 DTEND;TZID=Europe/Paris:20211214T120000 DTSTAMP:20211207T132617Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marco-tarzia-lptmc-2/ SUMMARY:Séminaire du LPTMS : Marco Tarzia (LPTMC) - Petit amphi\, bâtimen t Pascal n° 530 - 14 Déc 21 11:00 DESCRIPTION:Fully localized and partially delocalized but non-ergodic state s in the tails of critical Erdos-Renyi graphs\nMarco Tarzia (Laboratoire d e Physique Théorique de la Matière Condensée)\nOnsite seminar + zoom (I D: 933 8982 7691\, PW: V75fAY\, link:\nhttps://cnrs.zoom.us/j/93389827691 ?pwd=eGtrLzg0eDJZdGdUR1ZuWEhsRnlhQT09).\n\nIn this talk I will discuss th e spectral properties of the adjacency matrix of critical Erdos-Renyi grap hs\, i.e. when the average degree is of order log N. In a series of recent inspiring papers Alt\, Ducatez\, and Knowles have rigorously shown that t hese systems exhibit a "semilocalized" phase in the tails of the spectrum where the eigenvectors are exponentially localized on a sub-extensive fra ction of nodes with anomalously large degree. We  propose two approximate analytical strategies to analyze this regime based respectively on the si mple "rules of thumb" for localization and ergodicity and on an approximat e treatment of the self-consistent cavity equation for the resolvent. Both approaches suggest that the tails of the spectrum split in two different phases: a fully Anderson localized phase at the spectral edges\, in which the eigenvectors are localized around a unique center\, and an intermediat e partially delocalized but non-ergodic phase\, where the eigenvectors spr ead over many resonant localization centers. In this phase the exponential decay of the effective tunneling amplitudes between the localization cent ers is counterbalanced by the large number of nodes towards which tunnelin g can occur\, and the system exhibits mini-bands in the local spectrum ove r which the Wigner-Dyson statistics establishes. We complement these resul ts by a detailed numerical study of the finite-size scaling behavior of s everal observables that fully supports the theoretical predictions and all ows us to determine the critical properties of the two transitions. Critic al Erdos-Renyi graphs provide a pictorial representation of the Hilbert space of a generic many-body Hamiltonian with short range interaction. In particular we argue that their phase diagram can be mapped onto the out-of -equilibrium phase diagram of the quantum random energy model. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-810@lptms.universite-paris-saclay.fr DTSTART:20220105T110000Z DTEND:20220105T120000Z DTSTAMP:20220104T150026Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-antoine-fruleux/ SUMMARY:Physics-Biology interface seminar: Antoine Fruleux - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 5 Jan 22 11:00 DESCRIPTION:Time persistence as a source of large-scale fluctuations in gro wing tissues\nAntoine Fruleux (LPTMS)\n\nDue to the current health situati on\, this week's seminar will be held online only:\nhttps://cnrs.zoom.us/j /96254507481?pwd=VHd4SzFSUzhXZ2hJOWJ4ajhza2dmdz09\nMeeting ID: 962 5450 74 81\nPasscode: physbi0\n\n\nIn biological tissues\, the space and time vari ations of certain properties appear greatly random. Many recent studies in vestigate the impact of this randomness on the development of tissues. Suc h studies aim\, for example\, at understanding its role in the self-organi zation of tissues or at describing how the cellular responses it induces i mpact the developments of organs. To better understand the role played by random fluctuations during morphogenesis\, a first step is to have a bette r characterization of their properties. Using theoretical modeling\, we pr edicted that the spatial extend of fluctuations is large and results from the combined effects of growth and the fluctuation's time persistence. Thi s prediction\, which generally applies to any expending media\, has strong consequences when considering biological tissues. It notably implies long ranged space correlations\, which tend to give rise to random organ shape s\, in contradiction with the observed robustness of many organ shapes. An explanation for this apparent paradox may be found in the fine tuning of some of the tissue properties to minimize the heterogeneity of organs\, an d we investigated the influence of the tissue's response to the mechanical stress on the organ shape. Our model’s predictions prompted us to analy ze the spectra of fluctuations in growing tissues\, developing a novel app roach that is applicable to geometrically disordered materials. After intr oducing the main predictions of the model\, I will present the experimenta l evidences supporting them in plant tissues. Finally\, I will express the questions raised by our findings. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-791@lptms.universite-paris-saclay.fr DTSTART:20220111T110000Z DTEND:20220111T123000Z DTSTAMP:20220102T183015Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexei-chepelianskii-lps/ SUMMARY:Séminaire du LPTMS: Alexei Chepelianskii (LPS) - Petit amphi\, bâ timent Pascal n° 530 - 11 Jan 22 11:00 DESCRIPTION:Monte Carlo sampling: convergence\, localization transition and optimality\nAlexei Chepelianskii  (Laboratoire de Physique des Solides)\ nOnsite + zoom.\n\nZoom link: https://cnrs.zoom.us/j/96861999262?pwd=bzlk QThNenNyYVdoMXpKUlF0VXloQT09\n\nMeeting ID: 968 6199 9262\nPasscode: 5C7NB W\nAmong random sampling methods\, Markov Chain Monte Carlo algorithms are foremost. From a combination of analytical and numerical approaches\, we study their convergence properties towards the steady state. We show that the deviations from the target steady-state distribution features a locali zation transition as a function of the characteristic length of the attemp ted jumps defining the random walk in a Metropolis scheme. This transition changes drastically the error which is introduced by incomplete convergen ce. Remarkably\, the localization transition occurs for parameters that al so provide the optimal Monte Carlo convergence speed. We show that the rel axation of the error in the localized regime has some similarities with re laxation in a greedy Monte Carlo algorithm where jumps always  occur to l ower energy sites (zero temperature limit). In both cases relaxation is de scribed by a self-similar ansatz instead of being dominated by the  eigen mode with the slowest relaxation rate as in diffusion problems.\n \; CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-790@lptms.universite-paris-saclay.fr DTSTART:20220118T110000Z DTEND:20220118T123000Z DTSTAMP:20220104T165303Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kay-wiese-lpens-2/ SUMMARY:Séminaire du LPTMS: Kay Wiese (LPENS) - Petit amphi\, bâtiment Pa scal n° 530 - 18 Jan 22 11:00 DESCRIPTION:Force correlations in disordered systems and this year’s Nobe l prize in physics\nKay Wiese (Laboratoire de Physique de l’Ecole Normal e Supérieure)\nOnsite + zoom.\n\nZoom link: https://cnrs.zoom.us/j/93731 951533?pwd=VUNMSW04dzFBOUtTWGFqYkFPKzhwdz09\n\nMeeting ID: 937 3195 1533\n Passcode: 4prAN9\nWe study the force-force correlator for disordered elast ic systems. We show that each of the relevant universality classes has its own function. The nicest experiments are for DNA unzipping and Barkhausen noise. For the latter we observe two distinct universality classes\, depe nding on the range of spin interactions. In all cases force-force correlat ions grow linearly at small distances\, while they are bounded at large di stances. As a consequence\, avalanches are anti-correlated\, i.e. reduced in size\, at short distances. Our theory is based on the functional renorm alization group\, which we compare to an alternative approach\, namely mea n-field theory with replica-symmetry breaking. The latter is one of the ke y achievements cited in this year’s Nobel prize for Giorgio Parisi. Anot her involves super mathematics\, which we use to map charge-density waves to loop-erased random walks.\n \; CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-795@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220125T110000 DTEND;TZID=Europe/Paris:20220125T120000 DTSTAMP:20220116T114759Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jacqueline-bloch-c2n/ SUMMARY:Séminaire du LPTMS : Jacqueline Bloch (C2N) - Petit amphi\, bâtim ent Pascal n° 530 - 25 Jan 22 11:00 DESCRIPTION:Using cavity polariton lattices as analog simulators\nJacquelin e Bloch (Center for Nanoscience and Nanotechnology)\nHybrid seminar: onsi te + zoom.\n\nZoom link: https://cnrs.zoom.us/j/97201630000?pwd=MlhLSFBtU kJQcXZDdXZHWkQrRm9hUT09\n\nMeeting ID: 972 0163 0000\nPasscode: 36PnNs\n\n An analog simulator is a synthetic physical system\, which emulates in a c ontrolled way a physical problem. You can get answers about the physical p roblem by directly performing experiments on the simulator. This approach is particularly relevant for quantum problems where computation times grow s exponentially with the system’s size. In the present seminar\, I will present the polariton platform and explain how it is relevant for analog s imulation of many interesting open problems. \n\nCavity polaritons are hy brid exciton-photon quasi-particle emerging from the strong coupling regim e between photons confined in an optical cavity and excitons confined in q uantum wells. They present physical properties reflecting their mixed natu re. From the photon part\, they inherit a small effective mass and can be confined in lattices with typical dimensions of the order of a few microns . Their excitonic part endows them with inter-particle interactions result ing  in a giant Kerr non linearity. Moreover the system is intrinsically open and out of equilibrium because photons constantly leak out from the c avity. Cavity polaritons have been shown to present fascinating properties such as Bose Einstein condensation at elevated temperature\, superfluidit y\, multistability etc [1].\n\nIn the present talk\, I will explain how th e polariton plateform is particularly suitable to realize analog simulatio n of open complex systems and explore fundamental physical phenomena.\n\nI will describe a few recent results of our group: \n\n How do wave local ize in exotic quasi-crystals and how fractality does develop? This physics can be emulated with polariton lattices [2]\n Polariton condensates are out of equilibrium and their phase dynamics has been predicted to obey the celebrated Kardar Parisi Zhang (KPZ) equation. We have been able to revea l experimentally universal KPZ scaling laws in the first order coherence o f a 1D polariton condensate.[3]\n Polariton lattices are also very intere sting for the investigation of topological photonics. In particular\, the ability to drive the system with controlled phases opens a new paradigm fo r non-linear topological photonics. [4] \n\nReferences :\n\n[1]  Ciuti & amp\; I. Carusotto\, Quantum fluids of light\, Rev. Mod. Phys. 85\, 299 (2 013)\n\n[2] V. Goblot et al. Emergence of criticality through a cascade of delocalization transitions in quasiperiodic chains\, Nature Physics 16\, 832 (2020)\n\n[3] Q. Fontaine et al.\, Observation of KPZ universal scalin g in a one-dimensional polariton condensate\, arXiv:2112.09550 (2021)\n\n[ 4] N. Pernet et al.\, N. Pernet\, et al.\, Topological gap solitons in a 1 D non-Hermitian lattice\, arXiv:2101.01038 (to appear 2022) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-805@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220201T110000 DTEND;TZID=Europe/Paris:20220201T120000 DTSTAMP:20220128T141718Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-guilhem-semerjian/ SUMMARY:Séminaire du LPTMS : Guilhem Semerjian (LPENS) - Petit amphi\, bâ timent Pascal n° 530 - 1 Fév 22 11:00 DESCRIPTION:The planted matching problem\nGuilhem Semerjian (Laboratoire de Physique de l'Ecole Normale Supérieure)\nZOOM seminar.\n\nLink: https: //cnrs.zoom.us/j/95169859401?pwd=RUk5UVU4c05aVHRJcko4NnFWVVVldz09\n\nMeeti ng ID: 951 6985 9401\nPasscode: AsC43q\n\nThis talk will present some resu lts\, obtained with statistical mechanics techniques\, on the planted matc hing problem. The latter is an inference problem\, where the goal is to re cover a perfect matching hidden (planted)  in a weighted graph\, the weig hts on the planted and non-planted edges being drawn with two different di stributions.\nJoint work with Gabriele Sicuro and Lenka Zdeborova. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-802@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220208T110000 DTEND;TZID=Europe/Paris:20220208T120000 DTSTAMP:20220203T090915Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-aurelien-grabsch-lptmc/ SUMMARY:Séminaire du LPTMS : Aurelien Grabsch (LPTMC) - Petit amphi\, bât iment Pascal n° 530 - 8 Fév 22 11:00 DESCRIPTION:Generalised Density Profiles in Single-File Systems\nAurélien Grabsch (Laboratoire de Physique Théorique de la Matière Condensée)\nHy brid seminar: onsite seminar + zoom.\n\n\nLink: https://cnrs.zoom.us/j/98 484104034?pwd=bStnaUpSZFJjQTRuL2c4WmxoMDVaUT09\n\nMeeting ID: 984 8410 403 4\nPasscode: tU424R\n\n\n\nSingle-file transport\, where particles diffuse in narrow channels while not overtaking each other\, is a fundamental mod el for the tracer subdiffusion observed in confined systems\, such as zeol ites or carbon nanotubes. This anomalous behavior originates from strong b ath-tracer correlations in 1D\, which we characterise in this talk through Generalised Density Profiles (GDPs). These GDPs have however remained elu sive\, because they involve an infinite hierarchy of equations. Here\, for the Symmetric Exclusion Process\, a paradigmatic model of single-file dif fusion\, we break the hierarchy and unveil a closed equation satisfied by these correlations\, which we solve. Beyond quantifying the correlations\, the central role of this equation as a novel tool for interacting particl e systems will be further demonstrated by showing that it applies to out-o f equilibrium situations\, other observables and other representative sing le-file systems.\n\nRefs:\n\n* Generalized Correlation Profiles in Single- File Systems\nAlexis Poncet\, Aurélien Grabsch\, Pierre Illien\, Olivier Bénichou\nPhys. Rev. Lett. 127\, 220601 (2021)\, arXiv:2103.13083\n* Clos ing and Solving the Hierarchy for Large Deviations and Spatial Correlation s in Single-File Diffusion\nAurélien Grabsch\, Alexis Poncet\, Pierre Riz kallah\, Pierre Illien\, Olivier Bénichou\narXiv:2110.09269 CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-804@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220215T110000 DTEND;TZID=Europe/Paris:20220215T120000 DTSTAMP:20220208T133906Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-adam-nahum-lpens/ SUMMARY:Séminaire du LPTMS : Adam Nahum (LPENS) - Petit amphi\, bâtiment Pascal n° 530 - 15 Fév 22 11:00 DESCRIPTION:Quantum dynamics with an observer: the measurement phase transi tion\nAdam Nahum (Laboratoire de Physique de l’Ecole Normale Supérieure )\nOnsite seminar + zoom.\n\nZoom link:\nhttps://cnrs.zoom.us/j/9228360542 9?pwd=ZTRuWmR4T0dHVWh2M0VRUzhrc2p6QT09\n\nMeeting ID: 922 8360 5429\nPassc ode: vv58du\n\n\nIn the quantum world\, measurements inevitably affect the state of a system\, via wavefunction collapse. This means that the dynami cs of a system which is continually being monitored by an observer is fund amentally different from the dynamics of a closed system. In particular\, for a spatially extended system\, local measurements of the degrees of fre edom can “compete" with chaotic dynamics: while chaotic dynamics tends t o produce complex\, entangled quantum wavefunctions\, local measurements t end to collapse the wavefunction into something simpler. I will describe h ow this leads to a dynamical phase transition between a weak monitoring ph ase\, where the state is complex and entangled\, and a strong monitoring p hase\, where the state is simple and “classical”. I will sketch the re levance of this transition to the classical simulation of quantum dynamics \, and some theoretical approaches to understanding the transition. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-801@lptms.universite-paris-saclay.fr DTSTART:20220216T110000Z DTEND:20220216T120000Z DTSTAMP:20220211T081748Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jennifer-mcmanus/ SUMMARY:Physics-Biology interface seminar: Jennifer McManus - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Fév 22 11:00 DESCRIPTION:Understanding protein phase transitions for globular\, membrane and de novo proteins\nJennifer McManus (University of Bristol)\n\nProtein phase transitions in biology are associated with disease pathogenesis\, f or example in cataract disease or sickle cell anaemia\, but they also occu r as part of normal biological processes\, such as liquid-liquid phase sep aration in cells. While protein phase behaviour has been understood from a physics perspective for globular proteins for some time\, how we can appl y what we already know to biomolecular condensation\, or the phase transit ions of other protein types is less clear. In my talk\, I’ll briefly rev iew what we understand about the phase transitions of globular proteins an d then present recent results on the phase behaviour of membrane proteins and the rational design of de novo proteins to undergo liquid-liquid phase separation in cells. I’ll highlight what common features exist between these different protein types and how this might be important for biomolec ular condensation in cells.\n\nBio\nJennifer McManus completed her BSc and PhD degrees in Chemistry at University College Dublin. Following postdoct oral appointments at the University of Fribourg in Switzerland and the Mas sachusetts Institute of Technology\, she established the Soft Matter and B iophysical Chemistry research group at Maynooth University in Ireland as a Science Foundation Ireland Stokes Lecturer. She was promoted to Associate Professor in 2016 and served as Head of Department between 2017 and 2020. She moved to the School of Physics at the University of Bristol in Februa ry 2020. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-814@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220222T110000 DTEND;TZID=Europe/Paris:20220222T120000 DTSTAMP:20220210T105253Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-daniel-cabra-laplata/ SUMMARY:Séminaire du LPTMS : Daniel Cabra (La Plata) - Petit amphi\, bât iment Pascal n° 530 - 22 Fév 22 11:00 DESCRIPTION:Multiferroics: Lattice assisted magneto-electric coupling\nDani el Cabra (Universidad Nacional de La Plata)\nHybrid seminar: onsite + zoom .\n\n\nZoom Link: https://cnrs.zoom.us/j/97529623199?pwd=Tm9tLy8vUUZDY2tq QmpNQnZFRTlqdz09\n\nMeeting ID: 975 2962 3199\nPasscode: 1kCW7x\n\n\nWe pr opose a microscopic magneto-electric model in which the coupling between s pins\nand electric dipoles is mediated by lattice distortions. The magnet ic sector is described\nby a Heisenberg model coupled directly to the latt ice via a standard spin-Peierls term and\nindirectly to the electric dipo le variables via the distortion of the surrounding electronic clouds.\nEl ectric dipoles are described by Ising variables for simplicity. We show t hat the effective\nmagneto-electric coupling which arises due to the inter connecting lattice deformations is\nquite efficient in one-dimensional ar rays. More precisely\, we show using bosonization and\nextensive DMRG nume rical simulations that by increasing the magnetic field above the spin\nP eierls gap\, a massive polarization switch-off occurs due to the prolifer ation of soliton pairs.\nIntroducing further neighbors couplings and singl e ion anisotropy\, the system also shows the\n"uudd" (or so-called antip hase) magnetic ordering observed in several type II multiferroic materials .\nWe also discuss recent results for a two-dimensional generalization.\n CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-806@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220308T110000 DTEND;TZID=Europe/Paris:20220308T120000 DTSTAMP:20220301T175930Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-lorenzo-piroli-lpens/ SUMMARY:Séminaire du LPTMS : Lorenzo Piroli (LPENS) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Mar 22 11:00 DESCRIPTION:Synthetic models for quantum many-body physics out of equilibri um\nLorenzo Piroli (Laboratoire de Physique de l’Ecole Normale Supérieu re)\nOnsite seminar + zoom.\n\nZoom link:\nhttps://cnrs.zoom.us/j/91247177 739?pwd=bE9GZTFQaGFKTzNZbDZqbFk2eG5UQT09\n\nMeeting ID: 912 4717 7739\nPas scode: rxVCY0\n\n\nIn the past decade a great deal of progress has been ma de in the study of many-body systems out of equilibrium\, where certain in tegrable models have played a significant role in our understanding of spe cific but prototypical problems. Even in these cases\, however\, the full relaxation dynamics has proven to be hard to tackle in the presence of int eractions\, both analytically and numerically. In this talk\, I will discu ss how analytically tractable systems may be obtained by considering 1D “quantum circuit’’ toy models for the many-body dynamics\, allowing for analytic solutions even in the absence of conservation laws (i.e. inte grability). I will focus on a class of chaotic “dual-unitary” quantum circuits\, and certain integrable quantum cellular automata\, showing that in both cases the dynamics of correlation functions and entanglement can be described exactly. Our approach is based on a representation of the eff ect of the global evolution on finite subsystems in terms of tensor networ ks\, which is applicable even beyond the exactly solvable cases presented. I will conclude by discussing how related ideas may lead to the construct ion of more general solvable dynamics beyond integrability. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-807@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220315T110000 DTEND;TZID=Europe/Paris:20220315T120000 DTSTAMP:20220309T083519Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-louise-budzynski-polito/ SUMMARY:Séminaire du LPTMS : Louise Budzynski (DISAT) - Grand amphi\, bâ timent Pascal n° 530 - 15 Mar 22 11:00 DESCRIPTION:The closest vector problem and the spin glass model with extern al fields for lossy compression\nLouise Budzynski (Department of Applied S cience and Technology of Politecnico di Torino)\nHybrid seminar: onsite + zoom.\n\nZoom link: https://cnrs.zoom.us/j/96894507041?pwd=TVBYWU94UlJ5WUl DSENxZkljSFRvdz09\nMeeting ID: 968 9450 7041\nPasscode: PwEm1X\n\nWe consi der a high-dimensional random constrained optimization problem in which a set of binary variables is subjected to a linear system of equations. The cost function is a simple linear cost\, measuring the Hamming distance wit h respect to a reference configuration. Despite its apparent simplicity\, this problem exhibits a rich phenomenology.\nWe show that different situat ions arise depending on the random ensemble of linear systems. When each v ariable is involved in at most two linear constraints\, we show that the p roblem can be partially solved analytically\, in particular we show that u pon convergence\, the zero-temperature limit of the cavity equations retur ns the optimal solution.\nWe then study the geometrical properties of more general random ensembles. In particular we observe a range in the density of constraints at which the systems enters a glassy phase where the cost function has many minima.\nInterestingly\, the algorithmic performances ar e only sensitive to a further phase transition affecting the structure of configuration allowed by the linear constraints.\nWe also extend our resul ts to variables belonging to GF(q)\, the Galois Field of order q. We show that increasing the value of q allows to achieve a better optimum\, which is confirmed by the Replica Symmetric cavity method predictions. \n CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-817@lptms.universite-paris-saclay.fr DTSTART:20220316T110000Z DTEND:20220316T120000Z DTSTAMP:20220221T095253Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-ram-adar/ SUMMARY:Physics-Biology interface seminar: Ram Adar - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Mar 22 11:00 DESCRIPTION:Active-gel Theory for Multicellular Migration in the Extra-cell ular Matrix\nRam Adar (Collège de France)\nWe formulate an active-gel the ory for multicellular migration in the extracellular\nmatrix (ECM). The ce lls are modeled as an active\, polar solvent\, and the\nECM as a viscoelas tic solid. Our theory enables to analyze the dynamic reciprocity\nbetween the migrating cells and their environment in terms of distinct relative fo rces\nand alignment mechanisms. We analyze the linear stability of polar c ells migrating\nhomogeneously in the ECM. Our theory predicts that\, as a consequence of cell-matrix\nalignment\, contractile cells migrate homogene ously for small wave vectors\, while\nsufficiently extensile cells migrate in domains. Homogeneous cell migration of both\nextensile and contractile cells may be unstable for larger wave vectors\, due to active\nforces and the alignment of cells with their concentration gradient. These mechanism s\nare stabilized by cellular alignment to the migration flow and matrix s tiffness. They\nare expected to be suppressed entirely for rigid matrices with elastic moduli of order\n10 kPa. Our theory should be useful in analy zing multicellular migration and ECM\npatterning at the mesoscopic scale. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-811@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220322T110000 DTEND;TZID=Europe/Paris:20220322T120000 DTSTAMP:20220315T145957Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-scott-robertson-lcf/ SUMMARY:Séminaire du LPTMS : Scott Robertson (LCF) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 22 Mar 22 11:00 DESCRIPTION:Analogue preheating in a 1D condensate\nScott Robertson (Labora toire Charles Fabry)\n\nHybrid seminar: onsite + zoom.\n\nZoom link: https ://cnrs.zoom.us/j/91374371715?pwd=U3N3VjE2UTlFbmlseVBId0pTNEVEZz09\nMeetin g ID: 913 7437 1715\nPasscode: K8BYvu\n\n\nThe Analogue Gravity program ha s had considerable success recently\, with ultracold gases playing a parti cularly prominent role as a system in which quantum aspects of field theor y in curved spacetime can be explored. In this talk\, I will present the analogy between a modulated 1D condensate and the preheating stage of cosm ology\, whereby a large number of quasiparticle pairs are excited out of v acuum. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-809@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220329T110000 DTEND;TZID=Europe/Paris:20220329T120000 DTSTAMP:20220317T123519Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-fabian-essler-university-of-oxford/ SUMMARY:Séminaire du LPTMS : Fabian Essler (Oxford) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Mar 22 11:00 DESCRIPTION:Integrability meets Perturbation Theory: GHD from BBGKY\nFabian Essler (University of Oxford)\n\nHybrid Seminar: onsite + zoom.\n\nZoom l ink: https://cnrs.zoom.us/j/93987357933?pwd=Q01rZ3pZaU5uVnYzZTAvN1duZUlTZz 09\nMeeting ID: 939 8735 7933\nPasscode: XP27pW\n\nStandard approaches to non-equilibrium dynamics in many-particle quantum systems such as the Quan tum Boltzmann equation are based on perturbative truncations of the BBGKY hierarchy. In contrast\, integrable systems (in the Euler scaling limit) a re described by the recently developed theory of Generalised Hydrodynamics . I show how the two viewpoints can be explicitly related by developing a perturbative approach to integrability. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-808@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220405T110000 DTEND;TZID=Europe/Paris:20220405T120000 DTSTAMP:20220329T082211Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-tomaz-prosen-lubiana/ SUMMARY:Séminaire du LPTMS : Tomaž Prosen (Ljubljana University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 5 Avr 22 11:00 DESCRIPTION:Random Matrix Spectral Fuctuations in Quantum Lattice Systems\n Tomaž Prosen (University of Ljubljana)\n\nHybrid seminar: onsite + zoom.\ nZoom link: https://cnrs.zoom.us/j/97843053392?pwd=N2NYSUdsRFlvb1FpcVdtQU5 aTmpSdz09\nMeeting ID: 978 4305 3392\nPasscode: 0X7Axi\n\n\nI will discuss the problem of unreasobable effectivenes of random matrix theory for desc ription of spectral fluctuations in extended quantum lattice systems. A cl ass of interacting spin systems has been recently identified where the spe ctral form factor is proven to match with gaussian or circular ensembles o f random matrix theory. The key ideas of novel methodology needed in the p roofs will be discussed which are very different than the standard periodi c-orbit based methods in quantum chaos of few body semiclassical systems.\ n\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-813@lptms.universite-paris-saclay.fr DTSTART:20220408T093000Z DTEND:20220408T133000Z DTSTAMP:20220311T123259Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-hdr-le onardo-mazza/ SUMMARY:Soutenance HDR: Leonardo Mazza - Grand amphi\, bâtiment Pascal n° 530 - 8 Avr 22 09:30 DESCRIPTION:Topological matter and out-of-equilibrium physics in cold-atom setups\nLeonardo Mazza (LPTMS)\nThe study of ultra-cold gases is currently offering a new vision of many-body quantum physics. In this seminar I wil l briefly overview my recent contributions to the field\, focusing on topo logical physics and out-of-equilibrium dynamics.\nIn the first part\, moti vated by the studies on the quantum Hall effect and Chern insulators with cold atoms\, I will discuss my recent contributions on the fractional stat istics of the quasiholes of several paradigmatic states\, with a specific focus on Laughlin and Halperin wavefunctions. The goal is to show that it is possible to extract information on the statistics using only density-pr ofile measurements and without resorting in any way to interference scheme s.\nIn the second part of the talk I will discuss my contributions to the field of out-of-equilibrium dynamics of correlated quantum gases\, focusin g on the effect of two-body losses in one-dimensional setups. Motivated by recent experiments\, I will show that losses can induced intriguing trans ient dynamics and even stabilize entangled stationary states. The strongly -dissipative limit\, also known as quantum Zeno limit\, lends itself to an insightful analytical description in terms of appropriate rate equations. \n \;\n\nJury : Isabelle Bouchoule (Institut d'Optique)\, Nigel R. Coo per (University of Cambridge)\, Mark O. Goerbig (LPS Orsay)\, Anna Minguzz i (LPMMC Grenoble)\, Sylvain Nascimbene (LKB\, Collège de France)\, Tomma so Roscilde (ENS Lyon) CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-812@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220412T110000 DTEND;TZID=Europe/Paris:20220412T120000 DTSTAMP:20220402T175419Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-christophe-texier-lptms/ SUMMARY:Séminaire du LPTMS : Christophe Texier (LPTMS) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Avr 22 11:00 DESCRIPTION:Exponential functional of the matrix Brownian motion: matrix Du fresne identity and Wigner-Smith time delay matrix\nChristophe Texier  (L PTMS)\n\nHybrid seminar: onsite + zoom.\nZoom link: https://cnrs.zoom.us/j /91529089336?pwd=SlZYYnRNYjJBNjFHMVZ6YlA3WWl5dz09\nMeeting ID: 915 2908 93 36\nPasscode: msUnp7\n\nExponential functionals of the Brownian motion app ear in many different contexts (classical diffusion in random media\, quan tum scattering\, finance\,...). I will discuss a recent generalization to the case of matrix Brownian motion. This problem has a natural motivation within the study of quantum scattering on a disordered wire with several c onducting channels. I will show that the Wigner-Smith time delay matrix\, a fundamental matrix in quantum scattering encoding several characteristic time scales\, can be represented as an exponential functional of the matr ix BM.\nThe Dufresne identity is an interesting identity in law for expone ntial functionals of the BM\, providing the distribution of a perpetuity i n risk theory. Its matrix generalization can be related to the distributio n of the Wigner-Smith matrix for a semi-infinite disordered multichannel w ire.\n\nReference:\nAurélien Grabsch &\; Christophe Texier\, Wigner-Sm ith matrix\, exponential functional of the matrix Brownian motion and matr ix Dufresne identity\, J. Phys. A: Math. Theor. 53\, 425003 (2020)\n\n&nbs p\;\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-825@lptms.universite-paris-saclay.fr DTSTART:20220413T113000Z DTEND:20220413T123000Z DTSTAMP:20220413T083408Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-anne-virgine-salsac/ SUMMARY:Physics-Biology interface seminar: Anne-Virgine Salsac - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Avr 22 11:3 0 DESCRIPTION:Fluid structure interaction of a microcapsule in flow: applicat ion to the characterization\, enrichment and sorting of capsule suspension s\nAnne-Virgine Salsac (Université de Technologie de Compiègne)\nEncapsu lation consists in enclosing an internal medium in a solid semi-permeable membrane to protect it and control the exchanges with the environment. Bei ng at the source of innovative applications in the fields of biotechnologi es\, pharmacology\, or food industry\, capsules offer tremendous potential in the process engineering world. But scientific challenges remain to be met\, such as finding the optimal compromise between payload and membrane thickness\, characterizing the membrane resistance and controlling the mom ent of rupture.\nWe will explore the challenges to use deformable liquid-c ore capsules of micrometric size to efficiently transport active material\ , with a primary focus on health-related applications. Being used suspende d in a carrying fluid in flow\, microcapsules constitute a formidable prob lem of complex fluid-structure interactions. I will briefly present how th e three-dimensional capsule-flow interactions may be modeled and how these sophisticated numerical models can dialogue with microfluidic experimenta tions to produce innovative techniques to characterize the mechanical prop erties of deformable capsules\, sort them upon their rigidity or enrich su spensions.\n\nBiosketch\nAfter graduating from University of California Sa n Diego (USA) in 2005 with a PhD in Biofluids\, Anne-Virginie Salsac was r ecruited as Lecturer in the Department of Mechanical Engineering of Univer sity College London (UK). In 2007\, she became Researcher at the CNRS (Cen tre National de Recherche Scientifique). She joined the Biomechanics and B ioengineering Laboratory in Compiègne (France)\, where she conducts origi nal experimental and numerical modeling of blood flows\, from the microcir culation to the hemodynamics in large vessels. In particular\, she focuses on the behavior of bioartificial or natural capsules in micro-channels an d on the influence of innovative vascular therapeutic techniques on blood flow.\nShe is at the head of the Biological Fluid Structure Interaction re search group since 2011\, and is Visiting Professor at the Institute of Bi oengineering\, Queen Mary University of London (England) since 2014. She h as been awarded various prices\, including the CNRS bronze medal\, Trophé es des Femmes en Or in 2015 and Medal of the National Order of Merit in 20 16\, in recognition for her pluridisciplinary work. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-820@lptms.universite-paris-saclay.fr DTSTART:20220414T093000Z DTEND:20220414T123000Z DTSTAMP:20220411T152349Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/ipht-lptms-days-q uantum-day/ SUMMARY:IPhT/LPTMS Days: Quantum Day - Petit amphi\, bâtiment Pascal n° 5 30 - 14 Avr 22 09:30 DESCRIPTION:\nThe IPhT/LPTMS days: Quantum Day at the "Petit amphi" at Pasc al Building (9h15 - 12h30)\n\n9h15 : Opening speech by the directors\n9h30 : Leonardo Mazza (LPTMS)\nFractional spin and fractional statistics of qu antum Hall quasiparticles from density profiles\nWe present a study of the quasiparticle excitations that appear in the fractional quantum Hall effe ct. Focusing on several examples\, including the Laughlin state\, the Halp erin 221 state and the Moore-Read state\, we show that the density profile of the liquid hosting them contains information about their fractional sp in and statistics. In particular\, by studying the second moment of the so -called depletion density\, it is possible to compute the fractional spin of the quasiparticles\, and using the spin-statistics theorem to compute t heir fractional statistics. The possibility of accessing these properties without using interferometric schemes may open the way to novel experiment s using for instance ultra-cold gases or fluids of light.\n\n10h : Cristin a Bena (IPHT)\nMajorana and other boundary modes from impurity states via T-matrix\nWe provide a new and exact formalism to describe the formation o f end\, edge or surface states through the evolution of impurity-induced s tates. We propose a general algorithm that consists of finding the impurit y states via the T-matrix formalism and showing that they evolve into boun dary modes when the impurity potential goes to infinity. We apply this tec hnique to obtain Majorana states\, topological insulator edges states and graphene edges states. We also show that this approach provides us with a new direct and non-numerical technique to obtain the surface Green's funct ions for three-dimensional systems and we apply it to Weyl semimetals. \n \n10h30 : Coffee Break\n11h : Dmitry Petrov (LPTMS)\nBeyond-mean-field eff ects in quantum gases\n11h30 : Jean-Daniel Bancal (IPHT)\nDevice-independe nt quantum key distribution\n12h : Mikhail Zvonarev (LPTMS)\nMobile impuri ty in one dimension\n12h30 : Lunch buffet CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-821@lptms.universite-paris-saclay.fr DTSTART:20220420T093000Z DTEND:20220420T123000Z DTSTAMP:20220411T152512Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/ipht-lptms-days-s tatphys-day/ SUMMARY:IPhT/LPTMS Days: StatPhys Day - - 20 Avr 22 09:30 DESCRIPTION:The  IPhT/LPTMS Days: StatPhys Day at Bloch amphi at IPHT buil ding  (9h30 - 12h30)\nSpeakers:\n\nCecile Monthus (IPHT)\n\nSilvain Ribau lt (IPHT)\n\nMarc Barthelemi (IPHT)\n\nSilvio Franz (LPTMS)\n\nValentina R os (LPTMS) CATEGORIES:seminars END:VEVENT BEGIN:VEVENT UID:0-816@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220510T110000 DTEND;TZID=Europe/Paris:20220510T120000 DTSTAMP:20220428T120229Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-tommaso-roscilde-ens-lyon/ SUMMARY:Séminaire du LPTMS : Tommaso Roscilde (ENS Lyon) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Mai 22 11:00 DESCRIPTION:Many-body entanglement: a look from the tower (of states)\nTomm aso Roscilde (Ecole Normale Supérieure de Lyon)\n\nHybrid seminar: onsite + zoom.\n\nhttps://cnrs.zoom.us/j/93722201378?pwd=c2hMZDE5N09GQlBqSkc0RFh vYllWdz09\nMeeting ID: 937 2220 1378\nPasscode: 9xJxgQ\n\nThe non-equilibr ium dynamics of many-body quantum systems is among the most effective mech anisms for the production of entanglement. The general paradigm of entangl ement dynamics involves the propagation of finite-momentum quasi-particle excitations\, which propagate ballistically and generate correlations with in a causal cone around every point in space. In fact this picture is rath er incomplete\, as it neglects the existence of zero-momentum excitations: such excitations are dominant at low energy in systems breaking spontaneo usly a continuous symmetry\, and they form the so-called Anderson tower of states. In this talk I will discuss how the low-energy tower of states in spin models can be effectively described within an approximate separation of variables between finite- and zero-momentum excitations\; and how such states are responsible for the dramatic entanglement dynamics observed in U(1) symmetric models -- most importantly\, dipolar spin systems realized in Rydberg-atom arrays -- which develop a cascade of multipartite entangl ed states completely missed by any quasiparticle picture. \n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-827@lptms.universite-paris-saclay.fr DTSTART:20220511T110000Z DTEND:20220511T120000Z DTSTAMP:20220425T141340Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-silvia-grigolon/ SUMMARY:Physics-Biology interface seminar: Silvia Grigolon - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 11 Mai 22 11:00 DESCRIPTION:Robustness in miRNA-based circuits\nSilvia Grigolon (Laboratoir e Jean Perrin\, Sorbonne U.)\nPhenotypic differentiation often relies on b imodal distributions of gene expression levels\, which can normally be ach ieved by different molecular mechanisms. During the past decades microRNAs \, small noncoding RNA molecules\, were found to downregulate the expressi on of preferred mRNA targets by sequestering and successively degrading th em\, thus influencing the level of gene expression. In this talk\, I will show how miRNAs play an important role in filtering noise in gene expressi on. Starting from purely intrinsic noise\, I will talk about how this can be buffered by miRNAs\, which yet become apparently inefficient in the pre sence of sources of extrinsic noise. I will then theoretically address the question on how microRNA-mediated regulation can induce the appearance of bimodal phenotypes. Our findings show that the presence of extrinsic nois e favours bimodal distributions. This suggests a simple mechanism for obta ining bimodal populations where the presence of extrinsic noise relaxes th e requirements on parameters fine tuning. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-823@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220517T110000 DTEND;TZID=Europe/Paris:20220517T120000 DTSTAMP:20220502T115122Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-pietro-rotondo-infn-milano/ SUMMARY:Séminaire du LPTMS : Pietro Rotondo (Infn Milano) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Mai 22 11:00 DESCRIPTION:Universal mean field upper bound for the generalisation gap of deep neural networks\n Pietro Rotondo (Infn Milano)\n\nHybrid seminar: ons ite + zoom.\n\nhttps://cnrs.zoom.us/j/92485497120?pwd=c0dBZVkxT2xmUzNNZDhZ bU9lM2dsQT09\nMeeting ID: 924 8549 7120\nPasscode: dSQ0B2\n\n\nModern deep neural networks (DNNs) represent a formidable challenge for theorists: ac cording to the commonly accepted probabilistic framework that describes th eir performance\, these architectures should overfit due to the huge numbe r of parameters to train\, but in practice they do not. Here we employ res ults from replica mean field theory to compute the generalisation gap of m achine learning models with quenched features\, in the teacher-student sce nario and for regression problems with quadratic loss function. Notably\, this framework includes the case of DNNs where the last layer is optimised given a specific realisation of the remaining weights. We show how these results – combined with ideas from statistical learning theory – provi de a stringent asymptotic upper bound on the generalisation gap of fully t rained DNN as a function of the size of the dataset P. In particular\, in the limit of large P and Nout (where Nout is the size of the last layer) a nd Nout ≪ P \, the generalisation gap approaches zero faster than 2Nout/ P\, for any choice of both architecture and teacher function. Notably\, th is result greatly improves existing bounds from statistical learning theor y. We test our predictions on a broad range of architectures\, from toy fu lly-connected neural networks with few hidden layers to state-of-the-art d eep convolutional neural networks.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-822@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220524T110000 DTEND;TZID=Europe/Paris:20220524T120000 DTSTAMP:20220524T074657Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-remi-monasson-ens/ SUMMARY:Séminaire du LPTMS : Remi Monasson (CNRS et ENS) - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Mai 22 11:00 DESCRIPTION:Restricted Boltzmann Machines revisited: from landscape to tran sition path sampling\nRemi Monasson (Cnrs et Ecole Normale Supérieure)\n\ nHybrid seminar: onsite + zoom.\n\n\nhttps://cnrs.zoom.us/j/93762609075?pw d=eXhrNUQ3clhDNGx6dHpBQjVIdXVkZz09\nMeeting ID: 937 6260 9075\nPasscode: p 5SKcT\n\n\n\n\nRestricted Boltzmann Machines (RBM) were introduced thirty- five years ago in the context of unsupervised learning of data distributio ns. The simplicity of their architecture make RBM both potentially interp retable and amenable to analytical treatment with statistical physics meth ods. I will show how these methods can help understand "good" operation re gimes for RBMs\, in particular how to stack RBMs to speed up sampling\, an idea first introduced under the name of deep tempering by Bengio and coll aborators. I will also briefly discuss recent applications to transition p ath sampling for protein design. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-803@lptms.universite-paris-saclay.fr DTSTART:20220525T110000Z DTEND:20220525T120000Z DTSTAMP:20220511T094412Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-davide-michieletto/ SUMMARY:Physics-Biology interface seminar: Davide Michieletto - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 25 Mai 22 11:00 DESCRIPTION:Topologically Active Polymers\nDavide Michieletto (University o f Edinburgh)\nPolymer physics successfully describes most of the polymeri c materials that we encounter everyday. In spite of this\, it heavily re lies on the assumption that polymers do not change topology (or architect ure) in time or that\, if they do alter their morphology\, they do so in e quilibrium. This assumption spectacularly fails for DNA in vivo\, which is constantly topologically re-arranged by ATP-consuming proteins within th e cell nucleus.\nInspired by this\, here I will discuss some non-equilibr ium complex fluids in which DNA topology is selectively altered in time by proteins. I argue that solutions of "topologically active” polymers ca n display unconventional viscoelastic behaviours and can be conveniently  realised using solutions of DNA functionalised by certain families of vit ally important proteins.\nMore specifically\, in this talk I will present some results using both theory/simulations and experiments on the microrh eology of entangled DNA undergoing digestion by restriction enzymes and l igation by ligase. I will try to convince you that that we can harness the se topological processes to design complex fluids with exotic and time-var ying viscoelastic behaviours. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-819@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220531T110000 DTEND;TZID=Europe/Paris:20220531T120000 DTSTAMP:20220519T071526Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kirone-mallick-ipht-2/ SUMMARY:Séminaire du LPTMS : Kirone Mallick (IPhT) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 31 Mai 22 11:00 DESCRIPTION:An exact solution of the macroscopic fluctuation theory\nKirone Mallick (Institut de Physique Théorique)\nHybrid seminar: onsite + zoom. \nhttps://cnrs.zoom.us/j/98365274646?pwd=eFhoaENWWHM5YmRYZXBhWkNXMjhJUT09\ nMeeting ID: 983 6527 4646\nPasscode: y6T8vv\n\nInteracting diffusive part icle systems are considered as paradigms for non-equilibrium statistical p hysics. Their macroscopic behaviour follows a variational principle\, prop osed by G. Jona-Lasinio and his collaborators\, known as the Macroscopic F luctuation Theory (MFT). Optimal fluctuations far from equilibrium are thu s determined at a coarse-grained scale by two coupled non-linear hydrodyna mic equations.However\, for a long time\, only stationary or perturbative solutions of the MFT equations were known.\n\nIn this talk\, we shall show that\, for the exclusion process\, the MFT equations are classically inte grable and can be solved with the help of the inverse scattering method\, originally used to study solitons in the KdV or the NLS equations. Thi s exact solution will allow us to calculate the large deviations of the current and the optimal profiles that generates a given fluctuation\, bot h at initial and final times. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-828@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220607T113000 DTEND;TZID=Europe/Paris:20220607T123000 DTSTAMP:20220527T164120Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-joachim-krug-cologne/ SUMMARY:Séminaire du LPTMS : Joachim Krug (Uni Cologne) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Juin 22 11:30 DESCRIPTION:Discrete and continuous geometry of fitness landscapes\nJoachim Krug (University of Cologne)\nHybrid: onsite seminar + zoom.\n\nhttps://c nrs.zoom.us/j/97115217092?pwd=VWRlT3MvV1NIRmlraXZ4Q3BpYzVvZz09\nMeeting ID : 971 1521 7092\nPasscode: UKZV8d\n\nDarwinian evolution is driven by rand om mutations and selection that favors genotypes with high fitness. Genoty pes are commonly represented by bitstrings of length L. An overview of pos sible evolutionary trajectories is then provided by the acyclic oriented L -cube graph {0\,1}^L with nodes labeled by genotypes and edges directed to wards higher fitness. The same formal description applies to energy landsc apes of spin systems. Some notion of curvature is necessary for a more com plete analysis. For this purpose\, Beerenwinkel\, Pachter and Sturmfels (S tatistica Sinice\, 2007) have introduced triangulations of the continuous cube [0\,1]^L that are induced by the landscape. Points in the continuous cube are vectors of allele frequencies\, corresponding to the average magn etization of individual spins. The talk focuses on the constraints imposed by the triangulations on the geometric pattern of fitness peaks (metastab le states)\, and is based on joint work with Kristina Crona\, Daniel Oros and Malvika Srivastava. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-815@lptms.universite-paris-saclay.fr DTSTART:20220608T110000Z DTEND:20220608T120000Z DTSTAMP:20220524T200634Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-bertrand-benazeraf/ SUMMARY:Physics-Biology interface seminar: Bertrand Benazeraf - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Juin 22 11:00 DESCRIPTION:From stem cells heterogeneity to tissue morphogenesis during ve rtebrate embryo development.\nBertrand Benazeraf (U. Paul Sabatier\, Toulo use)\nUnderstanding the formation of embryonic shapes is one of the fundam ental themes in developmental biology and a significant challenge to bette r understand congenital diseases. Posterior axis elongation is the morphog enetic event that produces the typical head-to-tail elongated body shape o f vertebrate embryos. While the mechanisms of tissue elongation have mostl y been studied in separate tissue types\, the principles allowing for the coordination of elongation between tissues remain largely unknown. By usin g a combination of classical embryological techniques\, live imaging of bi rd embryos\, image analysis\, and mathematical modeling\, we are currently exploring different aspects of axis elongation at the multi-tissue scale. To better understand the coordination between cell specification and morp hogenesis we are also studying neuro-mesodermal progenitors\, a stem cell population located in the embryonic tail. Our results suggest that spatial cell-to-cell heterogeneity within progenitor cells is playing a key role in the robustness of multi-tissue morphogenetic processes. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-818@lptms.universite-paris-saclay.fr DTSTART:20220610T140000Z DTEND:20220610T173000Z DTSTAMP:20220601T093558Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-francesco-mori/ SUMMARY:Soutenance de thèse: Francesco Mori - Petit amphi\, bâtiment Pasc al n° 530 - 10 Juin 22 14:00 DESCRIPTION:Extreme value statistics of stochastic processes : from Brownia n motion to active particles\npar\n\nFrancesco Mori\n \;\n\nRare extre me events tend to play a major role in a wide range of contexts\, from fin ance to climate. Hence\, understanding their statistical properties is a r elevant task\, which opens the way to many applications. In this thesis\, we investigate the extremal properties of several stochastic processes\, i ncluding Brownian motion (BM)\, active particles\, and BM with resetting.   In the first part\, we investigate the times at which extrema of one-di mensional stochastic processes occur. In particular\, in the case of a BM of fixed duration\, we compute the probability distribution of the time be tween the global maximum and the global minimum. Moreover\, we derive the distribution of the time of the maximum for stationary stochastic processe s\, both at equilibrium and out-of-equilibrium. This analysis leads to the formulation of a simple criterion to detect nonequilibrium fluctuations i n steady states. In the second part\, we focus on the run-and-tumble parti cle (RTP) model. We compute exactly the survival probability for a single RTP in d dimensions\, showing that this quantity is completely universal\, i.e.\, independent of d and the speed fluctuations of the particle. We ex tend this universality to other observables (time of the maximum and recor ds) and generalized RTP models. Moreover\, we also investigate the positio n distribution of a single RTP at late times. We show that\, under certain conditions\, a condensation transition can be observed in the large-devia tion regime where the particle is far from its starting position. Finally\ , we introduce a new technique\, analog to the Hamilton-Jacobi-Bellman equ ation\, to optimally control a dynamical system through stochastic resetti ng.\n\nJury :\n\nS. Majumdar (directeur de thèse)\n\nD. Dean (rapporteur) \n\nM. Marsili (rapporteur)\n\nM. Evans\n\nJ. Krug\n\nC. Monthus\n\nG. Sch ehr\n\nR. Voiturier CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-829@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220614T110000 DTEND;TZID=Europe/Paris:20220614T120000 DTSTAMP:20220601T172751Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-grigori-astrakharchik-upc/ SUMMARY:Séminaire du LPTMS : Grigori Astrakharchik (UPC-BQMC) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Juin 22 11: 00 DESCRIPTION:Formation of liquids in low-dimensional dipolar systems\nGrigor i Astrakharchik (Barcelona Tech - UPC)\nHybrid: onsite seminar + zoom.\n\n https://cnrs.zoom.us/j/95875919260?pwd=eW4vK2JwV05BNnh3bWoyVlMveVVTZz09\n\ nMeeting ID: 958 7591 9260\nPasscode: 4Jq11e\n\nWe show that ultradilute q uantum liquids can be formed with ultracold bosonic dipolar atoms in a bil ayer geometry. Contrary to previous realizations of ultradilute liquids\, there is no need for stabilizing the system with an additional repulsive s hort-range potential. The advantage of the proposed system is that dipolar interactions on their own are sufficient for creation of a self-bound sta te and no additional short-range potential is needed for the stabilization . We perform quantum Monte Carlo simulations and find a rich ground-state phase diagram that contains quantum phase transitions between liquid\, sol id\, atomic gas\, and molecular gas phases.\n\nOptical lattices with dipol ar bosons provide a unique platform for fundamental studies of the extende d Bose-Hubbard model. The interplay between anisotropic long-range interac tion\, strong on-site repulsion and periodic confinement give rise to unex pected phases of matter that have not been explored so far in experiments. We propose a mechanism that stabilizes quantum liquids in strongly intera cting dipolar gases in a one-dimensional optical lattice. The mechanism is based on the enhanced role of the superexchange processes close to a self -bound Mott insulator state. To support this finding\, we contrast our per turbative calculations with full density-matrix renormalization group simu lations and characterize the properties of different phases of the system. \n\n[1] G. Guijarro\, G. E. Astrakharchik\, J. Boronat\, Ultradilute quant um liquid of dipolar atoms in a bilayer\, Phys. Rev. Lett. 128\, 063401 (2 022)\n\n[2] Ivan Morera\, Rafał Ołdziejewski\, Grigori E. Astrakharchik\ , Bruno Juliá-Díaz\, Superexchange liquefaction of strongly correlated l attice dipolar bosons\, arXiv:2204.03906 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-824@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220621T110000 DTEND;TZID=Europe/Paris:20220621T120000 DTSTAMP:20220610T090034Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marko-znidaric-lubiana/ SUMMARY:Séminaire du LPTMS : Marko Žnidarič (Ljubljana University) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Jui n 22 11:00 DESCRIPTION:Non-Hermitian phantoms\nMarko Žnidarič (University of Ljublja na)\n\nHybrid seminar: onsite + zoom.\n\nhttps://cnrs.zoom.us/j/9600269725 7?pwd=VXViU0EvMWJDa0FFMXhXbE5qMjdsZz09\nMeeting ID: 960 0269 7257\nPasscod e: qi8a9S\n\n\nDescribing full unitary dynamics of a many-body system is d ifficult and also unpractical. Focusing on a coarse-grained dynamics\, or few select smooth observables\, often results in a more compact non-unitar y evolution. Studying bipartite entanglement dynamics in random circuits o ne can derive a Markovian transfer matrix description that harbors rather intriguing many-body non-Hermitian physics. The speed of generating entang lement is not given by the 2nd largest eigenvalue of the transfer matrix\, but rather by a phantom eigenvalue that is not in the spectrum of any fin ite transfer matrix. Resolution of this seeming paradox will involve a spe ctrum that is completely discontinuous in the thermodynamic limit. When de aling with finite non-Hermitian matrices it can turn out that being exact is actually wrong\, while being slightly wrong is correct. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-826@lptms.universite-paris-saclay.fr DTSTART:20220622T110000Z DTEND:20220622T120000Z DTSTAMP:20220615T072743Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-emmanuel-levy/ SUMMARY:Physics-Biology interface seminar: Emmanuel Levy - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 22 Juin 22 11:00 DESCRIPTION:Principles of Protein Assembly\, From Molecules to Cells\nEmman uel Levy (Weizmann Institute of Science\, Israel)\nLife processes involve an intricate choreography between tens of millions of protein building blo cks that form the infrastructure of cells. Recent technological advances h ave revealed the catalogs of proteins present in various cells and organis ms. However\, understanding how these protein building-blocks assemble and work together is an extraordinarily complex task. I will present our work aimed at addressing this challenge. First\, I will describe how stickines s\, defined as the chemical propensity of protein surfaces to bind to each other\, is tuned across entire proteomes to minimize promiscuous interact ions. Second\, I will show that even single point-mutations changing the s urface stickiness of homo-oligomeric proteins can trigger their infinite f olded-state self-assembly. Finally\, I will describe the design of synthet ic protein condensates with tractable and tunable phase behavior\; and wor k-in-progress\, on how we are using these condensates to identify genes gl obally regulating macromolecular self-assembly in cells. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-831@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220623T110000 DTEND;TZID=Europe/Paris:20220623T120000 DTSTAMP:20220616T072409Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marina-gonchenko-upc/ SUMMARY:Séminaire du LPTMS : Marina Gonchenko (Universitat de Barcelona) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 23 Juin 22 11:00 DESCRIPTION:Homoclinic phenomena in conservative dynamical systems\nMarina Gonchenko (Universitat de Barcelona)\n\n**Unusual day**\n\nhttps://cnrs.zo om.us/j/92337937169?pwd=SlFBdXNyV2hYL0VkbHpxa2lOMENMQT09\nMeeting ID: 923 3793 7169\nPasscode: ZSG43P\n \nWe study homoclinic orbits in conservative dynamical systems. Such orbits\, called homoclinic by Poincaré\, are of great interest in the theory of dynamical systems since their presence imp lies chaotic dynamics. We study area-preserving maps (APMs) with a nontran sversal homoclinic orbit (homoclinic tangency) to a saddle fixed point and we prove the existence of cascades of elliptic periodic points near the g iven homoclinic trajectory. We also study the phenomenon of the coexistenc e of infinitely many periodic orbits of different large periods (called gl obal resonance). We consider the related problems in different types of AP Ms (symplectic maps and non-orientable APMs) with quadratic or cubic tange ncies. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-830@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220628T110000 DTEND;TZID=Europe/Paris:20220628T120000 DTSTAMP:20220623T113817Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ramazashvili-revaz-toulouse/ SUMMARY:Séminaire du LPTMS : Revaz Ramazashvili (LPT Toulouse) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 28 Juin 22 11 :00 DESCRIPTION:Skyrmion-electron bound states in a Néel antiferromagnet \nRev az Ramazashvili (Laboratoire de Physique Théorique - Toulouse)\n\nHybrid seminar: onsite + zoom.\n\nhttps://cnrs.zoom.us/j/94651547014?pwd=cUQ2aXRp Vkg0NWJxRVl2dHBJLzdJZz09\nMeeting ID: 946 5154 7014\nPasscode: N9t4y9\n\nW e show that\, in a Néel antiferromagnet with a particular location\nof el ectron band extrema\, a Skyrmion and an electron form a bound\nstate with energy of the order of the gap $\\Delta$ in the electron\nspectrum. The bo und state turns the Skyrmion into a charged particle\,\nthat can be manipu lated by electric field.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-833@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220705T110000 DTEND;TZID=Europe/Paris:20220705T120000 DTSTAMP:20220628T155924Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thomas-barthel-duke/ SUMMARY:Séminaire du LPTMS : Thomas Barthel (Duke University) - Petit amp hi\, bâtiment Pascal n° 530 - 5 Juil 22 11:00 DESCRIPTION:Crossover functions for entanglement entropy in many-body energ y eigenstates\nand universality\nThomas Barthel (Duke University)\n\nHybri d seminar\, speaker on zoom.\n\nhttps://cnrs.zoom.us/j/96907356383?pwd=OHl tMFV6N3JEY3BxS1VjNHlEUWdTQT09\nMeeting ID: 969 0735 6383\nPasscode: KJfeh7 \n\n\n\nWe consider the entanglement entropies of energy eigenstates in qu antum many-body systems. For the typical models that allow for a field-the oretical description of the long-range physics\, we find that the entangle ment entropy of (almost) all eigenstates is described by a single crossove r function. The eigenstate thermalization hypothesis (ETH) implies that su ch crossover functions can be deduced from subsystem entropies of thermal ensembles and that they assume universal scaling forms in quantum-critical regimes. They describe the full crossover from the groundstate entangleme nt scaling for low energies and small subsystem size (area or log-area law ) to the extensive volume-law regime for high energies or large subsystem size. For critical 1d systems\, the scaling function follows from conforma l field theory (CFT). We use it to also deduce the scaling function for Fe rmi liquids in d>\;1 dimensions. These analytical results are complement ed by numerics for large non-interacting systems of fermions in d=1\,2\,3 and the harmonic lattice model (free scalar field theory) in d=1\,2. Lastl y\, we demonstrate ETH for entanglement entropies and the validity of the scaling arguments in integrable and non-integrable interacting spin chains .\n\n[1] "Eigenstate entanglement: Crossover from the ground state to volu me laws”\, Phys. Rev. Lett. 127\, 040603 (2021)\n[2] "Scaling functions for eigenstate entanglement crossovers in harmonic lattices"\, Phys. Rev. A 104\, 022414 (2021)\n[3] "Eigenstate entanglement scaling for critical i nteracting spin chains”\, Quantum 6\, 642 (2022) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-832@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220712T110000 DTEND;TZID=Europe/Paris:20220712T120000 DTSTAMP:20220628T160612Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thomas-franosch-innsbruck/ SUMMARY:Séminaire du LPTMS : Thomas Franosch (University of Innsbruck) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 J uil 22 11:00 DESCRIPTION:Gravitaxis of a single active particle\nThomas Franosch (Instit ut für Theoretische Physik - Universität Innsbruck)\nHybrid seminar: ons ite + zoom.\n\nhttps://cnrs.zoom.us/j/91436831925?pwd=MHpFTVlXWGU1d0N1VCtL cWsxRW92Zz09\nMeeting ID: 914 3683 1925\nPasscode: n5P5Ct\n\nThe active Br ownian particle (ABP) model has become a paradigm for dynamics far from eq uilibrium and has attracted considerable attention in the statistical-phys ics/soft-matter community [1\,2]. In this model particles undergo directed motion along their axis of orientation which is subject to orientational diffusion. While it is rather easy to simulate the dynamics of such agents in a prescribed potential landscape\, analytical progress even for the si mplest set-ups has been difficult. Here I present an exact solution for th e dynamics of active Brownian particle in a uniform gravitational field as described by the equations of motion of Ref. [3]. We show that the proble m maps to the noisy overdamped pendulum or dynamics in a tilted washboard potential. Close to the underlying classical bifurction we unravel a reson ance for the diffusion coefficient. We derive the corresponding Fokker-Pla nck equation and use techniques familiar from quantum mechanics to provide a complete solution. The scaling behavior at the resonance is rationalize d in terms of a simple harmonic oscillator picture.\n\n[1] Clemens Beching er\, Roberto Di Leonardo\, Hartmut Löwen\, Charles Reichhardt\, Giorgio V olpe\, and Giovanni Volpe\, Active particles in complex and crowded enviro nments\, Rev. Mod. Phys. 88\, 045006 (2016).\n\n[2] C. Kurzthaler\, C. Dev ailly\, J. Arlt\, T. Franosch\, W. C. K. Poon\, V. A. Martinez\, and A. T. Brown\, Probing\nthe spatiotemporal dynamics of catalytic janus particles with single-particle tracking and differential dynamic microscopy\, Physi cal Review Letters 121\, 078001 (2018).\n\n[3] B. ten Hagen\, F. Kümmel\, R. Wittkowski\, D. Takagi\, H. Löwen\, and C. Bechinger\, Gravitaxis of asymmetric\nself-propelled colloidal particles\, Nature Communications 5\, 4829 (2014). CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-834@lptms.universite-paris-saclay.fr DTSTART:20220915T090000Z DTEND:20220915T173000Z DTSTAMP:20220915T144605Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journees-des-labo ratoires-ffj/ SUMMARY:Journées des laboratoires FFJ - Salle des séminaires du FAST et d u LPTMS\, bâtiment Pascal n°530 - 15 Sep 22 09:00 DESCRIPTION:ProgrammeFFJ2022 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-840@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220920T110000 DTEND;TZID=Europe/Paris:20220920T120000 DTSTAMP:20220912T110941Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alberto-nardin-unitn/ SUMMARY:Séminaire du LPTMS : Alberto Nardin (UniTn) - Salle des séminaire s du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Sep 22 11:00 DESCRIPTION:Linear and non-linear edge dynamics of trapped fractional quant um Hall droplets\nAlberto Nardin (University of Trento)\n\nHybrid: onsite seminar + zoom.\n\nhttps://cnrs.zoom.us/j/95695271626?pwd=THV6OHUvaWt0Z1lX a052c3Vzd3Evdz09\nMeeting ID: 956 9527 1626\nPasscode: AVzm2b\n\nWe study the dynamics of the edge modes of non-harmonically confined macroscopic dr oplets of fractional quantum Hall fluids\, excited by applying some extern al time-dependent potential to an incompressible ground state belonging to the prominent Laughlin's series. The neutral edge excitations have been c haracterized by restricting the Hamiltonian to a suitably truncated subspa ce of Laughlin-like states\, where the the relevant transition matrix elem ents can be evaluated by Monte Carlo techniques. In the long-wavelength an d weak excitation limit we recover observable consequences of the fraction al transverse conductivity. The first non-universal corrections to the chi ral Luttinger liquid model are then characterized: for weak excitations in the linear response regime\, cubic corrections to the dispersion of linea r waves and a broadening of the dynamical structure factor of the edge exc itations are identified. Sizeable nonlinear effects are found in the dynam ics for stronger excitations or on longer timescales. All the observed fea tures are quantitatively captured by a simple nonlinear extension of the s tandard chiral Luttinger liquid quantum Hamiltonian\, whose edge-density e volution equation reduces to a driven Korteweg-de Vries equation in the se miclassical limit.\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-843@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20220927T110000 DTEND;TZID=Europe/Paris:20220927T120000 DTSTAMP:20220920T143413Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-olivier-martin-inrae/ SUMMARY:Séminaire du LPTMS : Olivier Martin (IPS2) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 27 Sep 22 11:00 DESCRIPTION:Minimum complexity drives regulatory logic in Boolean models of living systems\nOlivier Martin (Institut for Plant Sciences Paris Saclay) \n\n\nHybrid: onsite seminar + zoom.\n\nRegister for this meeting:\nhttps: //cnrs.zoom.us/meeting/register/tJIqde6gpjsoHNRUFnSHp__QPqHYPzkNQd8N \nAft er registering\, you will receive a confirmation email containing informat ion about joining the meeting.\n\n\nWe study the preponderance of particul ar types of Boolean functions in gene regulatory networks. We first compil e a reference dataset of 2687 functions extracted from published models. T his dataset shows strong enrichments in "read-once" functions and in neste d canalyzing functions. These enrichments can be justified by selection fo r minimum complexity\, either Boolean complexity based on string lengths i n formal logic which is yet unexplored in the biological context\, or aver age sensitivity which corresponds to maximizing robustness to noise.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-838@lptms.universite-paris-saclay.fr DTSTART:20220928T143000Z DTEND:20220928T143000Z DTSTAMP:20220919T074521Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-felix-benoist/ SUMMARY:Soutenance de thèse: Félix Benoist - Petit amphi\, bâtiment Pasc al n° 530 - 28 Sep 22 14:30 DESCRIPTION:Complex Materials : Frustrated Self-Assembly and Nonlinear Elas ticity\n\npar\n\nFélix Benoist\n\n\nThis thesis is divided into two parts with little overlap. The first part deals with the pathological self-asse mbly of normally soluble proteins. In a number of cases\, they tend to for m "frustrated" aggregates which grow only in one direction. We hereby stud y the shape and size of the equilibrium clusters formed by particles with directional interactions. This investigation hopefully leads to a better u nderstanding of the underlying mechanism of fiber-formation.\nThe second p art focuses on the transmission of internal stresses in complex materials such as biological fiber networks and granular matter. We develop a contin uum model of such materials\, which accounts for the measured asymmetry in their response to tension versus compression. We show analytically and nu merically that this may lead fibrous networks to rectify internal stresses towards contraction\, and granular media to rectify towards expansion.\nJ ury :\n\nM. Lenz (directeur de thèse\n\nH. Diamant\n\nB. Roman\n\nA. Sari c\n\nY. Shokef CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-836@lptms.universite-paris-saclay.fr DTSTART:20220930T110000Z DTEND:20220930T120000Z DTSTAMP:20220927T091115Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-anne-marie-haghiri/ SUMMARY:Physics-Biology interface seminar: Anne-Marie Haghiri - Moyen Amphi \, Building 510\, Université Paris-Saclay Orsay - 30 Sep 22 11:00 DESCRIPTION:Microfluidics and “Organs-on-chip”: is it possible to mimic blood vessels?\nAnne-Marie Haghiri (C2N)\n“Organs-on-a-chip” aim to c apture key functions that are indispensable for the physiological function ing of a specific organ by mimicking the tissue elements that perform thes e functions in vivo. In this context\, microfluidics offers the ability to reconstruct in vitro biological microenvironments with all the biophysica l and biochemical expected parameters including cellular coatings. Along t his talk\, I will focus on microfluidic devices aiming to mimic blood micr ovessels based on two complementary approaches.\n\nThe first approach conc erns the microfluidic wearable artificial lung that recovers on chip the p hysiological function of breath. A microfluidic oxygenator mainly consists of three layers with a thin gas permeable membrane sandwiched between a b lood microcapillaries network and a gas network. To meet clinical demands\ , such device must therefore meet certain requirements\, which are 1/ supp ort high blood flow without reducing the gas transfer efficiency\, 2/ mini mize pressure drop and shear stress in the blood module\, 3/ enhance hemoc ompatibility by coatings. Our device has been designed at the 4-inch wafer scale with very dense curved blood and oxygen microcapillaries separated by a 15 µm-thick porous membrane [1]. Such design allows reducing both pr iming volume while maintaining efficient gas exchange. Biomimetic blood fl ow paths with low shear rate also promotes sustainable endothelialization since cells can be maintained viable for up to 2 weeks after initial seedi ng. The simplicity of connecting different units in the stacked architectu re has also been demonstrated for 3- or 5-unit stacked devices that exhibi t remarkable performance with low primary volume\, high oxygen uptake and carbon dioxide release and high flow rate up to 80 ml/min [2].\n\nThe seco nd more conventional approach consists to generate microvasculature direct ly inside the chip where a tumor model is growing. Here\, we developed a s imple method to fabricate high aspect ratio 3D microfluidic devices\, as g eometrically optimized microenvironment for long-term culture and vascular ization of 3D tumor models (i.e.\, spheroids). The role of the height of t he central chamber on the growth of a heterotypic pancreatic tumor spheroi d\, made of cancer cells and fibroblasts is under study. We recently demon strated that a 500µm-thick microfluidic chamber promotes more gradual cel l growth and migration\, thanks to the availability of space for spheroid evolution. Finally\, I will conclude on the importance of innovative desig n/architecture coupled with adapted microfabrication processes.\n\nReferen ces:\n[1] A-M. Haghiri-Gosnet\, Lyas Djeghlaf\, Julie Lachaux\, Alisier Pa ris\, Gilgueng Hwang\, European Patent EP18306405.4 (29 Oct. 2018) "Microf luidic gas exchange devices and methods for making same"\n[2] Julie Lachau x\, Gilgueng Hwang\, Nassim Arouche\, Sina Naserian\, Abdelmounaim Harouri \, V. Lotito\, C. Casari\, T. Lok\, J B. Menager\, J. Issard\, J. Guihaire \, C. V. Denis\, P. J. Lenting\, A. I. Barakat\, G. Uzan\, O. Mercier\, An ne Marie Haghiri-Gosnet\, Lab Chip\, 2021\, 21\, 4791 DOI:10.1039/d1lc0035 6a\n\n \;\n\nMerci de contacter eric.raspaud@universite-paris-saclay.f r et antoine.fruleux@universite-paris-saclay.fr si vous désirez rencontre r\nl’oratrice/l'orateur ou déjeuner avec nous. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-845@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221004T140000 DTEND;TZID=Europe/Paris:20221004T150000 DTSTAMP:20220921T100227Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-emilio-trevisani-ipht/ SUMMARY:Séminaire du LPTMS : Emilio Trevisani (IPhT) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Oct 22 14:00 DESCRIPTION:Random field models and Parisi-Sourlas supersymmetry\nEmilio Tr evisani (Institut de Physique Theorique)\n\n*** UNUSUAL TIME!! ***\n\nHybr id: onsite seminar + zoom.\n\nRegister for this meeting:\nhttps://cnrs.zoo m.us/meeting/register/tJMuf--oqzIuHt2mjcx_ksGra4epEaJNOu9C \nAfter registe ring\, you will receive a confirmation email containing information about joining the meeting.\n\nQuenched disorder is very important but notoriousl y hard. In 1979\, Parisi and Sourlas proposed an interesting and powerful conjecture about the infrared fixed points with random field (RF) type of disorder: such fixed points should possess an unusual supersymmetry\, by w hich they reduce in two less spatial dimensions to usual non-supersymmetri c non-disordered fixed points. The conjecture is known to hold for the RF φ^3 model but not for RF φ^4 model in d < 5 dimensions\, however there i s no consensus on why this happens. We argue that: \n1) dimensional reduc tion works for any Parisi-Sourlas SUSY fixed point\;\n2) the SUSY fixed po int is not always reached because of new relevant SUSY-breaking interactio ns. \nWe attack the point 1) using axiomatic CFT techniques while we study the point 2) using the perturbative renormalization group in a judicious ly chosen field basis\, allowing systematic exploration of the space of in teractions. Our computations agree with the numerical results for both cub ic and quartic potential. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-841@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221011T110000 DTEND;TZID=Europe/Paris:20221011T120000 DTSTAMP:20220929T072319Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-guillaume-barraquand-ens/ SUMMARY:Séminaire du LPTMS : Guillaume Barraquand (ENS Paris) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 11 Oct 22 11:0 0 DESCRIPTION: Stationary measures for the KPZ equation\nGuillaume Barraquand (École normale supérieure)\n\nHybrid: onsite seminar + zoom.\n\nLink to register for zoom:\nhttps://cnrs.zoom.us/meeting/register/tJcscOqtqT4uHdL e8UF5b8FoPCa5Cg3OUT3y \nAfter registering\, you will receive a confirmatio n email containing information about joining the meeting.\n\nA solution h( x\,t) of the KPZ equation in one dimension typically grows linearly in tim e with t^{1/3} fluctuations. The height gradient\, however\, or the differ ences of height between any two points\, will reach a stationary state. In that sense\, it has been known for a long time that the Brownian motion i s a stationary measure for the KPZ equation on the full-line. For domains with boundaries such as [0\,L] or R_+\, stationary measures were character ized only recently using a combination of works by several groups\, and ca n be described using Brownian motions reweighted by exponential functional s. The talk is based on joint works with Pierre Le Doussal and Ivan Corwin . CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-839@lptms.universite-paris-saclay.fr DTSTART:20221012T140000Z DTEND:20221012T140000Z DTSTAMP:20220916T095958Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-pierre-mergny/ SUMMARY:Soutenance de thèse Pierre Mergny - LPTMS (100% online seminar) - 12 Oct 22 14:00 DESCRIPTION:Spherical integrals and their applications to random matrix th eory\npar\n\nPierre Mergny\n\n\n\n\nRandom matrix theory has found applica tions in many fields of physics (disordered systems\, stability of dynamic al systems\, interface models\, electronic transport\,...) and mathematics (operator algebra\, enumerative combinatorics\, number theory\,...). A re current problem in many domains is understanding how the spectra of two ra ndom matrices recombine when we perform their sum or product. In this the sis\, we study this problem through the prism of spherical integrals and w ith the help of statistical physics tools. These spherical integrals play the role of the Fourier transform in random matrix theory and their study allows us to understand better the properties of both the limiting spectra l density and the largest eigenvalue of these matrix models.\n\n\n\n\n\nJu ry : Marc Potters (directeur de thèse)\, Satya Majumdar (co-directeur de thèse)\, Adam W. Marcus\, Pierpaolo Vivo\, Florent Benaych-Georges\, Giul io Biroli\, Alice Guionnet\, Jorge Kurchan.\n\nLa soutenance aura lieu dan s les locaux de CFM au 23 rue de l'Université 75007 Paris CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-850@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221018T110000 DTEND;TZID=Europe/Paris:20221018T120000 DTSTAMP:20221017T082909Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-david-carpentier-ens-lyon/ SUMMARY:Séminaire du LPTMS : David Carpentier (ENS Lyon) - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 18 Oct 22 11:00 DESCRIPTION:Anomalous Luttinger equivalence between temperature and curved spacetime: From black holes to thermal quenches\nDavid Carpentier (Laborat oire de Physique\, ENS Lyon)\n\nOnline seminar.\nRegister in advance for t his meeting on zoom:\nhttps://cnrs.zoom.us/meeting/register/tJ0scu2srjwoGN yMDjYouGtXYKHyKDLSSuA_ \nAfter registering\, you will receive a confirmati on email containing information about joining the meeting.\n\nIn condensed matter\, thermal response theory relies on a deep connection\nbetween gra vitational fields and thermal transport\, established in 1964 by Luttinger \, building on earlier ideas of Tolman and Ehrenfest. Does this connection extend beyond pure technical considerations ? In this work\, we revisit t he celebrated Tolman-Ehrenfest and Luttinger relations and show how to inc orporate anomalous quantum fluctuations that become paramount in a strongl y curved spacetime. Our extended correspondence between temperature variat ions and curvature of spacetime incorporates new quantum energy scales ass ociated with these fluctuations\, captured by the so-called gravitational anomalies of quantum field theories.\nOn one hand we point out that such anomalous fluctuations naturally occur in the quantum atmosphere of a blac k hole. On the other hand\, our extended correspondance implies that anal ogous fluctuations are also observable in thermal conductors in the flat-s pace time of a laboratory\, provided that the local temperature varies st rongly. As a consequence\, we establish that the gravitational anomalies m anifest themselves naturally in non-linear thermal response of a quantum w ire. In addition\, we propose a systematic way to identify thermal analogu es of black hole’s anomalous quantum fluctuations associated to gravitat ional anomalies. We identify their signatures in propagating energy waves following a thermal quench\, as well as in the energy density of heating F loquet states induced by repeated thermal quenches. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-852@lptms.universite-paris-saclay.fr DTSTART:20221021T110000Z DTEND:20221021T120000Z DTSTAMP:20221018T140310Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-debarghya-banerjee/ SUMMARY:Physics-Biology interface seminar: Debarghya Banerjee - Moyen Amphi \, Building 510\, Université Paris-Saclay Orsay - 21 Oct 22 11:00 DESCRIPTION:Odd Cosserat elasticity in active materials\nDebarghya Banerjee (MPIPKS\, Dresden)\nStress-strain constitutive relations in solids with a n internal angular degree of freedom can be modelled using the Cosserat or micropolar elasticity. In the theory of \\emph{chiral active} Cosserat ma terials one would find an \\emph{odd} elastic term in addition to the usua l Cosserat term in the constitutive relations. In this talk\, I will devel op a natural extension of Cosserat materials to include odd elasticity and discuss the phenomenological effects of these terms. I will discuss about static elastic properties of such a solid\, where\, we show that static r esponse to vortical stresses lead to strains that depend on both the Cosse rat and odd elasticity. We then compute the dispersion of linear solutions in these odd-Cosserat materials\, where\, we find the presence of \\emph{ exceptional points} in the dispersion relation. Finally\, we show the effe ct of Cosserat and odd elastic terms on the polarization of Rayleigh edge waves.\n\nMerci de contacter eric.raspaud@universite-paris-saclay.fr et an toine.fruleux@universite-paris-saclay.fr si vous désirez rencontrer\nl’ oratrice/l'orateur ou déjeuner avec nous. CATEGORIES:seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-835@lptms.universite-paris-saclay.fr DTSTART:20221108T100000Z DTEND:20221108T100000Z DTSTAMP:20221103T105927Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-lorenzo-gotta-lptms/ SUMMARY:Soutenance de thèse : Lorenzo Gotta (LPTMS) - Petit amphi\, bâtim ent Pascal n° 530 - 8 Nov 22 10:00 DESCRIPTION:Pairing and two-fluid physics in low-dimensional quantum system s\npar\n\nLorenzo Gotta\nThe present thesis deals mainly with the ground-s tate properties of quantum many-body systems of spinless fermions that dis play bound-state formation. We start by discussing the pairing phenomena i nduced by density-density interactions\, showing that extending the range of the latter can lead to the observation of exotic Luttinger liquid phase s with cluster granularity. We continue the study of pairing in a one-dime nsional chain of spinless fermions where single-particle hopping competes with a correlated pair-hopping interaction. We unveil a novel transition f rom a weak-coupling Luttinger liquid phase to a paired Luttinger liquid ph ase\, that occurs through an intervening phase where a liquid of isolated fermions coexists with a liquid of pairs without phase separation. We conf i\\u001Crm the stability of this novel coexistence phase against the addit ion of a weak nearest-neighbor density-density interaction\, which is show n to induce instead phase separation between paired and unpaired fermions in the strong-coupling regime. Finally\, we generalize the pair-hopping te rm to a generic multimer-hopping term\, thereby proving the robustness of the coexistence phase as the generic transition scenario between a Lutting er liquid with single-particle granularity and one with molecular granular ity. We conclude by showing that models of spinless fermions featuring pai r-hopping can host quantum many-body scars\, thus opening further routes t owards the study of weak ergodicity breaking in isolated many-body quantum systems.\n\n \;\n\nJury:\n\nL. Mazza (co-directeur de thèse)\n\nG. R oux (co-directeur de thèse)\n\nP. Simone (co-directeur de thèse)\n\nK. L e Hur\n\nG. Pupillo\n\nJ. Ruhman\n\nO. Zilberberg CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-853@lptms.universite-paris-saclay.fr DTSTART:20221108T141500Z DTEND:20221108T141500Z DTSTAMP:20221101T085026Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mini-workshop/ SUMMARY:Mini-workshop on modern trends in condensed-matter physics - Petit amphi\, bâtiment Pascal n° 530 - 8 Nov 22 14:15 DESCRIPTION:14h15 Oded Zilberberg (Uni Konstanz) : The impact of open syste m fluctuations on critical quantum impurity physics.\n14h50 Guido Pupillo (Uni Strasbourg) : Semilocalization in long-range random spin models\n15h2 5 Jonathan Ruhman (Uni Bar-Ilan) : The Measurement phase transition\nAbstr act:\nAs time goes by\, the degrees of freedom in a closed quantum system tend to get more entangled with each other due to their interactions. On t he other hand\, an observer from outside can reduce this internal entangle ment by performing a measurement. This raises the question: Which of these two processes is more dominant in a system that is simultaneously evolvin g in time and undergoing measurement? In this talk I will show evidence th at both processes can be dominant\, and there is a dynamical phase transit ion tuned by their relative strength. The transition is between an "entang led" phase\, where the internal scrambling of quantum information prevails and a second "disentangled" phase where the observer drains in the intern al information and renders all quantum correlations to be of the "few-body " type. In 1D systems we have evidence of this transition for fine tuned m odels\, mapping to classical percolation and from numerics on small system s. However\, for 0D systems\, where all degrees of freedom interact equall y we can make the argument more concrete in the generic case\, by taking a dvantage of local tree-like structures in the circuit representation of th e non-unitary time evolution operator.\n16h00 Karyn Le Hur (Ecole Polytech nique) : Engineering a p+ip Superconductor and Majorana Fermions in Quant um Wires\nReference: F. Yang\, V. Perrin\, A. Petrescu\, I. Garate and K. Le Hur\, Phys. Rev. B. 101\, 085116 (2020) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-857@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221109T110000 DTEND;TZID=Europe/Paris:20221109T120000 DTSTAMP:20221101T185259Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-benjamin-bertrand-lacroix-kcl-london/ SUMMARY:Séminaire du LPTMS : Bertrand Lacroix-A-Chez-Toine (KCL) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Nov 22 11 :00 DESCRIPTION:Superposition of random plane waves in high dimension as a rand om landscape\nBertrand Lacroix-A-Chez-Toine (King’s College London)\n\n* *SPECIAL DAY**\nHybrid: onsite seminar + zoom.\nRegister in advance for th is meeting:\nhttps://cnrs.zoom.us/meeting/register/tJYpcOCqrjwjHNMzYke5j7B 722dWyNmLVNN3\nAfter registering\, you will receive a confirmation email c ontaining information about joining the meeting.\n\nSuperpositions of rand om plane waves play important roles in the semi-classical description of q uantum billiard as pointed out by Berry’s conjecture [1]. In this contex t\, they can describe the eigenfunctions of the Laplacian operator at high energy. While their properties have been explored in depth in low spatial dimensions\, we consider in this talk a large superposition of M ≫ 1 ra ndom plane waves in high dimension N ≫ 1 with M/N = α > 1. Here\, we co nsider instead this object as a (random) energy landscape and\, adding an isotropic harmonic confinement of strength μ\, we characterise the ergodi city breaking in such a landscape.\nTo characterise this property we consi der two quantities: the quenched free-energy and the annealed total comple xity\, i.e. the rate of exponential growth of the average number of statio nary points of the energy landscape with the spatial dimension N .\nWhile similar high-dimensional random landscapes display topology trivialisation transition [2]\, whereby the complexity vanishes above some finite value of the confinement μ\, the complexity vanishes only as μ → ∞ in this system [3]. One might thus expect that ergodicity is always broken at zer o temperature in this model. This is confirmed and enriched by our quenche d free-energy computations.\n\n\nReferences:\n[1] M. V. Berry\, Regular an d irregular semiclassical wavefunctions\, J. Phys. A 10 2083 (1977).\n[2] Y. V. Fyodorov\, Complexity of Random Energy Landscapes\, Glass Transition \, and Absolute Value of the Spectral Determinant of Random Matrices\, Phy s. Rev. Lett. 92\, 240601 (2004) Erratum: Phys. Rev. Lett. 93\, 149901(E) (2004).\n[3] B. Lacroix-A-Chez-Toine\, S. Belga-Fedeli\, Y. V. Fyodorov\, Superposition of Random Plane Waves in High Spatial Dimensions: Random Mat rix Approach to Landscape Complexity\, J. Math. Phys. 63 (9)\, 093301 (202 2)\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-844@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221115T110000 DTEND;TZID=Europe/Paris:20221115T120000 DTSTAMP:20221110T133932Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-benjamin-walter/ SUMMARY:Séminaire du LPTMS : Benjamin Walter (Imperial College London) - S alle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 No v 22 11:00 DESCRIPTION:First passage problems in classical and quantum processes\nBenj amin Walter (Imperial College London)\n\nHybrid: onsite seminar + zoom.\nR egister in advance for this meeting:\nhttps://cnrs.zoom.us/meeting/registe r/tJMtc-GtrzoiH91Fdg5TmtBM4LKkuzB-TEWJ \nAfter registering\, you will rece ive a confirmation email containing information about joining the meeting. \n\n\nIn the first part of my talk I discuss the problem of first-passage times of a certain class of non-Markovian “active thermal” processes [ 1\,2]. These are one-dimensional stochastic processes that are driven by b oth an uncorrelated (thermal) noise as well as a self-correlated (“activ e”) noise. I present a field theoretic perturbation theory\, valid in th e low-activity regime\, which systematically computes the corrections to t he survival probability\, and hence allows one to extract distributions of first-passage times\, running maxima and mean range via some simple relat ions. I further give a brief outlook on current work regarding processes d riven by fractional Gaussian noise.\n\nIn the second part of my talk\, I p resent some preliminary findings of an ongoing research project [3] studyi ng the first detection time [4] of a many body quantum system. The first d etection time is the first time that a quantum system is observed to be in a predefined state under repeated projective measurements. We study N\, p ossibly infinite\, free fermions which are arranged adjacently on a linear lattice. Under periodical projective measurements\, performed at a period of \\tau\, we study the statistics of the return probability F_k(\\tau)\; the probability to find the system in its initial state for the first tim e at the k-th attempt of measurement. The statistics of F_k(\\tau) depend non-trivially on \\tau\, and we provide some analytical estimates based on recently found results on the N-fermion return amplitude [5]\, which are compared to exact computations.\n\n(Jointly with Andrea Gambassi\, Gabriel e Perfetto\, Gunnar Pruessner and Guillaume Salbreux) \n\n\nReferences\n\n 1 B. Walter\, G. Pruessner\, G. Salbreux\, Phys. Rev. Res. 3\, 013075 (202 1)\n2 B. Walter\, G. Pruessner\, G. Salbreux\, Phys. Rev. Res.\, in print (2022)\n3 B. Walter\, G. Perfetto\, A. Gambassi\, In preparation\n4 H. Fri edman\, D. A. Kessler\, E. Barkai\, Phys. Rev. E \, 95\, 032141 (2017)\n5 P. L. Krapivsky\, J. M. Luck\, K Mallick\, Journal of Statistical Mechanic s: Theory and Experiment 2018\, 023104 (2018)\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-837@lptms.universite-paris-saclay.fr DTSTART:20221118T110000Z DTEND:20221118T120000Z DTSTAMP:20221019T094128Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-lea-chazot-franguiadakis/ SUMMARY:Physics-Biology interface seminar: Léa Chazot-Franguiadakis - Moye n Amphi\, Building 510\, Université Paris-Saclay Orsay - 18 Nov 22 11:00 DESCRIPTION:Nanofluidics for the study of viral particle transport\nLéa Ch azot-Franguiadakis (ENS Lyon)\nFrom a physical point of view\, viruses are biological objects with remarkable mechanical and thermodynamic propertie s. Their detection and characterisation are currently major public health issues. In this context\, the transport of viruses through nanopores is of interest both\nfrom a fundamental and a technological point of view\, as a method to probe viral properties. We use a mimetic approach of a biologi cal pore\, the nuclear pore complex\, which is taken by some viruses to ac cess the nucleus. It has an exceptional selectivity due to the presence of a network of polymers forming a dynamic gel within its central channel. T o better understand the characteristics of this transport we build a simpl ified and controlled environment based on functionalized nanoporous membra nes. The transport of viral particles is studied using an optical detectio n method with adjustable specificity. Our device allows real-time detectio n of single viral particle transport at the level of a single pore. Our ap proach allows us to address technological issues\, such as the quantificat ion of virus concentration\, for which we have developed a versatile metho d with a low detection limit. It also enables to address fundamental quest ions about viruspore interactions. In particular\, we have highlighted an aggregation phenomenon related to the strong confinement of viruses under flow in the nanopore. The modelling of this phenomenon provides access to interaction parameters between the viruses and between the viruses and the pore.\n\nMerci de contacter eric.raspaud@universite-paris-saclay.fr et an toine.fruleux@universite-paris-saclay.fr si vous désirez rencontrer\nl’ oratrice/l’orateur ou déjeuner avec nous. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-848@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221122T110000 DTEND;TZID=Europe/Paris:20221122T120000 DTSTAMP:20221115T135121Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-martin-evans-edinburgh-3/ SUMMARY:Séminaire du LPTMS : Martin Evans (Edinburgh University) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 22 Nov 22 1 1:00 DESCRIPTION:Interacting Persistent Random Walkers\nMartin Evans (University of Edinburgh)\n\nHybrid: onsite seminar + zoom.\nRegister in advance for this meeting:\nhttps://cnrs.zoom.us/meeting/register/tJcldumrpjkqGdWYFLoHp 0xVov_xj7sDwbHh \nAfter registering\, you will receive a confirmation emai l containing information about joining the meeting.\n\nIn this talk I will consider persistent random walkers\, also known as run and tumble particl es\, which are emerging as a fundamental microscopic model of active matte r. I will first review the properties of a single persistent walker and sh ow how it interpolates between ballistic and diffusive motion.\nThe dynami cal spectrum of a persistent random walker exhibits `exceptional points' i ndicating dynamical transitions - a familiar example of an exceptional poi nt is the critical damping of the simple harmonic oscillator.\nI will then consider the case of two persistent random walkers that interact through an exclusion interaction. An exact expression for the stationary state of two such walkers on a periodic lattice reveals how the particles jam and g enerate an effective attractive potential. The full spectrum of the two-pa rticle problem can also be computed and again exhibits exceptional points\ , which correspond to dynamical transitions in the relaxation time. Finall y\, I will discuss a more general `recoil' interaction between the persist ent walkers and show\nhow tuning the persistence length can generate attra ctive or repulsive effective interactions.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-860@lptms.universite-paris-saclay.fr DTSTART:20221124T103000Z DTEND:20221124T120000Z DTSTAMP:20221122T153456Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-yuval-scher-tel-aviv-university/ SUMMARY:Séminaire exceptionnel du LPTMS: Yuval Scher (Tel Aviv University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 4 Nov 22 10:30 DESCRIPTION:Gated First-passage Processes\nYuval Scher (Tel Aviv University )\n\n\nHybrid seminar: onsite + zoom.\nRegister in advance for this meetin g:\nhttps://cnrs.zoom.us/meeting/register/tJwqc-mvrz0uHtKc-5MIF2LmN0JFbOkl SQyQ \nAfter registering\, you will receive a confirmation email containin g information about joining the meeting. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-856@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221129T110000 DTEND;TZID=Europe/Paris:20221129T120000 DTSTAMP:20221116T101922Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexis-poncet-ens-lyon/ SUMMARY:Séminaire du LPTMS : Alexis Poncet (ENS Lyon) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Nov 22 11:00 DESCRIPTION:Collective effects in driven matter: from one-dimensional crowd ing to 2D melting\n Alexis Poncet (ENS Lyon)\n\n\nHybrid: onsite seminar + zoom.\nRegister in advance for this meeting:\nhttps://cnrs.zoom.us/meetin g/register/tJYtcuqvpjouGtOzHwyWErNx7GEQEv6xZV_4 \nAfter registering\, you will receive a confirmation email containing information about joining the meeting.\n\n\n\nThe theoretical description of the structure and dynamics of matter far from thermal equilibrium is at the heart of modern statisti cal physics.\nIn this seminar\, I will focus on two prototypical exemples of interacting agents driven out of equilibrium: driven hard-core particle s confined in 1D geometries\, and 2D colloidal crystals whose the elementa ry units are activated\, either by torques or forces. The first exemple wi ll be discussed from a fundamental perspective combining analytical theory and extensive numerical simulations\, the second exemple will be discusse d combing experiments\, simulations and theory.\n\nIn the first part of my talk I will address some fundamental questions about the response of non- equilibrium matter to point forces far beyond linear response theory. To t ackle this challenge\, I will focus on the dynamic response of single-fil e systems locally driven by intruders. While at high density intruders ca n only follow one another\, at low density they can unbind and separate. T o explain this unbinding transition [1]\, I will introduce a hydrodynamic description of the density field. Strikingly\, such an approach can be ext ended to all orders of displacement-density correlations [2]\, proving a c omplete characterization of the one-tag process in single-file lattices cl osely related to their integrability.\n\nIn the second part of my talk\, I will describe two seemingly unrelated experiments where spinning particl es [3] and confined emulsions form highly dynamical polycrystals kneaded b y the constant reconfigurations of grains boundaries. I will show that in both cases the lively dynamics of the crystal originate from hydrodynamic interactions that violate Newton's third law. I will investigate the impac t of non-reciprocity on stabilized crystalline phases [4]. In particular I will show that non-reciprocal interactions propel the topological defects of crystals thereby suppressing long-range order and giving rise to intri nsically dynamical polycrystalline phases.\n\n[1] Bénichou\, Démery & Po ncet\; Phys. Rev. Lett. 120\, 070601 (2018)\n[2] Poncet\, Grabsch\, Illien & Bénichou\; Phys. Rev. Lett. 127\, 220601 (2021)\n[3] Bililign\, Usabia ga\, Ganan\, Poncet\, Soni\, Magkiriadou\, Shelley\, Bartolo & Irvine\; Na t. Phys. 18\, 212–218 (2021)\n[4] Poncet & Bartolo\; Phys. Rev. Lett. 12 8\, 048002 (2022) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-847@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221206T110000 DTEND;TZID=Europe/Paris:20221206T120000 DTSTAMP:20221201T084738Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-elisabeth-agoritsas-epfl/ SUMMARY:Séminaire du LPTMS : Elisabeth Agoritsas (EPFL and University of G eneva) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°5 30 - 6 Déc 22 11:00 DESCRIPTION:Towards a unifying (mean-field) picture of driven disordered sy stems\n Elisabeth Agoritsas (EPFL and University of Geneva)\n\nHybrid: ons ite seminar + zoom.\n\nRegister in advance for this meeting:\nhttps://cnrs .zoom.us/meeting/register/tJcrd-yvrjgsH9NhSH2WxoMgM-npghTmncWx \nAfter reg istering\, you will receive a confirmation email containing information ab out joining the meeting.\n\nDisorder is ubiquitous in physical systems\, a nd can radically alter their physical properties compared to their ‘pure ’ counterparts. For instance\, amorphous materials such as emulsions\, f oams\, metallic glasses or biological tissues are all structurally disorde red\, and this has key implications for their rheological\, mechanical or transport properties. Nevertheless\, theoretical descriptions of such ‘d riven' amorphous materials remain challenging\, despite decades of extensi ve analytical and computational studies. The difficulties pertain to the i nterplay of competing sources of stochasticity\, and to the resulting out- of-equilibrium nature of these systems.\nA standard model for amorphous ma terials\, which allows one to focus on the key role of their structural (p ositional) disorder\, is provided by dense many-body systems of pairwise i nteracting particles. Here I will introduce an exact Dynamical Mean-Field Theory (DMFT) for these many-body systems\, derived in the limit of infini te spatial dimension. In this framework\, the many-body Langevin dynamics of the whole problem can be exactly reduced to a single scalar effective s tochastic process\, and dynamical observables such as pressure or shear st ress can be computed for arbitrary driving protocols. Using this DMFT\, we were in particular able to establish a direct equivalence between a globa l forcing (external shear) and a random local forcing (reminiscent of acti ve matter)\, upon a simple rescaling of the control parameter (the accumul ated strain). In this framework\, global shear is thus simply a special ca se of a much broader family of local forcing that can be explored by tunin g its spatial correlations. Our predictions were moreover found to be in r emarkably good agreement with two-dimensional numerical simulations. These results hint at a unifying framework for establishing rigorous analogies\ , at the mean-field level\, between different families of driven disordere d systems\, such as sheared granular materials and active matter\, or mach ine-learning algorithms. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-862@lptms.universite-paris-saclay.fr DTSTART:20221209T110000Z DTEND:20221209T120000Z DTSTAMP:20221209T082509Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-doron-grossman/ SUMMARY:Physics-Biology interface seminar: Doron Grossman - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 9 Déc 22 11:00 DESCRIPTION:Instabilities and Geometry of Growing Tissues\nDoron Grossman ( College de France - for this work\; LadHyX\, Ecole polytechnique - current )\n\nWe present a covariant continuum formulation of a generalized two-dim ensional vertexlike model\nof epithelial tissues which describes tissues w ith different underlying geometries\, and allows for an\nanalytical macros copic description. Using a geometrical approach and out-of-equilibrium\nst atistical mechanics\, we calculate both mechanical and dynamical instabili ties of a tissue\, and\ntheir dependences on various variables\, including activity\, and cell-shape heterogeneity (disorder).\nWe show how both pla stic cellular rearrangements and the tissue elastic response depend on the \nexistence of mechanical residual stresses at the cellular level. Even fr eely growing tissues may\nexhibit a growth instability depending on the in trinsic proliferation rate. Our main result is an\nexplicit calculation of the cell pressure in a homeostatic state of a confined growing tissue. We \nshow that the homeostatic pressure can be negative and depends on the ex istence of mechanical\nresidual stresses. This geometric model allows us t o sort out elastic and plastic effects in a growing\,\nflowing\, tissue.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-849@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20221213T110000 DTEND;TZID=Europe/Paris:20221213T120000 DTSTAMP:20221202T161947Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-martin-robert-de-saint-vincent-lpl/ SUMMARY:Séminaire du LPTMS : Martin Robert-de-Saint-Vincent (LPL) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Déc 22 11:00 DESCRIPTION:Manipulating the spins of degenerate SU(10)-symmetric fermi gas es\nMartin Robert-de-Saint-Vincent (Laboratoire de Physique des Lasers)\n\ n\nHybrid: onsite seminar + zoom.\n\nRegister in advance for this meeting: \nhttps://cnrs.zoom.us/meeting/register/tJMscu-hrjssHtcOKfIhHgsjCUDte0Y2jo d- \nAfter registering\, you will receive a confirmation email containing information about joining the meeting.\n\n\nUltracold alkaline-earth atoms offer the possibility to study the effect of a large spin degree of freed om in interacting fermionic ensembles. I will present the recent developme nts of our experiment\, on which we produce degenerate Fermi gases of stro ntium 87\, held in optical lattices to realize the Fermi-Hubbard model gen eralized to large-spin atoms (F = 9/2).\n\nIn this seminar\, I will focus on our capabilities for measurement and control of the spins\, and connect this to our intended approach for the study of the antiferromagnetic Heis enberg model of magnetism. For our atomic species\, the spins are of nucle ar nature\, which is both a strength and a complication as standard spin m easurement or manipulation schemes based on magnetic gradients are ineffec tive. I will show nevertheless that a narrow line with large hyperfine str ucture offers us very powerful tools\, associated with the engineering of effective spin-orbit coupling\, that we will use on several central aspect s of our studies. First\, we applied adiabatically a three-level coupling involving a dark atomic state\, reminiscent of EIT or STIRAP\, to transfer momentum in a spin-selective manner [1]. This\, we now use for spin measu rements\, and could provide information through spin-momentum noise correl ations. Second\, we have demonstrated controlled coherent adiabatic operat ions in the 10-component spin-manifold\, on degenerate gases prepared dete rministically in a single spin state. I will connect this to our present e ffort at using microstructured optical fields to adiabatically reach low-e nergy states of the Heisenberg Hamiltonian\, by the controlled breaking of its symmetries [2].\n\n[1] P. Bataille et. al.\, Phys. Rev. A 102\, 01331 7 (2020).\n[2] Comparin et.al.\, Phys. Rev. Lett. 129\, 113201 (2022)\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-846@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230110T110000 DTEND;TZID=Europe/Paris:20230110T120000 DTSTAMP:20230106T134731Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrei-rotaru-lpthe/ SUMMARY:Séminaire du LPTMS : Andrei Rotaru (LPTHE) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Jan 23 11:00 DESCRIPTION:New results for Rényi entanglement entropies in one-dimensiona l quantum\ncritical systems with boundaries\nAndrei Rotaru (LPTHE)\n\nHybr id: onsite seminar + zoom.\nhttps://cnrs.zoom.us/j/94693401724?pwd=UUF5b2p JOHE1ZmhSWGpGa2NrL09iUT09\n\n\n\nEntanglement measures have turned out to be a powerful probe into the physics of 1D quantum critical systems.\nMost known exact results address the entanglement in critical quantum systems with periodic BC. For open systems\, there are results for the Rényi ent ropies and other entanglement measures of an interval touching one of two identical boundaries with the rest of the system. However\, for more gener ic bipartitions or mixed boundaries\, few exact calculations have been com pleted.\nIn this talk\, we will present new results for the Rényi entropi es of an interval in systems with open boundaries\, and sketch\, in a peda gogical manner\, the key ideas of their computation through 2D CFT methods . This will be supplemented by comparison with spin chain numerics and a discussion of finite-size effects. Partly based on arXiv:2112.01929. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-865@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230117T150000 DTEND;TZID=Europe/Paris:20230117T160000 DTSTAMP:20230116T183537Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-etienne-granet-chicago-university/ SUMMARY:Séminaire du LPTMS : Etienne Granet (Chicago University) - Petit a mphi\, bâtiment Pascal n° 530 - 17 Jan 23 15:00 DESCRIPTION:Out-of-equilibrium dynamics in Gaussian systems: from quantum q uenches to measurement-induced phase transitions\nEtienne Granet (Chicago University)\nZoom link:\n\nhttps://cnrs.zoom.us/j/95651129119?pwd=bzZNbTdh TDBZa1B6TkM5MVhxNE84QT09\n\nMeeting ID: 956 5112 9119\nPasscode: Y8Rgv7\nU nusual time: 3pm!\nSolvable models are invaluable to understand the comple x dynamics of many-body quantum systems. I will present two exact results on free fermions driven out of equilibrium. I will first show how to compu te the time-dependent magnetization in the infinite-size Ising model when an arbitrary magnetic field is monitored\, which was unknown before. In a second part I will show how to build solvable models for measurement-induc ed phase transitions between volume-law and area-law entangled states\, an d compute the associated critical exponents. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-861@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230124T110000 DTEND;TZID=Europe/Paris:20230124T120000 DTSTAMP:20230117T170003Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-patrick-cheinet-lac-saclay/ SUMMARY:Séminaire du LPTMS : Patrick Cheinet (LAC) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Jan 23 11:00 DESCRIPTION:Controlling auto-ionization of doubly excited Rydberg states\, a new tool for Rydberg-based quantum processors\nPatrick Cheinet (Laborato ire Aimé Cotton)\nHybrid: onsite seminar + zoom.\nhttps://cnrs.zoom.us/j/ 99258460338?pwd=dlhJUzRUVmx6c21MRWJrS2xtRlNYdz09\nIn a recent paper [Pham2 022]\, our team has demonstrated the possibility to tune a laser close to the auto-ionizing doubly-excited Rydberg states of ytterbium atoms and obt ain a large AC-Stark shift while suppressing the usual auto-ionization:\nI n a divalent atom like ytterbium\, after exciting a first electron to a Ry dberg state\, the second electron will display optical transitions similar to the ones existing in the corresponding ion. The excitation of these tr ansitions is called Isolated Core Excitation (ICE). Unfortunately\, the re sulting doubly excited atom will usually auto-ionize quickly. Indeed the t otal energy is far above the first ionization limit and the Coulomb intera ction allows the two electrons to exchange energy. It is known though that many doubly excited states exist and that quantum interferences allow to control the auto-ionization down to zero for the correct destructive inter ferences. We have thus studied these auto-ionization zeros\, with a specif ic interest to the resulting AC-Stark shift to check if it also vanishes o r not. We have demonstrated both theoretically and experimentally that it does not vanish\, thus proving the possibility to use ICE light to perform quantum operations on Rydberg qbits in atomic quantum processors.\n\n[Pha m2022] K.-L. Pham et al.\, PRX Quantum 3\, 020327 (2022).\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-859@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230207T150000 DTEND;TZID=Europe/Paris:20230207T160000 DTSTAMP:20230202T091400Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sanjay-moudgalya-caltech/ SUMMARY:Séminaire du LPTMS : Sanjay Moudgalya (Caltech) - Petit amphi\, b âtiment Pascal n° 530 - 7 Fév 23 15:00 DESCRIPTION:Unconventional Symmetries from Commutant Algebras\nSanjay Moudg alya (Caltech)\nSpecial time: 3pM!\nZoom seminar:\n\n\nhttps://cnrs.zoom.u s/j/98434226211?pwd=dGJHSlgrNDNhbDcyUE1KdzBSQjc1Zz09\n\nMeeting ID: 984 34 22 6211\nPasscode: RbqTd5\n\n\n\nThe study of symmetry lies at the heart o f various parts of physics. In equilibrium physics\, symmetries are useful in classifying phases of matter and in non-equilibrium physics\, they are necessary to understand the phenomenon of thermalization. Most symmetries conventionally studied in the literature are examples of so-called on-sit e unitary symmetries. While such symmetries are sufficient to explain seve ral physical phenomena\, the recent discovery of weak ergodicity breaking in quantum many-body systems\, particularly the phenomena of Hilbert Space Fragmentation and Quantum Many-Body Scars\, has called for a generalizati on of the notion of symmetry. The conventional theory of thermalization i n quantum many-body systems demands that all states within a given symmetr y sector can be connected to each other under the dynamics of the system.  However\, quantum many-body systems exhibiting weak ergodicity breaking possess additional closed subspaces that are dynamically disconnected from the rest of the Hilbert space. These subspaces cannot be explained in ter ms of conventional symmetries\, which leads to a breakdown of conventional thermalization in such systems. In this talk\, I will discuss a general mathematical framework to define symmetries based on so-called commutant a lgebras\, which leads to a generalization of the notion of symmetry beyond the conventional ones. This provides a precise explanation of weak ergodi city breaking in terms of unconventional non-local symmetries\, allows us to cast various different dynamical phenomena in the literature into a si ngle unified framework\, and also opens up several questions on symmetries .\n\nReferences:\nhttps://arxiv.org/abs/2108.10324\nhttps://arxiv.org/abs/ 2209.03370\nhttps://arxiv.org/abs/2209.03377 CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-858@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230214T110000 DTEND;TZID=Europe/Paris:20230214T120000 DTSTAMP:20230130T123844Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-muhittin-mungan-cologne/ SUMMARY:Séminaire du LPTMS : Muhittin Mungan (Cologne University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Fév 23 11:00 DESCRIPTION:Memory Formation in Driven Disordered Systems - Dead or Alive\n Muhittin Mungan (Institute of Biological Physics\, University of Cologne)\ nHybrid: onsite seminar + zoom.\n\nhttps://cnrs.zoom.us/j/94214588287?pwd= SUZuV1BlcnF4UUVxekR2d2JmY1Vzdz09\n\nMemory formation and ageing are abunda nt in many soft matter systems. The disorder underlying these systems give s rise to a rich energy landscape\, consisting of a large number of metast able states. These landscapes are accompanied by a plethora of pathways\, along which such systems can evolve when exposed to a varying temperature or mechanical load. The resulting dynamics can be rather complex\, giving rise to dynamically critical phenomena such as irreversibility and yieldin g. At the same time\, such system exhibit parallels with the adaptive evol ution of biological populations in time-varying environments. In this talk I will present a general framework to analyze the dynamics and memory for mation of driven disordered systems. I will then show how this framework c an be applied to understand both the response of a cyclically sheared amor phous solid\, as well as the antibiotic resistance evolution of a microbia l population subject to time-varying drug concentrations. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-854@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230221T110000 DTEND;TZID=Europe/Paris:20230221T120000 DTSTAMP:20230130T112711Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-igor-bodrenko-cagliari-university/ SUMMARY:Séminaire du LPTMS : Igor Bodrenko (Cagliari University) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Fév 23 11:00 DESCRIPTION:Diffusion of flexible molecules through flexible nanochannels:  the concept of size.\nIgor Bodrenko (Cagliari University)\nHybrid: onsit e seminar + zoom.\n\nhttps://cnrs.zoom.us/j/96968433581?pwd=UStqem83UzFYTF F4ODlSclExSGZXZz09\n\nFlexible molecules can adopt their shape and diffuse through nanopores which are significantly more tight than the average dim ension of the molecules in bulk solution.  This phenomenon is known for p olymers which can unfold\, translocate through a tight pore and then refol d again [1]. Recently\, we have demonstrated that the effect of molecule/p ore flexibility is of crucial importance for the penetration of biological ly related small molecules\, like nutrients and drugs\, into bacterial cel ls [2\,3].\n\nHere\, we will discuss a statistical approach [3] which allo ws one to separate the effect of steric hindrance from other the molecule- pore-solute interactions. We will also  define the concepts of the molecu le and the pore size adequate for the diffusive transport through nanopore s. The average cross sectional area profile along the channel and the aver age minimal projection area of the molecule are the two major quantities d etermining the steric part of the free energy barrier for the translocatio n of the particle in the case of a small rigid particle and a large rigid channel. In this case\, the description is reduced to the Fick-Jacobs mode l. However\, the flexibility of the channel's cross section and that of th e molecule's size play a crucial role when a large molecule goes through a narrow channel. We treat the flexibility in terms of the equilibrium fluc tuations of the pore and of the molecule\, independently.\n\nFor the case of gaussian fluctuations\, we derived simple analytical expressions for th e steric free energy barrier and for the permeability coefficient of the p ore. The model is compared with the all-atom MD simulations of the transpo rt of Van-der-Waals spheres of various radii through a biological nanochan nel\, as well as of the transport of real molecules through artificial rig id pores of different radii. \n\n[1] M. Muthukumar\, “Polymer Transloca tion”\, CRC Press\, 2011\n\n[2] Julia Vergalli\, et.al. \, “Porins and small-mol-ecule translocation across the outer membrane of Gram-negative bacteria”\,  Nature Reviews Microbiology\, 18\,164–176 (2020)\; DOI: 10.1038/s41579-019-0294-2\n\n[3] Igor V Bodrenko et.al\, “Diffusion of l arge particles through small pores: From  entropic to enthalpic transport ”\, J. Chem. Phys.\, 150 (2019) 211102\; DOI: 10.1063/1.5098868 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-855@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230307T110000 DTEND;TZID=Europe/Paris:20230307T120000 DTSTAMP:20221027T131647Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mathias-rousset-irmar/ SUMMARY:Séminaire du LPTMS : Mathias Rousset (IRMAR) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Mar 23 11:00 DESCRIPTION:TBA\n Mathias Rousset (Rennes University)\n\n\nHybrid: onsite seminar + zoom.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-864@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230314T110000 DTEND;TZID=Europe/Paris:20230314T120000 DTSTAMP:20221211T201743Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kirill-polovnikov-curie-skoltech/ SUMMARY:Séminaire du LPTMS : Kirill Polovnikov ( Institut Curie and Skolte ch) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Mar 23 11:00 DESCRIPTION:TBA\n Kirill Polovnikov (Institut Curie and Skoltech)\n\n\nHybr id: onsite seminar + zoom.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-842@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230321T110000 DTEND;TZID=Europe/Paris:20230321T120000 DTSTAMP:20221028T150725Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-chris-baldwin-jqi/ SUMMARY:Séminaire du LPTMS : Christopher Lee Baldwin (JQI) - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Mar 23 11:00 DESCRIPTION:TBA\nChristopher Lee Baldwin (University of Maryland)\n\nHybrid : onsite seminar + zoom. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-876@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230321T110000 DTEND;TZID=Europe/Paris:20230321T120000 DTSTAMP:20230504T111828Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-luca-peliti-smri-rome/ SUMMARY:Séminaire du LPTMS : Luca Peliti (SMRI Rome) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Mar 23 11:00 DESCRIPTION:Fluctuation Relations and Fitness in Cell Populations\nLuca Pel iti (Santa Marinella Research Institute)\n\nHybrid: onsite seminar + zoom. \n\nhttps://cnrs.zoom.us/j/96871767341?pwd=QngzWUd6cDV2K1R4UUpkNTB0UFkwUT0 9\nMeeting ID: 968 7176 7341\nPasscode: 6Wm4Fm\n\n\n\n\nRecent advances in single-cell lapse microscopy allow to monitor the division dynamics and t he phenotypic state in growing cell populations. The resulting data allow to infer the fitness of a phenotype in constant and varying environments\, by exploiting fluctuation relations similar to those of stochastic thermo dynamics. I shall summarize these techniques\, highlighting their strong p oints and possible pitfalls.\n\nJoint work with Arthur Genthon and David L acoste (ESPCI) and Takeshi Nozoe (Tokyo) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-863@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230328T110000 DTEND;TZID=Europe/Paris:20230328T120000 DTSTAMP:20221209T164040Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-enrico-malatesta-bocconi/ SUMMARY:Séminaire du LPTMS : Enrico Malatesta (Bocconi University) - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 28 Mar 2 3 11:00 DESCRIPTION:TBA\n Enrico Malatesta (Bocconi University)\n\n\nHybrid: onsit e seminar + zoom.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-868@lptms.universite-paris-saclay.fr DTSTART:20230330T090000Z DTEND:20230330T180000Z DTSTAMP:20230118T152522Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journees-interdis ciplinaires-de-physique-statistique/ SUMMARY:Journées interdisciplinaires de physique statistique - Petit amphi \, bâtiment Pascal n° 530 - 30 Mar 23 09:00 DESCRIPTION:Organisateurs : Silvio Franz\, Mauro Pastore CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-869@lptms.universite-paris-saclay.fr DTSTART:20230331T090000Z DTEND:20230331T180000Z DTSTAMP:20230118T152502Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journees-interdis ciplinaires-de-physique-statistique-2/ SUMMARY:Journées interdisciplinaires de physique statistique - Petit amphi \, bâtiment Pascal n° 530 - 31 Mar 23 09:00 DESCRIPTION:Organisateurs : Silvio Franz\, Mauro Pastore CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-877@lptms.universite-paris-saclay.fr DTSTART:20230331T110000Z DTEND:20230331T120000Z DTSTAMP:20230504T111909Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnaire-du-lptms-benjamin-doyon-kings-college/ SUMMARY:Séminaire exceptionnel du LPTMS: Benjamin Doyon (King'\;s Coll ege) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 31 Mar 23 11:00 DESCRIPTION:A family of integrable Hamiltonian systems of classical particl es with arbitrary two-body scattering shifts\nBenjamin Doyon (King's Colle ge)\nSome special systems of classical particles are integrable in the sen se of Liouville: there are as many conserved quantities\, including the Ha miltonian itself\, as there are particles. When this happens\, the system is typically not chaotic\, and many of its properties can be evaluated exa ctly. It is interesting to find many-body systems that are integrable: int eraction potentials that can written for any number of particles N\, and s uch that the system is integrable for all N. When the interaction is local enough\, such a many-body integrable system has the property of elastic a nd factorised scattering: in any scattering event\, the sets of in- and ou t-momenta are the same. The trajectories are still shifted from linear tra jectories due to the interaction\, but these shifts are "factorised" into two-body shifts\, as if the many-body scattering happened as a succession of separate two-body scattering events. Amongst the known locally interact ing integrable models\, only very specific functions of momenta do play th e role of two-body shifts. I will overview a new family of many-body integ rable systems for which the scattering two-body function can be taken as a ny (differentiable\, positive) function. It can be seen as a certain flow on interactions\, starting from free particles\, and produced by perturbin g by bilinear terms in conserved densities and currents. If time permits\, I will explain how we evaluate the thermodynamics of this system\, which gives the classical version of the so-called thermodynamic Bethe ansatz\, and its hydrodynamics\, which gives generalised hydrodynamics. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-878@lptms.universite-paris-saclay.fr DTSTART:20230407T110000Z DTEND:20230407T121500Z DTSTAMP:20230504T111920Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-albertus-viljoen/ SUMMARY:Physics-Biology interface seminar: Albertus Viljoen - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 7 Avr 23 11:00 DESCRIPTION:AFM force spectroscopy studies unravel how functional nanodomai ns on pathogenic bacteria drive selective recognition by host immune cells .\nAlbertus Viljoen (Louvain Institute of Biomolecular Science and Technol ogy\, UC Louvain)\nAdhesion to host cells and tissues is an important firs t step in infection employed by many bacterial pathogens. In mycobacteria\ , surface hydrophobic properties and specialized receptor-ligand bonds det ermine how these pathogens adhere to host immune cells. We recently used f ast quantitative imaging (QI) atomic force microscopy (AFM) combined with hydrophobic tips to quantitatively map hydrophobic properties of mycobacte rial pathogens\, at high spatial resolution1. We discovered that abundant polar outer membrane lipids modulate the nanoscale distribution of hydroph obicity on the bacterial surface\, which could be modulated by treatments with specific antibiotics. This led us to hypothesize that the presence of nanodomains enriched in specific surface molecules have a functional role in pathogen-host interactions. We have now found support for this hypothe sis by studying recognition of pathogenic mycobacteria by the pathogen rec ognition receptor DC-SIGN 2. By probing live mycobacteria with AFM tips mo dified with single tetramers of the soluble extracellular domain of DC-SIG N we observed that the receptor forms complexes with ligands on pathogenic and nonpathogenic mycobacteria. Moreover\, the complexes are mechanically weak\, rupturing at ~30 pN under physiological force loading rates. Howev er\, by relying on the specific force-extension signatures generated we co uld map the locations of single DC-SIGN ligands at a resolution of ~20 nm\ , which revealed concentration of ligands into dense nanodomains on pathog enic mycobacteria exclusively. Upon bacteria-host cell contact\, ligand na nodomains induce the recruitment and clustering of DC-SIGN\, resulting in mechanically stable adhesion. This work highlights the key role of cluster ing of both ligands on pathogenic bacteria and DC-SIGN host receptors in p athogen recognition\, a mechanism that might be widespread in host-pathoge n interactions.\n \;\n\n Viljoen\, A.\, Viela\, F.\, Kremer\, L. & \; Dufrêne\, Y. F. Fast chemical force microscopy demonstrates that glyco peptidolipids define nanodomains of varying hydrophobicity on mycobacteria . Nanoscale Horiz. 5\, 944–953 (2020).\n Viljoen\, A. et al. Nanoscale clustering of mycobacterial ligands and DC-SIGN host receptors are key det erminants for pathogen recognition. Sci. Adv. accepted\, (2023).\n CATEGORIES:seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-879@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230413T110000 DTEND;TZID=Europe/Paris:20230413T120000 DTSTAMP:20230504T111926Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-steven-tomsovic-washington-state-university/ SUMMARY:Séminaire du LPTMS : Steven Tomsovic (Washington State University) - Grand amphi\, bâtiment Pascal n° 530 - 13 Avr 23 11:00 DESCRIPTION:Controlling Many-Body Quantum Chaos: Optimal Coherent Targeting \nSteven Tomsovic (Washington State University)\nHybrid: onsite seminar + zoom.\n\nhttps://cnrs.zoom.us/j/98130328474?pwd=UHBsOWR5SW9mYzFFa1ZiSVM3WD Vkdz09\n\nMeeting ID: 981 3032 8474\nPasscode: uB0vej\n\nOne of the princi pal goals of controlling classically chaotic dynamical systems is known as targeting\, which is the very weakly perturbative process of using the sy stem's extreme sensitivity to initial conditions in order to arrive at a p redetermined target state.  It is shown that a generalization to chaotic quantum systems is possible in the semiclassical regime\, but requires tai lored perturbations whose effects must undo the dynamical spreading of the evolving quantum state.  For simplicity\, the procedure described here i s first applied to a simple paradigm of chaos that has been realized in qu antum simulations with ultracold atoms\, the quantum kicked rotor\, to ill ustrate the method\, and investigate its accuracy.  Starting with a minim um uncertainty wave packet\, it is shown that coherent targeting leads to vanishing errors as $\\hbar \\rightarrow 0$.  An approximate\, simpler me thod is also shown\, illustrating the flexibility of the concept.  Finall y\, quantum targeting is illustrated for initial coherent states in the Bo se-Hubbard model in a chaotic regime. CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-880@lptms.universite-paris-saclay.fr DTSTART:20230420T110000Z DTEND:20230420T120000Z DTSTAMP:20230504T111940Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-phys ique-statistique-du-lptms-christophe-texier-lptms/ SUMMARY:Séminaire de Physique Statistique du LPTMS: Christophe Texier (LPT MS) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Avr 23 11:00 DESCRIPTION:Random matrix products : from the Lyapunov exponent to the gene ralized Lyapunov exponent\nChristophe Texier (LPTMS)\n\nRandom matrix prod ucts (RMP) appear in various contexts of statistical physics. The most sim ple property of RMP is the Lyapunov exponent\, which measures the typical exponential growth rate.\nFocusing on the case of 2*2 matrices\, I will pr ovide a brief review of the methods and some known results.\nThe study of fluctuations of random matrix products can also be relevant in some cases. This requires to introduce the generalized Lyapunov exponent (GLE)\, i.e. the cumulant generating function of the log of the matrix product. Its de termination is much more difficult and requires to identify the largest ei genvalue of a certain non-Hermitian operator. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-875@lptms.universite-paris-saclay.fr DTSTART:20230421T110000Z DTEND:20230421T121500Z DTSTAMP:20230504T111757Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-romain-levayer/ SUMMARY:Physics-Biology interface seminar: Romain Levayer - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 21 Avr 23 11:00 DESCRIPTION:Collective effects in epithelial cell elimination\nRomain Levay er\, Department of Developmental and Stem Cell Biology\, Institut Pasteur\ , Paris\, France\nWhile the signals regulating apoptosis during developmen t are rather well known\, what sets the precise spatio-temporal distributi on of cell death and the adjustment of cell elimination to local perturbat ions is not well understood. Similarly\, how cells eventually engage in ap optosis and how the removal of cells from epithelial layer is orchestrated through cell extrusion remained poorly understood\, especially in vivo. I n this seminar\, I will illustrate the multi-layered regulation of cell de ath through three examples\, the first one describing the impact of mechan ical stress on cell elimination\, the second one on local feedbacks that c an fine tune the distribution of cell elimination in space and time reveal ing interesting self-organising properties\, and the last one focusing on the engagement in apoptosis and the coordination of cell extrusion by casp ases. Altogether\, I will propose a roadmap to build a more predictive und erstanding of cell death in vivo that can directly impact tissue homeostas is\, morphogenesis\, growth and clonal selection. CATEGORIES:seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-874@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230502T110000 DTEND;TZID=Europe/Paris:20230502T120000 DTSTAMP:20230504T111658Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ken-ichiro-imura-tokyo-university/ SUMMARY:Séminaire du LPTMS : Ken Ichiro Imura (University of Tokyo) - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Mai 23 11:00 DESCRIPTION:Entanglement dynamics in a non-Hermitian quantum system\n Ken Ichiro Imura (University of Tokyo)\n\n\nHybrid: onsite seminar + zoom.\n\n https://cnrs.zoom.us/j/99158344817?pwd=UXJhNUpQZG45RXJqU29oNThrM0x2UT09\nM eeting ID: 991 5834 4817\nPasscode: 5pDCkx\n\n\nQuantum mechanics describe d by a non-Hermitian Hamiltonian has been of much interest recently. In re ality\, such a Hamiltonain is associated with an open quantum system. Here \, we will particularly focus on a specific type of non-Hermiticity\, repr esented by a non-reciprocal (asymmetric) hopping in a 1D tight-binding mod el: the so-called Hatano-Nelson model [1]. Effects of on-site disorder and inter-particle interaction is also taken into account. In the regime of w eak disorder\, the eigen wave functions are extended\, and corresponding e igen energies are complex under the periodic boundary. In the time evoluti on an initial wave packet with many eigenstates superposed tends to evolve into a single eigen state with a maximal imaginary part. This results in a non-monotonic time evolution of the entanglement entropy in the regime o f intermediate disorder\; in the regime\, collapse of the superposition is not too fast but occurs in the time scale comparable to the growth of the entanglement entropy [2]. The effect of on-site disorder W is also non-mo notonic. With increasing W\, it first enhances the entanglement entropy th en suppresses it. After a long enough time in the quench dynamics\, the en tanglement entropy in the clean and non-interacting limit obeys a logarith mic scaling [3]\, reminiscent of the one known (in the Hermitian case) in conformal field theory [4].\n\n[1] N. Hatano and D. R. Nelson\, Phys. Rev. Lett. 77\, 570 (1996).\n[2] T. Orito and K.-I. Imura\, Phys. Rev. B 105\, 024303 (2022).\n[3] T. Orito and K.-I. Imura\, in preparation.\n[4] P. Ca labrese\, J. Cardy\, J. Phys. A: Math. Theor. 42 504005 (2009).\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-870@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230509T110000 DTEND;TZID=Europe/Paris:20230509T120000 DTSTAMP:20230504T111539Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-stephane-ouvry-lptms/ SUMMARY:Séminaire du LPTMS : Stéphane Ouvry (LPTMS) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Mai 23 11:00 DESCRIPTION:Inclusion statistics and particle condensation in 2 dimensions\ nStéphane Ouvry (LPTMS)\nHybrid: onsite seminar + zoom.\nhttps://cnrs.zoo m.us/j/99846836701?pwd=bEZkb1pxWFpYL3JDSTlvTHpnd2g0UT09\nMeeting ID: 998 4 683 6701\nPasscode: 9Lvu0U\n\nWe propose a new type of quantum statistics\ , which we call inclusion statistics\, in which particles tend to coalesce more than ordinary bosons. Inclusion statistics is defined in analogy wit h exclusion statistics\, in which statistical exclusion is stronger than i n Fermi statistics\, but now extrapolating beyond Bose statistics\, result ing in statistical inclusion. A consequence of inclusion statistics is tha t the lowest space di- mension in which particles can condense in the abse nce of potentials is d = 2\, unlike d = 3 for the usual Bose-Einstein cond ensation. This reduction in the dimension happens for any inclusion strong er than bosons\, and the critical temperature in- creases with stronger in clusion. Possible physical realizations of inclusion statistics involving attractive interactions between bosons may be experimentally achievable. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-871@lptms.universite-paris-saclay.fr DTSTART:20230511T110000Z DTEND:20230511T110000Z DTSTAMP:20230504T111604Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-phys ique-theorique-du-lptms-jean-philippe-bouchaud-cfm/ SUMMARY:Séminaire de Physique Statistique du LPTMS : Jean-Philippe Bouchau d (CFM) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n° 530 - 11 Mai 23 11:00 DESCRIPTION:May's instability in network economies\nJean Philippe Bouchaud (CFM) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-872@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230516T110000 DTEND;TZID=Europe/Paris:20230516T120000 DTSTAMP:20230504T111617Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-denis-bernard-ens-paris/ SUMMARY:Séminaire du LPTMS : Denis Bernard (ENS Paris) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Mai 23 11:00 DESCRIPTION:TBA\nDenis Bernard (ENS Paris)\nHybrid: onsite seminar + zoom. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-851@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230530T110000 DTEND;TZID=Europe/Paris:20230530T120000 DTSTAMP:20230109T101412Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-luca-salasnich-padova/ SUMMARY:Séminaire du LPTMS : Luca Salasnich (Padua University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 30 Mai 23 11: 00 DESCRIPTION:Superfluid thermodynamics of the unitary Fermi gas\n Luca Salas nich (Padua University)\n\n\nHybrid: onsite seminar + zoom.\n\n\nWe invest igate the superfluid thermodynamics of the unitary Fermi gas by introducin g a model based on the\nzero-temperature spectra of both bosonic collectiv e modes and fermionic single-particle excitations.\nWe calculate the Helmh oltz free energy and from it we obtain the entropy\, the internal energy a nd\nthe chemical potential as a function of the temperature. By using thes e quantities and the Landau's\nexpression for the superfluid density we de termine analytically the superfluid fraction\, the critical\ntemperature\, the first sound velocity and the second sound velocity. We compare recent \nexperimental results [Science 375\, 528 (2022)] of the superfluid unitar y Fermi gas near the critical\ntemperature with our model. We find very go od agreement between experimental data and our\ntheory for several quantit ies such as first sound\, second sound\, and superfluid fraction. We also\ nshow that mode mixing between first and second sound occurs. Finally\, we characterize the\nresponse amplitude to a density perturbation: close to the critical temperature both first and second\nsound can be excited throu gh a density perturbation\, whereas at lower temperatures only the first\n sound mode exhibits a significant response. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-882@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230620T110000 DTEND;TZID=Europe/Paris:20230620T120000 DTSTAMP:20230619T120143Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-amit-ghosal-iiser-calcutta/ SUMMARY:Séminaire du LPTMS : Amit Ghosal (IISER\, Kolkata) - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Juin 23 11:00 DESCRIPTION:TBA\n Amit Ghosal (IISER\, Kolkata)\nOnsite seminar. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-888@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230622T110000 DTEND;TZID=Europe/Paris:20230622T110000 DTSTAMP:20230619T120905Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-de-phys ique-theorique/ SUMMARY:Séminaire de Physique Statistique du LPTMS : Gérard Ben Arous (Ne w York Univ.) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pasc al n°530 - 22 Juin 23 11:00 DESCRIPTION: CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-883@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230627T110000 DTEND;TZID=Europe/Paris:20230627T120000 DTSTAMP:20230619T120150Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-olesia-dogonasheva-ens-paris-and-moscow-university/ SUMMARY:Séminaire du LPTMS : Olesia Dogonasheva (ENS Paris and Moscow Univ ersity) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n° 530 - 27 Juin 23 11:00 DESCRIPTION:Delta-theta-gamma interplay for contextualized speech parsing\n Olesia Dogonasheva (ENS Paris and Moscow University)\nHybrid: onsite semin ar + zoom.\n\nhttps://cnrs.zoom.us/j/91877559782?pwd=UnhCQlEzVTJ1Y0FLczNIQ 0hIdWJPdz09\n\nMeeting ID: 918 7755 9782\n\nPasscode: Fab4G9\n\nRhythms st retching across multiple interacting frequencies and spatial scales are ub iquitous in brain activity during complex cognitive tasks. Yet their funct ional significance is hotly debated between a structural epiphenomenon of brain activity and mechanisms implementing computations. Speech processing \, with its temporal cadence and multi-scale of syntactic invariants (syll ables\, words)\, is a paradigmatic example where rhythms have been propose d to play a key role\, with a speech-modulated hierarchical structure of i ntercoupled cortical oscillations correlating with successful comprehensio n. Experiments show that speech recognition remains largely intact when co mpressed up to a certain temporal factor\, and the re-spacing of chunks of incomprehensible compressed speech with silences recovers comprehension. Previous models proposed that theta-gamma interactions enable syllable par sing. However\, this did not resolve questions about word/phrase recogniti on and\, notably\, the observed role of delta rhythm in top-down informati on flow. To address the above questions\, we propose an inference model (B RyBI) that incorporates a wide range of brain-rhythm data mechanistically and accounts for time-invariant word recognition. Our model predicts that delta-implemented word context allows for syllable parsing without precise locking of the theta-rhythmic activity. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-873@lptms.universite-paris-saclay.fr DTSTART:20230710T140000Z DTEND:20230710T140000Z DTSTAMP:20230623T073658Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-lara-koehler/ SUMMARY:Soutenance de thèse : Lara Koehler - Petit amphi\, bâtiment Pasca l n° 530 - 10 Juil 23 14:00 DESCRIPTION:Principles of self-assembly for particles with simple geometrie s and complex interactions\n \;\nLara Koehler (LPTMS)\n \;\n\nIn l iving cells\, proteins self-assemble into large-scale functional structure s based both on the specific interactions between different spots on their surfaces. The general principles that allow complex interactions to cont rol self-assembly are largely unknown. Here\, we introduce model lattice p articles with trivial geometries but highly complex interactions and stud y their self-assembly using numerical simulations. We find that strongly a nisotropic particles produce non-trivial aggregates that fall into a few s tereotypical categories. Using machine learning\, we accurately predict th e outcome of this aggregation based on the presence of pair interactions t hat locally favor periodic un-frustrated arrangements. We also show that the stereotypical aggregates are fixed-points of a numerical real-space re normalization transformation.These results offer a first overview of the r ich design space associated with identical particles with complex interact ions\, and could inspire engineered self-assembling nano-objects as well a s help understand the emergence of robust functional protein structures.  In particular\, we show that local interaction can robustly control the s ize of spherical or fibrous self-assemblies of identical particle. Finall y\, we suggest that it is possible to systematically identify the con\n\n& nbsp\;\n\nJury : Martin Lenz (directeur de thèse)\, Mikhail Brenner (rapp orteur)\, Ralf Evenaers (rapporteur)\, Friedrich Simmel (examinateur)\, Zo rana Zeravcic (examinatrice)\, Chase Broederz (examinateur) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-884@lptms.universite-paris-saclay.fr DTSTART:20230718T100000Z DTEND:20230718T100000Z DTSTAMP:20230623T073756Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-lorenzo-rosso-2/ SUMMARY:Soutenance de thèse: Lorenzo Rosso - Petit amphi\, bâtiment Pasca l n° 530 - 18 Juil 23 10:00 DESCRIPTION:Dissipative Yb gases\n \;\nLorenzo Rosso (LPTMS)\n \;\n \nUltracold atomic gases are an experimental platform to study quantum man y-body physics\, allowing the observation of non-trivial many-body phenome na in and out of equilibrium\, thus making their theoretical understanding a priority. They usually feature a high degree of control over system par ameters and allow for an almost perfect decoupling from the surrounding en vironment. However\, despite the tremendous  experimental progress\, a pe rfect isolation has never been reached\, for instance because of particle losses\, causing energy relaxation and decoherence phenomena. As such\, di ssipation is generally seen as an enemy to be fought harshly since it tend s to destroy and wash out the interesting quantum effects that can be inve stigated. On the other hand\, a research line that developed in the last d ecade has shown that this is not always the case. In particular\, the inte rplay between the coherent unitary evolution and the coupling to the envir onment can lead to a non-trivial dynamics and to stationary states featuri ng strong quantum correlations and critical behaviors. Although of primary interest to understand the limitations of the simulation of quantum many- body physics\, a complete theoretical description of the effect of losses on correlated quantum gases is still lacking. Even if several experiments have studied the dynamics of correlated one-dimensional quantum gases in t he presence of losses\, both in the bosonic and fermionic cases\, the theo retical characterisation of the interplay between the unitary and lossy dy namics has only recently emerged as an important challenge and it is curre ntly starting to attract novel attention. This thesis aims at the study of lossy correlated gases. Our work puts a particular emphasis on the theore tical characterisation of the interplay between the Hamiltonian unitary dy namics and losses. We consider different bosonic and fermionic models in t he presence of mainly two-body losses\, we devise effective descriptions f or the relevant degrees of freedom of such systems\, capable of predicting the real time dynamics of the main observables\, which we then benchmark against exact numerical simulation of the full master equation.\n\nJury : Leonardo Mazza (directeur de thèse)\, Igor Lesanovsky (rapporteur)\, Joha nnes Schachenmayer (rapporteur)\, Isabelle Bouchoule (examinatrice)\, Andr ea De Luca (examinateur)\, Laurent Sanzhez-Palencia (examinateur) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-885@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230905T110000 DTEND;TZID=Europe/Paris:20230905T120000 DTSTAMP:20230829T151917Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-david-martin-chicago/ SUMMARY:Séminaire du LPTMS : David Martin (Chicago University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 5 Sep 23 11:0 0 DESCRIPTION:Emergent phenomena in active matter and beyond\nDavid Martin (C hicago University)\n \;\n\nActive Matter deals with the study of micro scopic agents able to exert self-propulsion forces on their medium. These microscopic agents can model various entities evolving in a large range of scales in Nature\; from bacterias and flying birds to man-made self-phore tic colloids. The presence of self-propulsion drives the active agents out of equilibrium and allows for the emergence of landmark phenomena\, both at the level of a single agent and at the collective level in ensembles of agents. In this presentation\, I will first characterize such nonequilibr ium phenomena for a single active particle. I will then move to the charac terization of different collective behaviors as a function of the microsco pic interactions between the active agents. In particular\, I will assess how topological\, repulsive and nonreciprocal interactions interplay with the emergence of collective motion.\n\nhttps://universite-paris-saclay-fr. zoom.us/j/98599274512?pwd=MWZKQ2xGN01ha1JxbUwwQlFYV0hlQT09\n\nMeeting ID: 985 9927 4512\nPasscode: 589327 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-889@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230914T090000 DTEND;TZID=Europe/Paris:20230914T183000 DTSTAMP:20230914T065129Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journee-ffj/ SUMMARY:Journée FFJ - Amphi BLANDIN du LPS de la Faculté des Sciences d ’Orsay (Bâtiment 510) - 14 Sep 23 09:00 DESCRIPTION:Affiche Journée FFJ 2023\n9h00-12h30 Présentations orales (L PS (bât. 510)\, Amphi Blandin)\n9h00- 9h30 René Farcy\, LAC\n"Perception fonctionnelle de l'espace en 3D pour les non-voyants par la\ntélémétri e laser et la rééducation"\n9h30-10h00 Erika Porcel\, ISMO\n"Les nanopar ticules combinées à la radiothérapie\, un nouvel outil contre le\ncance r"\n10h00-10h30 Anne Davaille\, FAST\n"Fluid dynamics in a soft planet - D ynamique des fluides dans une planète molle"\n10h30-11h00 PAUSE CAFÉ\n11 h00-11h30 Aniina Salonen et Sandrine Mariot\, LPS\n"Controlling foam stabi lity through interfaces or the bulk"\n11h30-12h00 Satya Majumdar\, LPTMS\n "Stochastic resetting"\n12h00-12h30 Fabienne Goldfarb\, LUMIN\n"Quantum op tics and spin noise spectroscopy in a metastable Helium vapor at\nroom tem perature"\n12h30-14h00 Buffet (Parvis du Bâtiment Pascal n° 530)\n14h00- 17h00 Visite des laboratoires par groupes\nFAST : Plateforme expérimental e de caractérisation des propriétés\nmécaniques et physicochimiques de fluides et solides.\nISMO : Expérience de microscopie à fluorescence av ec optique adaptative\npour la bio-imagerie à haute résolution.\nPlatefo rme de Caractérisation Physico Chimique.\nLAC : Expérience "BaF: refroid issement de molécules dipolaires"\nLPS : Microscopes électroniques à tr ansmission\nLUMIN : A définir CATEGORIES:seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-902@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230915T110000 DTEND;TZID=Europe/Paris:20230915T120000 DTSTAMP:20230911T124400Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-quantifying-uncertainty-in-symmetric-particle-based-model s-for-statistical-inference/ SUMMARY:Physics-Biology Interface seminar: Quantifying Uncertainty in Symme tric Particle-Based Models for Statistical Inference - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 Sep 23 11:00 DESCRIPTION:Quantifying Uncertainty in Symmetric Particle-Based Models for Statistical Inference\n\nAntonin Della Noce (Institut Gustave Roussy)\n\nA bstract: Particle-based or Individual-Based Models (IBMs)\, initially deve loped for kinetic gas theory\, have found applications across various scie ntific disciplines\, including computational biology\, for the purpose of explaining emergent macroscopic phenomena from microscopic interactions. I n many applications\, some parameters of the system need to be inferred fr om observation data carrying very partial information on the underlying po pulation / particle assembly This presentation is divided in two parts. Th e initial part addresses the issue of parameter inference in scenarios whe re observational data provide limited information about the underlying pop ulation or particle assembly. It will discuss the propagation of this part ial system knowledge into uncertainties associated with parameter values. The subsequent part focuses on the evaluation of the consistency of mean-f ield approximations\, specifically within the framework of a model represe nting plant populations in competition for light\, which is partially obse rved.\n\n\nBio: Antonin Della Noce obtained his Ph.D. in Applied Mathemati cs from the Laboratory of Mathematics and Computer Science for Complex Sys tems (MICS) at Université Paris-Saclay. His doctoral research focused on population dynamical systems. Following his Ph.D.\, Antonin collaborated w ith Institut Gustave Roussy to conduct biostatistical research aimed at pr edicting breast cancer toxicities through the use of high-throughput prote omics. Additionally\, he worked with Hôpital Bichat on developing screeni ng strategies for sequencing patients suspected of having connective tissu e disorders. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-893@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230919T110000 DTEND;TZID=Europe/Paris:20230919T120000 DTSTAMP:20230906T161636Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ruben-zakine-polytechnique/ SUMMARY:Séminaire du LPTMS : Ruben Zakine (Ecole Polytechnique) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Sep 23 11 :00 DESCRIPTION:Socioeconomic agents as active matter and nucleation paths in a ctive field theories\n \;\nRuben Zakine (Ecole Polytechnique)\n \; \n\n\nIn this seminar\, we will tackle two subjects whose common thread is active matter.\nIn a first part\, I will focus on a socio-economic occupa tion model in the spirit of the Sakoda-Schelling model\, historically intr oduced to shed light on segregation dynamics among human groups. For a lar ge class of utility functions and decision rules that drive the system out of equilibrium\, we recover an equilibrium-like phase separation phenomen ology. Within the mean-field approximation I will show how the model can b e mapped\, to some extent\, onto an active matter field description\, pavi ng the way for a unifying framework which considers population and price d ynamics within a field theoretic approach.\nIn a second part\, using the n ucleation-induced active phase separation as a starting observation\, I wi ll ask a general question: How can one predict the final phase of a nonequ ilibrium system where several phases compete? Since resorting to the free energy minimization is impossible\, the transition depends crucially on th e system’s dynamics. By using a minimum action method\, we will pinpoint the first-order phase transition in some spatially-extended nonequilibriu m systems\, including the Active Model B\, the natural nonequilibrium exte nsion of the Cahn-Hilliard dynamics. The paths of the transitions and thei r critical nuclei are notably identified\n\nhttps://universite-paris-sacla y-fr.zoom.us/j/92254477857?pwd=MDRXYVcrQW9oSjFlbElWV3I1UW1HQT09\n\nMeeting ID: 922 5447 7857\nPasscode: 700442\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-907@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230920T100000 DTEND;TZID=Europe/Paris:20230920T110000 DTSTAMP:20230918T081254Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-informe l-kinya-takahashi-kyushu-institute-of-technology/ SUMMARY:Séminaire informel : Kin'Ya Takahashi (Kyoto University) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Sep 23 1 0:00 DESCRIPTION:Noninstanton tunneling for a periodically perturbed rounded-rec tangular potential\n \;\nKin'Ya Takahashi (Kyoto University)\n \;\ n\nWe study tunneling probabilities with changing Planck’s constant for a periodically perturbed rounded rectangular potential\, for which instant on tunneling is substantially prohibited. The periodical perturbation crea tes an energy ladder of harmonic channels at En = EI + n hbar　ω. Harmon ic channels above the potential height V0 induce multi-quanta absorption t unneling (MQAT)\, and the harmonic channel just above V0 dominantly contri butes to noninstanton tunneling. The replacement of the dominant harmonic channel makes a sawtooth structure with changing 1/hbar. The sawtooth stru cture made by the tunneling probability in the potential region is accompa nied by resonance peaks due to the resonance states above the potential. T he sawtooth structure is also observed with changing ω. Thus\, this is th e essential nature of MQAT. We introduce an effective formula to character ize the profile of the sawtooth structure. Furthermore\, the sawtooth stru cture can be reproduced by the complex semiclassical method except for sma ll neighborhoods the switching regions including resonance peaks. The Meln ikov method\, i.e.\, approximate semiclassical method\, provides the essen tially same formula as mentioned above. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-891@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230922T140000 DTEND;TZID=Europe/Paris:20230922T180000 DTSTAMP:20230904T094314Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-saverio-bocini/ SUMMARY:Soutenance de thèse : Saverio Bocini - Grand amphi\, bâtiment Pas cal n° 530 - 22 Sep 23 14:00 DESCRIPTION:Non-equilibrium dynamics in inhomogeneous quantum many-body sys tems\n \;\n\n\n\n\n\nWe study the non-equilibrium dynamics of quantum spin chains described by translationally-invariant Hamiltonians with short -range interactions. Special attention is given to initial states with loc alized inhomogeneities. Although such scenarios are often addressed by Gen eralized hydrodynamics (GHD)\, we consider special setups that go beyond t his framework. First\, we investigate the system at non-local scales that are not accounted for by GHD\; by deriving exact results for connected cor relations in partitioning protocols\, the locality conditions necessary fo r GHD to work in the non-interacting case are established. Second\, we ex plore macroscopic effects from local perturbations\, showing that minimal modifications\, such as a spin flip\, of an otherwise-stationary initial s tate can induce a global reconfiguration of the spin chain\; this phenomen on is observed perturbing jammed states and quantum scars. Finally\, inspi red by the low bipartite entanglement of the states exhibiting macroscopic effects from local perturbations\, entanglement properties of the spectru m in non-interacting quantum spin chains are investigated\; the study reve als that at most a finite small number of eigenstates satisfy the area law \, also showing that several relevant models exhibit none.\n\n\n\n\n\n&nbs p\;\n\nJury : Benjamin Doyon\, Viktor Eisler\, Maurizio Fagotti (co-direct eur de thèse)\, Laura Foini\, Dragi Karevski\, Léa F. Santos\, Véroniqu e Terras (co-directrice de thèse) CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-886@lptms.universite-paris-saclay.fr DTSTART:20230925T160000Z DTEND:20230925T160000Z DTSTAMP:20230901T095309Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-ana-flack/ SUMMARY:Soutenance de thèse : Ana Flack - Petit amphi\, bâtiment Pascal n ° 530 - 25 Sep 23 16:00 DESCRIPTION:Statistics of particles with long-ranged pairwise interactions\ nIn this thesis\, we investigate the equilibrium and dynamical properties of charged particles in one dimension interacting via long-range interacti ons. First\, we focus on the equilibrium one-dimensional one-component pla sma (1dOCP)\, also known as the jellium model. It consists of $N$ harmonic ally confined charges on a line interacting via pairwise repulsive Coulomb interactions. First\, we introduce some well-known equilibrium properties of the model. Then we present the Coulomb gas method\, which we later use to analyze the behavior of large deviations of different observables in t he limit of a large number of particles. We find the large deviation form for the general full linear statistics\, and we derive the exact formula f or its variance. We continue by computing typical as well as large deviati ons of the gap between two middle particles. We also analyze typical and a typical fluctuations of the number of particles inside of a symmetric inte rval that is in the bulk of the system. The last equilibrium observable th at we study is the truncated linear statistics\, which describes the sum o f the positions of the $N'$ rightmost particles. In the last chapter\, we investigate the Langevin dynamics of the jellium model without the confini ng potential. We find that\, for large times\, there exists a corresponden ce between the dynamical system and the equilibrium 1dOCP. We use this con nection to study fluctuations of the particle positions in the dynamical s ystem.\n\n \;\n\nJury : Ada Altieri\, Fabio Cunden (rapporteur)\, Davi d Dean\, Satya Majumdar (co-directeur de thèse)\, Sergei Nechaev (co-dire cteur de thèse)\, Grégory Schehr (invité)\, Gabriel Tellez (rapporteur) \, Christophe Texier. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-866@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230926T110000 DTEND;TZID=Europe/Paris:20230926T120000 DTSTAMP:20230829T150922Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-laure-dumaz-dma-ens/ SUMMARY:Séminaire du LPTMS : Laure Dumaz (DMA\, ENS Paris) - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Sep 23 11:00 DESCRIPTION:Some aspects of the Anderson Hamiltonian in 1D\nLaure Dumaz (DM A\, ENS Paris)\n \;\n\nIn this talk\, I will present several results o n the Anderson Hamiltonian with white noise potential in dimension 1. This operator formally writes « - Laplacian + white noise ». It arises as th e scaling limit of various discrete models and its explicit potential allo ws for a detailed description of its spectrum. We will discuss localizatio n of its eigenfunctions as well as the behavior of the local statistics of its eigenvalues. Around large energies\, we will see that the eigenfuncti ons are delocalized and follow a universal shape given by the exponential of a Brownian motion plus a drift\, a behavior already observed by Rifkind and Virag in tridiagonal matrix models. Based on joint works with Cyril L abbé. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-909@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230929T110000 DTEND;TZID=Europe/Paris:20230929T120000 DTSTAMP:20230921T170648Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-elisa-floris/ SUMMARY:Physics-Biology interface seminar: Elisa Floris - Moyen Amphi\, Bui lding 510\, Université Paris-Saclay Orsay - 29 Sep 23 11:00 DESCRIPTION:Statistical physics of molecular sorting in living cells\nJoint seminar with the Soft Matter group at LPS\nElisa Floris (Politecnico de T orino\, Italy)\nMolecular sorting is a fundamental process responsible for the organization of intracellular matter: biomolecules that dwell on the outer and inner membranes of the cell are partitioned into spatially local ized domains and engulfed into small vesicles\, that detach from the membr ane to be delivered to their right destinations. A recently proposed theor etical model of this process is based on the coupling of a) phase-separati on-driven formation of sorting domains and b) domain-induced membrane bend ing\, leading to vesicle nucleation [1]. In this minimal model\, molecules are randomly inserted on the lipid membrane\, can diffuse laterally and a ggregate into domains\, and are extracted as part of a domain once it has reached a characteristic extraction size\, representing the average size o f mature vesicles. The predictions of the theory and numerical investigati ons of a latticegas realization of the model show the existence of an opti mal region of parameter space where sorting is most efficient. In the expe riments\, detected domains are commonly classified into two groups: produc tive domains\, if their growth eventually terminates in the nucleation of a vesicle\, and unproductive domains which rapidly dissolve. To interpret these data\, we use central notions of the classical theory of phase separ ation\, such as the boundary tension and the critical domain size. Compari son with experimental results shows that the statistical properties of pro ductive and unproductive domains inferred from experimental data are in ag reement with those predicted from numerical simulations of the model\, com patibly with the hypothesis that molecular sorting is driven by a phase se paration process. The model is further extended to account for the simulta neous sorting of a multiplicity of molecular species\, revealing that\, wh en keeping fixed the total incoming molecular flux\, the average molecule residence time increases with the heterogeneity of the molecular pool acco rding to a simple scaling law. Molecular sorting is further investigated b y means of a simplified one-dimensional lattice-gas model\, where the memb rane is allowed to undergo the topological transformations corresponding t o fusion and detachment of molecule-loaded vesicles.\n\nReferences\n[1] Ma rco Zamparo\, Donatella Valdembri\, Guido Serini\, Igor V Kolokolov\, Vlad imir V Lebedev\, Luca Dall’Asta\, and Andrea Gamba. Optimality in self-o rganized molecular sorting. Physical Review Letters\, 126(8):088101\, 2021 . CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-913@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20230929T134500 DTEND;TZID=Europe/Paris:20230929T153000 DTSTAMP:20230927T115150Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-andrea-tononi-lptms/ SUMMARY:Informal Quantum Seminar - Andrea Tononi (LPTMS) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Sep 23 13:45 DESCRIPTION:Gas-to-soliton transition of attractive bosons on the surface o f a sphere. Andrea Tononi (LPTMS) The many-body physics of condensed mat ter systems in low-dimensional flat geometries has been the object of an e normous amount of studies in the past. Nowadays\, new research possibiliti es are emerging by considering many-body quantum systems confined on curve d manifolds. In systems of ultracold atoms\, for instance\, the recent exp erimental advances allow to confine gases of bosonic atoms in curved setup s such as ellipsoidal shells. A simple and fundamental model of this geome try\, which allows to capture the interplay of spatial curvature and quant um physics in a nontrivial topology\, is constituted by a bosonic gas conf ined on the surface of a sphere. In my talk\, I will present preliminary r esults on this system\, analyzing how an attractive zero-range interaction between the particles can induce a crossover from a weakly-interacting ga s regime to a localized solitonic state. We believe that this crossover\, analyzed through Monte Carlo simulations\, mean-field methods and perturba tion theory\, becomes a first-order phase transition as the number of boso ns confined on the sphere tends to infinity.  CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-906@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231003T110000 DTEND;TZID=Europe/Paris:20231003T120000 DTSTAMP:20230926T173507Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-denis-boyer-universidad-mexico/ SUMMARY:Séminaire du LPTMS : Denis Boyer (Universidad de México) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 3 Oct 23 1 1:00 DESCRIPTION:Optimising the random search of a target with finite lifetime  Denis Boyer (Universidad de México) Random searches find applications in a broad range of problems in biology\, chemistry or everyday life.  In a typical set-up\, a searcher follows a random motion and reacts with a fix ed target site upon first encounter. In many situations\, however\, the ta rget has a finite lifetime after which it becomes inactive\, lost or no lo nger available for reaction.  To be successful\, the searcher must theref ore find the target site before the latter becomes inactive. We present ex act results on a minimal model\, namely\, a one-dimensional searcher perfo rming a discrete time random walk or Lévy flight\, while the target has a n exponentially distributed lifetime. In contrast with the case of a perma nent target\, it is possible to optimise the capture probability and the c onditional mean first passage time at the target. The optimal Lévy index takes a non-trivial value\, even by taking the infinite lifetime limit\, a nd exhibits a "phase transition" as the initial distance to the target sit e is varied. This transition can be discontinuous or continuous depending on the target lifetime. We outline connections between this problem and se arch processes based on resetting. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-890@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231010T110000 DTEND;TZID=Europe/Paris:20231010T120000 DTSTAMP:20231003T131647Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alessandra-carbone-sorbonne-university/ SUMMARY:Séminaire du LPTMS : Alessandra Carbone (IBPS Sorbonne) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Oct 23 11 :00 DESCRIPTION:The complexity of protein interactionsAlessandra Carbone (Sorbo nne University\, CNRS) I will describe two facets of the interaction of p roteins with other biological molecules. Firstly\, I will define soft diso rdered (flexible\, amorphous\, or intrinsically disordered) regions in a p rotein with increasing numbers of bound interactors and analyze the correl ation between disorder\, interfaces and assembly. Secondly\, I will addre ss the question of reconstructing\, ab initio\, protein-protein interactio n networks from protein language models and Neural Networks (NN) with memo ry from sequences with SENSE-PPI. SENSE-PPI addresses interactions between protein sequences\, possibly intrinsically disordered\, belonging to a mo del or non-model organism\, or to different species such as human and viru ses. References: K.Volzhenin\, L.Bittner\, A.Carbone\, SENSE-PPI reconst ructs protein-protein interactions of various complexities\, within\, acro ss\, and between species\, with sequence-based evolutionary scale modeling and deep learning\, BIORXIV/2023/558413 B. Seoane\, A. Carbone\, Soft di sorder modulates the assembly path of protein complexes\, PLoS Computation al Biology\, 2022. B.Seoane\, A.Carbone. The complexity of protein intera ctions unravelled from structural disorder\, PLoS Computational Biology\, 2021  CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-910@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231013T110000 DTEND;TZID=Europe/Paris:20231013T120000 DTSTAMP:20230921T170201Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-iva-ganeva/ SUMMARY:Physics-Biology interface seminar: Iva Ganeva - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Oct 23 11:00 DESCRIPTION:The architecture and mechanism of lipid transfer at interfaces between lipid droplets\nIva Ganeva (University of Bern\, Switzerland)\n\nL ipid droplets (LDs) are intracellular organelles responsible for regulated storage and release of neutral lipids. LDs feature a neutral lipid core e nclosed by a phospholipid monolayer and surface proteins involved in lipid metabolism. The protein Cidec is crucial for LD enlargement and accumulat es at interfaces between LDs where it facilitates directional neutral lipi d transfer from the smaller to the larger LD. Deciphering the structure of the LD-LD interface is key in understanding the molecular mechanism of li pid transfer. We use live cell imaging and electron cryo-tomography of hum an cells to visualize interfaces between LDs and understand the mechanism of lipid transfer directly inside cells. Furthermore\, by biochemical reco nstitutions using recombinant Cidec and various artificial membrane system s\, we aim at uncovering the minimal machinery for interface architecture and lipid transfer function. Our current model is that lipid transfer occu rs through largely intact monolayers at an interface which resembles an or ganelle contact site. We hypothesise that this process is facilitated by t he ability of Cidec to induce lipid packing defects into the monolayers\, thereby making them permeable for neutral lipids. \n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-917@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231013T134500 DTEND;TZID=Europe/Paris:20231013T150000 DTSTAMP:20231010T121024Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-michele-fava-ens-ulm/ SUMMARY:Informal Quantum Seminar: Michele Fava (ENS Ulm) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Oct 23 13:45 DESCRIPTION:What can we learn by measuring nonlinear response functions?Mic hele Fava (ENS Ulm)Most conventional experimental probes used in condensed matter systems can be interpreted through the framework of linear respons e. There are however cases where linear response functions alone are insu fficient to discriminate between different physical scenarios. In these si tuations\, nonlinear response functions could provide a valuable resource to sharpen our understanding. However\, currently\, a major limitation is the ability to provide a qualitative interpretation of the measured signal s.In this talk\, I will discuss two setups where the long-time divergence of nonlinear response functions can be understood and potentially provide insights into condensed matter systems.In the first part of the seminar\, I will show that long-time divergences in 1D systems are produced by scatt ering processes [1\,2].In the second part\, I will focus on 2D quantum sys tems with topological order and featuring anyonic excitations. I will argu e that\, in this case\, a stronger long-time divergence appears\, which co uld used as a unique fingerprint of anyons in experimental systems [3].[1] MF\, S. Gopalakrishnan\, R. Vasseur\, F. Essler\, S. A. Parameswaran\,  arXiv:2208.09490[2] MF\, S. Gopalakrishnan\, R. Vasseur\, S. A. Parameswar an\, F. Essler\, in preparation[3] M. McGinley\, MF\, S. A. Parameswaran\, arXiv:2210.16249 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-867@lptms.universite-paris-saclay.fr DTSTART:20231016T143000Z DTEND:20231016T143000Z DTSTAMP:20231012T072140Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-benjamin-de-bruyne/ SUMMARY:Soutenance de thèse: Benjamin De Bruyne - Grand amphi\, bâtiment Pascal n° 530 - 16 Oct 23 14:30 DESCRIPTION:Extreme value statistics and optimization problems in stochasti c processes This thesis is devoted to the study of extreme value statisti cs in stochastic processes and their applications. In the first part\, we obtain exact analytical results on the extreme value statistics of both di screte-time and continuous-time random walks. In particular\, we focus on the gap statistics of random walks and exhibit their asymptotic universali ty with respect to the jump distribution in the limit of a large number of steps. In addition\, we  compute the asymptotic behavior of the expected maximum of random walks in the presence of a bridge constraint and reveal a rich behavior in their finite-size correction. Moreover\, we compute th e expected length of the convex hull of Brownian motion confined in a disk and show that it converges slowly to the perimeter of the disk with a str etched exponential decay. In the second part\, we focus on numerically sam pling rare trajectories of stochastic processes. We introduce an efficient method to sample bridge discrete-time random walks. We illustrate it and apply it to various examples. We further extend the method to other stocha stic processes\, both Markovian and non-Markovian. We apply our method to sample surviving particles in the presence of a periodic trapping environm ent. Finally\, we discuss several optimization problems in stochastic proc esses involving extreme value statistics. In particular\, we introduce a n ew technique to optimally control dynamical systems undergoing a resetting policy Jury : Grégory Schehr (directeur de thèse)\, Pierpaolo Vivo (ra pporteur)\, Eric Bertin (rapporteur)\, Cécile Monthus (examinatrice)\, Ma rtin Evans (examinateur)\, Kilian Raschel (examinateur)\, Satya Majumdar ( co-directeur de thèse) CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-894@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231017T110000 DTEND;TZID=Europe/Paris:20231017T120000 DTSTAMP:20231006T145600Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-dario-poletti-sutd-singapore/ SUMMARY:Séminaire du LPTMS : Dario Poletti (SUTD\, Singapore) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Oct 23 11:0 0 DESCRIPTION:Towards steady state currents in superconducting quantum proces sorsDario Poletti (SUTD\, Singapore) A deeper understanding of the emerge nce of out-of-equilibrium statistical physics\, and enhanced ability to co ntrol quantum many-body systems with single-site precision\, can lead to a new era of quantum transport exploration. In order to reach that\, we foc us on a nonequilibrium scenario in which two nonintegrable systems prepare d in different states are locally and non-extensively coupled to each othe r. We show the emergence of steady-like currents which are well defined an d typical. We identify their origin to be from a prethermalization mechani sm. We then discuss a path for the experimental realization of these findi ngs on state-of-the-art experimental setups. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-904@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231019T110000 DTEND;TZID=Europe/Paris:20231019T120000 DTSTAMP:20231003T133736Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mehran-kardar-mit-usa/ SUMMARY:Séminaire du LPTMS : Mehran Kardar (MIT\, Cambridge) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Oct 23 11:00 DESCRIPTION:Competition at the front of expanding populations Mehran Karda r (MIT\, Cambridge) When competing species grow into new territory\, the population is dominated by descendants of successful ancestors at the expa nsion front. Successful ancestry depends of the reproductive advantage (fi tness)\, as well as ability and opportunity to colonize new domains. (1) B ased on symmetry considerations\, we present a model that  integrates bo th elements by coupling the classic description of one-dimensional competi tion (Fisher equation) to the minimal model of front shape (KPZ equation). Macroscopic manifestations of these equations on growth morphology are ex plored\, providing a framework to study spatial competition\, fixation\, a nd differentiation\, In particular\, we find that ability to expand in spa ce may overcome reproductive advantage in colonizing new territory. (2) Va riations of fitness\, as well as fixation time upon differentiation\, are shown to belong to distinct universality classes depending on limits to ga in of fitness. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-895@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231103T100000 DTEND;TZID=Europe/Paris:20231103T150000 DTSTAMP:20231025T064740Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-federi co-lanza/ SUMMARY:Soutenance de thèse: Federico Lanza - LPTMS (100% online seminar) - 3 Nov 23 10:00 DESCRIPTION:Optimal path for the flow of yield stress fluid Federico Lanza (LPTMS - NTNU)   Numerous industrial and environmental applications rel y on an understanding of fluid behavior within porous materials\, from rem ediating groundwater contamination to carbon dioxide storage. Yield stress fluids\, which resist flow until a critical stress threshold is exceeded\ , present both unique challenges and opportunities. Capillary forces\, res ponsible for separating immiscible fluids\, significantly influence multi- phase flow in porous structures. This thesis embarks on a theoretical expl oration of non-linear flow within porous media\, where both forces contrib ute to the overall rheology\, interacting with the geometrical disorder at the pore level. The present study investigates the steady-state flow of y ield stress blobs in a capillary fiber bundle filled with Newtonian liquid \, as well as the flow of a single Bingham fluid in a tree-like pore netwo rk. We derive expressions for the pressure threshold and the average flow rate as a function of the applied pressure drop. In both problems\, the no n-linearity observed stems from the sequential opening of flowing paths wi th increasing pressure drop\, and the distribution of pressure thresholds related to these paths defines the specific flow rate law. Furthermore\, w e explore the transition from viscous fingering to foam during immiscible drainage in a two-dimensional porous medium. We characterize this transiti on through numerical simulations using a dynamic pore network model\, meas uring the transition location\, overall flow rate\, and local pressure gra dient as a function of imposed global pressure and viscosity ratio. We dis cuss potential mechanisms leading to this transition\, considering local f low rate fluctuations\, which we also measure and characterize. In all thr ee cases studied\, the porous medium's heterogeneity emerges as a pivotal factor.Jury : Harold Auradou\, Dag Werner Breiby\, Alex Hansen\, Rainer He lmig\, Hans Herrmann\, Marie-Laure Olivier\, Alberto RossoNTNU\, Salle C20 1\, Kolbjørn Hejes vei 1B\, 7034 Trondheim\, Norway CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-898@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231107T110000 DTEND;TZID=Europe/Paris:20231107T120000 DTSTAMP:20231103T130825Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-antonello-scardicchio-ictp-trieste/ SUMMARY:Séminaire du LPTMS : Antonello Scardicchio (ICTP Trieste) - Petit amphi\, bâtiment Pascal n° 530 - 7 Nov 23 11:00 DESCRIPTION:Renormalization group analysis of the Anderson model in finite and infinite dimensionsAntonello Scardicchio (ICTP Trieste) (Speaker onli ne\, see zoom info below)I will discuss the localization-delocalization tr ansitions in the Anderson model. Starting from the classic one-parameter s caling theory of Anderson et al\, I will show for modern observables how t he RG flow evolves as the number of dimensions is increased\, and how this becomes the flow of the Anderson model on expander graphs and other infin ite dimensional lattices\, explaining the numerical observation of recent years. The implications for a critical theory of the Many-Body Localizatio n transition will also be discussed. https://universite-paris-saclay-fr.z oom.us/j/2458481009?pwd=dWd6bk5rSmlLKzFGVXlQYmhPR3JKUT09Meeting ID: 245 84 8 1009Passcode: 005531  CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-922@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231110T110000 DTEND;TZID=Europe/Paris:20231110T120000 DTSTAMP:20231020T171141Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-emmanuel-derivery/ SUMMARY:Physics-Biology interface seminar: Emmanuel Derivery - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Nov 23 11:00 DESCRIPTION:Macromolecular condensation buffers intracellular water potenti al\nEmmanuel Derivery (Cambridge U.)\n\nOptimum protein function and bioch emical activity critically depends on water availability inside cells. Mac romolecules restrict the movement of “structured” water molecules in t heir hydration layers\, reducing the available “free” bulk solvent and therefore the total thermodynamic potential energy of water\, or water po tential. Within concentrated macromolecular solutions like the cytosol\, w e found that modest changes in temperature greatly impact the water potent ial. We predicted that lower temperatures would reduce the available “fr ee” intracellular water in a similar manner to external hyperosmotic con ditions\, and vice versa for higher temperatures and hypoosmotic condition s. We validated this duality of temperature and osmotic strength on cellul ar physiology: hypoosmotic conditions mimicked high temperature in thermos ensitive yeast mutants\, whereas cold temperatures induced chondrocyte Ca2 + signalling similar to hyperosmotic conditions. Most remarkably\, simple manipulations of solvent thermodynamics were sufficient to prevent cell de ath upon extreme cold or heat shock. Physiologically\, cells must sustain their activity in the face of fluctuating temperature\, pressure and osmot ic strength that impact water potential within seconds\, but established m echanisms of water homeostasis act over much slower timescales\, so we pos tulated the existence of a rapid compensatory response. We find this funct ion is performed by water potential-driven changes in macromolecular assem bly\, particularly biomolecular condensation of intrinsically-disordered p roteins\, which is determined by the water potential rather than the conce ntration of any specific macromolecule. In cells\, formation or dissolutio n of biomolecular condensates counteracted thermal or osmotic perturbation s of water potential\, which was robustly buffered in isolated cytoplasm. Our results indicate that biomolecular condensation constitutes an intrins ic biophysical feedback response that rapidly compensates for intracellula r osmotic and thermal fluctuations. We suggest preserving water availabili ty within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function.\n\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-924@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231110T134500 DTEND;TZID=Europe/Paris:20231110T151500 DTSTAMP:20231027T142951Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-jules-givois/ SUMMARY:Informal Quantum Seminar: Jules Givois - Salle des séminaires du F AST et du LPTMS\, bâtiment Pascal n°530 - 10 Nov 23 13:45 DESCRIPTION:Binding of $N+1$-clusters in mass-imbalanced fermionic mixtures in low dimensions Jules Givois (LPTMS)In the last 10 years\, the few-bod y bound states made of $1$ light fermion interacting attractively with $N$ heavy fermions were analyzed in all spatial dimensions. To address the la rge $N$ limit and to investigate the formation of $N+1$ clusters in fermio nic mixtures with weak attraction\, we developed a mean-field approach bas ed on the Thomas-Fermi approximation for the heavy atoms kinetic energy in both one and two dimensions. We find that in the two cases the $N$ heavy fermions can be bound by a single light fermion as long as the mass-ratio is large enough. We show that the bound character of the system can be des cribed by a single parameter that depends on the dimensions and which comb ines the mass-ratio and $N$. In two dimensions\, scale invariance plays a determinant role and we present a way to overcome it using beyond mean-fie ld corrections. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-896@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231116T140000 DTEND;TZID=Europe/Paris:20231116T180000 DTSTAMP:20230918T090847Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-saptarshi-majumdar/ SUMMARY:Soutenance de thèse: Saptarshi Majumdar - Petit amphi\, bâtiment Pascal n° 530 - 16 Nov 23 14:00 DESCRIPTION:Localisation in open quantum systems\nWe investigate the zero-t emperature phase diagram of a one-dimensional XXZ spin chain coupled with local dissipative baths composed of simple harmonic oscillators. In a fini te magnetization sector\, we map this system onto a two-dimensional classi cal action using bosonization. From this classical field theory\, we find the existence of a BKT phase transition between the pre-existing Luttinger liquid phase and a new dissipative phase at zero temperature. This new ph ase is a gapless spin density wave with unaltered susceptibility and vanis hing spin stiffness. These analytical predictions are verified against num erical Langevin dynamics simulations of the action. The local baths in the spin chain can also be interpreted as annealed disorder and they affect t he transport properties. Particularly for subohmic baths\, the static cond uctivity vanishes\, which can be interpreted as a localization effect indu ced by the presence of dynamical disorder. Moreover\, we analyze the model at zero magnetization and argue that in that case\, the gapless spin dens ity wave is replaced by a gapped antiferromagnetic phase.\n\nJury : Rosari o Fazio (rapporteur)\, Laura Foini (co-directrice de thèse)\, Edmond Orig nac (rapporteur)\, Alberto Rosso (directeur de thèse)\, Inès Safi\, Gré gory Schehr. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-900@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231121T110000 DTEND;TZID=Europe/Paris:20231121T120000 DTSTAMP:20231108T143328Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-cyrille-hamon-lps-orsay/ SUMMARY:Séminaire du LPTMS : Cyrille Hamon (LPS) - Salle des séminaires d u FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Nov 23 11:00 DESCRIPTION:Colloidal design of nanoparticles and hierarchical nanostructur esCyrille Hamon (Laboratoire de physique des Solides)The production of sol id materials with nanoscale building blocks can be conveniently achieved b y colloidal self-assembly and with a minimal synthetic effort. This presen tation will revolve around elongated nanoparticles with a pentagonal base. In the first part\, I will show the different methods we use to self-asse mble and study NPs self-assembly. In the second part\, I will focus on the self-assembly of the pentagonal NPs into low-symmetry supercrystals where in the loss of symmetry can be understood through an analogy with the opti mal packing of regular pentagons in the plane: the individual objects have rotational symmetry of order 5\, but they associate in pairs which create s an inversion center. In doing so\, they reduce their rotational symmetry to order 2. Assemblies are studied by X-ray scattering and electron micro scopy as well as some numerical simulations reproducing the symmetry and d ensity of the packing. Moreover\, the Raman signal of molecules is enhance d in the vicinity of these assemblies\, with an exaltation that depends on the exposed facet of the crystal. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-897@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231123T090000 DTEND;TZID=Europe/Paris:20231123T140000 DTSTAMP:20231114T102102Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-vincenzo-schimmenti/ SUMMARY:Soutenance de thèse : Vincenzo Schimmenti - Grand amphi\, bâtimen t Pascal n° 530 - 23 Nov 23 09:00 DESCRIPTION:Temporal and spatial correlations in earthquake dynamics: physi cal modeling and data analysis In seismology\, aftershocks are smaller ea rthquakes originating from the destabilised crust in the regions close to a larger earthquake\, the mainshock. In this thesis we study this phenomen on from three distinct perspectives. In the first one we unveil the connec tions between simple models of aftershocks occurrence and record statistic s of stochastic processes. The second approach builds up on the similariti es between earthquake sequences and mainshock-aftershocks groups with the creep dynamics of a domain wall expanding in a thin magnetic film. Finally \, we use machine learning tools to construct a forecasting method for aft ershock occurrence by exploiting measurements of surface deformation comin g from Global Positioning System (GPS) satellites. As an addendum\, in the last part of the thesis\, we discuss the physics of yield-stress fluids i n porous media and its links to the physics of disorder systems and direct ed polymers in random media. Jury : Aurélien Decelle\, François Landes (co-directeur de thèse)\, Cécile Monthus\, Alberto Rosso (directeur de t hèse)\, Herbert Spohn (rapporteur)\, Jérôme Weiss (rapporteur) CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-911@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231124T110000 DTEND;TZID=Europe/Paris:20231124T120000 DTSTAMP:20231115T162124Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-alexandre-ciaccafava/ SUMMARY:Physics-biology interface seminar: Alexandre Ciaccafava - Moyen Amp hi\, Building 510\, Université Paris-Saclay Orsay - 24 Nov 23 11:00 DESCRIPTION:Taming gas-converting metalloenzymes: (spectro)electrochemical insights\nJoint seminar with the Soft Matter group at LPS\nAlexandre Ciacc afava (Marseille Molecular Science Institute\, France)\nMetalloenzymes are at the heart of a wide range of bioenergetic processes essential to all l iving organisms. They are responsible for the exchange and conversion of e nergy by making or breaking chemical bonds with the concomitant exchange o f electrons (e–) and protons (H+). They are extremely efficient biocatal ysts that convert with high efficiency and affinity a multitude of substra tes\, from the simplest molecule such as hydrogen (H2) to much larger poly meric entities (cellulose)\, opening the way to high-impact biotechnologic al applications. Because of the biodiversity of the microorganisms from wh ich they are derived (notably extremophiles adapted to various unusual bio topes)\, redox metalloenzymes can operate under a wide range of experiment al conditions. Most redox enzymes contain non-noble metals (Ni\, Fe\, Cu\, Mo\,… )\, assembled in a more or less complex way in the active center where their catalytic activity is located or in electronic relays that tra nsfer electrons to other physiological partners\, constituting a larger se t of multi-partner electron transfer chains. As a result\, redox metalloen zymes can advantageously replace chemical catalysts based on noble metals\ , whose scarcity generates a consequent cost\, limiting their large-scale development. This set of remarkable properties shared by redox metalloenzy mes has fuelled both the desire to control their reactivity and the attent ion of chemists to create bio-inspired catalysts. However\, a thorough und erstanding of the functioning of redox metalloenzymes is a prerequisite fo r taming their exceptional properties and ultimately for their integration into biotechnological processes. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-912@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231128T110000 DTEND;TZID=Europe/Paris:20231128T120000 DTSTAMP:20231125T175207Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-raoul-santachiara-lptms-n/ SUMMARY:Séminaire du LPTMS : Raoul Santachiara (LPTMS) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 28 Nov 23 11:00 DESCRIPTION:Critical behavior of 2D Ising model with long-range correlated bond disorderRaoul Santachiara (LPTMS)Very recently\, we have obtained new numerical and analytical results on the 2D Ising model (and on its natura l extension\, the Potts model) with long-range correlated bond disorder. I n particular we have computed\, for the first time\, the corresponding mag netic exponent and the effects of the higher-moments of non-Gaussian disor der distribution on the thermal exponent. In this talk I will gently intro duce you to this (old) problem and to the theoretical approach used to tac kle it. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-918@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231201T134500 DTEND;TZID=Europe/Paris:20231201T144500 DTSTAMP:20231129T151323Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-blagoje-oblak-ulb-brussels/ SUMMARY:Informal Quantum Seminar : Blagoje Oblak (ULB Brussels) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 1 Déc 23 13: 45 DESCRIPTION:Anisotropic Quantum Hall DropletsBlagoje Oblak (ULB Brussels)Th is talk is devoted to 2D droplets of noninteracting electrons in a strong magnetic field\, placed in an arbitrary confining potential. I show that s emiclassical methods in the lowest Landau level yield near-Gaussian energy eigenstates localized on level curves of the potential\, implying explici t formulas for local many-body observables in the thermodynamic limit. In particular\, correlations along a droplet's edge are long-ranged\, in acco rdance with the 1D chiral conformal field theory that describes its low-en ergy dynamics. This notably involves inhomogeneous correlations and positi on-dependent guiding centre velocities\, but still results in a homogeneou s theory thanks to remarkable cancellations between the radial and angular dependencies of eigenfunctions. Finally\, I describe realistic microwave absorption experiments that probe the detailed shape of a droplet without resorting to local imaging.  CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-919@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231205T110000 DTEND;TZID=Europe/Paris:20231205T120000 DTSTAMP:20231201T105443Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-antonio-sclocchi-epfl-2/ SUMMARY:Séminaire du LPTMS : Antonio Sclocchi (EPFL Lausanne) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 5 Déc 23 11:0 0 DESCRIPTION:On the different regimes of Stochastic Gradient DescentAntonio Sclocchi (EPFL Lausanne)The success of modern deep learning relies on the way neural networks are trained\, which consists in the optimization of a high-dimensional loss landscape. This is done with the Stochastic Gradient Descent (SGD) algorithm\, where the loss gradients are estimated on a sma ll batch of the data at each time step. The choice of the batch size and t he step size (or learning rate) is observed to be important to have good p erformances in real applications\, but it is poorly theoretically understo od and relies heavily on expensive grid-search procedures. In this work\, we clarify how the batch size and the learning rate affect the training dy namics of neural networks\, leading to a phase diagram with three distinct dynamical regimes: (i) a noise-dominated phase\, where SGD is described b y a stochastic process\, (ii) a large-first-step dominated phase\, and (ii i) a phase where it is equivalent to simple Gradient Descent (GD). We obta in these results in a teacher-student perceptron model and show empiricall y that our predictions still apply to deep networks on benchmark tasks\, l ike image classification. Our results lead to new predictions on how the s ize of the training dataset and the hardness of the task affect the traini ng dynamics\, and open the way to understanding its relationship with neur al network performances.------ This seminar will be on zoom also: https:// universite-paris-saclay-fr.zoom.us/j/93668397465?pwd=YWJUMkQ1dUdaV1lXWmFPe WZIT3R5QT09 Meeting ID: 936 6839 7465 Passcode: 870463 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-892@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231207T143000 DTEND;TZID=Europe/Paris:20231207T180000 DTSTAMP:20231129T080136Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-li-gan-2/ SUMMARY:Soutenance de thèse : Li Gan - Petit amphi\, bâtiment Pascal n° 530 - 7 Déc 23 14:30 DESCRIPTION:Algebraic Area of Lattice Random Walks and Exclusion Statistics  Join Zoom Meetinghttps://universite-paris-saclay-fr.zoom.us/j/9575529780 4?pwd=NWk4TW8rdjd4d0oyZjlpSHNia01KZz09Meeting ID: 957 5529 7804Passcode: 3 93787 We focus on the enumeration of closed lattice random walks accordin g to their algebraic area\, with connections to quantum exclusion statisti cs\, as well as the combinatorics of generalized Dyck and Motzkin paths. F irst\, taking the closed square lattice walks as an example\, we review th e concept of the algebraic area and its connections to the Hofstadter mode l. Then\, we introduce two approaches for the algebraic area enumeration. The first approach relies on the computation of the secular determinant of the Hofstadter Hamiltonian and its relation to the exclusion statistics. Precisely\, the coefficients of the secular determinant are interpreted in terms of partition functions with exclusion parameter $g=2$. The algebrai c area enumeration is obtained in terms of the associated cluster coeffici ents. The second approach involves a direct computation of the trace of th e $n$th power of the Hofstadter matrix\, where $n$ is the length of the wa lks. We study the combinatorics of periodic Dyck paths and obtain explicit expressions for counting Dyck paths with a fixed number of up steps start ing from each floor\, which provide a combinatorial interpretation to the factor in the algebraic area enumeration formula obtained in the first app roach. Then\, we study the closed random walks on a honeycomb lattice and establish a correspondence to a system of particles obeying a mixture of $ g=1$ (fermions) and $g=2$ exclusion statistics\, together with the connect ion to the combinatorics of periodic Motzkin paths. Furthermore\, we exten d the algebraic area concept to closed cubic lattice walks and map the enu meration onto the cluster coefficients of three types of particles obeying $g=1$\, $g=1$\, and $g=2$ exclusion statistics\, respectively\, with the constraint that the numbers of $g=1$ exclusion particles of the two types are equal.Jury : Cyril Banderier\, Cyril Furtlehner\, Brian Hopkins (rappo rteur)\, Stéphane Ouvry (directeur de thèse)\, Valentina Ros\, Clément Sire\, Stephan Wagner (rapporteur). CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-914@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231208T110000 DTEND;TZID=Europe/Paris:20231208T120000 DTSTAMP:20231127T092626Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-carles-blanch-mercader/ SUMMARY:Physics-Biology interface seminar: Carles Blanch Mercader - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Déc 23 1 1:00 DESCRIPTION:From interfacial tubulation in Alcanivorax borkumensis biofilms to folding of membranes with nematic order.Carles Blanch Mercader ( Physi co-Chimie Curie ) Assemblies of anisotropic cells can exhibit long-range orientational order and topological defects\, which often influence proces ses of shape formation. In the first part of this talk\, I will introduce conditions for a morphological transition between a spherical and a dendri tic phase in Alcanivorax borkumensis biofilm-covered oil microdroplets. Ex perimental observations demonstrate preferential interfacial tubulation at topological defects\; bacteria assemblies on these tubes exhibit long-ran ge nematic order. The second part of this talk focuses on the role of orde r-curvature couplings on equilibrium states of a membrane with nematic ord er that are generated by an integer topological defect. For varying elasti c parameters and boundary anchoring conditions\, the instability of a flat disc towards an out-of-plane deformed surface will be discussed. Finally\ , I will argue how these results can be relevant for biological systems an d show how bacteria biofilms can utilize topological defects to facilitate membrane deformation and enhance oil access.The first part is a joint wor k with M. Prasad\, N. Obana\, S.-Z. Lin\, K. Sakai\, J. Prost\, N. Nomura\ , J.-F. Rupprecht\, J. Fattaccioli\, and A.S. Utada. The second part is a joint work with C. Thibault\, Q. Chaboche\, and D.J.G. Pearce. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-928@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231208T134500 DTEND;TZID=Europe/Paris:20231208T144500 DTSTAMP:20231123T170340Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-despres-julien-lptms-college-de-france/ SUMMARY:Informal Quantum Seminar : Despres Julien (LPTMS - Collège de Fran ce) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Déc 23 13:45 DESCRIPTION:Spreading of correlations in Hermitian and non-Hermitian quantu m systemsDespres Julien (LPTMS - Collège de France)During this presentati on\, I will give you an overview of one part of my research work done duri ng my PhD and my postdoc concerning the spreading of correlations in isola ted quantum systems governed by a Hermitian or a non-Hermitian Hamiltonian . For the Hermitian case\, I will introduce a generic form of the equal-ti me correlation function found using a quasiparticle picture which is valid for a large number of quantum systems. From the latter\, I will extract t he scaling laws of the correlation edge also called Lieb-Robinson bound de pending if short-range or long-range interactions are considered. For the non-Hermitian case\, I will present several results concerning the spreadi ng of correlations for the non-Hermitian short-range Ising model.   CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-920@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231212T110000 DTEND;TZID=Europe/Paris:20231212T120000 DTSTAMP:20231206T095755Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jorge-cossio-ens/ SUMMARY:Séminaire du LPTMS : Jorge Fernandez-de-Cossio-Diaz (ENS Paris) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 D éc 23 11:00 DESCRIPTION:Disentangling Representations in Restricted Boltzmann Machines without AdversariesJorge Fernandez-de-Cossio-Diaz (ENS Paris)A goal of uns upervised machine learning is to build representations of complex high-dim ensional data\, with simple relations to their properties. Such disentangl ed representations make it easier to interpret the significant latent fact ors of variation in the data\, as well as to generate new data with desira ble features. The methods for disentangling representations often rely on an adversarial scheme\, in which representations are tuned to avoid discri minators from being able to reconstruct information about the data propert ies (labels). Unfortunately\, adversarial training is generally difficult to implement in practice. Here we propose a simple\, effective way of dise ntangling representations without any need to train adversarial discrimina tors and apply our approach to Restricted Boltzmann Machines\, one of the simplest representation-based generative models. Our approach relies on th e introduction of adequate constraints on the weights during training\, wh ich allows us to concentrate information about labels on a small subset of latent variables. The effectiveness of the approach is illustrated with f our examples: the CelebA dataset of facial images\, the two-dimensional Is ing model\, the MNIST dataset of handwritten digits\, and the taxonomy of protein families. In addition\, we show how our framework allows for analy tically computing the cost\, in terms of the log-likelihood of the data\, associated with the disentanglement of their representations.\n\nPaper lin k: https://journals.aps.org/prx/abstract/10.1103/PhysRevX.13.021003\n\n--- --- This seminar will be on zoom also: https://universite-paris-saclay-fr. zoom.us/j/93026726739?pwd=TFhIdHMrSy8vRkNMdzZMT3ptSFRxQT09\nMeeting ID: 93 0 2672 6739 Passcode: 244859\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-901@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231214T110000 DTEND;TZID=Europe/Paris:20231214T120000 DTSTAMP:20231130T085411Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sumilan-banerjee-iis-bangalore/ SUMMARY:Séminaire exceptionnel du LPTMS : Sumilan Banerjee (IIS Bangalore) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 1 4 Déc 23 11:00 DESCRIPTION:Semiclassical limit of a measurement-induced phase transitionSu milan Banerjee (IIS Bangalore)Chaotic-to-non-chaotic transitions play a pr ominent role in our understanding of the dynamical phase diagram of both q uantum and classical systems. In quantum many-body systems\, a certain kin d of chaotic-non-chaotic transitions\, dubbed ‘measurement-induced phase transitions’ (MIPT)\, have led to a new paradigm for dynamical phase tr ansitions in recent years. On the other hand\, prominent examples of trans ition in chaos in classical dynamical systems are the stochastic synchroni zation transitions (ST). In this case\, classical trajectories starting fr om different initial conditions synchronize when subjected to sufficiently strong common random stochastic noise. In this talk\, I will establish a possible link between MIPT and ST by considering models of interacting qua ntum particles whose positions are measured continuously\, albeit weakly. In the semiclassical limit\, the dynamics of the system is described by a stochastic Langevin equation where the noise and the dissipation terms are both controlled by the small quantum parameter and measurement strength. I will show the existence of a chaotic-to-non-chaotic transition in the La ngevin evolution as a function of either interaction or noise/dissipation strength.  CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-931@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231215T134500 DTEND;TZID=Europe/Paris:20231215T144500 DTSTAMP:20231129T151143Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-han-ma-perimeter-institute/ SUMMARY:Quantum Seminar du LPTMS: Han Ma (Perimeter Institute) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 Déc 23 13: 45 DESCRIPTION:Renormalization group for metals: application to Fermi liquids and experimental consequencesHan Ma (Perimeter Institute)Metals\, commonly found in various quantum materials\, are characterized by the presence of Fermi surfaces\, where all zero-energy modes contribute to the low-energy dynamics. In this talk\, I will present our recent work on the simplest m etallic state\, the Fermi liquid phase\, from the RG perspective. The nove l functional framework enables us to capture the non-trivial RG flow aroun d the Fermi liquid fixed-point and uncovers the collective modes and Fermi liquid instabilities. I will also discuss our study on the Fermi liquid w ith non-circular Fermi surface\, especially on the collective modes associ ated with the inflection points.__________________________________________ _____________________________________________________The seminar will be b roadcasted via Zoomhttps://cnrs.zoom.us/j/99619966409?pwd=Z25nUDBhaDBuMm42 a2MxaDcvREswZz09Meeting ID: 996 1996 6409 Passcode: 4kbEd6     CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-908@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20231219T110000 DTEND;TZID=Europe/Paris:20231219T120000 DTSTAMP:20231211T082325Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-olivier-gauthe-epfl/ SUMMARY:Séminaire du LPTMS : Olivier Gauthé (EPFL Lausanne) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Déc 23 11:0 0 DESCRIPTION:Tensor network methods for frustrated magnets at finite tempera tureOlivier Gauthé (EPFL Lausanne)\nWithin strongly correlated systems\, frustrated magnetism is the field that study magnetic insulators when diff erent microscopic magnetic interactions favor incompatible orders and no c lassical spin configuration can fulfill all of them. This realm offers a f ertile ground for experimental and fundamental exploration\, giving rise t o unconventional phenomena such as order by disorder or the enigmatic quan tum spin liquid phase. Nevertheless\, its study poses challenges due to th e presence of competing interactions of comparable magnitude\, confounding perturbation theory. On the numerical side\, frustration usually prevents the use of quantum Monte Carlo algorithms.\n\nOver the last decades\, ten sor network methods have emerged as the one of the most powerful numerical approach to tackle the many-body problem in both classical and quantum ph ysics. In this talk\, we will review the core principles of tensor network and their applications in condensed matter physics. We will focus on stro ngly correlated systems in two dimensions and discuss the simulation of fr ustrated quantum magnets at thermal equilibrium using Projected Entangled Pair States (PEPS).\n\nTo illustrate this approach\, we will address the s pin-1/2 Heisenberg model on the square lattice with nearest-neighbor coupl ing J1 and next-nearest coupling J2 (J1-J2 model) at finite temperature [1 ]. We will consider both antiferromagnetic (J1 > 0) and ferromagnetic (J1 < 0) cases. We will expose the first unambiguous and direct evidence of an Ising transition associated with the spontaneous breaking of the C_4v sym metry within the collinear antiferromagnet region of the phase diagram.\n\ n[1] O. Gauthé & F. Mila\, PRL\, 128\, 227202 (2022) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-915@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240109T110000 DTEND;TZID=Europe/Paris:20240109T120000 DTSTAMP:20240104T100930Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-florian-goirand-tum-munich/ SUMMARY:Séminaire du LPTMS : Florian Goirand (TUM Munich) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Jan 24 11:00 DESCRIPTION:Structure-Function Interplay in Biological NetworksFlorian Goir and (TUM Munich)\nLiving matter exhibits properties that are commonly foun d to be shared far more widely than just among different individuals of th e same species. The ubiquity of these properties makes it possible to inve stigate in model systems elementary processes that belong to more complex phenomena and for systems where biological data are lacking. Yet\, the und erstanding of the fundamental mechanisms that lead to their emergence is s till an active field of research. In particular\, deciphering the relation ship between the structure and function(s) of evolving systems has been th e subject of numerous studies\, even recently. Indeed\, if infering the im pact of the system structure on the realization of a given task is relativ ely straightforward\, it is much less obvious to consider task performance as the main driver of the emergence of structure and dynamics. However\, the latter approach\, pioneered by Murray nearly a century ago\, has prove d to be relevant for successfully predicting the emergence of geometric an d topological properties in many adaptive biological systems. Following bo th approaches\, we use numerical and analytical methods to investigate the relationship between structure and function in brain microvascular networ ks. First\, we show how structure drives properties in healthy and altered brain microvascular networks. In particular\, we focus on the response of the system to perturbations such as (micro)strokes in the context of earl y detecting and treating brain pathologies with novel therapeutic approach es. Second\, we present how function may contribute to the morphogenesis o f brain microvascular networks\, highlighting that fundamental topological properties of brain microvascular networks can emerge spontaneously from a basic optimization process. Finally\, we present stimulating perspective s for future research\, stressing on two specific research directions. On the one hand\, we discuss the possibility of designing microfluidic device s of function-driven tunable properties. On the other hand\, we propose me ans to investigate the robustness of the neurovascular couple\, seen as a network of networks\, in the context of neurodegenerative diseases such as Alzheimer's.\n\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-921@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240116T110000 DTEND;TZID=Europe/Paris:20240116T120000 DTSTAMP:20240108T214020Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ivan-khaymovich-nordita/ SUMMARY:Séminaire du LPTMS : Ivan Khaymovich (Nordita Stockholm) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Jan 24 1 1:00 DESCRIPTION:Localization enhancement in gain-loss non-Hermitian disordered modelsIvan Khaymovich (Nordita Stockholm)Recently the interest in non-Herm itian disordered models has been revived\, due to the claims of instabilit y of a many-body localization to a coupling to a bath. To describe such op en quantum systems\, one often focuses on an energy leakage to a bath\, us ing effective non-Hermitian Hamiltonians. A well-known Hatano-Nelson model [1]\, being a 1d Anderson localization (AL) model\, with different hoppin g amplitudes to the right/left\, shows AL breakdown\, as non-Hermiticity s uppresses the interference.Unlike this\, we consider models with the compl ex gain-loss disorder and show that in general these systems tend to the l ocalization due to non-Hermiticity. First\, we focus on a non-Hermitian ve rsion [2] of a Rosenzweig-Porter model [3]\, known to carry a fractal phas e [4] along with the AL and ergodic ones. We show that ergodic and localiz ed phases are stable against the non-Hermitian matrix entries\, while the fractal phase\, intact to non-Hermiticity of off-diagonal terms\, gives a way to AL in a gain-loss disorder. The understanding of this counterintuit ive phenomenon is given in terms of the cavity method and in addition in s imple hand-waving terms from the Fermi's golden rule\, applicable\, strict ly speaking\, to a Hermitian RP model. The main effect in this model is gi ven by the fact that the generally complex diagonal potential forms an eff ectively 2d (complex) distribution\, which parametrically increases the ba re level spacing and suppresses the resonances.Next\, we consider a power- law random banded matrix ensemble (PLRBM) [5]\, known to show AL transitio n (ALT) at the power of the power-law hopping decay a=d equal to the dimen sion d. In [6]\, we show that a non-Hermitian gain-loss disorder in PLRBM shifts ALT to smaller values $d/2<\;a_{AT}(W)<\;d$\, dependent on the disorder on-site W. A similar effect of the reduced critical disorder due to the gain-loss complex-valued disorder has been recently observed by us numerically [7]. In order to analytically explain the above numerical resu lts\, we derive an effective non-Hermitian resonance counting and show tha t the delocalization transition is driven by so-called "bad resonances"\, which cannot be removed by the wave-function hybridization (e.g.\, in the renormalization group approach)\, while the usual "Hermitian" resonances a re suppressed in the same way as in the non-Hermitian RP model.In the last part\, if time permits\, I will consider the effects of non-Hermitian dia gonal disorder on many-body localization in interacting systems and the lo calization in quantum random energy model [8] and show that the above para digm also works there.[1] N. Hatano\, D. R. Nelson\, "Localization Transit ions in Non-Hermitian Quantum Mechanics"\, PRL 77\, 570 (1996).[2] G. De T omasi\, I. M. K. "Non-Hermitian Rosenzweig-Porter random-matrix ensemble: Obstruction to the fractal phase"\, Phys. Rev. B\, 106\, 094204 (2022).[3] N. Rosenzweig and C. E. Porter\, “Repulsion of energy levels” in comp lex atomic spectra\,” Phys. Rev. B 120\, 1698 (1960).[4] V. E. Kravtsov\ , I. M. K.\, E. Cuevas\, and M. Amini\, “A random matrix model with loca lization and ergodic transitions\,” New J. Phys. 17\, 122002 (2015).[5] A. D. Mirlin\, Y. V. Fyodorov\, F.-M. Dittes\, J. Quezada\, and T. H. Seli gman\, “Transition from localized to extended eigenstates in the ensembl e of power-law random banded matrices\,” Phys. Rev. E 54\, 3221–3230 ( 1996).[6] G. De Tomasi\, I. M. K. "Non-Hermiticity induces localization: g ood and bad resonances in power-law random banded matrices"\, Phys. Rev. B 108\, L180202 (2023).[7] L. S. Levitov "Absence of localization of vibrat ional modes due to dipole-dipole interaction"\, EPL 9\, 83 (1989).[8] G. D e Tomasi\, I. M. K. "Stable many-body localization under random continuous measurements in the no-click limit"\, arXiv:2311.00019 . CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-916@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240119T110000 DTEND;TZID=Europe/Paris:20240119T120000 DTSTAMP:20240116T200101Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-catherine-villard/ SUMMARY:Physics-Biology Interface seminar: Catherine Villard - Moyen Amphi\ , Building 510\, Université Paris-Saclay Orsay - 19 Jan 24 11:00 DESCRIPTION:Fast deformation under flow and morphological recovery of cance r cells\nCatherine Villard (U. Paris-Cité)\nWarning: joint seminar with L PS\, takes place at LPS\n\nThe cancer metastatic cascade includes a blood circulation step for cells detached from the primary tumor. This stage inv olves significant shear stress as well as large and fast deformations as t he cells circulate through the microvasculature. The recovery dynamics aft er deformation is pivotal to understand how a cell can pass through the mu ltiple capillary constrictions encountered during a single hemodynamic cyc le. \n\nI will present results on the recovery dynamics of circulating c ells representative of different cancer phenotypes and their nuclei\, obta ined thanks to a dedicated microfluidic system we have recently developed. \n\nIn brief\, all cell types display an elastic recovery behavior followe d by a slower viscoelastic regime\, while nuclei\, depending on the cell t ype\, can strikingly recover purely elastically over a time scale of 20 ms . The fast elastic cell recovery regime is under the control of cell contr actility ensured by the integrity of the cell acto-myosin cortex while the presence of a vimentin cage around the nuclei confers elastic properties to this organelle.\n\nI will finally discuss how these behaviors can poss ibly impact cell transit and survival into the blood circulation. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-935@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240119T134500 DTEND;TZID=Europe/Paris:20240119T144500 DTSTAMP:20240108T161511Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/quantum-seminar-d u-lptms-francesco-mattiotti-strasburg/ SUMMARY:Quantum Seminar du LPTMS: Francesco Mattiotti (Strasbourg Universit y) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Jan 24 13:45 DESCRIPTION:Strong light-matter coupling in disordered systems: multifracta lity and protected transportFrancesco Mattiotti (Strasbourg University)\n\ nWhen two-level quantum emitters and a cavity mode coherently exchange ene rgy at a rate faster than their decay\, the system enters the strong coupl ing regime of cavity-QED\, where light-matter polaritonic states play an i mportant role. Such states are superpositions composed of “bright” emi tter modes and cavity photons\, while numerous remaining emitter states ha ve no photon contribution\, i.e.\, remain “dark”. Over the past decade \, the strong coupling regime has been explored as a tool to engineer fund amental properties of matter such as the chemical reaction rates [1]. Much interest is currently raised by the possibility of modifying energy trans port\, for which disorder plays a crucial role. While it is well known tha t coherent transport in disordered media can be inhibited due to Anderson localization of the eigenstates [2]\, the impact of strong light-matter co upling on Anderson localization has been explored only very recently [3-8] . As a paradigmatic example\, I will discuss the spectral and transport pr operties of the disordered Tavis-Cummings model\, showing that the dark st ates can feature unusual critical properties characterized by extended but non-ergodic (multifractal) wavefunctions [3\,5\,8].\n\n[1] J. A. Hutchiso n et al.\, Angew. Chem. Int. Ed. 51\, 1592 (2012)\n[2] P.W. Anderson\, Phy s. Rev. 109\, 1492 (1958)\n[3] T. Botzung et al.\, Phys. Rev. B 102\, 1442 02 (2020)\n[4] N. C. Chávez et al.\, Phys. Rev. Lett. 126\, 153201 (2021) \n[5] J. Dubail et al.\, Phys. Rev. A 105\, 023714 (2022)\n[6] G. Engelhar dt and J. Cao\, Phys. Rev. B 105\, 064205 (2022)\n[7] T. F. Allard and G. Weick\, Phys. Rev. B 106\, 245424 (2022)\n[8] F. Mattiotti et al.\, arXiv: 2302.14718 (2023)\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-923@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240123T110000 DTEND;TZID=Europe/Paris:20240123T120000 DTSTAMP:20240115T192017Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-markus-mueller-psi/ SUMMARY:Séminaire du LPTMS : Markus Mueller (PSI Villigen\, Switzerland) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 23 Jan 24 11:00 DESCRIPTION:Exact solution of the classical and quantum Heisenberg mean fie ld spin glassesMarkus Mueller (PSI Villigen\, Switzerland)While the physic s of classical and quantum Ising spin glasses has been rather thoroughly u nderstood\, glasses of Heisenberg (vector) spins have remained a difficult and largely unsolved problem\, including especially its quantum version\, which governs the local moments in randomly doped\, strongly correlated m aterials. I will present the numerically exact mean field solution of quan tum and classical Heisenberg spin glasses\, based on the combination of a high precision numerical solution of the Parisi full replica symmetry brea king equations and a continuous time Quantum Monte Carlo. We find that the Heisenberg (vector) spin glasses have a rougher energy landscape than the ir Ising analogues\, which affects their avalanche response to external st imuli. The (short time) quantum dynamics and collective excitations exhibi t a surprisingly slow temperature evolution\, that\, at asymptotically low temperatures\, tend to the superuniversal form found so far in all insula ting mean field glasses. We extend our analysis to the doped\, metallic He isenberg spin glass\, which displays an unexpectedly slow spin dynamics re flecting the proximity to the melting quantum critical point and its assoc iated Sachdev-Ye-Kitaev Planckian dynamics. Ref: N. Kavokine\, M. Müller\ , A. Georges\, and O. Parcollet https://doi.org/10.48550/arXiv.2312.14598 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-932@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240125T110000 DTEND;TZID=Europe/Paris:20240125T120000 DTSTAMP:20240112T221324Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-claudia-artiaco-kth-stoccolma/ SUMMARY:Séminaire du LPTMS : Claudia Artiaco (KTH Stockholm) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 25 Jan 24 11:00 DESCRIPTION:The time evolution of local informationClaudia Artiaco (KTH Sto ckholm)During the time evolution of many-body systems entanglement spreads rapidly\, limiting exact simulations to small-scale systems and small tim escales. Quantum information tends\, however\, to flow towards larger scal es without returning to local scales\, such that its detailed large-scale structure does not directly affect local observables. This allows for the removal of large-scale quantum information in a way that preserves all loc al observables and gives access to large-scale and large-time quantum dyna mics. To this end\, in [2] we proposed a novel approach that uses the rece ntly introduced information lattice to organize quantum information into d ifferent scales [1]\, allowing us to define local information and informat ion currents which we employ to systematically discard long-range quantum correlations in a controlled way. Our approach relies on decomposing the s ystem into subsystems up to a maximum scale and time evolving the subsyste m density matrices by solving the subsystem von Neumann equations in paral lel. Importantly\, the information flow needs to be preserved during the d iscarding of large-scale information. To achieve this without the need to make assumptions about the microscopic details of the information current\ , we introduce a second scale at which information is discarded while usin g the state at the maximum scale to accurately obtain the information flow . The resulting algorithm\, to which we refer to as local-information time evolution (LITE)\, is highly versatile and suitable for investigating man y-body quantum dynamics in both closed and open quantum systems with diver se hydrodynamic behaviors.In this talk\, I will present results obtained v ia LITE for the energy transport in the mixed-field Ising model\, where we accurately determine the power-law exponent and the energy diffusion cons tant [2]. Furthermore\, I will sketch how we used the LITE approach to rep roduce and interpret the results found in a recent experiment with NV cent ers in diamonds [3]. Finally\, I will briefly mention how the information lattice can be employed to obtain insightful results about the spatial str ucture of entanglement in generic many-body quantum states [4].[1] T. Klei n Kvorning\, L. Herviou\, and J. H. Bardarson\, Time-evolution of local in formation: Thermalization dynamics of local observables\, SciPost Phys. 13 \, 080 (2022).[2] C. Artiaco\, C. Fleckenstein\, D. Aceituno\, T. Klein Kv orning\, and J. H. Bardarson\, Efficient Large-Scale Many- Body Quantum Dy namics via Local-Information Time Evolution\, arXiv:2310:06036.[3] K. Hark ins et al.\, Nanoscale engineering and dynamical stabilization of mesoscop ic spin textures\, arXiv:2310:05635.[4] C. Artiaco\, T. Klein Kvorning\, D . Aceituno\, L. Herviou\, and J. H. Bardarson\, In preparation\, 2024. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-927@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240130T110000 DTEND;TZID=Europe/Paris:20240130T120000 DTSTAMP:20240125T142204Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-joel-mabillard-ulb-bruxelles/ SUMMARY:Séminaire du LPTMS : Joël Mabillard (Université libre de Bruxell es) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 30 Jan 24 11:00 DESCRIPTION:Dissipative hydrodynamics of systems with broken symmetriesJoë l Mabillard (ULB Bruxelles) In phases of condensed matter with broken con tinuous symmetries\, as well as in fluids\, transport processes generate i rreversibility at the macroscale. To be complete\, the hydrodynamic equati ons must include these dissipative effects. A fundamental question is to d educe all of them from the microscopic Hamiltonian dynamics of the particl es with the methods of non-equilibrium statistical mechanics. In this pres entation\, a first-principle derivation based on a local-equilibrium appro ach is introduced. As an example of application\, the crystalline solid is considered. The breaking of the three-dimensional continuous group of spa tial translations implies the existence of three slow modes in addition to the five slow modes arising from the fundamental conservation laws of mas s\, energy\, and linear momentum. Finally\, based on the results of the lo cal-equilibrium approach\, the equilibrium and nonequilibrium properties r elevant to the hydrodynamics of the perfect hard-sphere crystal are obtain ed with molecular dynamics simulations. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-905@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240202T110000 DTEND;TZID=Europe/Paris:20240202T120000 DTSTAMP:20240118T101330Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-francois-nedelec-2/ SUMMARY:Physics-Biology Interface Seminar: François Nédélec - Amphi de l 'Institut Curie\, bâtiment 111 - 2 Fév 24 11:00 DESCRIPTION:Simple Chromosome Partitioning Mechanisms and Dynamics of a Mit otic Spindle.\n(Beware of the unusual location)\nFrançois Nédélec (Camb ridge University)\nWe are using theory to explore simple mechanisms of chr omosome partitioning with the aim of understanding the design principles o f mitotic spindle assembly. Firstly\, I will present how artificial evolut ion in a computer can uncover simple combinations of cytoskeletal elements that will self-organize to pull on a kinetochore pair symmetrically and r eliably. I will then discuss the requirements to extend such elementary me chanisms to build a mitotic spindle that can handle multiple chromosomes. Secondly\, I will present the characteristics of the mitotic spindles foun d in the roots of Arabidopsis thaliana\, and argue that given these quanti ties\, this plant spindle stands out as an ideal subject to build a quanti tatively accurate 3D simulation. I will present our attempts to build such a model\, detailing some key assumptions and using a simulation to illust rate the remarkable dynamics of a metaphase mitotic spindle. CATEGORIES:physbio,seminars LOCATION:Amphi de l'Institut Curie\, bâtiment 111\, 111\, Rue Jean-Dominiq ue Cassini\, Bures-sur-Yvette\, 91440\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=111\, Rue Jean-Dominique Ca ssini\, Bures-sur-Yvette\, 91440\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi de l'Institut Curie\, bâtiment 111:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-942@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240202T110000 DTEND;TZID=Europe/Paris:20240202T123000 DTSTAMP:20240201T091207Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-eugene-demler-eth-switzerland/ SUMMARY:Séminaire exceptionnel: Eugene Demler (ETH\, Switzerland) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Fév 24 11:00 DESCRIPTION:Quantum simulators: pointilist perspective on many-body physics  Eugene Demler (ETH\, Switzerland) I will discuss recent progress of the optical lattice emulators of the Fermi Hubbard model. The new feature of these experiments is availability of snapshots of many-body states with si ngle particle resolution. I will review new insights from these experiment s on the properties of doped Mott insulators\, including demonstration of magnetically mediated pairing. I will also discuss how experiments with co ld atoms provide new perspective on kinetic magnetism in moire materials.    CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-930@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240206T110000 DTEND;TZID=Europe/Paris:20240206T120000 DTSTAMP:20240131T095410Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-giovanni-catania-ucm/ SUMMARY:Séminaire du LPTMS : Giovanni Catania (UCM) - Salle des séminaire s du FAST et du LPTMS\, bâtiment Pascal n°530 - 6 Fév 24 11:00 DESCRIPTION:The Copycat Perceptron: Smashing Barriers Through Collective Le arningGiovanni Catania (Complutense University of Madrid)The context of th is talk is related to inference problems in the so-called teacher-student scenario (or planted setting)\, where the goal is to retrieve a ground-tru th signal (specified by a teacher) from a set of - possibly noisy\, or inc omplete - data provided to a student. This setting offers a natural connec tion with Bayesian inference and statistical physics\, which allows to det ermine specific algorithmic thresholds separating regimes - or phases in a thermodynamic sense - where signal recovery is possible or not. Among the class of inference problems that are typically studied\, some of them are characterized by a "hard" inference regime\, a mechanism related to the p resence of first-order transitions where any polynomial optimization algor ithm fails to find the solution. I this talk\, I will focus on a famous ex ample of an inference problem with an inference-hard phase\, namely the bi nary perceptron in the teacher-student scenario\, and the algorithmic prop erties of a specific optimization algorithm - Simulated Annealing (SA) - i n its ability to find the planted configuration (i.e\, the teacher's weigh t vector)\, depending on the fraction of examples provided to the student and an external thermal noise. It is well known how SA is sensible to the presence of metastable states that can trap the dynamics into local minima with poor generalization performances\; in this model\, such a phenomenon occurs even in a portion of the thermodynamically easy-inference phase\, where other Bayes-optimal algorithms are supposed to find the solution in polynomial time . In a different inference problem\, it has recently been conjectured that replicating the systems and adding a ferromagnetic intera ction between real replicas favours the resulting algorithm (Replicated SA \, or RSA) to find solutions where the single system does not\, as a conse quence of a peculiar modification of the free energy landscape that allows the coupled system to avoid these metastable local minima. I will discuss how to characterize the phase diagram of a system made of several coupled perceptron students using techniques stemming from the statistical physic s of spin-glasses\, and how it modifies when considering a thermal noise a ffecting the generation capabilities of each of them. In this context\, th e replicated system can be considered as a model of collective learning am ong a class of students that try to learn the teacher's rule while "cooper ating" with each other. These results provide additional analytic and nume rical evidence for the recently conjectured Bayes-optimal property of Repl icated Simulated Annealing (RSA) for a sufficient number of replicas. From a learning perspective\, these results also suggest that multiple student s working together (in this case reviewing the same data) are able to lear n the same rule both faster and with fewer examples\, a property that coul d be exploited in the context of federated learning. Reference: G. Catania \, A. Decelle\, B. Seoane\, arXiv:2308.03743 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-940@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240208T110000 DTEND;TZID=Europe/Paris:20240208T120000 DTSTAMP:20240201T084435Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alvise-bastianello-tum/ SUMMARY:Séminaire du LPTMS : Alvise Bastianello (TUM Munich) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Fév 24 11:00 DESCRIPTION:Chasing Cold Atoms with Generalized HydrodynamicsAlvise Bastian ello (TUM Munich)Ultracold quantum gases are the ideal experimental venue to investigate strongly interacting phases of matter and their dynamic pro perties\, in many instances exceeding the capability of conventional numer ical methods. Hence\, new strategies must be devised to overcome these cha llenges. In one dimension\, the role of interactions is enhanced and corre lations are strong\, nonetheless a special class of systems\, known as int egrable models\, allows for analytical progress directly at the thermodyna mic scale. In this talk\, I will introduce the exact large-scale hydrodyna mics of integrable models\, known as Generalized Hydrodynamics (GHD)\, and present theoretical developments\, such as inhomogeneous interactions\, q uasiparticle instabilitities and semiclassical limits. These results are r elevant for experimental applications: I will discuss results obtained wit h ongoing experimental collaborations\, and future directions. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-925@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240220T140000 DTEND;TZID=Europe/Paris:20240220T150000 DTSTAMP:20240213T142636Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alessia-annibale-kcl-london-2/ SUMMARY:Séminaire du LPTMS : Alessia Annibale (KCL London) - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Fév 24 14:00 DESCRIPTION:Two types of criticality in neural network rate models: mapping to equilibrium phase transitionsAlessia Annibale (KCL London) *SPECIAL T IME: 14 h*The seminar will be onsite\, and also on zoom (see below). We c onsider a simple neural network model\, evolving via non-linear coupled st ochastic differential equations\, where neural couplings are randomly asym metric Gaussian variables with non-vanishing mean. We analyze the dynamics \, averaged over the network ensemble\, in the thermodynamic limit\, using generating functional analysis. In the absence of noise\, the fixed point s of the dynamics can be characterized by two order parameters\, namely th e mean and variance of the neural activity\, determined through a set of s elf-consistency equations\, which close when couplings are fully asymmetri c. These equations show that\, for any degree of coupling asymmetry\, two types of criticality emerge\, corresponding to ferromagnetic and spin-glas s order\, respectively. The transition from the disordered phase to either of the ordered phases is consistent with spectral properties of the coupl ing matrix. Non-fixed point steady states are analysed for fully asymmetr ic interactions. Such solutions cannot be described by a closed set of equ ations for the stationary mean and variance\, as the latter depends on a n on-persistent order parameter\, which quantifies time correlations in neur al activity. This\, in turn\, evolves according to a gradient-descent dyna mics on a potential\, which depends on the variance itself. Our analysis r eveals how the variance is dynamically selected by the system: whenever th e potential is confining\, so to allow a multitude of bounded steady-state solutions\, the system selects the steady state corresponding to the sepa ratrix curve. Chaotic motion is the manifestation\, at the level of single network instances\, of such ensemble-averaged dynamics laying on the curv e that separates different realizable steady states. Finally\, we show tha t when either the external signal or the noise exceed a certain threshold\ , that we calculate explicitly\, the system is brought to a phase where on ly one bounded solution exists and chaos is suppressed.Zoom info:https://u niversite-paris-saclay-fr.zoom.us/j/99172093004?pwd=eUwrN2ZWd2RWNUJCWmxvcE xPNjMzZz09Meeting ID: 991 7209 3004Passcode: 812296   CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-937@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240227T110000 DTEND;TZID=Europe/Paris:20240227T120000 DTSTAMP:20240215T092024Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-dganit-meidan-negev/ SUMMARY:Séminaire du LPTMS : Dganit Meidan (Ben-Gurion University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 27 Fév 2 4 11:00 DESCRIPTION:Theory of free fermion dynamics - from monitored to post select ed evolutionDganit Meidan (Ben-Gurion University)Monitored quantum systems undergo Measurement-induced Phase Transitions (MiPTs) stemming from the i nterplay between measurements and unitary dynamics. When the detector read out is post- selected to match a given value\, the dynamics is generated b y a Non-Hermitian Hamiltonian with MiPTs characterized by different univer sal features. Here\, we derive a partial post-selected stochastic Schrodin ger equation based on a microscopic description of continuous weak measure ment. This formalism connects the monitored and post-selected dynamics to a broader family of stochastic evolution. We apply the formalism to a chai n of free fermions subject to partial post-selected monitoring of local fe rmion parities. Within a 2-replica approach\, we obtained an effective bos onized Hamiltonian in the strong post-selected limit. Using a renormalizat ion group analysis\, we find that the universality of the non-Hermitian Mi PT is stable against a finite (weak) amount of stochasticity. We further s how that the passage to the monitored universality occurs abruptly at fini te partial post-selection\, which we confirm from the numerical finite siz e scaling of the MiPT. Our approach establishes a way to study MiPTs for a rbitrary subsets of quantum trajectories and provides a potential route to tackle the experimental post-selected problem. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-938@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240229T110000 DTEND;TZID=Europe/Paris:20240229T120000 DTSTAMP:20240220T153306Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-arnab-das-kolkata/ SUMMARY:Séminaire du LPTMS : Arnab Das (IACS Kolkata) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Fév 24 11:00 DESCRIPTION:Dynamical Freezing and Emergent Floquet Conservation LawsArnab Das (IACS Kolkata)A periodically driven quantum system with several degree s of freedom is naïvely expected to heat up indefinitely leading a locall y infinite temperature -like state at long time. Here we show\, a strong e xception to this intuitive picture is observed if the drive strength cross es a threshold. Below the threshold\, the expected Floquet Thermalization prevails\, while above it\, a set of approximate but perpetual conservatio n law emerge\,  fragmenting the Hilbert space stably into their eigensubs paces. This has been demonstrated for a large class of text book many-body systems including quantum Ising model of any dimension\, and interaction distribution (including homogeneous)\, and any Heisenberg system\, with st rong manifestations in both finite and infinite systems. Here we will disc uss the salient features of the phenomenology of Dynamical Freezing\, and also review the marginal analytical understanding of the subject obtained so far. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-948@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240229T140000 DTEND;TZID=Europe/Paris:20240229T153000 DTSTAMP:20240221T203156Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-sandro-stringari-pitaevskii-bec-center-universita-di-trento / SUMMARY:Séminaire exceptionnel du LPTMS : Sandro Stringari (Pitaevskii BEC Center\, Universita di Trento) - Petit amphi\, bâtiment Pascal n° 530 - 29 Fév 24 14:00 DESCRIPTION:Propagation of sound in density modulated superfluidsSandro Str ingari (Pitaevskii BEC Center\, Universita di Trento) I will discuss the propagation of sound in superfluid quantum gases breaking translational in variance. I will consider both the case of a quantum  gas subject to an e xternal periodic potential and the case where translational symmetry is br oken in a spontaneous way\, giving rise to supersolidity. The role of the superfluid density in determining the sound velocity at zero temperature i s explicitly pointed out in  both cases.  CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-933@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240305T110000 DTEND;TZID=Europe/Paris:20240305T120000 DTSTAMP:20231206T181108Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sergei-nechaev-lptms/ SUMMARY:Séminaire du LPTMS : Sergei Nechaev (LPTMS) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 5 Mar 24 11:00 DESCRIPTION:Eastern and Western Mentalities as Golden and Silver Stationary Points in Probe Particle Dynamics within a Modular DomainSergei Nechaev ( LPTMS)\n\nWe analyze flows generated by iterative dynamics of reflections of triangles. We interpret these flows as the probe particle adiabatic dyn amics in the fundamental domain of the modular group. We consider two spec ific cases of lattices: (a) generated by reflections of equilateral triang les\, and (b) generated by reflections of rectangular isosceles triangles. We show that stationary points of the flows for equilateral and isosceles triangles are correspondingly the ``Golden'' and the ``Silver'' ratios. We speculate about the manifestation of the difference between the Golden and the Silver ratios in cultural traditions of the ``Western'' and the `` Eastern'' world. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-949@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240308T134500 DTEND;TZID=Europe/Paris:20240308T144500 DTSTAMP:20240226T095601Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-quantum-sem inar-lea-dubois-laboratoire-charles-fabry/ SUMMARY:LPTMS Quantum Seminar: ​​​​​​​Léa Dubois (Laboratoir e Charles Fabry) - Salle des séminaires du FAST et du LPTMS\, bâtiment P ascal n°530 - 8 Mar 24 13:45 DESCRIPTION:Probing the local rapidity distribution of a 1D Bose gasAfter r elaxation\, an integrable quantum system\, in particular a one-dimensional gas of bosons\, is characterized by the rapidities distribution\, a quant ity preserved throughout the dynamics. The rapidities distribution is noth ing else than the asymptotic momentum distribution of particles after a on e-dimensional expansion of the system. This definition is directly linked to an experimental procedure allowing to access this quantity. We can also study the different stages of the expansion by using the Generalized Hydr oDynamics theory\, an emerging hydrodynamic theory applicable to quantum i ntegrable systems.  In our experiment\, 87Rb atoms are trapped by an atom chip to reach the one-dimensional regime. A spatial selection tool has be en integrated in our setup allowing to locally probe the rapidity  distri bution by performing one-dimensional expansions of selected parts of the c loud. I will present the comparisons between the experimental expansions w ith the predicted profiles by Generalized HydroDynamics [1]. I will also p resent you some preliminary results about new protocols that we implemente d thanks to the spatial selection tool in order to test the Generalized Hy drodynamics theory with initial out-of equilibrium 1D Bose gas. [1] L. Du bois\, G. Thémèze\, J. Dubail and I. Bouchoule\, arXiv: 2312.15344 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-934@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240312T110000 DTEND;TZID=Europe/Paris:20240312T120000 DTSTAMP:20240305T123905Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-hosho-katsura-tokyo/ SUMMARY:Séminaire du LPTMS : Hosho Katsura (Tokyo University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Mar 24 11:0 0 DESCRIPTION:Frustration-free systems and beyond\nHosho Katsura (Tokyo Unive rsity)\nFrustration-free systems refer to a class of exactly solvable quan tum many-body systems for which the ground state is obtained as a simultan eous ground state of all local Hamiltonians. They have a variety of applic ations in condensed matter physics and quantum information\, with notable examples including the Affleck-Kennedy-Lieb-Tasaki model and Kitaev's tori c code. A slightly more general concept called the local divergence condit ion\, often discussed in the context of classical stochastic processes\, h as recently found use in constructing special eigenstates of non-integrabl e models called quantum many-body scar (QMBS) states. In this talk\, I wil l provide an overview of these technical concepts and then present our rec ent results. In particular\, I will argue that Witten's conjugation\, orig inally introduced in supersymmetric quantum mechanics\, is useful for cons tructing a family of frustration-free systems based on simple models such as the classical Ising model. If time permits\, I will also discuss how to construct QMBS states systematically.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-945@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240315T110000 DTEND;TZID=Europe/Paris:20240315T120000 DTSTAMP:20240308T094640Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-emily-gehrels/ SUMMARY:Physics-Biology Interface Seminar: Emily Gehrels - Moyen Amphi\, Bu ilding 510\, Université Paris-Saclay Orsay - 15 Mar 24 11:00 DESCRIPTION:How to create form and dynamics in a living embryo\nEmily Gehre ls (Aix-Marseille Université)\nBeware of the unusual location\nBiological organisms are able to develop from simple eggs to complex adult forms via a series of dynamic rearrangements\, during which embryonic tissues gener ate stress\, deform\, and flow. What can we learn about the rules and poss ibilities of autonomous structure formation by studying their development? I will present one such study where we uncover how Drosophila embryos use symmetric forces to create a polarized flow of cells needed to achieve th eir final form.\nCell flows in the early Drosophila embryo are driven by a n interplay between biological signaling and tissue mechanics. Using live imaging\, we observe how changes in the presence of force-generating prote ins and the geometry of the tissue relate to tissue dynamics at the onset of morphogenesis. We use theoretical and computational methods to model th e behavior of the tissue and experimentally challenge our findings using s elect genetic perturbations of the embryos. With this combination of exper imental and modeling approaches\, we have uncovered how organized multicel lular dynamics emerge from genetic\, mechanical\, and geometric “informa tion” during early Drosophila development. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-936@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240319T110000 DTEND;TZID=Europe/Paris:20240319T120000 DTSTAMP:20240314T140639Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-fabrizio-minganti-epfl-lausanne/ SUMMARY:Séminaire du LPTMS : Fabrizio Minganti (EPFL Lausanne) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Mar 24 11: 00 DESCRIPTION:Criticality\, computing\, and chaos in open quantum systemsFabr izio Minganti (EPFL Lausanne)Quantum technologies represent a frontier of both fundamental and applied research\, with global efforts aimed at devel oping quantum computers and simulation platforms that address practical ch allenges. However\, the current era\, known as the Noisy Intermediate-Scal e Quantum (NISQ) era [1]\, presents a unique set of challenges. In NISQ sy stems\, quantum devices are open\, interacting with their environment and experiencing dissipation. This dissipation poses a significant obstacle to the large-scale fabrication of quantum hardware\, potentially limiting qu antum advantages by degrading crucial properties like entanglement. NISQ d evices consist of numerous interacting particles undergoing both local and non-local unitary processes. They are also subject to non-unitary effects from the environment\, active measurements\, and feedback operations. As such\, they can only be modeled within the framework of many-body open qua ntum systems. In these systems\, the interplay between dissipative and Ham iltonian evolution leads to states and phenomena distinct from those obser ved in equilibrium condensed matter physics. In this presentation\, I will delve into the understanding and investigation of these emergent properti es in open quantum systems. The focus will particularly be on critical phe nomena like phase transitions [2] and chaos [3]\, highlighting their uniqu e features. I will also showcase the recent experimental demonstrations of our theoretical predictions [4\,5]. While in many applications dissipatio n is a barrier to overcome\, given appropriate engineering of the system-e nvironment coupling\, dissipation can be a resource. Indeed\, dissipative processes can be used to steer the dynamics of NISQ systems\, bypassing th e hardware limitation determined by design and fabrication\, such as energ y\, couplings\, connectivity\, etc. I will discuss how leveraging the dist inctive features of open quantum systems and its emergent phenomena signif icantly boost the performance of quantum hardware\, with a specific focus on their applications in quantum information encoding [6] and precision me trology [7]. [1] J. Preskill\, Quantum Computing in the NISQ era and beyon d\, Quantum 2\, 79 (2018). [2] FM\, A. Biella\, N. Bartolo\, and C. Ciuti\ , Spectral theory of Liouvillians for dissipative phase transitions\, Phys . Rev. A 98\, 042118 (2018). [3] F. Ferrari\, L. Gravina\, D. Eeltink\, P. Scarlino\, V. Savona\, and FM\, Transient and steady-state quantum chaos in driven-dissipative bosonic systems\, arXiv 2305.15479 (2023). [4] G. Be aulieu\, FM\, S. Frasca\, V. Savona\, S. Felicetti\, R. D. Candia\, and P. Scarlino\, Observation of first- and second-order dissipative phase trans itions in a two-photon driven Kerr resonator\, arXiv 2310.13636 (2023). [5 ] L. P. Peyruchat\, F. Ferrari\, FM\, and P. Scarlino\, Signature of dissi pative quantum chaos in coupled nonlinear driven resonators\, in preparati on. [6] L. Gravina\, FM\, and V. Savona\, Critical Schrödinger Cat Qubit\ , PRX Quantum 4\, 020337 (2023). [7] R. Di Candia\, FM\, K. V. Petrovnin\, G. S. Paraoanu\, and S. Felicetti\, Critical parametric quantum sensing\, npj Quantum Information 9\, 23 (2023). CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-941@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240326T110000 DTEND;TZID=Europe/Paris:20240326T120000 DTSTAMP:20240313T090115Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-karolina-kolodziej-dr4/ SUMMARY:Séminaire du LPTMS : Service partenariat et valorisation DR4 - Sal le des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Mar 24 11:00 DESCRIPTION:Presentation of European projects and fundingsMathilde Boff\, V eronique Chague\, Karolina Kolodziej\, Loryne Souffron (DR4) The teams in charge of European projects at the délégation régionale du CNRS will c ome to LPTMS to present the opportunities open to us and how they can help us apply for them. They will also be happy to stay afterwards for individ ual discussions with you. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-946@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240329T110000 DTEND;TZID=Europe/Paris:20240329T120000 DTSTAMP:20240219T090810Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-russell-spencer/ SUMMARY:Physics-Biology Interface Seminar: Russell Spencer - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Mar 24 11:00 DESCRIPTION:Exploring Membrane Topology Transformations using Polymer Field Theory\nRussell Spencer (University of Göttingen)\n\nMembrane remodeling \, including fusion and fission\, plays a crucial role in various cellular processes. However\, understanding the intricacies of these topological c hanges can be challenging due to the involvement of large-scale membrane r earrangements and their sensitivity to small-scale molecular behavior. Mor eover\, these remodeling events face significant free-energy barriers that necessitate the presence of catalytic proteins. In this work\, we utilize self-consistent field theory (SCFT) in combination with the string method to identify the Minimum Free Energy Path (MFEP). We thereby determine the most probable pathway for specific remodeling transitions implicated in c ellular signaling and organelle division. This approach has allowed us to discover a new pathway by which the fusion of membranes may catalyze their fission. Furthermore\, we extend conventional SCFT methods\, introducing proteins inspired by the dynamin family. These proteins facilitate fission by constricting membrane tubes. We find that the free energy barrier to f ission depends strongly on membrane tension and constriction. In addition to simply constricting the membrane\, dynamin's PH domains are inserted be tween lipid head groups\, inducing membrane distortion. Our results emphas ize the crucial role of this distortion in reducing the free energy barrie r to fission. This research sheds light on the underlying mechanisms of me mbrane remodeling and provide insights into cellular processes involving t opological changes.\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-951@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240402T110000 DTEND;TZID=Europe/Paris:20240402T120000 DTSTAMP:20240326T153223Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ariane-soret-luxembourg/ SUMMARY:Séminaire du LPTMS : Ariane Soret (University of Luxembourg) - Sal le des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Avr 2 4 11:00 DESCRIPTION:Symmetry shapes thermodynamics in macroscopic quantum systemsAr iane Soret (University of Luxembourg)Symmetries play a fundamental role in shaping physical theories\, from quantum mechanics to thermodynamics. Stu dying the entropic\, energetic\, or dynamic signatures of underlying symme tries in quantum systems is an active field of research\, from fundamental questions about entropy scalings\, ground state properties\, or thermaliz ation\, to the optimization of quantum computing or numerical simulation p rocedures\, and is gaining momentum due to rapid experimental advances\, p articularly in cold atoms [1]. In this work [2]\, we derive a systematic a pproach to the thermodynamics of quantum systems based on the underlying s ymmetry groups. We show that the entropy of a system can be described in t erms of group-theoretical quantities that are largely independent of the d etails of its density matrix. We apply our technique to generic N identica l interacting d-level quantum systems. Using permutation invariance\, we f ind that\, for large N\, the entropy displays a universal large deviation behavior with a rate function s(x) that is completely independent of the m icroscopic details of the model\, but depends only on the size of the irre ducible representations of the permutation group. In turn\, the partition function is shown to satisfy a large deviation principle with a free energ y f (x) = e(x) − \\beta^{−1}s(x) \, where e(x) is a rate function that only depends on the ground state energy of particular subspaces determine d by group representation theory. We demonstrate the power of our approach by applying it to the nontrivial task of describing phase transitions gov erned by the interplay of quantum and thermal fluctuations in the transver se-field Curie-Weiss model.[1] Masahito Ueda. Quantum equilibration\, ther malization and prethermalization in ultracold atoms. Nat. Rev. Phys.\, 2(1 2):669\, 2020.[2] Vasco Cavina\, Ariane Soret\, Timur Aslyamov\, Krzysztof Ptaszynski\, and Massimiliano Esposito. Symmetry shapes thermodynamics of macroscopic quantum systems. arXiv:2402.04214\, 2024. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-952@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240423T110000 DTEND;TZID=Europe/Paris:20240423T120000 DTSTAMP:20240415T112902Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alessio-lerose-university-of-oxford/ SUMMARY:Séminaire du LPTMS : Alessio Lerose (University of Oxford) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 23 Avr 24 11:00 DESCRIPTION:Theory of robust ergodicity breaking in quantum many-body syste ms with long-range interactions\nAlessio Lerose (University of Oxford)\nRe cent years have seen the discovery of a number of routes to (strong or wea k forms of) ergodicity breaking in isolated quantum many-body systems\, ev en in absence of quenched disorder. Quantum many-body scars (QMBS) - excep tional energy eigenstates associated with violations of thermalization for special non-equilibrium initial states - rank as a novel remarkable possi bility. The various systematic constructions of QMBS\, however\, require f ine-tuning of local Hamiltonian parameters. In this talk I will demonstrat e that long-range interacting quantum spin lattices generically host robus t QMBS. This result is based on an analysis of spectral properties upon ra ising the power-law decay exponent α of spin-spin interactions from the s olvable permutationally-symmetric limit α=0:\n\n Firstly we numerically establish that\, despite spectral signatures of quantum chaos appear for i nfinitesimal α\, the towers of α=0 energy eigenstates with large collect ive spin are smoothly deformed as α is increased\, and exhibit characteri stic QMBS features.\n  To elucidate the nature and fate of these states in larger systems we introduce a novel analytical approach based on mappin g the quantum spin Hamiltonian onto a relativistic quantum rotor non-linea rly coupled to an extensive set of bosonic modes. We provide an original e xact solution for the eigenstates of this interacting impurity model\, and show their self-consistent localization in large-spin sectors of the orig inal spin Hamiltonian for 0<\;α<\;d.\n\nOur theory unveils the stabil ity mechanism of such QMBS for arbitrary system size\, and predicts instan ces of its breakdown e.g. near dynamical critical points or in presence of semiclassical chaos\, which we verify numerically in long-range quantum I sing chains. As a byproduct\, we find a predictive criterion for absence o f heating under periodic driving beyond existing Floquet-prethermalization theorems. I will finally briefly discuss how the multipartite entanglemen t structure of the persistent non-equilibrium states discovered here has p otential metrological applications in present-day experimental platforms.\ n\nMain Ref: https://arxiv.org/abs/2309.12504 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-943@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240426T110000 DTEND;TZID=Europe/Paris:20240426T120000 DTSTAMP:20240411T145658Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-buzz-baum/ SUMMARY:Physics-Biology Interface Seminar: Buzz Baum - Salle des séminaire s du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Avr 24 11:00 DESCRIPTION:The evolution\, structure and function of ESCRT-III\nBuzz Baum (Cambridge University)\nIn this talk we will explore the evolution of the eukaryotic cytoskeleton.\nAs we will see\, much of the machinery\, includi ng actin\, tubulin and ESCRT-III\, has its origins in archaea.\nWe can the refore use archaea as a simple model in which to understand the evolution\ , structure and function\nof ESCRT-III polymers in membrane remodelling an d cytokinesis.\n\n \; CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-953@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240430T110000 DTEND;TZID=Europe/Paris:20240430T120000 DTSTAMP:20240422T133909Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-berislav-buca-niels-bohr/ SUMMARY:Séminaire du LPTMS : Berislav Buca (Niels Bohr Institute) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 30 Avr 24 11:00 DESCRIPTION:Eigenoperator thermalization\nBerislav Buca (Niels Bohr Institu te)\n**Online seminar**\n\nI will provide a framework for computing time-a veraged dynamics in locally interacting systems in any dimension. It is ba sed on pseudolocal dynamical symmetries generalising pseudolocal charges a nd unifies seemingly disparate manifestations of quantum non-ergodic dynam ics including quantum many-body scars\, continuous\, discrete and dissipat ive time crystals\, Hilbert space fragmentation\, lattice gauge theories\, and disorder-free localization. Using the theory two novel types of phase transitions are introduced: 1) The "scarring phase transition" where the order parameter is the locality of the projected local quantities - for ce rtain initial states persistent oscillations are present. 2) The "fragment ation phase transition" for which long-range order is established in an en tire phase due to presence of certain non-local strings. Two prototypical\ , but otherwise mostly intractable\, models are solved using the theory: 1 ) a spin 1 scarred model and 2) the t-J_z model with fragmentation.\n\nRef erences:\nBerislav Buca. Unified theory of local quantum many-body dynamic s: Eigenoperator thermalization theorems. Phys. Rev. X 13\, 031013 (2023). \nBenjamin Doyon. Thermalization and pseudolocality in extended quantum sy stems. Commun. Math. Phys. 351: 155-200 (2017).\n\nZoom information:\nhttp s://universite-paris-saclay-fr.zoom.us/j/96277574790?pwd=NGRjYkZOdWZmTk91M G1KQUxQaC9Ldz09\nMeeting ID: 962 7757 4790 Passcode: 844783 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-944@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240514T110000 DTEND;TZID=Europe/Paris:20240514T120000 DTSTAMP:20240211T122420Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-clement-sire-lpt-toulouse/ SUMMARY:Séminaire du LPTMS : Clément Sire (LPT Toulouse) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Mai 24 11:00 DESCRIPTION:When poor little fish are confronted with AI\, robot-fish\, vir tual reality\, and dronesClément Sire (LPT Toulouse)After introducing the collective behaviors observed in fish schools\, I will outline a methodol ogy for quantitatively measuring social interactions (attraction/repulsion \; alignment) within animal groups. The reconstructed interactions can the n be directly implemented in analytical models which quantitatively reprod uce the collective motion of fish. I will also briefly address an alternat ive machine learning approach designed to produce realistic fish trajector ies. In the latter part of the presentation\, I will explore various appli cations of such analytical or machine learning behavioral models in the co ntext of robotic and drone platforms\, and a virtual reality setup... for fish! In particular\, our robot-fish and VR setups constitute original and powerful tools to study the social dynamics of fish and their response to controlled perturbations. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-956@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240521T110000 DTEND;TZID=Europe/Paris:20240521T120000 DTSTAMP:20240515T100534Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ricardo-marino-google-paris/ SUMMARY:Séminaire du LPTMS : Ricardo Marino (Google Paris) - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Mai 24 11:00 DESCRIPTION:\nHow do we know our classification is better than humans?\nRic ardo Marino (Google Paris)\n \;\n\n\nLarge language models have taken the world by storm in the past year. Many are used for classification task s and their performance is compared to non-expert crowdsourced human annot ators. But if they disagree\, how can we tell who is actually wrong? And h ow to do this without relying on experts\, who are too expensive and less available? CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-957@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240524T110000 DTEND;TZID=Europe/Paris:20240524T120000 DTSTAMP:20240514T091708Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-jasper-van-der-gucht/ SUMMARY:Physics-Biology Interface Seminar: Jasper van der Gucht - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Mai 24 11: 00 DESCRIPTION:Catching up: towards bio-inspired catch-bonded materials \nJasp er van der Gucht (Wageningen U.\, the Netherlands)\n\nMany biological mate rials face conflicting mechanical demands: they must be dynamic and adapta ble on the one hand\, and robust and resilient on the other. Dynamicity as ks for labile bonds that readily dissociate and reform\, while resilience asks for strong and long-lived bonds. Nature has found a solution for thes e seemingly contrasting requirements: catch bonds. While conventional bond s weaken under tension\, catch bonds do the opposite: they strengthen unde r stress. Under quiescent conditions the bonds are weak\, allowing for the dynamic rearrangements necessary for cell functioning\, but under conditi ons of high stress they stabilize\, thereby protecting the cells against m echanical stress. Since their discovery two decades ago\, catch bonds are now recognized as a crucial design element for controlling cellular mechan ics. Yet\, how catch bonds exactly perform their task at the scale of netw orks and cells is not well understood. \n\n\nIn this presentation\, I will discuss two recent approaches from our group that aim to shed insight on this. In the first part\, I will discuss simulation results of catch-bonde d polymer networks that show how catch bonds collectively protect networks against mechanical damage\, and in particular how the mobility of the bon ds influences this. In the second part\, I will share our efforts to desig n a synthetic DNA-based catch bond\, by using a combination of computation al design\, experiments and simulations. \n\n\nJ. Ruiz-Franco\, J. Tauber & J. van der Gucht\, “Cross-linker Mobility Governs Fracture Behavior o f Catch-Bonded Networks”\, Physical Review Letters 130 (118203)\, 2023.\ nM. van Galen\, A. Bok\, T. Peshkovsky\, J. van der Gucht\, B. Albada & J. Sprakel\, “De novo DNA-based catch bonds”\, Nature Chemistry\, in pre ss\, 2024.\n\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-959@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240528T110000 DTEND;TZID=Europe/Paris:20240528T120000 DTSTAMP:20240521T162143Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mehmet-can-ucar-ista-vienna/ SUMMARY:Séminaire du LPTMS : Mehmet Can Uçar (ISTA\, Austria) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 28 Mai 24 11: 00 DESCRIPTION:\nSelf-organized versus controlled guidance of cells and tissue s\nMehmet Can Uçar (ISTA\, Austria)\nIn living organisms\, coordinated ce ll and tissue movement is crucial for processes like morphogenesis\, immun e response\, and cancer invasion. While it is commonly assumed that collec tive motion is steered by global\, pre-patterned chemical or mechanical cu es\, limited evidence supports such long-range guidance in living organism s. In contrast\, recent findings are unveiling the prominence of local\, s elf-generated cues across different systems\, prompting a shift towards in vestigating controlled vs. self-organized guidance. In this talk I will fo cus on two distinct systems to explore their guidance principles: (i) The development of branched structures\, such as neurons and lymphatic network s\, and (ii) collective migration of immune cells. I will introduce theore tical models to predict quantitative signatures of self-organized vs. cont rolled guidance\, which I will compare with experimental data at both scal es. Finally\, I will discuss the potential of self-organized guidance as a robust mechanism to navigate heterogeneous cell populations\, and conclud e with some perspectives to link cell- and tissue-scale guidance strategie s.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-947@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240604T110000 DTEND;TZID=Europe/Paris:20240604T120000 DTSTAMP:20240528T140830Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexios-polychronakos-cuny-ny/ SUMMARY:Séminaire du LPTMS : Alexios P. Polychronakos (CUNY New York) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Juin 24 11:00 DESCRIPTION:\nObserved Observers and the Consistency of Quantum Theory\nAl exios P. Polychronakos (CUNY New York)\n\nThe special role that observers play in Quantum Mechanics leads to conceptual and interpretational issues when observers become part of the quantum state. This was recently elevate d to a contradiction by Frauchiger and Renner\, thus casting doubt at the logical consistency of quantum theory.\nI argue that unitary quantum mech anics implies that observers who will themselves be subjected to "cat" me asurements cannot\, in general\, apply the standard Born rules to deduce t he results of experiments\, and thus can neither make reliable predictions nor communicate reliable information to other observers. This restores th e logical consistency of quantum mechanics\, at the price of introducing a n additional element of uncertainty when cat measurements are a possibilit y. I discuss the feasibility of cat measurements and speculate that thermo dynamics and/or quantum field theory may make them physically unattainable . CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-958@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240607T110000 DTEND;TZID=Europe/Paris:20240607T120000 DTSTAMP:20240527T140209Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-martin-michael-muller-2/ SUMMARY:Physics-Biology Interface seminar: Martin Michael Müller - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Juin 24 1 1:00 DESCRIPTION:Protein-membrane interactions with a twist\nMartin Michael Mül ler (U. de Lorraine)\n\nTo understand how a biofilament can interact with a lipid membrane\, mesoscopic models are of particular interest. \nWithin a framework of elasticity theory and geometry\, two mechanisms have been p roposed\, which can induce membrane deformations \ndue to a biofilament: t he Twister and the Darboux torque mechanism [1]. Whereas the Darboux torqu e mechanism has been shown to \nexplain membrane deformations by a polymer in several important biological systems\, the Twister mechanism has been studied more \ncarefully only recently [2]. \n\n\nIn my talk I will discus s how the Twister mechanism together with numerical simulations can explai n the membrane translocation \nof botulinium toxins\, which are among the most powerful toxins produced in nature. The initial deformation of the me mbrane by \nthe toxin is caused by the presence of local torques arising f rom asymmetric positions of hydrophobic residues. Different\ntorque distri butions are observed in the simulations and permit an origin for the mecha nism opening the membrane to be proposed.\n\n\n\n[1] J. Fierling et al. So ft Matter\, 12:5747\, 2016.\n\n\n[2] A. Delort et al. IJMS\, 25:2481\, 202 4.\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-950@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240611T110000 DTEND;TZID=Europe/Paris:20240611T120000 DTSTAMP:20240601T134322Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-ritesh-bhola-tata-mumbai/ SUMMARY:Séminaire du LPTMS : Ritesh Bhola (Tata institute\, Mumbai) - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 11 Juin 24 11:00 DESCRIPTION:\nGallai-Edmonds percolation\nRitesh Bhola (Tata institute\, Mu mbai)\nMaximally-packed dimer coverings (maximum matchings) of non-biparti te site-diluted lattices\, such as the triangular and Shastry-Sutherland l attices in d = 2 dimensions and the stacked-triangular and corner-sharing octahedral lattices in d = 3\, generically exhibit a nonzero density of mo nomers (unmatched vertices). Following the construction of Ref. [1]\, we u se the the structure theory of Gallai and Edmonds to decompose the disorde red lattice into “R-type” regions which host the monomers of any maxim um matching\, and perfectly matched “P-type” regions from which such m onomers are excluded. When the density nv of quenched vacancies lies well within the low-nv geometrically percolated phase of the disordered lattice \, we find that the random geometry of these regions exhibits rather unusu al Gallai-Edmonds percolation phenomena. In d = 2\, we find two\nphases se parated by a critical point\, namely a phase in which all R-type and P-typ e regions are small and a percolated phase that displays a striking lack o f self-averaging in the thermodynamic limit: Each sample has a single perc olating region which is of type P or R with respective probability fP or 1 − fP\, where fP ≈ 0.5 independent of nv (away from the critical regio n). In d = 3\, apart from a phase with small R-type and P-type clusters\, the thermodynamic limit exhibits four distinct percolated phases separated by critical points at successively lower nv. In the first such phase\, ea ch sample has one percolating R-type region and no such P-type region. In the second\, each sample\nsimultaneously has one percolating region of eac h type (R and P). The third phase exhibits another interesting violation o f self-averaging in the thermodynamics limit: R-type regions percolate wit h unit probability\, while P-type regions percolate with probability fP ≈ 0.5. Finally\, the lowest-nv phase is identical in character to the un usual percolated phase found in d = 2\, again with fP ≈ 0.5 away from th e transition region. These phenomena have interesting implications for the vacancy-induced local moment instabilities of short-range resonating vale nce bond spin liquid states of frustrated magnets and for the character of disorder-induced collective Majorana excitations of Kitaev magnets and SU (2) symmetric Majorana spin liquids.\n\n[1] K. Damle\, Theory of collectiv e topologically protected Majorana fermion excitations of networks of loca lized Majorana modes\, Phys. Rev. B 105\, 235118 (2022).\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-954@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240625T110000 DTEND;TZID=Europe/Paris:20240625T120000 DTSTAMP:20240513T142540Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-anton-souslov-university-of-cambridge/ SUMMARY:Séminaire du LPTMS : Anton Souslov (University of Cambridge) - Sal le des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 25 Juin 24 11:00 DESCRIPTION:Optimal design and pattern formation in active solids\nAnton So uslov (University of Cambridge)\n\nActive solids consume energy to allow f or actuation and shape change not possible in equilibrium. I will focus on design principles for active materials with so-called odd elastic moduli\ , which are composed of non-reciprocal springs. We find that in floppy lat tices\, zero modes couple to microscopic non-reciprocity\, destroying odd moduli entirely. Instead\, an optimal odd lattice will be sufficiently sof t to activate elastic deformations\, but not too soft. I will then discuss how inertia and odd elasticity conspire and give rise to new varieties of pattern formation at the continuum scale. These results provide a theoret ical underpinning for recent experiments and point to the design of novel soft machines. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-960@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240717T020000 DTEND;TZID=Europe/Paris:20240717T030000 DTSTAMP:20240614T155520Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-s eminar-ajay-subbaroyan/ SUMMARY:Physics-Biology Seminar: Ajay Subbaroyan - la salle des conseils du LPTMS - 17 Juil 24 02:00 DESCRIPTION:Ajay Subbaroyan (IMSc Chennai\, India)\nUncovering and leveragi ng design principles in Boolean models of gene regulatory networks\nBeware of the unusual day and timeslot\n\nBoolean networks (BNs) are a well-esta blished framework for modeling the dynamics of gene regulatory networks (G RNs). In Boolean GRNs\, genes can be either "on" or "off"\, with their dyn amics dictated by regulatory logic rules or Boolean functions (BFs). The c omplete dynamics of BNs are encapsulated in its state transition graph (ST G). In this presentation\, I will aim to address three research lacunae. T he first is whether regulatory logic rules in reconstructed BNs that model cellular decision making\, are random. We show that certain biologically meaningful BFs\, namely\, the read-once functions (RoFs) and the nested ca nalyzing functions (NCFs) are highly preponderant in such reconstructed BN s. This observation is substantiated by proving that RoFs and NCFs possess minimal complexity based on two metrics\, Boolean complexity and average sensitivity\, respectively. The second is the proposal of a model selectio n framework for developmental Boolean GRNs. Our framework leverages relati ve stability constraints that are predicated on the hierarchy of cell stat es on the developmental landscape. The application of this framework to th e latest reconstructed Boolean GRN of the Arabidopsis thaliana root stem c ell niche yields several improved models. The third is how various types o f regulatory logic rules influence the structure of the STG of a BN. Certa in biologically meaningful BFs typically engender more "bushy" and converg ent STGs\, indicative of robust dynamics\, as opposed to STGs obtained usi ng random BFs. This investigation is made possible by our adaptation of me asures from the theory of cellular automata to the domain of BNs. CATEGORIES:physbio,seminars LOCATION:la salle des conseils du LPTMS\, rue André Rivière\, Orsay\, LPT MS – Bâtiment Pascal n° 530\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, LPTMS – Bâtiment Pascal n° 530\, 91405\, France;X-APPLE-RADIUS=100; X-TITLE=la salle des conseils du LPTMS:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-961@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240830T143000 DTEND;TZID=Europe/Paris:20240830T173000 DTSTAMP:20240715T082702Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-matteo-butano/ SUMMARY:Soutenance de thèse: Matteo Butano - Petit amphi\, bâtiment Pasca l n° 530 - 30 Août 24 14:30 DESCRIPTION:Mean-Field Games Applied to Pedestrian Dynamics\n\n\nThis thesi s explores pedestrian dynamics through experimental observations and simul ations\, focusing on the operational layer of pedestrian movement. Experim ents involving a controlled crowd and a moving cylindrical obstacle\, reve al that pedestrians exhibit anticipatory behaviors that deviate from granu lar behavior. The thesis challenges two existing pedestrian dynamics model s\, of different complexity showing their limitations in capturing the obs erved anticipatory behaviors. These models are found to be too myopic\, fo cusing on short-term decisions without adequately accounting for long-term anticipations. To address these shortcomings\, this work proposes a model based on the theory of Mean-Field Games (MFG). MFG models\, which combine optimal control and game theory\, describe interactions among a large num ber of agents via their average density\, simplifying the mathematical fra mework. The MFG model successfully predicts the experimental anticipation patterns by incorporating a discount factor that adjusts the weight of fut ure events in the optimization process. Additionally\, the thesis presents two corollary projects. The first has  the goal to integrate MFG with ag ent-based microscopic models to handle scenarios requiring detailed indivi dual interactions\, such as evacuations. The second explores using Physics Informed Neural Networks to solve MFG equations.\n\n\n\nJury : Cécile Ap pert-Rolland (directrice de thèse)\, Thierry Gobron (rapporteur)\, Bertra nd Maury\, Antoine Tordeux\, Denis Ullmo (directeur de thèse)\, Marie-The rese Wolfram (rapporteure) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-973@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240904T134500 DTEND;TZID=Europe/Paris:20240904T144500 DTSTAMP:20240830T081950Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-shunta-kitahama-tokyo-university/ SUMMARY:Informal Quantum Seminar: Shunta Kitahama (Tokyo University) - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Sep 24 13:45 DESCRIPTION:Higher-order exceptional points of many-body unidirectional Hat ano-Nelson model\nShunta Kitahama (Tokyo University)\n \;\n\nWe study higher-order exceptional points (EP) of the unidirectional Hatano-Nelson m odel\, which is one of the simplest non-Hermitian models.\n\nIn the first part\, we introduce the procedure to obtain the Jordan decomposition of th e unidirectional Hatano-Nelson model [1]. By identifying the Hamiltonian w ith one of the generators of sl₂ algebra\, it is proved that the Jordan decomposition is obtained from polynomials called q-binomial coefficients. \n\nIn the second part\, we investigate two physical properties of the uni directional Hatano-Nelson model caused by higher-order EP structure: pertu rbations and dynamics. First\, we focused on enhanced sensitivity of EP to perturbations. The energy level splitting due to perturbations around an n-th order EP exhibits 1/n-th power of the parameters [2]. By introducing a certain perturbation to the EP\, we were able to observe the level split ting expected from the Jordan decomposition calculated in [1]. Second\, we focused on the dynamics of observables. The dynamics at EPs shows polynom ial behavior over time. We calculated the particle number at each site as an observable. As a result\, we found power law dynamics in short time and long time dynamics.\n\n[1] S. Kitahama et al.\, J. Stat. Mech. 013101 (20 24).\n\n[2] H. Hodaei et al.\, Nature 23280 (2017). CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-981@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240920T134500 DTEND;TZID=Europe/Paris:20240920T150000 DTSTAMP:20240918T080753Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-arabi-seshappan-ucla/ SUMMARY:Informal Quantum Seminar: Arabi Seshappan (UCLA) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Sep 24 13:45 DESCRIPTION:Excited State Structure of Defected Solids (Co@S:WS2 and Si G-C enter) through GW/Bethe Salpeter Equation (GW/BSE) Approaches\nArabi Sesha ppan (UCLA)\n \;\n\nDefects in solid state materials have been identif ied as candidates for application in quantum information science (QIS) as single photon emitters\, quantum light sources\, and room-temperature soli d-state quantum bits (qubits). Accurate calculations of the exciton (coupl ed electron-hole pair) interactions in these materials is imperative to un derstanding these applications. In this work I study the ground- and excit ed-state energies for 2 promising QIS defected-solid candidates\, using th e many-body perturbation theory of the GW approximation and the Bethe-Salp eter Equation (BSE) approach. I show initial results of vertical excitatio n energies for monolayer cobalt-at-sulfur-site substituted WS2 (Co@S:WS2)\ , using a novel method of Spin-Flip on BSE [arXiv:2207.04549]. I will also discuss preliminary calculations of optical spectra of the Si G-center de fect—diamond structure Si with a C-Si-C substitution—using conventiona l GW/BSE through the open-source code BerkeleyGW. These defected structure s are of particular interest due to their ease of fabrication and emission s compatibility with current optical fiber/ telecommunications infrastruct ure. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-978@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240927T093000 DTEND;TZID=Europe/Paris:20240927T140000 DTSTAMP:20240926T144624Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journee-ffj-2/ SUMMARY:Journée FFJ - Amphi BLANDIN du LPS de la Faculté des Sciences d ’Orsay (Bâtiment 510) - 27 Sep 24 09:30 DESCRIPTION:Journée Fédération Friedel Jacquinot\nPrésentations à l'am phithéâtre du LPS - Bât.510 puis séance posters-buffet dans le hall du bâtiment Pascal n°530 CATEGORIES:seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-975@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240927T134500 DTEND;TZID=Europe/Paris:20240927T151500 DTSTAMP:20240919T122211Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-lorenzo-gotta-geneva-university/ SUMMARY:Informal Quantum Seminar: Lorenzo Gotta (Geneva University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 27 Sep 24 13:45 DESCRIPTION:Dirac impurity in a Luttinger liquid\nLorenzo Gotta (University of Geneva)\n \;\n\nWe consider a linearly-dispersing quantum impurity interacting through a contact density-density term with a one-dimensional superfluid described by Luttinger liquid theory. We employ field-theoreti cal tools to characterize the impurity dynamics by calculating approximate expressions for the single-particle Green's function and the time evoluti on of the density profile. We discover the existence of two different dyna mical regimes\, separated by a change in the relative magnitude of the imp urity velocity and of the sound velocity. When the latter is smaller than the former\, the impurity behavior is dominated by the quasiparticle unive rsality class\, signaled by the existence of a well-defined lifetime. In t he opposite case\, the dynamical properties of the mobile impurity are ins tead interpreted as a manifestation of Anderson's orthogonality catastroph e\, and result in an enhanced robustness of free impurity propagation with respect to the quasiparticle regime. Preliminary results on the effects o f a finite-temperature bath on the impurity probes are additionally presen ted. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-964@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20240930T140000 DTEND;TZID=Europe/Paris:20240930T180000 DTSTAMP:20240731T142049Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-jules-givois/ SUMMARY:Soutenance de thèse Jules Givois - Petit amphi\, bâtiment Pascal n° 530 - 30 Sep 24 14:00 DESCRIPTION:Binding of fermionic mixtures in low dimensions\n \;\n\nIn this thesis\, we study the problem of binding in ultra-cold fermionic mixt ures composed of N_h identical heavy fermions interacting with N_l light f ermions through a zero-range attractive potential in low-dimensional geome tries. The binding  phenomenon depends on the space dimension and on the heavy-light mass ratio and results from a subtle competition between the r epulsive Pauli pressure of identical fermions and the heavy-light attracti on. In one dimension\, by using an exact few-body analysis\, we establish and characterize states of a single light atom bound with up to five heavy atoms. Then\, using a mean-field approach valid for large N_h\, we find t hat such N_h+1 clusters are bound for any N_h as long as the mass ratio ex ceeds a threshold which scales as N_h^3. Extending this mean-field method to N_l>\;1\, we show that N+1-type clusters can attract each other and f orm self-bound chains resembling charge-density waves in the thermodynamic limit. We also extend this mean-field theory to the two-dimensional N_h+N _l problem and find that N_h+1 clusters can form for arbitrarily large N_h in two dimensions as well. However\, the mass-ratio threshold for binding scales as N_h^2. In order to find the energy and size of the clusters we take into account beyond-mean-field effects as the two-dimensional mean-fi eld theory is scale invariant. Finally\, we present numerical evidence tha t two two-dimensional N+1-type clusters always repel each other and form n o self-bound state\, contrary to the one-dimensional case.\n\nJury : I. Bo uchoule\, H.-W. Hammer (rapporteur)\, P. Massignan (rapporteur)\, C. Mora\ , D. Petrov (directeur de thèse) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-962@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241001T110000 DTEND;TZID=Europe/Paris:20241001T120000 DTSTAMP:20240912T093627Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jorge-jose-university-indiana/ SUMMARY:Séminaire du LPTMS : Jorge José (Indiana University) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 1 Oct 24 11:00 DESCRIPTION:Human movements are random. From a Deep Learning and Statistica l analysis of millisecond fluctuations found in the motor kinematic variab les\, we unravel diagnostics and biomarkers that quantify cognitive abilit ies\n \;\nJorge V. José (Physics Department and Stark Neuroscience Re search Institute\, Indiana University\, USA)\n \;\n\nMovement is an es sential part of the sequential dance of behaviors that comprise fluid soci al communications. The simple act of reaching an object — an act accompl ished easily many times per day—demands an incredible amount of coordina tion between the visual field to locate the object to initiate the reach m ovement toward the object. Daily movements considered separately or in an aggregate\, can reveal a great deal about neuromotor control and cognitive abilities. It has been recognized that atypical movements may interfere w ith the development of adaptive skills\, in particular for children with n eurodevelopmental disorders (NDD). We measured several rotational and tran slational kinematic variables using millisecond motor sensors\, away from naked eye detection\, when NDD individuals performed a reaching paradigm. Doing first a Deep Learning analyses of the electronic noisy signal we are able to diagnose NDD conditions of new individuals with close to 90% accu racy. We filtered out the electronic noise that allowed to introduce stati stical nearest-neighbor fluctuation biometrics that quantify the degree of severity of each NDD participant. In this lecture I will discuss the rela tionship between our personal movement DNA and corresponding cognitive abi lities [1-3].\n\n[1] E. B. Torres\, J. V. José et al. \, Autism: the micr o-movement perspective. Frontiers in integrative neuroscience 7\, 32 (2013 ).\n[2] D. Wu\, J. V. José\, J. I. Nurnberger\, E. B. Torres\, A biomarke r characterizingneurodevelopment with applications in autism. Scientific r eports (Nature) 8\, 1–14 (2018).\n[3] K. P. Doctor\, J. V. José et al. “AI Screening plus Statistical Severity Biometric Studies of Neurodiverg ent Disorders” (under review at PNAS Nexus).\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-967@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241002T160000 DTEND;TZID=Europe/Paris:20241002T163000 DTSTAMP:20240918T123651Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sara-murciano-caltech-university-2/ SUMMARY:Séminaire exceptionnel du LPTMS : Sara Murciano (Caltech Universit y) - Petit amphi\, bâtiment Pascal n° 530 - 2 Oct 24 16:00 DESCRIPTION:Measurement-altered quantum criticality\nSara Murciano (Caltech University)\n \;\n\nSeminar in the context of the OPENQMBP 2024 works hop at the Institut Pascal.\n\nQuantum critical systems constitute appeali ng platforms for the exploration of novel measurement-induced phenomena du e to their innate sensitivity to perturbations. I will discuss the impact of measurement on Ising chains using an explicit protocol\, whereby uncorr elated ancillae are entangled with the critical chain and then projectivel y measured. I can identify different protocols wherein measurements (i)  weakly modify the universal long-range entanglement and (ii) they complete ly obliterate it. I will also highlight a path to experimental realization in analog quantum simulators based on Rydberg atom arrays. Finally\, I wi ll describe how these ideas can establish a long-term quantum science appl ication of ‘measurement-altered quantum criticality’. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-966@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241008T140000 DTEND;TZID=Europe/Paris:20241008T150000 DTSTAMP:20240930T200229Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nathan-goldman-ulb/ SUMMARY:Séminaire du LPTMS : Nathan Goldman (ULB) - Salle des séminaire s du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Oct 24 14:00 DESCRIPTION:Quantized responses in topological quantum matter : From Streda ’s formula to circular dichroism\n \;\nNathan Goldman (Université L ibre de Bruxelles)\n\nThis talk will present recent developments in the to pological characterization of correlated insulators and time-periodic (Flo quet) systems. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-976@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241011T134500 DTEND;TZID=Europe/Paris:20241011T151500 DTSTAMP:20241004T080350Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-luca-capizzi-lptms/ SUMMARY:Informal Quantum Seminar: Luca Capizzi (LPTMS) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 11 Oct 24 13:45 DESCRIPTION:GROUND STATES OF QUANTUM MANY-BODY SYSTEMS AND EXPONENTIAL DECA Y OF CORRELATIONS \n \;\nLuca Capizzi (LPTMS)\n\n\nGround states of q uantum many-body systems are known to have qualitatively distinct properti es compared to eigenstates in the middle of the spectrum. Specifically\, i n the presence of a finite energy gap\, while the latter display volume-la w entanglement\, the former show area-law entanglement\; in other words\, the ground-state entanglement entropy of a subregion scales with its area. As a consequence\, these states can be efficiently simulated using state- of-the-art numerical tensor network methods\, such as Matrix Product State s (MPS). This fundamental result of modern quantum physics traces back to a series of mathematical theorems proven by M.B. Hastings at the beginning of this century [1-3]. In this seminar\, based on Ref. [1]\, I will show how a gap in the energy spectrum implies an exponential decay of spatial c orrelations\, a highly non-trivial result obtained via the Lieb-Robinson b ound and energy filters. Furthermore\, I will emphasize that having short- range correlations\, a property that holds generically even in the middle of the energy spectrum [4]\, does not directly relate to area-law entangle ment.\n\n\n\n\n\n[1] M. B. Hastings\, Locality in Quantum and Markov Dynam ics on Lattices and Networks\, Phys. Rev. Lett. 93\, 140402 (2004).\n[2] M . B. Hastings\, An Area Law for One Dimensional Quantum Systems\, JSTAT\, P08024 (2007).\n[3] M. B. Hastings\, Entropy and entanglement in quantum g round states\, Phys. Rev. B 76\, 035114 (2007).\n[4] Araki\, H. Gibbs stat es of a one dimensional quantum lattice\, Commun.Math. Phys. 14\, 120–15 7 (1969).\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-969@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241015T110000 DTEND;TZID=Europe/Paris:20241015T120000 DTSTAMP:20241003T075629Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jeremie-klinger-stanford/ SUMMARY:Séminaire du LPTMS : Jeremie Klinger (Stanford) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 Oct 24 11:00 DESCRIPTION:Matching method for first passage observables and diffusion sen sitivities of Langevin dynamics\nJeremie Klinger (Stanford University)\nIn this talk\, I will discuss two ongoing research projects whose common thr ead is dynamical analysis of stochastic systems. The first part 1. will fo cus on developping matching methods to reconcile discrepencies between exp erimentally measured first passage observables and continuous modelling\; in a second part 2. I will discuss response theory for out-of-equilibrium systems\, for which the fluctuation-dissipation theorem does not hold. Mor e precisely\n\n1. Because of limited time resolution in tracking instrumen ts\, time series are typical realisations of discrete time stochastic dyna mics. In turn\, any experimental estimation of relevant first passage obse rvables\, such as mean exit times or commitor functions\, cannot be direct ly mapped on a continuous stochastic model without parameter fitting. Star ting from the one dimensional commitor function for discrete time and cont inuous space random walks\, we show how to make the link with limiting con tinuous processes while safeguarding important specific discrete behavior. We then show how this one dimensional commitor is the single key to prope rly characterizing the limiting behavior of general first passage observab les across various dimensions and geometries.\n\n2. Analyzing the response properties of systems subject to perturbations provides useful insights o n the structural properties of the system\, and is of paramount importance in identifying phase transitions. For equilibrium Langevin systems\, the fluctuation-dissipation theorem (FDT) relates response to spontaneous fluc tuations\, such that sensitivity analysis can be carried out without actua lly perturbing the system. Out of equilibrium\, the FDT does not hold\; ho wever we construct general non-equilibrium response estimators that allow sensitivity analysis for both stationnary (NESS) and non stationnary syste ms. This estimator is based on the instantaneous score $\nabla \\log \\rho _t$ of the system\, a by-now classical object in machine learning\, that c an be estimated from system snapshots. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-984@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241018T110000 DTEND;TZID=Europe/Paris:20241018T120000 DTSTAMP:20241014T203524Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-amelie-leforestier/ SUMMARY:Physics-Biology Interface seminar: Amélie Leforestier - Moyen Amph i\, Building 510\, Université Paris-Saclay Orsay - 18 Oct 24 11:00 DESCRIPTION:Electrostatic zipper in curved DNA condensates\nAmélie Lefores tier (U. Paris-Saclay)\nJoint seminar with LPS: beware of the unusual loca tion\nIn helical polyelectrolytes like DNA\, the electrostatic zipper is a model of interaction\, which\, taking into account the helical surface ch arge distribution\, predicts mutual azimuthal orientation of close-packed molecules. This phenomenon is poorly documented experimentally. In particu lar\, electrostatic zipper is not compatible with curvature\, a general fe ature of dense states of DNA\, both in vitro and in vivo. Using cryo-EM im aging of DNA toroids\, we analyze the relationship between curvature\, hel ical correlations\, and DNA helical pitch. We show that in phase helical a lignments are preferred over a wide range of ionic concentrations. Optimiz ation of this preferred configuration is associated to rearrangements with in the toroid as it grows\, with establishment of the EZ followed by a glo bal polygonal shaping. In addition\, a local decrease in the DNA helical p itch is measured in highest curvature regions. This phenomenon\, at work i n DNA toroids\, is also likely to occur in spheroidal globules\, bacteriop hage chromosomes\, and\, more generally\, all forms of curved condensed DN A – and other helical polyelectrolytes – both in vivo and in vitro. In particular\, it should be taken into account in material design involving curved DNA origami. CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-986@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241029T110000 DTEND;TZID=Europe/Paris:20241029T121500 DTSTAMP:20241018T140238Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-martin-r-evans-university-of-edinburgh/ SUMMARY:Séminaire du LPTMS: Martin R. Evans (University of Edinburgh) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Oct 24 11:00 DESCRIPTION:Optimal resetting strategies (when you don't know where the tar get is)\n\nMartin R. Evans (University of Edinburgh)\n\nResetting has been shown to reduce the completion time for a stochastic process\, such as th e first passage time for a diffusive searcher to find a target.  In a nut shell\, resetting cuts off errant trajectories that wander off in the wron g direction.\nThe resetting protocol can be defined  by the waiting time distribution for the  random time between two consecutive resetting event s. Previously\, it had been shown that deterministic resetting process wit h a constant time period\, referred to as sharp restart\, can minimize the mean first passage time to a fixed target. Here we consider the more real istic problem of a target positioned at a random distance from the resetti ng site\, selected from a given target distribution. I will show that for a broad target distribution stochastic resetting out performs sharp reset. \n\nStochastic resetting prevails over sharp restart for broad target dist ributions\nMR Evans\, S Ray - arXiv preprint arXiv:2410.01941\, 2024 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-979@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241105T110000 DTEND;TZID=Europe/Paris:20241105T120000 DTSTAMP:20241017T152814Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-tuozo-gueneau-lpthe/ SUMMARY:Séminaire du LPTMS : Mathis Guéneau (LPTHE) and Léo Touzo (LPEN S) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 5 Nov 24 11:00 DESCRIPTION:Siegmund duality for physicists: a bridge between spatial and f irst-passage properties of continuous- and discrete-time stochastic proces ses\n \;\nMathis Guéneau (LPTHE) and Léo Touzo (LPENS)\n \;\n\nA ctive particles are systems — typically living organisms — capable of converting energy from their environment into directed motion. On the one hand\, there has been a lot of interest recently in the first-passage prop erties of these models\, partly motivated by applications to biology. On t he other hand\, active particles are known to exhibit exotic behaviors in the presence of confinement\, such as hard walls\, due to their non-equili brium nature.\n\nSurprisingly\, the first-passage properties of many stoch astic processes happen to be closely related to their spatial distribution in the presence of hard walls. This type of connection has a long history in mathematics\, where it is known as Siegmund duality. However\, it rema ins relatively unknown in the physics community and had never been shown f or active particles.\n\nIn this talk\, we will show how to extend this dua lity relation to a large class of stochastic processes which are particula rly relevant in physics\, including the most well-known models of active p articles\, but also diffusing diffusivity models\, and particles subjected to stochastic resetting. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-985@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241105T140000 DTEND;TZID=Europe/Paris:20241105T160000 DTSTAMP:20241017T083044Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-enrico-lorenzetti/ SUMMARY:Soutenance de thèse: Enrico Lorenzetti - LPTMS (100% online semina r) - 5 Nov 24 14:00 DESCRIPTION:Modelling And Data Analysis of Protein Dynamics applied to a Fi ssion Yeast Mechanosensor\n \;\nEnrico Lorenzetti (Ladhyx\, LPTMS)\n&n bsp\;\n\nIntracellular dynamics is fundamental for cells to maintain homeo stasis and respond to environmental stimuli. Among these\, mechanical forc es can be a potential source of damage as they can compromise the integrit y of the cell. To cope with this risk\, living organisms are endowed with mechanosensors\, i.e. receptor at the sub-cellular level able to trigger a biological pathway by a mechanical signal. In fission yeast\, a mechanose nsor\, Wsc1 protein\, perceives excessive stress on the the cell wall and activates the glucan synthesis to keep this layer reinforced. More interes tingly\, Wsc1 concentration in- creases in the compressed region of the ce ll wall for- ming clusters. This work investigates this mechanosensitive c lustering behaviour advancing models and inference method for\nexperimenta l data of protein dynamics.\nBy setting a mathematical framework based on deterministic partial differential equations\, I describe the Wsc1 dynamic s along the cell wall. In this model\, I consider two possible protein rec ruitment mechanisms for shaping clusters\, either from the sides due to di ffusion along the cell wall and from the cytoplasm by exocytotosis. Moreov er\, following chemical considerations\, I suppose an affinity\nbetween th e cell wall and the protein that increases with the cell wall com- pressio n. The resulting reaction-diffusion equations obtained by this model are a ble to reproduce the clustering behaviour after cell wall compression. In addition\, the model correctly predicts a longer time-scale of the dynamic s in the compressed region of the cell wall. This result is in agreement w ith the outcomes of FRAP (Fluorescence Recovery After Photobleaching) expe riment\, whose analysis is based on the study of time-lapse images that re flects the spatial-temporal concentration of the molecule. However\, it is not clear yet if the protein recruitment is due to diffusion\, exchange w ith cytoplasm\, or both. For this reason\, in my work I also develop a new inference method for FRAP experiment capable of discerning different type s of dynamics. My analysis aims at quantifying the dynamical parameters\, such as diffusion coefficient and exchange rate\, by minimising the distan ce between the reaction-diffusion model prediction and actual data. The sp ecificity of my approach is the use of dimensional reduction to efficientl y perform computation without having knowledge of the initial bleached pro file. This new method is then tested and validated on artificial data. The results show that this analysis is flexible since it can work with imperf ect data\, where the signal-to-noise ratio is low\, the number of frames i s reduced and the spatial window is restricted.\nMoreover\, this approach can be potentially generalised to complex geometries\, for instance curved surface. This versatility is wellsuited for studying protein dynamics in the fission yeast cell wall. The inference method is applied to experiment al data of another mechanosensor in the cell wall\, Mtl2\, yielding reason able values of diffusion coefficient. Nevertheless\, it still needs to be tested on real\ndata of Wsc1 protein.\nOverall\, this study offers novel m ethodologies for quantifying and understanding intricate protein dynamics within cells and tissues.\n\nLocalization: amphithéâtre Becquerel - Éco le Polytechnique. CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-993@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241108T134500 DTEND;TZID=Europe/Paris:20241108T151500 DTSTAMP:20241107T112714Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-du-lptms-luca-capizzi-lptms/ SUMMARY:Informal Quantum Seminar du LPTMS: Luca Capizzi (LPTMS) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Nov 24 13: 45 DESCRIPTION:Ground states of quantum many-body systems and exponential deca y of correlations \n\nLuca Capizzi (LPTMS)\n\n\n\nGround states of quantu m many-body systems are known to have qualitatively distinct properties co mpared to eigenstates in the middle of the spectrum. Specifically\, in the presence of a finite energy gap\, while the latter display volume-law ent anglement\, the former show area-law entanglement\; in other words\, the g round-state entanglement entropy of a subregion scales with its area. As a consequence\, these states can be efficiently simulated using state-of-th e-art numerical tensor network methods\, such as Matrix Product States (MP S). This fundamental result of modern quantum physics traces back to a ser ies of mathematical theorems proven by M.B. Hastings at the beginning of t his century [1-3]. In this seminar\, based on Ref. [1]\, I will show how a gap in the energy spectrum implies an exponential decay of spatial correl ations\, a highly non-trivial result obtained via the Lieb-Robinson bound and energy filters. Furthermore\, I will emphasize that having short-range correlations\, a property that holds generically even in the middle of th e energy spectrum [4]\, does not directly relate to area-law entanglement. \n\n[1] M. B. Hastings\, Locality in Quantum and Markov Dynamics on Lattic es and Networks\, Phys. Rev. Lett. 93\, 140402 (2004).\n[2] M. B. Hastings \, An Area Law for One Dimensional Quantum Systems\, JSTAT\, P08024 (2007) .\n[3] M. B. Hastings\, Entropy and entanglement in quantum ground states\ , Phys. Rev. B 76\, 035114 (2007).\n[4] Araki\, H. Gibbs states of a one d imensional quantum lattice\, Commun.Math. Phys. 14\, 120–157 (1969).\n\n  \;\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-998@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241112T110000 DTEND;TZID=Europe/Paris:20241112T120000 DTSTAMP:20241111T171511Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marcelo-guzman-upenn/ SUMMARY:Séminaire du LPTMS : Marcelo Guzmán (UPenn) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Nov 24 11:00 DESCRIPTION:Learning functionality under physical constraints: how physics shapes the way machines learn\n \;\nMarcelo Guzmán (University of Pen nsylvania)\n \;\n\nFrom biological systems to neuromorphic computing\,  learning is fundamentally constrained by physics. These constraints\, r anging from optimization principles (e.g.\, energy minimization) to conser vation laws and stochastic dynamics in the presence of noise\, shape learn ing dynamics and learned functions in ways absent in artificial neural net works (ANNs). In this two-part talk\, I explore how physical constraints i nfluence learning by examining two paradigmatic physical learning models: tunable mechanical networks and self-learning resistor networks.\n\nFirst\ , I will show that learning in these physical networks is a dual optimizat ion problem. In the case of resistor networks\, for example\, it is the mi nimization of a cost with respect to conductances and the minimization of the power dissipated with respect to voltages—the physical constraint. T his additional minimization couples cost and power\, enabling inference of key network components through simple physical measurements. I will demon strate that the high-curvature directions around the cost minima —highli ghting the key functional components— are captured by the network’s ph ysical susceptibilities. These susceptibilities\, encoded in the softest m odes of the power\, are measurable and provide clear insights into the net work’s functionality\, suggesting an interpretability advantage over ANN s and a new framework for studying biological systems for which the cost i s unknown.\n\nNext\, I will focus on the local dynamics of self-learning r esistor networks in laboratory settings. Learning in these systems is the outcome of the collective behavior of individual components. While these n etworks are energy-efficient\, they are sensitive to the presence of exter nal noise and internal biases\, two physical constraints. I will show how noise and bias affect the learning dynamics when training for two periodic ally alternating tasks. In ideal conditions\, periodic training converges to an optimal solution for both tasks. However\, in the presence of noise and bias\, learning leads to limit cycles in the space of conductances. Ba sed on theory and experiments\, I uncover a complex interplay between the geometry of the solution space (linked to task complexity)\, bias\, and no ise\, revealing distinct learning phases in terms of the training period. Finally\, I will show that under certain conditions\, bias can improve the networks’ learning capabilities. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-982@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241115T090000 DTEND;TZID=Europe/Paris:20241115T170000 DTSTAMP:20241114T154759Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/meeting_class_imb alance/ SUMMARY:Informal workshop on the problem of Class Imbalance - Petit amphi\, bâtiment Pascal n° 530 - 15 Nov 24 09:00 DESCRIPTION:This is an informal meeting revolving around the topic of class imbalance in machine learning. Anybody who is interested is welcome to jo in!\n\n9:30-10:30am: Emanuele Francazi - A theoretical analysis of the lea rning dynamics under class imbalance (petit Amphi)\n\n10:30-11:30am: Stefa no Sarao-Mannelli - Bias-inducing geometries: exactly solvable data model with fairness implications (petit Amphi)\n\n11:30-12:30am: Brainstorming ( petit Amphi)\n\n14:00-15:00 pm: Mauro Pastore - Restoring balance: princip led under/oversampling of data for optimal classification (petit Amphi)\n\ n15:00-16:00 pm: Francesco Saverio Pezzicoli - Anomaly-Detection Class Imb alance in Exactly Solvable Models (petit Amphi)\n\n16:00-17:00 Brainstormi ng (petit Amphi) CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-989@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241115T110000 DTEND;TZID=Europe/Paris:20241115T120000 DTSTAMP:20241108T130146Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-joseph-ackermann/ SUMMARY:Physics-Biology Interface seminar: Joseph Ackermann - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 15 Nov 24 11:00 DESCRIPTION:(Non-)Reciprocal interactions in oriented mixtures\nJoseph Acke rmann (LJP\, Sorbonne U.)\nJoint seminar with LPS - note the unusual locat ion and its change compared with previous announcements\n\nInteractions be tween the components determine the properties of mixtures. In particular\, non-reciprocal phase transitions have attracted attention in recent years due to features such as time-dependent phases [1]. In the context of canc er\, the heterogeneity of the environment requires the consideration of th e interplay between different components. In particular\, polar and nemati c orientations are ubiquitous. In this talk\, I will present two experimen ts and their physical description involving reciprocal and non-reciprocal nematic or polar interactions and some questions they raise [2\,3].\n\n[1] Fruchart\, Michel\, et al. "Non-reciprocal phase transitions." Nature 592 .7854 (2021): 363-369.\n[2] Jacques\, Cécile\, et al. "Aging and freezing of active nematic dynamics of cancer-associated fibroblasts by fibronecti n matrix remodeling." bioRxiv (2023): 2023-11.\n[3] Bell\, Samuel\, et al. "Ordering\, spontaneous flows and aging in active fluids depositing track s." arXiv preprint arXiv:2409.05195 (2024).\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-971@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241119T110000 DTEND;TZID=Europe/Paris:20241119T120000 DTSTAMP:20241107T093553Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gregoire-misguich-ipht/ SUMMARY:Séminaire du LPTMS : Grégoire Misguich (IPhT) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Nov 24 11:00 DESCRIPTION:Generalized hydrodynamics in box-ball systems\nGrégoire Misgui ch (IPhT Saclay)\n\nThe box-ball system (BBS) is an integrable cellular au tomata introduced\nin 1990 (Takahashi and J. Satsuma). This classical dyna mical system\ninvolves 'balls' placed in 'boxes' along on a line\, and wit h simple\ndeterministic rules governing how the balls move at each time st ep. We\ngive an introduction to the simplest single-color BBS\, focusing o n the\nproperties its solitons. Next we will discuss a problem where the\n initial state is a statistical ensemble of configurations with different\n ball densities in the left and in the right halves of the system. With\nth e help of numerical simulations we show how the dynamics triggered by\nsuc h a domain-wall initial state leads to the emergence of density\nplateaux. Using the generalized hydrodynamics framework we explain how\nto compute analytically the large-time and large-distance properties of\nthese platea ux structures. If time permits the end of the presentation\nwill show some exact results concerning the fluctuations of the number\nof balls crossin g a given point (including large deviations) as well as\nexact results on some current-current correlations (Drude weight).\n\nReferences: A. Kuniba \, G. Misguich and V. Pasquier\, J. Phys A. 53\,\n404001(2020). See also: SciPost Phys. 10\, 095 (2021) and J. Phys. A:\nMath. Theor. 55 244006 (202 2)\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-972@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris;VALUE=DATE:20241126 DTEND;TZID=Europe/Paris;VALUE=DATE:20241128 DTSTAMP:20241112T140914Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/visite-virtuelle- comite-hceres/ SUMMARY:Visite virtuelle Comité HCERES - Petit amphi\, bâtiment Pascal n ° 530 - 26 Nov 24 00:00 DESCRIPTION: CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1000@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241129T134500 DTEND;TZID=Europe/Paris:20241129T151500 DTSTAMP:20241128T104315Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-du-lptms-guglielmo-lami-sissa-trieste/ SUMMARY:Informal Quantum Seminar du LPTMS: Guglielmo Lami (Cergy-Paris Univ ersité) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n °530 - 29 Nov 24 13:45 DESCRIPTION:Magic in Matrix Product States and Fermionic Gaussian States\n\ nGuglielmo Lami (Cergy-Paris Université)\n\n\n\nWe will introduce the fra mework of quantum resource theories\, which provide a systematic way to qu antify and utilize resources in quantum systems. I will then focus on nons tabilizerness (aka quantum magic)\, a critical resource for achieving quan tum advantage in computational tasks. Building on my recent results\, I wi ll explore how magic emerges in two physically relevant classes of states: Matrix Product States (MPS) and fermionic Gaussian states. For both\, I w ill present numerical methods for quantifying magic\, as measured by the S tabilizer Rényi Entropies\, alongside analytical results that reveal its value for typical (random) realizations of these states.\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-999@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241203T110000 DTEND;TZID=Europe/Paris:20241203T120000 DTSTAMP:20241111T171155Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marco-baiesi/ SUMMARY:Séminaire du LPTMS : Marco Baiesi (University of Padova) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 3 Déc 24 1 1:00 DESCRIPTION:Fluctuations of driven probes reveal nonequilibrium transitions in complex fluids \n\n\nMarco Baiesi\n(Dept. of Physics and Astronomy\, University of Padova)\n\n\n\n\nComplex fluids under localized microscopic energy inputs exhibit nonequilibrium behaviors only partially understood. To identify changes in the fluid's microstructural conformation\, we intro duce a general method grounded in the breakdown of the equipartition theor em for laser-trapped probes dragged at a mean constant speed. Specifically \, we link the different scaling regimes in the probe's position variance\ , obtained through large-scale Brownian simulations of a polymeric fluid\, to transitions from diffusive to jump dynamics\, where the fluid intermit tently relaxes accumulated stress. This view suggests that stored elastic stress is a relevant physical mechanism behind recently measured nonlinear friction curves. Our approach overcomes some limitations of continuum mac roscopic descriptions and introduces an empirical method to experimentally detect nonequilibrium transitions in the fluids' structure.\n \;\n\n& nbsp\; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1004@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241213T110000 DTEND;TZID=Europe/Paris:20241213T120000 DTSTAMP:20241212T090157Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-laure-mancini-3/ SUMMARY:Physics-Biology Interface seminar: Laure Mancini - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Déc 24 11:00 DESCRIPTION:Establishment of phyllotaxy from a single cell in the moss Phys comitrium Patens\nLaure Mancini (ENS Lyon)\nTalk by the winner of the Phys Bio2024 best junior talk competition. The speaker will join us over Zoom\, but those interested can join us in the LPTMS seminar room to watch it.\n \nThe shape of living organisms follows robust architectural plans that de termine the main axis and the relative position of each organ. In plants\, organs such as leaves\narrange themselves around the stem with a mathemat ical regularity\, forming large-scale patterns like spirals. This organiza tion is called phyllotaxis and emerges thanks to the activity of stem cell s located at the apical meristem\, which corresponds to the tip of the lea fy shoot.\n\nDepending on the group of plant\, the apical meristem can be multi- or unicellular. In the case of the moss Physcomitrium Patens\, thi s structure is composed of a single stem cell\, the apical cell (AC)\, whi ch is responsible for producing all the leaves. As a result\, the position of each new leaf strongly depends on the division pattern of the AC. Howe ver\, the mechanisms that control the positioning of the apical cell divis ion plane to pattern moss phyllotaxis remain to be discovered.\n\nAs an en try point to the problem\, we studied the role of auxin signaling in this context because\, the hormone auxin is known to be instrumental in establi shing phyllotactic patterns in multicellular meristems. We asked if this h ormone can also act at the scale of a unique stem cell\, to insure a robus t phyllotactic pattern. To do so\, we used a combination of quantitative t ime-lapse imaging\, genetic tools and mutants as well as cellular shape an alysis and modeling. With these approaches\, we found that auxin is involv ed in the robustness of the spiral phyllotaxy of the moss and that it affe cts cellular properties such as growth anisotropy\, that can impact the gl obal architecture of the moss leafy shoot\nJoin Zoom Meeting\nhttps://cnrs .zoom.us/j/98437905934?pwd=oCbsaQq6pNbmfxpepR0Nrt2xVsKJXV.1\n\nMeeting ID: 984 3790 5934\nPasscode: 8191Vt CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-983@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241216T100000 DTEND;TZID=Europe/Paris:20241216T130000 DTSTAMP:20241206T135108Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-louis-bremaud/ SUMMARY:Soutenance de thèse : Louis Bremaud - Petit amphi\, bâtiment Pasc al n° 530 - 16 Déc 24 10:00 DESCRIPTION:Mean Field Game description of virus propagation\n \;\nThis thesis investigates the role of human behavior in epidemic modeling. Epid emics are influenced by both individuals’ spontaneous responses and gove rnment-imposed measures\, creating a feedback loop that shapes the outbrea k's progression. However\, many existing models treat human behavior as an external factor\, limiting their realism. To address this gap\, the thesi s applies the Mean Field Game (MFG) framework\, a theoretical tool for inc orporating individual decision-making into epidemic models.\nThe first par t of the thesis applies the MFG approach to an SIR (Susceptible-Infected-R ecovered) model with a social structure. Individuals balance infection ris k against the social and economic costs of reducing contact. Numerical sim ulations with realistic parameters identify a Nash equilibrium\, reflectin g self-interested behavior\, and we compare it to the social optimum\, whi ch minimizes overall societal costs. The gap between these scenarios is na rrowed through constrained Nash equilibria\, which include government inte rventions. The analysis also reveals that changes in population size or mo del duration can lead to phase transitions in optimal strategies\, emphasi zing the need for adaptive policies.\nIn the second part\, the MFG framewo rk is extended to complex networks\, where individuals differ in connectiv ity. Using pairwise approximation\, we derive epidemic dynamics and integr ate MFG principles. Simulations on realistic contact networks highlight ho w variations in social cost structures influence individual behavior\, wit h significant differences observed based on connectivity levels. A related project provides new analytical insights into the SIR model on regular ne tworks.\n\n\nJury : Alain Barrat (examinateur)\, Marc Barthelemy (préside nt du Jury)\, Laura di Domenico (examinatrice)\, Olivier Giraud (co-direct eur de thèse)\, Sergio Gomez (rapporteur)\, Gabriel Turinici (rapporteur) \, Denis Ullmo (directeur de thèse)\n\n\n\n CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-980@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20241219T100000 DTEND;TZID=Europe/Paris:20241219T130000 DTSTAMP:20241209T085116Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-giorgio-ciliberto/ SUMMARY:Soutenance de thèse: Giorgio Ciliberto - Petit amphi\, bâtiment P ascal n° 530 - 19 Déc 24 10:00 DESCRIPTION:\n\nNon-locality and Back-reaction in Acoustic Black Holes and Non-linearity in Quantum Fluid Dynamics\n\n\n \;\n\nThis thesis is mai nly about quantum correlations and non-linear fluctuations in quantum flui ds. It focuses especially on collective quantum fluctuations\, i.e. sound waves\, in the stationary flow of a 1D Bose-Einstein quasi- condensate whi ch exhibits an acoustic horizon\, i.e. a transition from subsonic to super sonic flow. Quantum phenomena generated by the presence of the horizon are investigated. The thesis also presents a brief excursus on two- dimension al turbulence in a quantum fluid. We study quantum non-separability\, non- locality and back-reaction of the acoustic Hawking radiation emitted by a n analog black hole. The entanglement and nonlocal correlations within the tripartite system of quasi-particles emitted from the acoustic horizon ar e first investigated. Back-reaction equations govern- ing the effect of su ch acoustic radiation on the inhomogeneous background are derived and stat ionary solutions are considered. Finally\, a phenomenological theory based on topological constraints for vortex creation and annihilation is effect ively applied to experimental data\, thus accounting for the growth and de cay of turbulence.\n\n \;\n\n \;\n\nJury : Jacqueline Bloch\, Andr eas Buchleitner (co-directeur de thèse)\, Marek Kus\, Nicolas Pavloff (di recteur de thèse)\, Heidi Rzehak\, Augusto Smerzi CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1002@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250110T134500 DTEND;TZID=Europe/Paris:20250110T151500 DTSTAMP:20250106T081816Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-du-lptms-federica-m-surace-caltech-2/ SUMMARY:Informal Quantum Seminar du LPTMS: Federica M. Surace (Caltech) - S alle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Ja n 25 13:45 DESCRIPTION:Slow thermalization in quantum many-body dynamics\n\nFederica M . Surace (Caltech)\n\n\nIn recent years\, there has been considerable inte rest in the investigation of the approach to thermal equilibrium in isolat ed quantum many-body systems. When thermalization occurs\, expectation val ues of local observables reach stationary values that depend only on few p roperties of the initial state and can be predicted with usual statistical mechanics ensembles. However\, as I will demonstrate in this presentation \, there exist scenarios where the time required for a system to thermaliz e can be extremely long. I will elucidate three distinct underlying mechan isms leading to anomalously slow thermalization in quantum systems.\n  \;\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-990@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250114T110000 DTEND;TZID=Europe/Paris:20250114T120000 DTSTAMP:20250106T080858Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicolo-beato-mpi-dresden/ SUMMARY:Séminaire du LPTMS : Nicolò Beato (MPIPKS\, Dresden) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Jan 25 11:0 0 DESCRIPTION:Phase transition in quantum control landscapes\n \;\nNicol ò Beato (MPIPKS\, Dresden)\n \;\nControl landscape phase transitions (CLPTs) occur as abrupt changes in the cost function landscape upon varyin g a control parameter and can be revealed by non-analytic points in statis tical order parameters [1]. A prime example are quantum speed limits (QSL) which mark the onset of controllability as the protocol duration is incre ased.\nIn this talk\, I present results from recent works introducing anal ytical and numerical methods designed to study CLPTs [2-3]:\n(i) Analytica l expansions: we lay the foundations of an analytical theory for CLPTs by developing different analytical expansions for the cost function that capt ure the behavior of CLPTs with controlled precision\;\n(ii) Stability anal ysis: we show that CLPTs can be associated with different types of instabi lities of the optimal protocol\; this allows us to explicitly relate CLPTs to critical structural rearrangements in the extrema of the control lands cape\n(iii) Universality of QSL transition: utilizing path integral method s from statistical field theory\, we trace back the critical scaling of th e order parameter at the QSL to the properties of the set of optimal proto cols\n(iv) Topological CLPTs: we introduce a numerical sampling algorithm designed to explore the set of optimal protocols via homotopic stochastic update rule\; this verifies our analytical predictions and reveals the exi stence of a new class of CLPTs\, of topological nature\, associated with s harp experimental signatures.\n-\n[1] Phys. Rev. Lett. 122\, 020601\n[2] a rXiv:2408.11110\n[3] arXiv:2411.08736 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1006@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250117T134500 DTEND;TZID=Europe/Paris:20250117T150000 DTSTAMP:20250106T082530Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-lptms-chunxiao-liu-uc-berkeley/ SUMMARY:Informal quantum seminar LPTMS: Chunxiao Liu (UC Berkeley) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Jan 25 13:45 DESCRIPTION:Characterizing 3D quantum paramagnets using Lieb-Schultz-Mattis constraints\n\nChunxiao Liu (UC Berkeley)\n \;\nQuantum paramagnets r epresent intriguing quantum phases that evade ordering even at absolute ze ro temperature. While detecting their presence is relatively straightforwa rd\, unraveling their fundamental nature can be a challenging task. In thi s talk\, I will present our recent work [1] on Lieb-Schultz-Mattis (LSM) c onstraints which prohibit certain quantum paramagnets from being a “triv ial” one. I will highlight the topological response theory underlying th e LSM constraints that we developed\, containing information about symmetr y\, excitations\, and lattice defects\, applicable to all 3D quantum param agnets. I will illustrate the use of these results through two examples: ( 1) the prediction of a Dirac spin liquid in the triangular lattice compoun d NaYbO2\, and (2) the characterization of U(1) quantum spin liquids in a pyrochlore S=1/2 antiferromagnet. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1007@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250121T110000 DTEND;TZID=Europe/Paris:20250121T123000 DTSTAMP:20250114T162700Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-marco-biroli-lptms/ SUMMARY:Séminaire du LPTMS: Marco Biroli (LPTMS) - Salle des séminaires d u FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Jan 25 11:00 DESCRIPTION:Unveiling Order in Disorder: The Role of Conditionally Independ ent Random Variables in Strongly Correlated Systems\n\n \;\nMarco Biro li (LPTMS)\n \;\nIn this seminar\, I will introduce the concept of con ditionally independent and identically distributed (CIID) random variables and demonstrate how they can be used to analytically describe certain str ongly correlated systems. We will see that conditional independence is not merely an artificial construct\; it also arises naturally in certain syst ems. Leveraging this structure\, we will uncover surprising regularities a nd derive robust predictions across a variety of models.\nUsing examples f rom resetting systems and many-body stochastic models\, I will illustrate how CIID variables serve as essential building blocks for modeling intrica te\, strongly correlated systems\, leading to fascinating scaling phenomen a. This seminar aims to provide a comprehensive understanding of the found ational theory of CIID variables and explore their practical applications. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-995@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250124T113000 DTEND;TZID=Europe/Paris:20250124T123000 DTSTAMP:20250124T074219Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-franziska-lautenschlager/ SUMMARY:Physics-Biology Interface seminar: Franziska Lautenschläger - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Jan 2 5 11:30 DESCRIPTION:SEMINAR CANCELLED\nFranziska Lautenschläger (U. Saarlandes\, G ermany) CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-991@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250128T110000 DTEND;TZID=Europe/Paris:20250128T120000 DTSTAMP:20250118T150646Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-joseph-baron-bath-uk/ SUMMARY:Séminaire du LPTMS : Joseph Baron (University of Bath) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 28 Jan 25 11: 00 DESCRIPTION:Perturbative and non-perturbative approximation schemes for spa rse random matrices\nJoseph Baron (University of Bath)\n\nRandom matrix th eory (RMT) has proved an invaluable tool for the study of systems with dis ordered interactions in many quite disparate research areas. Widely applic able results\, such as the celebrated elliptic law for dense random matric es\, allow one to understand when stability is possible in well-connected many-component dynamical systems\, for instance. However\, such simple and universal results have been more difficult to come by in the case of spar se random matrices\, for which the average number of non-zero entries per row (p) is small compared to the matrix size (N). This is despite the fact that sparsity is a common feature of interaction networks in many applica tions.\n\nIn this talk\, I will discuss the two ways in which the spectra of sparse random matrices deviate from the classic elliptic law\, and I wi ll present approximation schemes that allow us to characterise these novel features analytically. (1) I will show how diagrammatic series can be use d to understand the 1/p corrections to the elliptic law. A simple closed-f orm expression for the "warped ellipse"\, to which most of the eigenvalues are confined\, is derived. (2) I will also demonstrate how a cavity appro ach can be used to characterise the Lifshitz tails of the spectrum. We wil l see that eigenvalues in these tail regions of the spectrum correspond to abnormally well-connected hubs of the network (which the random matrix re presents)\, and that the corresponding eigenvectors are exponentially loca lised around these hubs. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1008@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250204T110000 DTEND;TZID=Europe/Paris:20250204T123000 DTSTAMP:20250127T143707Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-xiaowen-chen-lpens/ SUMMARY:Séminaire du LPTMS: Xiaowen Chen (LPENS) - Salle des séminaires d u FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Fév 25 11:00 DESCRIPTION:Inferring collective behavior from social interactions to popul ation coding\nXiaowen Chen (LPENS)\n \;\n\nFrom social animals to neur onal networks\, collective behavior is ubiquitous in living systems. How a re these behaviors encoded in interactions\, and how do they drive biologi cal functions? Recent insights from statistical physics applied to biologi cal data have offer exciting new perspectives. However\, previous research has mostly focused on the statics\, i.e. the steady-state distributions o f the collective behavior\, without taking into consideration of time. In this talk\, I will present two recent progresses tapping into the temporal domain. First\, I will present a study of collective behavior in social m ice from their co-localization patterns. To capture both static and dynami c features of the data\, we developed a novel inference method termed the generalized Glauber dynamics (GGD) that can tune the dynamics while keepin g the steady state distribution fixed. I will first outline the explanatio n power of the GGD dynamics\, then explain how to infer the dynamics from data. The inferred interactions characterize sociability for different mic e strains.  In the second example\, we studied information flow among neu rons in the larval zebrafish hindbrain. By adapting the method of Granger causality to single cell calcium transient data\, we were able to detect b oth a global information flow among neurons\, as well as identifying brain regions that are key in locomotion.  CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1012@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250206T110000 DTEND;TZID=Europe/Paris:20250206T120000 DTSTAMP:20250128T134405Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-nina-javerzat-liphy-grenoble/ SUMMARY:Séminaire exceptionnel du LPTMS: Nina Javerzat (LiPhy Grenoble) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 6 F év 25 11:00 DESCRIPTION:Rényi complexity in mean-field disordered systems\nNina Javerz at (LiPhy Grenoble)\n \;\n\nConfigurational entropy\, or complexity\,  quantifies the number of metastable states within (free) energy landsca pes\, and plays therefore a critical role in characterizing disordered s ystems such as glasses. Yet\, its measurement often requires significant c omputational resources. Recently\, Rényi entropy\, a one-parameter gener alization of the Shannon entropy\, has gained  attention across various fields of physics due to its simpler functional form\, making it more pra ctical for measurements. I will explain that the Rényi complexity corres ponds\, in disordered models\, to the difference of the free energy of a c loned system and the original one (a generalized Franz-Parisi potential). I will give a pedagogical overview of the case of the mean-field p-spin sp herical model\, where the computation of Rényi complexities can be perfor med analytically via the replica trick. Our results show that for models having one-step replica symmetry breaking (RSB)\, the Rényi complexities vanish at the Kauzmann temperature Tk\, suggesting that they are a usef ul observable for estimating Tk in practical applications. Moreover\, we s how that RSB solutions are required even in the liquid phase\, where inte resting relationships are found between Rényi complexities and the anneal ed Franz-Parisi potential.\n\nBased on arXiv:2411.19817 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1011@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250207T110000 DTEND;TZID=Europe/Paris:20250207T120000 DTSTAMP:20250127T202033Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-nicolas-tsapis/ SUMMARY:Physics-Biology Interface seminar: Nicolas Tsapis - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Fév 25 11:00 DESCRIPTION:Labeling nanoparticles with contrast agents to trace their accu mulation to diseased tissues\nNicolas Tsapis (Institut Galien)\nIn drug de livery\, nanomedicines are often associated with a contrast agent to yield nanotheranostic systems allowing both imaging and treatment. The theranos tic word was first mentioned in 2002 and comes from the contraction of the rapy and diagnostics. Nanotheranostics are designed to image nanoparticle biodistribution\, to survey the extent of the disease\, to deliver the tre atment and to monitor in real time its mechanism of action and its efficac y. In this presentation\, we will focus on the first goal and will present several examples of labeling polymer nanoparticles to detect them with on e of three different imaging modalities: ultrasound\, 19F magnetic resonan ce imaging or photoacoustics. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-963@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250211T110000 DTEND;TZID=Europe/Paris:20250211T120000 DTSTAMP:20250204T081422Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-daniel-amor-ens/ SUMMARY:Séminaire du LPTMS : Daniel Amor (ENS Paris) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 11 Fév 25 11:00 DESCRIPTION:Community transitions and the emergence of alternative stable s tates in microbial systems\nDaniel Amor (ENS Paris)\n \;\n\nMicrobial communities often face external perturbations that can induce lasting chan ges in their composition and functions. Responses to such perturbations ca n drive community functions\, including host health\, which urges for pred ictive understanding of community dynamics following perturbations. First in this talk\, I will present our work addressing how perturbations can in duce transitions between alternative stable states of a simple experimenta l community. For the case of antibiotic perturbations\, I will address how bacterial growth dynamics can overcome differences in antibiotic suscepti bility and determine the community outcome of antibiotic exposure. Combini ng theory and experiments\, we demonstrated that differences in the growth rates of community members can determine the resilience of stable communi ty states against several antibiotics\, a result that holds with relative independence of differences in antibiotic susceptibility. As our understan ding of response to perturbations in simple communities was growing\, we f aced a classical question in ecology: how does community complexity impact stability and dynamics? We addressed this question by assembling experime ntal communities under a large range of species pools\, controlling both i dentity and number of community members\, and a range of environments\, co ntrolling the average interaction strength between community members. Thes e experiments constitute the first empirical demonstration of complexity-d riven transitions between three generic phases of community dynamics predi cted by ecological theory. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1016@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250213T110000 DTEND;TZID=Europe/Paris:20250213T120000 DTSTAMP:20250207T095420Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti onnel-du-lptms-ajay-mohan-tifr-mumbai/ SUMMARY:Séminaire exceptionnel du LPTMS: Ajay Mohan (TIFR\, Mumbai) - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Fév 25 11:00 DESCRIPTION:Holography of the lowest Landau level problem\nAjay Mohan (TIFR Mumbai)\n \;\n\nWe consider a system of fermions on a 2 dimensional p lane with a perpendicular magnetic field (also called the Landau problem) whose spectrum is labelled by Landau levels. While it is well-known that t here is a classical description of the lowest Landau level in terms of an effectively 1 dimensional constrained system\, our recent findings suggest that this 1D-2D correspondence holds quantum-mechanically as well. Moreov er\, we find to our surprise that while certain physical quantities of the original 2D theory have a description in terms of an equivalent 1D theory (like the 2D fermion density of an N-fermion state)\, certain other quant ities (like the ground state entanglement entropy) partially remember the 2D origin of the system. In this talk\, I will present these findings in d etail. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-987@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250218T110000 DTEND;TZID=Europe/Paris:20250218T120000 DTSTAMP:20250130T143836Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-gianluca-teza-max-planck-dresden/ SUMMARY:Séminaire du LPTMS : Gianluca Teza (MPIPKS Dresden) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 18 Fév 25 11:0 0 DESCRIPTION:Nonequilibrium shortcuts and anomalous thermal relaxations: the Mpemba effect\nGianluca Teza (MPIPKS Dresden)\n\n\n\n\n\n\n\n\n\n\n\n\n\n Most of our intuition about the behavior of physical systems is shaped by observations at or near thermal equilibrium. However\, even a phenomenon a s basic as a thermal quench leads to states far from any thermal equilibri um\, where counterintuitive\, anomalous\, effects can occur. A prime examp le of anomalous thermal relaxation is the Mpemba effect a phenomenon in wh ich a system prepared at a hot temperature cools down to the temperature o f the cold environment faster than an identical system prepared at a warm temperature.\nIn this seminar\, I will review the phenomenology of this an d related anomalous relaxation effects\, in which nonmonotonic relaxation times act as the common denominator. With a focus on Ising systems\, I wil l provide some insight on the physical mechanisms that enable the emergenc e of these effects. I will show how they can survive boundary and even arb itrarily weak couplings to the thermal bath\, highlighting the role played by equilibrium and dynamical features.\nIf time allows\, I will showcase some experimental applications of these out-of-equilibrium effects in quan tum simulators.\n[1] GT\, R. Yaacoby\, and O. Raz\, Phys. Rev. Lett. 13 1\, 017101 (2023).\n[2] GT\, R. Yaacoby\, and O. Raz\, Phys. Rev. Lett.  130\, 207103 (2023).\n[3] R. Yaacoby\, O. Raz\, and GT\, arXiv:2203.116 44\, (2024).\n[4] S. Aharony Shapira\, Y. Shapira\, J. Markov\, GT\, N. A kerman\, O. Raz\, and R. Ozeri\, Phys. Rev. Lett. 133\, 010403 (2024).\n [5] GT\, J. Bechhoefer\, A. Lasanta\, O. Raz\, and M. Vucelja\, Physics Reports\, (to appear\, 2025).\n\n\n\n\n\n\n\n\n\n\n\n\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-988@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250225T110000 DTEND;TZID=Europe/Paris:20250225T120000 DTSTAMP:20250218T101829Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kristian-olsen-dusseldorf-university/ SUMMARY:Séminaire du LPTMS : Kristian Olsen (Düsseldorf University) - Sal le des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 25 Fév 25 11:00 DESCRIPTION:Optimal protocols out of equilibrium: from work extraction to e fficient stochastic resetting\nKristian Olsen (Düsseldorf University)\n&n bsp\;\nAs experimental techniques increasingly enable precise manipulation at the microscale\, extending thermodynamic principles to this regime bec omes essential. Stochastic thermodynamics provides a powerful framework fo r understanding small-scale systems\, where fluctuations and noise play a dominant role. A key challenge is designing optimal control strategies tha t minimize thermodynamic cost while guiding a system between desired state s. While much progress has been made in the control of passive colloids\, less is known about systems driven from equilibrium.\n\nIn this talk\, I w ill discuss optimal control strategies for transporting a particle between two locations under arbitrary time-dependent driving forces. These forces may arise from external fields\, such as fluid flows or electromagnetic f orces\, or internal mechanisms\, such as self-propulsion in active matter systems. I will present optimal protocols that incorporate information abo ut the non-equilibrium driving forces\, demonstrating how such information can enhance protocol efficiency and even result in net work extraction. T wo examples are considered\; i) a passive colloid experiencing periodic fo rces\, which acts as an automatic information engine\, and ii) optimal con trol of an active particle with a perspective towards stochastic resetting . CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1018@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250304T110000 DTEND;TZID=Europe/Paris:20250304T120000 DTSTAMP:20250218T134803Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicolas-loizeau-copenhagen/ SUMMARY:Séminaire du LPTMS : Nicolas Loizeau (Copenhagen) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Mar 25 11:00 DESCRIPTION:Opening Krylov space to solve long time dynamics via dynamical symmetries\nNicolas Loizeau (Copenhagen)\n \;\nSolving long time dynam ics of closed quantum many-body systems is one of the main challenges of t he field. For locally interacting closed systems\, the dynamics of local o bservables can always be expanded into (pseudolocal) eigenmodes of the the rmodynamic Liouvillian\, so called dynamical symmetries. These dynamical s ymmetries come in two classes - transient operators\, which decay in time and perpetual operators\, which either oscillate forever or stay the same (conservation laws). These operators provide a full characterization of sh ort and long time dynamics of the system.\nI will present a method to nume rically and analytically derive some of these dynamical symmetries in infi nite closed systems by introducing a naturally emergent open boundary cond ition on the Krylov chain. This boundary condition defines a partitioning of the Krylov space into system and environment degrees of freedom\, where non-local operators make up an effective bath for the local operators.\nW e demonstrate the practicality of the method on some numerical examples an d derive analytical results in two idealized cases. Our approach lets us d irectly relate the operator growth hypothesis to thermalization and expone ntial decay of observables in chaotic systems. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1014@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250311T110000 DTEND;TZID=Europe/Paris:20250311T120000 DTSTAMP:20250227T101612Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-david-gaspard-institut-langevin-espci-paris/ SUMMARY:Séminaire du LPTMS : David Gaspard (Institut Langevin\, ESPCI\, Pa ris) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 11 Mar 25 11:00 DESCRIPTION:Anisotropic Field Theory of Wave Transmission Statistics in Dis ordered Media\n \;\nDavid Gaspard (Institut Langevin\, ESPCI Paris)\n& nbsp\;\n\nRecent advances in wavefront shaping have revolutionized experim ental studies in mesoscopic physics\, providing new levels of control over coherent wave transport in scattering media\, particularly in optical sys tems. These experimental breakthroughs are founded on the substantial theo retical developments in quantum transport from the 1980s and 1990s\, espec ially those focused on disordered wires. A cornerstone of this body of wor k is the Dorokhov-Mello-Pereira-Kumar (DMPK) theory\, which characterizes the statistical properties of the transmission matrix of disordered media. However\, while powerful\, the DMPK theory cannot account for various exp erimentally relevant conditions\, including quasiballistic transport\, abs orption\, or partial control over the transmission matrix. Our work presen ts the first ab initio theory for the statistical properties of the transm ission matrix that successfully addresses all of these conditions within a unified framework. This achievement fills a critical gap\, providing expe rimentally useful predictions where current models fall short. A central r esult of this work is the derivation of a new nonlinear transport equation that captures the statistical properties of wavefront shaping performance . CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1024@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250314T140000 DTEND;TZID=Europe/Paris:20250314T150000 DTSTAMP:20250306T165443Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mlpp-seminars-hug o-cui-harvard/ SUMMARY:MLP@P seminars : Hugo Cui (Harvard) - LISN\, bat 660 salle 2014 (2 ° étage) - 14 Mar 25 14:00 DESCRIPTION:Learning diffusion models: asymptotic insights\nHugo Cui\nHarva rd\n\nSeminar of the Series MLP@P (Machine Learning Physics @ Plateau)\, j oint with LISN and IPhT.\nWhere: LISN\, bat 660 salle 2014 (2° étage)\n\ nAbstract: We consider the problem of learning a generative model paramet rized by a two-layer auto-encoder\, and trained with online stochastic gra dient descent\, to sample from a high-dimensional data distribution with a n underlying low-dimensional structure. We provide a tight asymptotic char acterization of low-dimensional projections of the resulting generated den sity\, and evidence how mode(l) collapse can arise. On the other hand\, w e discuss how in a case where the architectural bias is suited to the targ et density\, these simple models can efficiently learn to sample from a bi nary Gaussian mixture target distribution. Based on joint works with Yue M Lu\, Cengiz Pehlevan\, Lenka Zdeborová\, Florent Krzakala and Eric Vande n-Eijnden. CATEGORIES:MLP@P LOCATION:LISN\, bat 660 salle 2014 (2° étage)\, 660 Av. des Sciences\, 9 1190 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=660 Av. des Sciences\, 911 90 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France;X-APPLE-RADI US=100;X-TITLE=LISN\, bat 660 salle 2014 (2° étage):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1020@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250318T110000 DTEND;TZID=Europe/Paris:20250318T120000 DTSTAMP:20250303T145912Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-nicolas-pavloff-lptms/ SUMMARY:Séminaire du LPTMS : Nicolas Pavloff (LPTMS) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 18 Mar 25 11:00 DESCRIPTION:Topological Pathways to Two-Dimensional Quantum Turbulence\nNic olas Pavloff (LPTMS)\nI shall present a combined experimental and theoreti cal investigation of the formation and decay kinetics of vortices in a two -dimensional turbulent superfluid. Fundamental topological conservation la ws require that the formation and annihilation of vortices also involve cr itical points of the velocity field\, namely nodes and saddles. Identifyin g the simplest bifurcations underlying these processes enables to develop an effective kinetic model that closely aligns with experimental observati ons\, and shows that different mechanisms are responsible for vortex numbe r growth and decay. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1021@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250321T150000 DTEND;TZID=Europe/Paris:20250321T160000 DTSTAMP:20250306T100641Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mlp-urbani/ SUMMARY:MLP@P seminars : Pierfrancesco Urbani (IPhT) - LISN\, bat 660 salle 2014 (2° étage) - 21 Mar 25 15:00 DESCRIPTION:Generalization and overfitting in overparametrized two-layer ne ural networks\nPierfrancesco Urbani\nIPhT Saclay\n\nSeminar of the Series MLP@P (Machine Learning Physics @ Plateau)\, joint with LISN and IPhT.\nWh ere: LISN\, bat 660 salle 2014 (2° étage)\n\nUnderstanding the generaliz ation properties of large\, overparametrized\, neural networks is a centra l problem in theoretical machine learning. Several insightful ideas have b een proposed in this regard\, among them: the implicit regularization hypo thesis\, the possibility of having benign overfitting and the existence of feature learning regimes where neural networks learn the latent structure of data. However a precise understanding of the emergence/validity of the se behaviors cannot be disentangled from the study of the non-linear train ing dynamics. We use a technique from statistical physics\, dynamical mean field theory\, to study the training dynamics and obtain a rich picture o f how generalization and overfitting arise in large overparametrized model s. In particular we point out: (i) the emergence of a separation of timesc ales controlling feature learning and overfitting\, (ii) a non-monotone be havior of the test error and\, correspondingly\, a 'feature unlearning' ph ase at large times and (iii) the emergence of algorithmic inductive bias t owards small complexity. Joint work with Andrea Montanari.\n CATEGORIES:MLP@P LOCATION:LISN\, bat 660 salle 2014 (2° étage)\, 660 Av. des Sciences\, 9 1190 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=660 Av. des Sciences\, 911 90 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France;X-APPLE-RADI US=100;X-TITLE=LISN\, bat 660 salle 2014 (2° étage):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1029@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250325T110000 DTEND;TZID=Europe/Paris:20250325T120000 DTSTAMP:20250311T142851Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sara-murciano-lptms/ SUMMARY:Séminaire du LPTMS : Sara Murciano (LPTMS) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 25 Mar 25 11:00 DESCRIPTION:\nMeasurement-altered criticality: theory\, experiments and qua ntum applications\nSara Murciano (LPTMS)\n \;\n\nQuantum critical syst ems constitute appealing platforms for the exploration of novel measuremen t-induced phenomena due to their innate sensitivity to perturbations. I wi ll discuss the impact of measurement on Ising chains using an explicit pro tocol\, whereby uncorrelated ancillae are entangled with the critical chai n and then projectively measured. I will identify different protocols wher ein measurements (i) weakly modify the universal long-range entanglement a nd (ii) they completely obliterate it. I will also highlight a path to exp erimental realization in analog quantum simulators based on Rydberg atom a rrays. Finally\, I will describe how these ideas can establish a long-term quantum science application of ‘measurement-altered quantum criticality ’.\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1028@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250328T134500 DTEND;TZID=Europe/Paris:20250328T151500 DTSTAMP:20250318T162315Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-du-lptms-giuseppe-di-giulio-stockholm-university/ SUMMARY:Informal Quantum Seminar du LPTMS: Giuseppe Di Giulio (Stockholm Un iversity) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n °530 - 28 Mar 25 13:45 DESCRIPTION:Local Quenches from a Krylov Perspective\nGiuseppe Di Giulio (S tockholm University)\n \;\n\nIn the last few years\, quantifying the c omplexity of quantum states has found applications in many fields\, includ ing quantum information and computing\, quantum dynamics in many-body syst ems\, and black hole physics. Among these measures\, the spread complexity roughly quantifies the size of the space of states visited along quantum dynamics. It is obtained through Krylov space methods\, which consist of p rojecting the evolution of a state onto one-dimensional dynamics. In this talk\, I will discuss the evolution of the spread complexity after a local quantum quench in conformal field theories (CFT). Interestingly\, this qu antity depends on the central charge of the considered theory. I will also show that\, to get rid of all the non-universal contributions in the lead ing time behaviour\, it is convenient to study another Krylov space quanti ty\, the K-entropy\, an entropy measure defined for pure states without th e need for a bipartition. These results support the usefulness of the Kryl ov space methods to study quantum dynamics CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1030@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250401T110000 DTEND;TZID=Europe/Paris:20250401T120000 DTSTAMP:20250321T133854Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alessandro-manacorda-isc-italy/ SUMMARY:Séminaire du LPTMS : Alessandro Manacorda (ISC\, Italy) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 1 Avr 25 11: 00 DESCRIPTION:\nSometimes you shouldn't reset in the bulk: Finding an optimal stochastic resetting profile\nAlessandro Manacorda (ISC\, Italy)\n \; \n\nFinding a target for a purely Brownian searcher can be a hard task al ready in one dimension. Stochastic resetting qualitatively changes the gam e making the mean search time finite. An optimal homogeneous resetting r ate minimizing the MFPT exists and can be found given the fixed distance between the resetting and the target positions. Less is known when the d istance is not fixed in every trajectory but is drawn from a distribution\ , acting as a quenched disorder. Knowledge on the target distribution make s resetting desirable or not depending on the searcher's position. We pres ent an optimal solution for a heterogeneous resetting rate depending on the distribution of the target position. The optimal search strategy displ ays a transition from vanishing bulk resetting to a finite\, space-depende nt resetting profile\; we characterize the instabilities of the former and find the optimal resetting profiles numerically for two families of targe t distributions. The solution found is non-trivial and opens further resea rch questions in the field of optimal control with quenched disorder and i n search processes with resetting.\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1023@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250408T110000 DTEND;TZID=Europe/Paris:20250408T120000 DTSTAMP:20250404T080610Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-rupak-majumder/ SUMMARY:Séminaire du LPTMS : Rupak Majumder (TIFR Mumbai) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 8 Avr 25 11:00 DESCRIPTION:Manipulating phases in many-body interacting systems with subsy stem resetting\nRupak Majumder (TIFR Mumbai)\n \;\nConsider a thermody namic system that shows phase transition between an ordered and a disorde red phase. We ask: In the parameter regime in which the system exhibits a disordered phase\, can we induce order in the entire system by repeatedly resetting only a specific part of the system into an ordered state at ran dom times? If yes\, then we can control the macroscopic phase of a system by controlling only a (extensive) part of the system. More generally\, c an the macroscopic phase of a system be altered by resetting a part of it into a suitable phase?\nWe study these questions in different spin and osc illator models\, both equilibrium and non-equilibrium\, mean-field and non -mean-field\, with and without quenched disorder. We observe that\, just b y changing a few control parameters--the size of the subsystem we reset\, how fast we reset\, and at what configuration we reset--we can not only mo dify the system’s phases but also shift transition points and alter the nature of the transitions. Furthermore\, despite the non-reset subsystem retaining memory of the entire dynamics\, we obtain analytical predictions that are validated by simulations. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1034@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250411T150000 DTEND;TZID=Europe/Paris:20250411T160000 DTSTAMP:20250410T084323Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-du-lptms-aashish-clerk-the-university-of-chicago/ SUMMARY:Informal Quantum Seminar du LPTMS: Aashish Clerk (The University of Chicago) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n °530 - 11 Avr 25 15:00 DESCRIPTION:Insights into driven-dissipative quantum systems using hidden t ime-reversal symmetries \nAashish Clerk (The University of Chicago)\n&nbs p\;\n\nMany-body quantum systems subject to both driving and dissipation a re ubiquitous in physics\, and often possess complex steady states that do not have a simple thermal-equilibrium form.  I’ll discuss how a subtl e kind of quantum detailed balance (what we call “hidden time-reversal s ymmetry”) can yield exact insights into a range of different driven-dis sipative quantum systems\, including many-body systems relevant to a varie ty of experimental platforms.  These solutions directly enable understan ding of a variety of interesting phenomena\, ranging from the practical ( e.g. new methods for stabilizing remote many-qubit entanglement for modula r quantum computing)\, to the more fundamental (e.g. exact descriptions o f unusual driven-dissipative phase transitions).  I’ll discuss how the method applies to a range of different physical systems\, including a dr iven Bose-Hubbard model\, a driven transverse field Ising model (relevant to recent cold atom experiments on superradiant phase transitions)\, and a  coherently-driven interacting XXZ spin chain (something well suited to e xperiments using superconducting qubits).  \n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1019@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250415T110000 DTEND;TZID=Europe/Paris:20250415T120000 DTSTAMP:20250408T135758Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alia-abbara-epfl/ SUMMARY:Séminaire du LPTMS : Alia Abbara (EPFL) - Grand amphi\, bâtiment Pascal n° 530 - 15 Avr 25 11:00 DESCRIPTION:Stochastic graph models of evolution in populations\nAlia Abbar a (EPFL)\n \;\nIn this talk\, we first give a broad introduction to th e field of population genetics\, that was introduced by probabilists (J.B. S. Haldane\, S. Wright\, R. Fisher) to model genetic variations between in dividuals. We focus on the problem of a single mutant individual that has a fitness advantage with respect to all of the other identical individuals \, that we call the wild-types. Our goal is to characterize the spread of the mutant type within evolutionary trajectories. We briefly present a few fundamental models (Moran and Wright-Fisher) that rely on Markovian updat es of the state of the population and their analytical description within a diffusion approximation. We then present the problem of structured popul ations\, and introduce a new graph-based model\, where subpopulations are placed on the nodes of a given graph\, and stochastic migrations can happe n along the edges. We analyze this model with a branching process approxim ation\, and notably obtain the fixation probabilities of a single mutant\, i.e. how likely it is to take over the whole graph. CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1037@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250425T110000 DTEND;TZID=Europe/Paris:20250425T120000 DTSTAMP:20250422T085625Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mlpp-seminars-bea trice-achilli-bocconi/ SUMMARY:MLP@P seminars : Beatrice Achilli (Bocconi) - IPhT\, amphi Bloch\, CEA-Saclay - 25 Avr 25 11:00 DESCRIPTION:Life\, Death and Miracles of Diffusion Models\nBeatrice Achilli (Bocconi)\n\n\nSeminar of the Series MLP@P (Machine Learning Physics @ Pl ateau)\, joint with LISN and IPhT.\nWhere: IPhT\, Salle Itzykson *change o f place!*\n\nIn recent years\, generative diffusion models have emerged as powerful tools in unsupervised learning\, achieving impressive results in image\, text\, and data generation. In this presentation I will analyze f rom a geometric and statistical physics perspective how these models learn \, generalize\, and eventually memorize data. In particular\, I will highl ight how the intrinsic structure of manifold data impacts the dynamics of the diffusion process. Our analysis reveals the existence of distinct phas es during the generative process\, in particular a manifold coverage phase where the diffusion process fits the distribution internal to the manifol d\, and a consolidation phase where the score becomes orthogonal to the ma nifold. By mapping diffusion models driven by the empirical score function onto the Random Energy Model (REM)\, we are able to characterize memoriza tion and generalization timescales. These insights clarify the role of dat a structure in mitigating the curse of dimensionality and contribute to a deeper understanding of how diffusion models capture complex data distribu tions.\n CATEGORIES:MLP@P LOCATION:IPhT\, amphi Bloch\, CEA-Saclay\, CEA - Saclay\, Saclay\, France GEO:48.73668;2.180033999999978 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=CEA - Saclay\, Saclay\, Fra nce;X-APPLE-RADIUS=100;X-TITLE=IPhT\, amphi Bloch\, CEA-Saclay:geo:48.7366 8,2.180033999999978 END:VEVENT BEGIN:VEVENT UID:0-1031@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250429T110000 DTEND;TZID=Europe/Paris:20250429T120000 DTSTAMP:20250414T070751Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-greg-grason-u-mass-amherst/ SUMMARY:Séminaire du LPTMS : Greg Grason (U Mass\, Amherst) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Avr 25 11:00 DESCRIPTION:Geometrically-programmable assembly of self-limiting material s tructures\nGreg Grason (U Mass\, Amherst)\n \;\n\nLiving systems make a variety of functional and remarkably adaptive material structures via as sembly of highly complex\, nanoscale protein “building blocks”.  Man y of these architectures\, from viral capsid shells to multi-filament extr acellular protein fibers\, have well-defined and finite sizes\, and moreov er\, their functional properties (e.g. transport mediation\, mechanics) re ly on specific control of that finite size.  Notably this class “self- limiting” assembly is distinct from almost all types of synthetic self-a ssembled materials\, which often target well-defined and complex local str uctures\, such as crystals\, but exhibit unregulated\, if not unlimited\, dimensions at the large scale.  In this talk\, I discuss recent progress in understanding and engineering /self-limiting assemblies/\, in which th e equilibrium dimensions of complex material structure are encoded in comp lex building blocks from which they assemble.  This is motivated both by aspirational examples of finite-size\, functional assemblies in biology\, but also new classes of programmable particles that incorporate many key features of protein-like assembly (e.g. lock-and-key type “specific” i nteractions and geometrically-defined subunit shapes).   I will discuss combined experimental and theoretical studies of a basic mechanism of /se lf-closing\, curvature-controlled assembly/ of a range of bioinspired caps ules\, tubules and bicontinuous structures\, recently realized via DNA-ori gami based colloids.  These reveal basic trade-offs between design econo my and size-selectivity of target structures\, and further\, suggest stron g symmetry-based rules for minimal-complexity\, high-fidelity assembly in the limit of large self-closing size. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1043@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250513T110000 DTEND;TZID=Europe/Paris:20250513T120000 DTSTAMP:20250506T104605Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-sriram-ramaswamy-iisc-bangalore-india-postponed/ SUMMARY:Séminaire du LPTMS :Sriram Ramaswamy (IISc\, Bangalore\, India) po stponed - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n° 530 - 13 Mai 25 11:00 DESCRIPTION:TBA \n\nSriram Ramaswamy ( IISc Bangalore\, India)\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1032@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250516T110000 DTEND;TZID=Europe/Paris:20250516T120000 DTSTAMP:20250515T160105Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-pablo-sartori/ SUMMARY:Physics-Biology Interface seminar: Pablo Sartori - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Mai 25 11:00 DESCRIPTION:Semantic self-assembly in a meaning-less energy landscape far f rom equilibrium (seminar on Zoom)\nPablo Sartori (Gulbenkian Institute for Molecular Medicine)\n\nDue to an illness from the speaker\, the seminar h as been converted to a remote format - see Zoom link below. Some of us wil l gather in the seminar room to watch. Feel free to join us.\n\nLike the l etters in the alphabet forming words\, reusing components is an efficient strategy for assembling a large number of target structures from heterogen eous mixture of components. Examples range from synthetic DNA origami to p roteins self-assembling into complexes. The standard self-assembly paradig m views target structures as free-energy minima of a mixture. While this i s an appealing picture\, at high speed structures may be kinetically trapp ed in local minima\, reducing self-assembly accuracy. How then can high sp eed\, high accuracy\, and combinatorial usage of components coexist? We pr opose to reconcile these three concepts not by avoiding kinetic traps\, bu t by exploiting them to encode target structures. This can be achieved by sculpting the kinetic pathways of the mixture\, instead of its free-energy landscape. In other words\, targets structures with semantic value are no t enconded in the energy landscape\, but rather on the kinetics. We formal ize these ideas in a minimal toy model\, for which we analytically estimat e the encoding capacity and kinetic characteristics\, in agreement with si mulations. Our results may be generalized to other soft-matter systems cap able of computation\, such as liquid mixtures or elastic networks\, and pa ve the way for high-dimensional information processing far from equilibriu m.\n\n\nTime: May 16\, 2025 11:00 AM Paris\nhttps://cnrs.zoom.us/j/9370119 1981?pwd=abTkbFq72axppbR2pHUgIumGG6Ojk0.1\nMeeting ID: 937 0119 1981\nPass code: Ufwf5x\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1035@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250516T134500 DTEND;TZID=Europe/Paris:20250516T151500 DTSTAMP:20250410T102714Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-du-lptms-vittorio-vitale-pasqal/ SUMMARY:Informal Quantum Seminar du LPTMS: Vittorio Vitale (Pasqal) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Mai 25 13:45 DESCRIPTION:Scalable stochastic classification of quantum states of matter \nVittorio Vitale (Pasqal)\n \;\n\nQuantum computers and simulators\, in the noisy intermediate-scale quantum era\, offer a unique ability to co ntrol and probe individual quantum states at the many-body level. This cap ability allows for wave function snapshots via collective projective measu rements\, which are key to understanding the power of quantum computations . However\, the connection between these snapshots and many-body collectiv e properties remains poorly understood. We develop a network theory framew ork to link quantum phases of matter to their snapshots. First\, we identi fy a minimal-complexity basis by analyzing the information compressibility of snapshots over different basis. Then\, we build a wave-function networ k to study correlations in this basis. This approach reveals a stochastic classification of quantum states in one dimension: low-complexity networks correspond to paramagnetic and symmetry-broken phases\, while high-comple xity networks characterize conformal and topological phases. The latter ca n be distinguished by their network structures - which are either scale-fr ee or Erdős–Rényi.\n\nWe corroborate this classification using extensi ve tensor network numerical experiments\, complemented with state-of-the-a rt network theory analysis. The classification is of immediate experimenta l relevance\,  and draws a clear connection between probability distribut ion sampling and physical properties that is uncovered by network theory. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1005@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250603T100000 DTEND;TZID=Europe/Paris:20250603T110000 DTSTAMP:20250602T143831Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-cristina-marchetti/ SUMMARY:Physics-Biology Interface seminar: Cristina Marchetti - Salle polyv alente de l'Institut Curie\, bâtiment 111 - 3 Juin 25 10:00 DESCRIPTION:Biological tissues as materials: fluidity\, rigidity and rheolo gy\nCristina Marchetti (UCSB\, USA)\nJoint seminar with Institut Curie Ors ay. Note the unusual location and time.\n\nOver the last decade there has been growing evidence that dense biological tissue can spontaneously unde rgo transitions between a solid-like rigid state and a fluid-like state. T he rheological state of the tissue in turn influences the transmission of mechanical deformations\, which plays a central role in driving developmen tal processes\, such as wound healing and morphogenesis\, and tumor progre ssion. In this talk I will describe our computational and analytical inves tigations of the linear and nonlinear mechanical response of confluent tis sue to shear deformations.\n CATEGORIES:physbio,seminars LOCATION:Salle polyvalente de l'Institut Curie\, bâtiment 111\, 111\, Rue Jean-Dominique Cassini\, Bures-sur-Yvette\, 91440\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=111\, Rue Jean-Dominique Ca ssini\, Bures-sur-Yvette\, 91440\, France;X-APPLE-RADIUS=100;X-TITLE=Salle polyvalente de l'Institut Curie\, bâtiment 111:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1036@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250606T123000 DTEND;TZID=Europe/Paris:20250606T133000 DTSTAMP:20250414T150455Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/inauguration-1-ar tistique-2/ SUMMARY:Inauguration 1% artistique - Salle des séminaires du FAST et du LP TMS\, bâtiment Pascal n°530 - 6 Juin 25 12:30 DESCRIPTION:Hall ou parvis Nord CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1044@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250606T134500 DTEND;TZID=Europe/Paris:20250606T151500 DTSTAMP:20250603T091317Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-du-lptms-nandagopal-manoj-caltech-2/ SUMMARY:Informal Quantum Seminar du LPTMS: Nandagopal Manoj (Caltech) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 6 Juin 25 13:45 DESCRIPTION:Non-commutative effective field theory of the lowest Landau lev el superfluid\nNandagopal Manoj (Caltech)\n \;\nA 2+1d superfluid in a rapidly rotating trap forms an array of vortices\, with collective “ph onon” oscillations called Tkachenko modes. Ref. [1] argued based on the symmetries of the problem that an effective field theory describing these Tkachenko modes will be a field theory living on non-commutative space. In this talk\, I present some ongoing work which elucidates the microscopic origin of these non-commutative fields\, and a novel derivation of the eff ective field theory (EFT) for this superfluid using a coherent state path integral approach. Besides conceptual clarity\, this approach also helps m ake quantitative predictions about the long-wavelength\, low-energy behavi or of the weakly interacting lowest Landau level superfluid — relevant t o trapped BEC experiments.\n\n[1] Y.-H. Du\, S. Moroz\, D. X. Nguyen\, and D. T. Son\, Phys. Rev. Res. 6\, L012040 (2024).\n[2] N. Manoj\, arXiv:250 2.03528 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1042@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250610T110000 DTEND;TZID=Europe/Paris:20250610T120000 DTSTAMP:20250506T143641Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexios-polychronakos-cuny-usa/ SUMMARY:Séminaire du LPTMS : Alexios Polychronakos (CUNY\, USA) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Juin 25 1 1:00 DESCRIPTION:SU(N) ferromagnets and their intricate phase structure\nAlexios Polychronakos (CUNY\, USA)\n \;\nMagnetic systems with higher interna l SU(N) symmetry have recently been experimentally realized in ultracold a toms and interacting atoms on lattice cites. Although the theoretical stud y of their microscopic spectrum and dynamics is challenging\, their thermo dynamics in the ferromagnetic regime can be exactly derived using pure gro up theoretic techniques. I will give an overview of SU(N) ferromagnets\, d erive their thermodynamics and phase structure in the presence of external nonabelian magnetic fields\, and present recent results for atoms with a generalized internal structure. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1010@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250611T110000 DTEND;TZID=Europe/Paris:20250611T130000 DTSTAMP:20250606T084257Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-marco-biroli/ SUMMARY:Soutenance de thèse: Marco Biroli - Petit amphi\, bâtiment Pascal n° 530 - 11 Juin 25 11:00 DESCRIPTION:Strongly correlated stochastic systems\n \;\nMarco Biroli\n  \;\n\nThis thesis develops exact analytical tools to study strongly c orrelated stochastic systems\, with a focus on extreme value statistics\, gap statistics\, and full counting statistics in multi-particle processes. A central contribution is the universal characterization of conditionally independent identically distributed variables —random variables that be come independent upon conditioning on latent parameters. This structure ar ises naturally in systems with stochastic resetting\, a mechanism that gen erates strong long-range correlations while retaining analytical tractabil ity. Using this framework\, we derive universal closed-form expressions fo r several observables across diverse models\, including Brownian motion\, Lévy flights\, ballistic particles\, and Dyson Brownian motion\, under va rious resetting protocols. Inparticular\, we demonstrate that resetting in duces analytically tractable non-equilibrium steady states characterized. Theoretical predictions are supported by numerical comparisons and experim ental comparisons in systems such as diffusive particles in switching harm onic traps. Applications to search optimization are also explored\, identi fying regimes where resetting enhances or impairs first-passage efficiency \, and proposing rescaling-based protocols that out perform traditional re setting. CATEGORIES:seminars LOCATION:Petit amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Petit amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1013@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250613T113000 DTEND;TZID=Europe/Paris:20250613T123000 DTSTAMP:20250124T104324Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-franziska-lautenschlager-2/ SUMMARY:Physics-Biology Interface seminar: Franziska Lautenschläger - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Juin 25 11:30 DESCRIPTION:Migration and Seach of Immune Cells\nFranziska Lautenschläger (Saarland University\, Germany)\nBeware the unusual seminar time\nImmune c ells are often called the ‚sentinels‘ of the immune system\, constantl y searching for any kind of pathogen. During this search\, immune cells sp read over a given area with the task of finding objects in the most effici ent way. Parameters that influence this search are migration speed\, migra tion persistence and the correlation between the two [1]. These parameters can be modulated to diversify search strategies [2]. We have investigated how we can modify either the cellular environment or the cellular cytoske leton (all types) to control migration and the search efficiency [3\, 4].\ n\nShaebani\, M.R.\, et al.\, Persistence-Speed Coupling Enhances the Sear ch Efficiency of Migrating Immune Cells. Phys Rev Lett\, 2020. 125(26): p. 268102.\nShaebani\, M.R.\, M. Piel\, and F. Lautenschläger\, Distinct sp eed and direction memories of migrating dendritic cells diversify their se arch strategies. Biophys. J.\, 2022. 121(21): p. 4099-4108.\nShaebani\, M. R.\, et al.\, Effects of vimentin on the migration\, search efficiency\, a nd mechanical resilience of dendritic cells. Biophys. J.\, 2022. 121(20): p. 3950-3961.\nSadjadi\, Z.\, et al.\, Ameboid cell migration through regu lar arrays of micropillars under confinement. Biophys J\, 2022. 121(23): p . 4615-4623.\n CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1026@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250617T110000 DTEND;TZID=Europe/Paris:20250617T120000 DTSTAMP:20250505T144652Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-daniel-amor-ens-2/ SUMMARY:Séminaire du LPTMS : Daniel Amor (ENS) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Juin 25 11:00 DESCRIPTION:Community transitions and the emergence of alternative stable s tates in microbial systems\nDaniel Amor (ENS)\nMicrobial communities often face external perturbations that can induce lasting changes in their comp osition and functions. Responses to such perturbations can drive community functions\, including host health\, which urges for predictive understand ing of community dynamics following perturbations. First in this talk\, I will present our work addressing how perturbations can induce transitions between alternative stable states of a simple experimental community. For the case of antibiotic perturbations\, I will address how bacterial growth dynamics can overcome differences in antibiotic susceptibility and determ ine the community outcome of antibiotic exposure. Combining theory and exp eriments\, we demonstrated that differences in the growth rates of communi ty members can determine the resilience of stable community states against several antibiotics\, a result that holds with relative independence of d ifferences in antibiotic susceptibility. As our understanding of response to perturbations in simple communities was growing\, we faced a classical question in ecology: how does community complexity impact stability and dy namics? We addressed this question by assembling experimental communities under a large range of species pools\, controlling both identity and numbe r of community members\, and a range of environments\, controlling the ave rage interaction strength between community members. These experiments con stitute the first empirical demonstration of complexity-driven transitions between three generic phases of community dynamics predicted by ecologica l theory. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1039@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250620T140000 DTEND;TZID=Europe/Paris:20250620T150000 DTSTAMP:20250425T082816Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-matteo-brunelli-college-de-france/ SUMMARY:Informal quantum seminar: Matteo Brunelli (Collège de France) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Jui n 25 14:00 DESCRIPTION:Nonreciprocal quantum matter\n \;\nMatteo Brunelli (Collèg e de France)\n \;\n\nNonreciprocal interactions\, in which an agent A attracts another agent B while B repels A\, lead to exciting phenomena in classical systems\, such as novel phase transitions and time-crystal behav ior. Whether such phenomena occur in quantum many-body systems remains to a large extent an open question. In this talk\, I will discuss how nonreci procal interactions can be engineered in interacting quantum systems. I wi ll present a model of two ensembles of driven quantum spins featuring attr action-repulsion type interactions\, analogous to predator-prey dynamics. The model can be realized with two atomic ensembles coupled via chiral wav eguides. In the thermodynamic limit\, nonreciprocal interactions result in a nonreciprocal phase transition into time-crystalline states\, associate d with spontaneous breaking of parity-time symmetry. Continuous monitoring of the waveguide’s output field also induces a time-crystal state in fi nite-size systems\, where parity-time symmetry is spontaneously broken\, a nd the corresponding quantum trajectories reveal quantum traveling-wave st ates. I will then show that nonreciprocal interactions arise in a model of superradiant laser in which a fraction of the atoms are not driven\, resu lting in frequency shift and spectral broadening of the emitted radiation. This represents a fundamental limitation for the operation of super radia nt lasers ultra-stable frequency reference. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1045@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250624T110000 DTEND;TZID=Europe/Paris:20250624T120000 DTSTAMP:20250619T151150Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-bertrand-lacroix-a-chez-toine-kcl-uk/ SUMMARY:Séminaire du LPTMS : Bertrand Lacroix a chez Toine (KCL\, UK) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Jui n 25 11:00 DESCRIPTION:Superposition of plane waves in high spatial dimensions: from l andscape complexity to the ground state value\n \;\nBertrand Lacroix a chez Toine (KCL\, UK)\n \;\n\nWe will discuss some statistical proper ties of a class of models of high-dimensional random landscapes defined in a Euclidean space of large dimension $N\\gg 1$ via a superposition of $M$ plane waves whose amplitudes\, directions of the wavevectors\, and phases are taken to be random. Our main efforts are directed towards deriving\, and then analysing for $N\\to \\infty\, M\\to \\infty$ while keeping $\\al pha=M/N$ finite\,\n(i)  the rates of asymptotic exponential growth with $ N$ of the mean number of all critical points and of local minima known as the annealed complexities and\n(ii)  the expression for the mean (also ex pected to be typical) value of the deepest landscape minimum (the ground-s tate energy).\nIn particular\, for the latter we derive the Parisi-like op timization functional and\nanalyze conditions for the optimizer to reflect various phases:  replica-symmetric\, one-step and full replica symmetry broken\, as well as criteria for the continuous\,  Gardner and random fir st order transitions between those phases. This work is done in collabora tion with Yan V. Fyodorov (King’s College London).\n\nRef.: arXiv prepri nt arXiv:2411.09687\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1009@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250627T110000 DTEND;TZID=Europe/Paris:20250627T120000 DTSTAMP:20250306T165929Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-simona-mura/ SUMMARY:Physics-Biology Interface seminar: Simona Mura - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 27 Juin 25 11:00 DESCRIPTION:Breaking barriers: nanomedicine fate from administration target site\nS. Mura\, Orsay/France\nNanoscale systems for drug delivery have th e potential to overcome the limitations of conventional treatments\, thus providing a solution to unmet medical needs.\nThe therapeutic benefits of this approach have led to the commercialization of more than 50 nanomedici nes such as doxorubicin-loaded liposomes (Doxil®\, Myocet®)\, paclitaxel -albumin nanoparticles (Abraxane®)\, and more recently\, lipid carriers f or the delivery of siRNA (Patisiran/ONPATTRO®) or mRNA (BioNTech/Pfizer a nd Moderna COVID-19 vaccines).\nAlthough these results provide clear evide nce of the potential of nanomedicines for the efficient delivery of chemot herapeutics\, there is still a substantial gap between the favorable precl inical results and the real clinical performances.\nThe introduction of na nomedicine in the clinic has been partly hampered by the lack of effective delivery to the target in vivo. Among the multiplicity of imputable facto rs\, a major role can be attributed to: (i) the modifications undergone by nanomedicines after interaction with molecules/proteins in the bloodstrea m that endow them with a specific molecular signature and (ii) the numerou s biological barriers that these nanomedicines must cross (e.g.\, the vasc ular endothelium\, the tumor extracellular matrix\, etc…). \nIn this con text\, it is necessary to have a clearer comprehension of their fate after administration.\nOur research group is focusing on this topic\, and we ar e developing different tools to investigate and better understand the barr iers encountered nanomedicines both in the circulation after intravenous a dministration and\, after extravasation\, in the complex tumor microenviro nment.\nDuring this talk\, the most significant results we have obtained w ill be presented\nLiterature:\n[1] Sobot D\, Mura S\, Yesylevskyy SO\, Dal bin L\, Cayre F\, Bort G\, Mougin J\, Desmaële D\, Lepetre-Mouelhi S\, Pi eters G\, Andreiuk B\, Klymchenko AS\, Paul JL\, Ramseyer C\, Couvreur P. Nature Comm 2017\, 8\, 15678 \n[2] Lazzari G\, Nicolas V\, Matsusaki M\, A kashi M\, Couvreur P\, Mura S. Acta Biomaterialia 2018\, 78\, 296.\n[3] Bi dan N\, Dunsmore G\, Ugrinic M\, Bied M\, Moreira M\, Deloménie C\, Ginho ux F\, Blériot C\, de la Fuente M\, Mura S. Drug Deliv Transl Res. 2023 CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1053@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250704T140000 DTEND;TZID=Europe/Paris:20250704T150000 DTSTAMP:20250626T132957Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-andrew-urichuk-universite-paris-cergy/ SUMMARY:Informal quantum seminar: Andrew Urichuk (Université Paris-Cergy) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Juil 25 14:00 DESCRIPTION:Generalized fluids in 1D as a wave packet gas\nAndrew Urichuk ( Université Paris-Cergy)\n \;\n\nMacroscopic transport in one dimensio nal integrable and quasi-integrable models is characterized by a universal framework known as Generalized Hydrodynamics (GHD). In its standard\, Eul er-scale\, form GHD mirrors the description of a two-dimensional compressi ble fluid\, however this standard formulation neglects fluctuations (both thermal and quantum) and becomes unwieldy upon the introduction of integra bility breaking effects. Instead of introducing these corrections into the evolution equations our approach is to come up with a more precise charac terization of initial fluctuations\, analogous to fluctuating conventional hydrodynamics. To this end I will introduce a method wherein the fluid is modeled as a gas of semiclassical wavepackets\, which can easily incorpor ate both integrability breaking terms and a correct fluctuating extension to GHD.  In this talk I will review conventional GHD and demonstrate how to implement our numerically efficient wave packet gas extension. From the wave packet gas approach I will demonstrate the presence of long-range co rrelations at long-times\, where one-point observables appear thermal\, su ggesting deviation from 'true' thermalization at diffusive time-scales. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1049@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250916T110000 DTEND;TZID=Europe/Paris:20250916T120000 DTSTAMP:20250911T140618Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-kim-kreienkamp-tu-berlin/ SUMMARY:Séminaire du LPTMS : Kim Kreienkamp (TU Berlin) - Salle des sémin aires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Sep 25 11:00 DESCRIPTION:Symmetry breaking in active non-reciprocal systems\n \;\nKi m Kreienkamp (TU Berlin)\n \;\n\nNon-reciprocal couplings significantl y impact the dynamical behavior in mixtures. A particularly striking conse quence of such couplings is the spontaneous emergence of time-dependent ph ases that break parity-time symmetry. Here\, we study a paradigmatic model of a non-reciprocal polar active mixture with completely symmetric repuls ion. Using a combination of field theory and particle-based simulations\, we identify two qualitatively distinct regimes of non-reciprocity-induced dynamics. In the regime of weak intra-species alignment\, non-reciprocity leads to asymmetric clustering in which predominantly one of the two speci es forms clusters. Notably\, the asymmetric density dynamics is driven alo ne by non-reciprocal orientational couplings. In contrast\, in the strongl y coupled regime\, the corresponding field\ntheory exhibits exceptional po ints that have been associated with the emergence of chiral phases where t he polarization direction rotates over time. Our simulations confirm that spontaneous chirality arises at the particle level. In particular\, we obs erve chimera-like states with coexisting locally synchronized and disorder ed regions. Both the spontaneous chirality and entropy production rate pea k at coupling\nstrengths associated with exceptional points. Our results h ighlight the diverse effects of non-reciprocity across different scales. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1046@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250923T110000 DTEND;TZID=Europe/Paris:20250923T120000 DTSTAMP:20250919T084342Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-malte-henkel-universite-de-lorraine-nancy/ SUMMARY:Séminaire du LPTMS : Malte Henkel (Université de Lorraine\, Nancy ) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 23 Sep 25 11:00 DESCRIPTION:Invariance sous translations temporelles généralisées dans l e vieillissement physique\n\nMalte Henkel (Laboratoire de Physique et Chim ie Théoriques\, Université de Lorraine\, Nancy)\n \;\nLa phénoméno logie générique du vieillissement physique des systèmes classiques s’ obtient de la combinaison de son invariance d’échelle dynamique et de l ’invariance sous translations temporelles généralisées\, déduite à l’aide d’un changement de représentation des générateurs temporel-s patiaux de l’algèbre de Lie sous-jacente. Ces conséquences phénoméno logiques seront décrites. De plus\, un critère sera formulé sur la non- pertinence aux temps longs des non-linéarités dans l’équation de mouv ement stochastique.\n[1] M. Henkel\, Nucl. Phys. B1017\, 116968 (2025) [ar xiv:2504.16857]\n[2] M. Henkel\, S. Stoimenov\, [arxiv:2505.22301] CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1050@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20250930T110000 DTEND;TZID=Europe/Paris:20250930T120000 DTSTAMP:20250925T135858Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alexander-k-hartmann-institute-for-physics-university-of-oldenburg-germa ny/ SUMMARY:Séminaire du LPTMS : Alexander K. Hartmann (Institute for Physics\ , University of Oldenburg\, Germany) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 30 Sep 25 11:00 DESCRIPTION:Complex behavior for numerically simple problems\n\nAlexander K . Hartmann (Institute for Physics\, University of Oldenburg\, Germany)\n&n bsp\;\n\nThe description of complex system by the concept of Replica Symme try Breaking (RSB) was shaped by Giorgio Parisi in the 1980s to solve the mean-field spin glass\, as honored by the Nobel price in 2021. RSB has bee n used to analyze systems such as spin glasses\, neural networks\, optimiz ation problems\, or machine learning. Unfortunately\, numerically these we ll known RSB-exhibiting problems are difficult since only exponential-time exact algorithm are available.\n\nHere two models are considered\, direct ed polymers in random media and increasing subsequences\, called Ulam's pr oblem for the ground states. These models are interesting in many ways. Fo r example\, the distributions of free energies or sequence lengths\, respe ctively\, exhibit complex large-deviation behavior\, which can be numerica lly addressed by rare-event sampling algorithms.\n\nFor both models it is possible to sample exactly in perfect thermal equilibrium with polynomial- time algorithms. This means\, large\nsystem sizes are accessible\, in cont rast to\, e.g.\, the case of spin glasses. The results from perfect sampli ng of some problem disorder ensembles indicate the presence of RSB with co mplex structured landscapes. Thus\, the study of complex RSB behavior is a ccessible numerically for some models. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1051@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251003T090000 DTEND;TZID=Europe/Paris:20251003T170000 DTSTAMP:20250619T130507Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/fete-de-la-scienc e/ SUMMARY:Fête de la Science - Salle des séminaires du FAST et du LPTMS\, b âtiment Pascal n°530 - 3 Oct 25 09:00 DESCRIPTION:Fête de la Science\négalement sur https://www.fetedelascience .fr/\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1055@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251007T110000 DTEND;TZID=Europe/Paris:20251007T120000 DTSTAMP:20251001T145837Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-alberto-nardin-lptms-universite-paris-saclay/ SUMMARY:Séminaire du LPTMS : Alberto Nardin (LPTMS\, Université Paris Sac lay) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Oct 25 11:00 DESCRIPTION:Nonlinear dynamics at the fractional quantum Hall edge: quantum Korteweg-de Vries equation and solitons\nAlberto Nardin (LPTMS)\n \;\ n\nOne of the hallmark features of fractional quantum Hall liquids is the existence of chirally propagating edge modes at their boundary\, whose pre sence has been an invaluable tool for probing the system’s exotic proper ties\, most notably the presence of fractionally charged quasiparticles wi th anyonic exchange statistics.\nThe description of these edge modes was p ioneered by Xiao Gang Wen already in the early nineties\; yet\, these  sy stems attract a lot of attention still today. During the talk\, I’ll bri efly describe how non-linear corrections to Wen’s chiral Luttinger liqui d naturally emerge\nin anharmonically confined atomic quantum Hall fluids\ , both in the continuum or on a lattice.  These corrections are both disp ersive and nonlinear\, giving rise to a rich high-energy dynamics beyond W en.\n\nIn particular\, the emergent\, effective description takes the form of a quantum version of the Korteweg-de Vries\nequation\, a well-studied fluid-dynamics equation which admits solitonic solutions.  I will mostly focus on how this quantum model gives rise to several intriguing new featu res of the one-dimensional  boundary\, such as solitons propagating along the system's boundary and quantum blockaded dynamics leading to the  pos sibility of generating non-classical states of the edge.\n\nI will finally touch on a different aspects of my reaserch at LPTMS: the study of a meas urable fractional quantum Hall  quasiparticles' spin\, a quantity which i s deeply intertwined with their anyonic statistics\,  and how such a spin is fractionalized between the quasiparticle itself and the system's edge\ , leading to its robustness. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1063@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251010T140000 DTEND;TZID=Europe/Paris:20251010T153000 DTSTAMP:20251009T081820Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-alexandre-fagerlund/ SUMMARY:Informal quantum seminar: Alexandre Fagerlund - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Oct 25 14:00 DESCRIPTION:A holesome story: quasiholes and other surprises in the fractio nal quantum Hall effect\nAlexandre Fagerlund\n \;\nThere is a wealth o f rich physics associated with the fractional quantum Hall effect. I will give an introduction to some of these ideas\, with a focus on the so-call ed k=3 Read-Rezayi state. The talk will assume only "an epsilon" of prere quisite knowledge\, and will gradually introduce some of the basic ideas relevant for the fractional quantum Hall effect. These include some use ful wave functions and the notion of quasiholes\, which are quasiparticl e dips in the electron fluid. I will briefly outline how these concepts ca n be related to conformal field theory (CFT). The CFT description provides a different perspective on some of the quantum Hall phenomena\, and is ev entually shown to naturally lead to the language of matrix product states (MPS)\, which can be used for efficient numerical computations for fractio nal quantum Hall states. \nIn the second part of the talk\, I will outlin e some of my own research. This includes a numerical technique developed together with my supervisor\, Eddy Ardonne. The technique is based on CFT and MPS\, and allows e.g. density profiles and spins of quasiholes in the k=3 Read-Rezayi state to be computed. From these spins\, braiding phases of quasiholes can be inferred. Together with Leonardo Mazza and Alberto Na rdin\, we have also used these methods to numerically demonstrate a form o f bulk-boundary correspondence in fractional quantum Hall states\, where s pin fractionalizes between a quasihole in the bulk and the distorted edge. This topic will be subject to more research during my stay here. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1057@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251013T140000 DTEND;TZID=Europe/Paris:20251013T151500 DTSTAMP:20250908T121142Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-andrea-pizzi-universite-de-cambridge/ SUMMARY:Informal quantum seminar: Andrea Pizzi (Université de Cambridge) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Oct 25 14:00 DESCRIPTION:Genuine quantum scars in many-body spin systems\n \;\nAndre a Pizzi (Université de Cambridge)\n \;\n\nChaos makes isolated system s of many interacting particles quickly thermalize and forget their past. While this picture applies to simple observables such as order parameters and correlators\, it need not extend to more complex quantities like many- body wavefunction amplitudes\, that are becoming accessible in quantum com puters and simulators and can reveal a richer structure. In this talk\, I will show that although the quantum eigenstates are thermal and strongly e ntangled\, many of them are genuinely scarred\, that is\, have an enlarged amplitude along underlying classical unstable periodic orbits. Scarring p roduces non-Porter-Thomas amplitude statistics and makes the system more l ikely to revisit the orbit it was initialized on\, retaining memory of its past and weakly breaking ergodicity. I will demonstrate the ubiquity of q uantum scarring across a broad family of spin models\, including widely st udied examples from condensed matter physics. Some features of scarring ev en extend beyond periodic orbits\, giving rise to “quantum trails” alo ng generic trajectories. These findings prove structure in spite of chaos in many-body quantum systems. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1052@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251014T100000 DTEND;TZID=Europe/Paris:20251014T160000 DTSTAMP:20250619T130732Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/journee-de-la-ffj / SUMMARY:Journée de la FFJ - Salle des séminaires du FAST et du LPTMS\, b âtiment Pascal n°530 - 14 Oct 25 10:00 DESCRIPTION:Journée de la FFJ\nà venir CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1041@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251015T100000 DTEND;TZID=Europe/Paris:20251015T140000 DTSTAMP:20250909T145248Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-alessandro-pacco/ SUMMARY:Soutenance de thèse : Alessandro Pacco - Grand amphi\, bâtiment P ascal n° 530 - 15 Oct 25 10:00 DESCRIPTION:Exploring high-dimensional random landscapes: from spin glasses to random matrices\, passing through simple chaotic systems\n \;\nAle ssandro Pacco\n\nHigh-dimensional random landscapes underlie phenomena as diverse as glassy physics and machine learning\, yet even their simplest t oy models already display extraordinarily rich behavior. This thesis aims to deepen our understanding of that behavior\, by combining landscape base d approaches\, via the Kac–Rice formalism\, with dynamical approaches\, paying special attention to both systems with reciprocal and with non-reci procal interactions. After surveying core techniques and results through t he pure spherical p-spin model\, this thesis delivers three main advances: (i) exact dynamic–static comparison in a class of solvable non-reciproc al models\, pinpointing differences and similarities of the two approaches \; (ii) a stability-based calculations of the mean number of fixed points in the Sompolinsky–Crisanti–Sommers random neural network\, for any le vel of non-reciprocity of the interactions\; (iii) two approaches to probe the barriers and the distribution of deep local minima in the landscape o f the p-spin model\; (iv) some results on overlaps among eigenvectors of s piked\, correlated random matrices\, which are useful when exploring the g eometry of energy landscapes. Together\, these results sharpen our underst anding of such systems\, while opening new doors for future research direc tions.\n \;\n\nJury : E. Bertin\, Y. Fyodorov\, C. Monthus\, F. Ricci- Tersenghi\, V. Ros (directrice de thèse)\, A. Rosso (co-directeur de thè se) CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1059@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251017T110000 DTEND;TZID=Europe/Paris:20251017T120000 DTSTAMP:20251006T215337Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-dennis-worthmuller/ SUMMARY:Physics-Biology Interface seminar: Dennis Wörthmüller - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Oct 25 11: 00 DESCRIPTION:When Actin Meets Curvature: Modeling Free-Standing Cell Protrus ions\nDennis Wörthmüller (Institut Curie)\nCell shape changes are largel y controlled by the actin cytoskeleton\, a dynamic filament network beneat h the plasma membrane. Some cell types can form extended free-standing pro trusions that are not supported by an extracellular substrate\, and whose initiation is thought to rely on proteins that modulate actin dynamics thr ough sensitivity to membrane curvature. I will present a theoretical model for a free-standing viscous actin network growing on a corrugated membran e\, which couples active-gel mechanics\, membrane deformation\, and the re cruitment of curvature-sensitive actin nucleators. The model shows that un iform actin polymerization stabilizes membrane shape\, whereas curvature-d ependent nucleation can render the membrane linearly unstable and drive sp ontaneous deformations with a well-defined wavelength that could initiate protrusions. To explore these processes beyond the linear regime\, we deve lop a finite-element framework that captures nonlinear deformations of flu id and elastic layers\, opening the way to realistic simulations of actin- driven membrane shape changes. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1072@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251030T160000 DTEND;TZID=Europe/Paris:20251030T170000 DTSTAMP:20251021T074402Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mlpp-seminars-jor ge-cossio-ipht/ SUMMARY:MLP@P seminars : Jorge Fernanzed-de-Cossio-Diaz (IPhT) - LISN\, bat 660 salle 2014 (2° étage) - 30 Oct 25 16:00 DESCRIPTION:TBA\nJorge Fernanzed-de-Cossio-Diaz\nIPhT\, Saclay\n\nSeminar o f the Series MLP@P (Machine Learning Physics @ Plateau)\, joint with LISN and IPhT.\nWhere: LISN\, bat 660 salle 2014 (2° étage)\n\n CATEGORIES:MLP@P LOCATION:LISN\, bat 660 salle 2014 (2° étage)\, 660 Av. des Sciences\, 9 1190 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=660 Av. des Sciences\, 911 90 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France;X-APPLE-RADI US=100;X-TITLE=LISN\, bat 660 salle 2014 (2° étage):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1048@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251104T110000 DTEND;TZID=Europe/Paris:20251104T120000 DTSTAMP:20251028T103252Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-dimitri-m-gangardt-university-of-birmingham-uk/ SUMMARY:Séminaire du LPTMS : Dimitri M. Gangardt (University of Birmingham \, UK) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°5 30 - 4 Nov 25 11:00 DESCRIPTION:Limit shapes and their phase transitions: classical and quantum \nDimitri M. Gangardt (University of Birmingham\, UK)\n \;\n\n \;\ n\n\nI will present examples of Limit Shapes - the most probable macroscop ic shape\nwith sharp boundaries separating frozen and fluctuating regions - which arise\nin a variety of classical and quantum systems. I will expla in a special role\nplayed by analytic functions defining Riemann surface w hose topology can be\nchanged abruptly across phase transitions. Most of t he examples are based on\nfree fermionic models\, however recently we stud ied a notable exception from\nthis rule - the Polytropic Gas with a power- law equation of state. The hydrodynamic\napproach to Emptiness Formation P robability in Polytropic Gas will be discussed.\n\n\n[1] J. Pallister\, D. M. Gangardt and  A. Abanov\, "Limit shape phase transitions: a merger of arctic circles"\,\n J. Phys. A 55\,  304001\, 2022\n\n[2] James S. Palli ster\, Samuel H. Pickering\, Dimitri M. Gangardt and  Alexander G. Abanov \, "Phase transitions in full counting statistics of free fermions and dir ected polymers"\, Phys. Rev. Research 7\, L022008\, 2025\n\n[3] Alexander G. Abanov\, Dimitri M. Gangardt\, "Emptiness instanton in quantum polytrop ic gas"\, SciPost Phys. 18\, 122\,  2025\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1074@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251106T160000 DTEND;TZID=Europe/Paris:20251106T170000 DTSTAMP:20251103T101248Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/damien-barbier/ SUMMARY:MLP@P seminars : Damien Barbier (Bocconi University) - LISN\, bat 6 60 salle 2014 (2° étage) - 6 Nov 25 16:00 DESCRIPTION:The strange case of the symmetric binary perceptron: when stand ard statistical mechanics fails\nDamien Barbier\nBocconi University\, Mila n\n\nSeminar of the Series MLP@P (Machine Learning Physics @ Plateau)\, jo int with LISN and IPhT.\nWhere: LISN\, bat 660 salle 2014 (2° étage)\n\n We define and study a statistical mechanics ensemble that characterizes co nnected solutions in\nconstraint satisfaction problems (CSPs). Built aroun d a well-known local entropy bias\, it allows\nus to better identify hardn ess transitions in problems where the energy landscape is dominated by\nis olated solutions. We apply this new device to the symmetric binary percept ron model (SBP)\, and\nstudy how its manifold of connected solutions behav es. We choose this particular problem because\,\nwhile its typical solutio ns are isolated\, it can be solved using local algorithms for a certain ra nge of\nconstraint density α and threshold κ. With this new ensemble\, w e unveil the presence of a cluster\ncomposed of delocalized connected solu tions. In particular\, we demonstrate its stability until a\ncritical thre shold κ_{no−mem loc. stab.} (dependent on α). This transition appears as paths of solutions shatter\,\na phenomenon that more conventional stati stical mechanics approaches fail to grasp. Finally\, we\ncompared our pred ictions to simulations. For this\, we used a modified Monte-Carlo algorith m\,\ndesigned specifically to target these delocalized solutions. We obtai ned\, as predicted\, that the\nalgorithm finds solutions until κ ≈ κ_{ no−mem loc. stab.}. CATEGORIES:MLP@P LOCATION:LISN\, bat 660 salle 2014 (2° étage)\, 660 Av. des Sciences\, 9 1190 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=660 Av. des Sciences\, 911 90 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France;X-APPLE-RADI US=100;X-TITLE=LISN\, bat 660 salle 2014 (2° étage):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1056@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251107T134500 DTEND;TZID=Europe/Paris:20251107T151500 DTSTAMP:20251031T160702Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-jacopo-de-nardis-universite-paris-cergy/ SUMMARY:Informal quantum seminar: Jacopo De Nardis (Université Paris-Cergy ) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 7 Nov 25 13:45 DESCRIPTION:Computing More with Less: Random Tensor Networks and New Algori thms for Time Evolution\n \;\nJacopo De Nardis (Université Paris-Cerg y)\n \;\n\nI will present recent analytical and numerical results on q uantum complexity and anticoncentration in many-body wave functions\, usin g random tensor-network ensembles as a powerful\, tractable testbed for no n-equilibrium dynamics. I will then introduce new algorithms for the class ical simulation of quantum time evolution: (i) hybrid tensor-network metho ds enhanced by Clifford unitaries\, and (ii) Monte Carlo sampling of spati ally contracted networks. Together\, these approaches extend the reach of tensor network simulations\, showing how less resources suffice to capture key quantum features. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1073@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251113T160000 DTEND;TZID=Europe/Paris:20251113T170000 DTSTAMP:20251109T081620Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/christophe-giraud / SUMMARY:MLP@P seminars : Christophe Giraud (Paris Saclay University) - LIS N\, bat 660 salle 2014 (2° étage) - 13 Nov 25 16:00 DESCRIPTION:Clustering and Community Recovery in Polynomial Time below the Kesten-Stigum Threshold\nChristophe Giraud\nParis Saclay University\n\nSem inar of the Series MLP@P (Machine Learning Physics @ Plateau)\, joint with LISN and IPhT.\nWhere: LISN\, bat 660 salle 2014 (2° étage)\n\nPredicti ons based on the cavity and replica methods stipulate that clustering in t he Gaussian Mixture Model and community recovery in the Stochastic Block M odel cannot be achieved in polynomial time below the Kesten-Stigum (KS) th reshold. These predictions have stimulated an active line of mathematical research\, and have been confirmed rigorously in a wide range of regimes: spectral based algorithms succeed above the KS threshold\, while computati onal hardness below the KS threshold has been proved within the low-degree polynomials framework. However\, the picture changes when the number of c lusters or communities is large. In such regimes\, the computational barri er appears to lie below the KS threshold\, and seems to be disconnected fr om spectral algorithms. In this talk\,I will present these recent results\ , and discuss some related open questions.\n\n CATEGORIES:MLP@P LOCATION:LISN\, bat 660 salle 2014 (2° étage)\, 660 Av. des Sciences\, 9 1190 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=660 Av. des Sciences\, 911 90 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France;X-APPLE-RADI US=100;X-TITLE=LISN\, bat 660 salle 2014 (2° étage):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1062@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251114T140000 DTEND;TZID=Europe/Paris:20251114T153000 DTSTAMP:20251107T093132Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-miha-srdinsek-cea-grenoble/ SUMMARY:Informal quantum seminar: Miha SRDINSEK (CEA Grenoble) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Nov 25 14:0 0 DESCRIPTION:Hybrid between biologically inspired and quantum inspired many- body states\nMiha SRDINSEK (CEA Grenoble)\n \;\nDeep neural networks c an represent very different sorts of functions\, including complex quantum many-body states. Tensor networks can also represent these states\, have more structure and are easier to optimize. However\, they can be prohibiti vely costly computationally in two or higher dimensions. In this seminar I will propose a hybrid network [1] which borrows features from the tw o different formalisms. I will showcase the ansatz by obtaining the repre sentation of a transverse field quantum Ising model with a long range 1/r ^6 antiferromagnetic interaction on a 10×10 square lattice. The model c orresponds to the Rydberg (cold) atoms platform proposed for quantum annea ling.\n[1] Srdinsek\, Waintal\, arXiv:2506.05050 (2025) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1068@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251118T110000 DTEND;TZID=Europe/Paris:20251118T120000 DTSTAMP:20251105T125745Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-filiberto-ares-sissa-trieste-italy/ SUMMARY:Séminaire du LPTMS : Filiberto Ares (SISSA\, Trieste\, Italy) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 18 Nov 25 11:00 DESCRIPTION:Entanglement asymmetry and the quantum Mpemba effect Filiberto  Ares (SISSA\, Trieste\, Italy)\n \;\n\nAbstract: One of the most fu ndamental questions connecting quantum and statistical physics is how a cl osed many-body quantum system\, evolving unitarily\, locally relaxes to a stationary state. The approach to equilibrium is exceedingly complex and c an be probed in a myriad of ways. In this seminar\, we will address this q uestion through the lens of entanglement asymmetry. This is a recently int roduced\, information-based observable that quantifies how much a symmetry is broken within a subsystem. As an illustration\, we will consider the c ase where a symmetry explicitly broken by the initial state is dynamically restored. Remarkably\, we find that the more the symmetry is initially br oken\, the faster it is restored\, a quantum analogue of the Mpemba effect . We will further discuss the conditions under which this phenomenon occur s and present direct experimental evidence from a trapped-ion quantum simu lator. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1076@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251119T140000 DTEND;TZID=Europe/Paris:20251119T153000 DTSTAMP:20251113T083209Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar/ SUMMARY:Informal Quantum Seminar: Pedro Ribeiro (Universidade de Lisboa) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 N ov 25 14:00 DESCRIPTION:Dissipative Quantum Chaos — from Theory to the Lab\nPedro Rib eiro (Universidade de Lisboa)\n \;\n\nDissipative quantum chaos is an emerging field that investigates how chaotic behavior arises in quantum sy stems coupled to their environments. Understanding the dynamics of such op en quantum systems is crucial\, particularly for describing quantum matter in realistic scenarios where environmental interactions cannot be neglect ed. In this talk\, I will outline recent theoretical advances in character izing universal features of dissipative quantum systems using non-Hermitia n random matrix theory. Key spectral signatures of dissipative chaos\, suc h as complex spacing ratios (CSRs)\, universal ring-to-disk transitions\, and a systematic symmetry-based classification of many-body superoperators under antiunitary involutions\, will be discussed. Turning from theory to practice\, I will present our recent experimental achievements demonstrat ing dissipative quantum chaos and integrability transitions. These results were obtained by measuring CSRs in the superoperator spectra of open many -body quantum systems implemented on a state-of-the-art superconducting qu antum processor\, providing the first direct laboratory observation of the se theoretical predictions. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1058@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251121T140000 DTEND;TZID=Europe/Paris:20251121T153000 DTSTAMP:20251106T090914Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-michele-mazzoni-universite-de-bologna/ SUMMARY:Informal quantum seminar: Michele Mazzoni (Université de Bologna) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Nov 25 14:00 DESCRIPTION:Entanglement dynamics and Page curves in random permutation cir cuits\nMichele Mazzoni (Université de Bologna)\n \;\n\nThe characteri zation of ensembles of many-qubit random states and their realization via quantum circuits are crucial tasks in quantum-information theory. In this work\, we study the ensembles generated by quantum circuits that randomly permute the computational basis\, thus acting classically on the correspon ding states. We focus on the averaged entanglement and present two main re sults. First\, we derive generically tight upper bounds on the entanglemen t that can be generated by applying permutation circuits to arbitrary init ial states. We show that the late-time "entanglement Page curves'' are bou nded in terms of the initial state participation entropies and its overlap with the "maximally antilocalized'' state.  Generally speaking\, this re sult states that the quantum correlations generated by classical circuits are bounded in terms of some quantum property of the initial state (namely \, the degree to which it can be written as a superposition of classical s tates). Second\, comparing the averaged R\\'enyi-$2$ entropies generated b y (i) an infinitely deep random circuit of two-qubit gates and (ii) global random permutations\, we show that the two quantities are different for f inite $N$ but the corresponding Page curves coincide in the thermodynamic limit. We also discuss how these conclusions are modified by additional ra ndom phases or considering circuits of $k$-local gates with $k\\geq 3$. Ou r results are exact and highlight the implications of classical features o n entanglement generation in many-body systems.\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1061@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251124T143000 DTEND;TZID=Europe/Paris:20251124T160000 DTSTAMP:20251120T161846Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-natalia-chepiga-delft-university-of-technology/ SUMMARY:Informal quantum seminar: Natalia Chepiga (Delft University of Tech nology) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n° 530 - 24 Nov 25 14:30 DESCRIPTION:Infinite randomness criticality and localization of the floatin g phase in arrays of Rydberg atoms trapped with non-perfect tweezers\nNata lia Chepiga (Delft University of Technology)\n \;\n\nThe success of Ry dberg-based platforms originates from the precise control of lattice geome tries provided by optical tweezers\, which allows access to a wide range o f synthetic quantum phases. Experiments on one-dimensional arrays have sti mulated tremendous progress in understanding quantum phase transitions int o crystalline phases. However\, the finite width of tweezers introduces sm all variations in interatomic distances\, leading to quenched disorder in the interactions. In this letter\, we numerically study how such disorder alters the nature of two critical regimes observed in experiments. Firstly \, following experimental protocols\, we analyze Kibble-Zurek dynamics and find a crossover from the clean Ising transition to the infinite-randomne ss fixed point as system size and disorder strength increase. Secondly\, w e show that the floating phase (an incommensurate Luttinger liquid phase e merging at stronger interactions) is localized by the disorder\, yet prese rves short-range incommensurate correlations with the same leading wave ve ctor. Our results clearly reveal an additional technical challenge in the scalability of Rydberg-based quantum simulators. \n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1047@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251125T110000 DTEND;TZID=Europe/Paris:20251125T120000 DTSTAMP:20251120T162156Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-leticia-cugliandolo-lpthe-sorbonne-universite-paris/ SUMMARY:Séminaire du LPTMS : Leticia Cugliandolo (LPTHE\, Sorbonne Univers ité\, Paris) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pasc al n°530 - 25 Nov 25 11:00 DESCRIPTION:Statistical Physics out of equilibrium\nLeticia Cugliandolo  ( LPTHE\, Sorbonne Université\, Paris)\n \;\n\nEquilibrium statistical physics provides a bridge between microscopic\ndynamics and macroscopic be havior. It explains the emergence of\nthermodynamic concepts such as tempe rature and pressure\, and accounts for\ncollective phenomena like phase tr ansitions. By contrast\, a comparable\nunderstanding of systems out of equ ilibrium remains elusive\, and is the\nfocus of intense research across ma ny areas of physics. In this talk\, I\nwill concentrate on a particular cl ass of nonequilibrium dynamics: those\nrealized in classical integrable sy stems. I will demonstrate how modest\nextensions of standard statistical p hysics tools can capture the long-term\nbehavior of these systems in vario us ways\, illustrating the results with a\nsimple model. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1078@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251128T110000 DTEND;TZID=Europe/Paris:20251128T120000 DTSTAMP:20251121T174555Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-marc-lagoin/ SUMMARY:Physics-Biology Interface seminar: Marc Lagoin - Moyen Amphi\, Buil ding 510\, Université Paris-Saclay Orsay - 28 Nov 25 11:00 DESCRIPTION:Thermodynamics of Nonequilibrium Systems\, from Maxwell Demons to Active Microswimmers in Confined Flows\nMarc Lagoin (LOMA\, U. Bordeaux )\n\nMany physical systems can be described using a few coarse variables\, ignoring most microscopic details. This idea\, formalized in Langevin’s theory of Brownian motion [3]\, allows us to understand how fluctuations and dissipation produce predictable behaviours even in systems far from eq uilibrium.In this talk\, I will present two experiments that illustrate th is approach.\n\n\nFirst\, in a driven granular gas\, we built a macroscopi c version of a Feynman-type ratchet [4\,7] and measured how fluctuations c an be rectified to produce motion. This work is described in Ref. [2] and provides a simple experimental test of stochastic models.Second\, we studi ed Chlamydomonas reinhardtii microswimmers in oscillatory Poiseuille flows . By tracking their motion\, we measured their long-time dispersion and in terpreted it using a coarse-grained Brownian-particle description [8]. Thi s leads to an active version of the classical Taylor–Aris dispersion [5\ ,6]\, as shown in Ref. [1].\n\n\nThese two studies show that simple stocha stic descriptions can help in understanding the behaviour of nonequilibriu m systems\, from macroscopic mechanical devices to suspensions of active m icroorganisms.\n\n\nM.Lagoin\, J. Lacherez\, G. de Tournemire\, A. Badr\, Y. Amarouchene\, A. Allard\, and T. Salez\, Enhanced dispersion of active microswimmers in confined flows\, PNAS (2025)\; arXiv:2507.08369.\nM. Lago in\, C. Crauste-Thibierge\, A. Naert\, A human-scale Brownian ratchet\, Ph ys. Rev. Lett. (2022)\; HAL: hal-03650213.\nP. Langevin\, Sur la théorie du mouvement brownien\, C. R. Acad. Sci. (1908).\nR. P. Feynman\, The Feyn man Lectures on Physics\, Vol. I\, Ch. 46: Ratchet and Pawl (1964).\nG. I. Taylor\, Dispersion of soluble matter in solvent flowing slowly through a tube\, Proc. R. Soc. A (1953).\nR. Aris\, On the dispersion of a solute i n a fluid flowing through a tube\, Proc. R. Soc. A (1956).\nM. von Smoluch owski\, early works on fluctuation-induced transport (1912).\nH. Risken\, The Fokker–Planck Equation: Methods of Solution and Applications.\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-1069@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251202T110000 DTEND;TZID=Europe/Paris:20251202T120000 DTSTAMP:20251125T171518Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-andrey-zelenskiy-lptms/ SUMMARY:Séminaire du LPTMS :Andrey Zelenskiy (LPTMS) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Déc 25 11:00 DESCRIPTION:From kagome antiferromagnets to self-assembly: anisotropic hier archy in dense and dilute systems\nAndrey Zelenskiy (LPTMS)\n \;\nGeom etric frustration arises when interactions favour local configurations tha t are incompatible with the global geometry of the system. To alleviate fr ustration\, many systems adopt locally suboptimal arrangements\, often lea ding to the emergence of complex structures and patterns.\nIn this talk\, I will explore geometric incompatibility in two contrasting systems: magne tic kagome crystals and solutions of patchy particles. In both cases\, inc reasing the anisotropy of interactions generates a hierarchy of competiti ons\, which manifests in the structure of the equilibrium phase.\nIn kago me magnets with AB-stacked layers\, while anisotropic interactions lower t he symmetry of the order parameter\, they at the same time induce self-dua lity mappings between distinct regions of parameter space. These mappings reveal extended regimes of high frustration\, where even moderate anisotro py drives a cascade of exotic phases\, including states that simultaneousl y exhibit both chiral and nematic order.\nBy contrast\, in solutions of an isotropic particles with short-range interactions\, frustration is often r elieved through changes in the overall density profile\, which defines the shape of the aggregate. Drawing analogies with frustrated magnets\, we id entify the anisotropic hierarchy for generic patchy particles\, and use it as a design principle for encoding structural features and motifs of self -assembled clusters. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1075@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251204T160000 DTEND;TZID=Europe/Paris:20251204T170000 DTSTAMP:20251117T103230Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/jerome-garnier-br un-bocconi/ SUMMARY:MLP@P seminars : Jerome Garnier-Brun (Bocconi) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 4 Déc 25 16:00 DESCRIPTION:Uncovering Structure: How Neural Networks Learn and Generalize from Tree-based Data\nJerome Garnier-Brun\nBocconi University\, Milan\n\nS eminar of the Series MLP@P (Machine Learning Physics @ Plateau)\, joint wi th LISN and IPhT.\nWhere: LPTMS\, Salle des Séminaires (1° étage)\n\nSt atistical-physics approaches have provided key insights into the functioni ng of neural networks\, yet most analyses assume high-dimensional random d ata. In contrast\, real-world data possess rich underlying structure that likely shapes how learning and generalization unfold. In an attempt to bri dge this gap\, this talk will focus on models trained on tree-based data\, a setting where Bayes-optimal performance can importantly still be comput ed exactly. By introducing a controlled filtering procedure that tunes the degree of correlation in the data\, we first probe how transformers progr essively uncover structure in both supervised and self-supervised inferenc e tasks. The results reveal a hierarchical discovery of correlations—fir st in time\, during training\, and in space\, across attention layers—wh ich closely mirrors the exact inference algorithm. In a second part\, we t urn to generative diffusion models\, where the same controlled data model exposes a novel biased generalization regime that precedes overt overfitti ng. There\, access to Bayes-optimal benchmarks allows a precise characteri zation of when and how this bias emerges\, suggesting new directions for o ptimizing diffusion schedules. CATEGORIES:MLP@P LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1065@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251209T093000 DTEND;TZID=Europe/Paris:20251209T123000 DTSTAMP:20251204T090034Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-charbel-abetian/ SUMMARY:Soutenance de thèse : Charbel Abetian - Grand amphi\, bâtiment Pa scal n° 530 - 9 Déc 25 09:30 DESCRIPTION:Overlaps after a boundary quantum quench in the integrable XXZ spin chain\n\nCharbel Abetian\n \;\n\nThe aim of this thesis is to pro vide an exact analytical approach for computing overlaps between eigenstat es of the open XXZ chain before and after a boundary quench\, that is\, an abrupt change of one of the boundary magnetic fields. These overlaps cons titute a fundamental building block for the description of the out-of-equi librium dynamics of quantum systems and play a crucial role in understandi ng their post-quench evolution. We focus on the open XXZ spin-½ chain wit h parallel boundary magnetic fields in the massive antiferromagnetic regim e\, one of the simplest (non-trivially interacting) integrable models with non-periodic boundary conditions. This system can be interpreted as a qua ntum chain interacting with its environment through boundary degrees of fr eedom. The Quantum Inverse Scattering Method (QISM) and the Algebraic Beth e Ansatz (ABA) provide a strong theoretical framework for studying such qu antities. The goal of our analysis is to derive\, within this formalism\, exact expressions for the overlaps in the thermodynamic limit. Using Slavn ov’s determinant formula for scalar products of Bethe states\, we first derive a determinant representation for the overlaps between pre- and post -quench eigenstates. By employing what we refer to as the Gaudin extractio n method\, we show that we can extract from this (typically encountered) r atio of determinants\, a Cauchy-like determinant\, suitable for taking the thermodynamic limit. We show that the overlap between the gapped ground s tates (i.e.\, states whose Bethe root configurations contain no holes) bef ore and after the quench can be written in a product form\, valid up to ex ponentially small corrections in the system size. This allows us to obtain a closed analytical expression for the overlap in the infinite-size limit \, that depends only on the physical parameters of the model\, namely\, th e anisotropy parameter and the boundary magnetic fields. We further verify this formula through direct comparison with numerical diagonalization res ults. We extend this analysis to a broader class of (ground/excited) state s characterized by the presence of a finite number of holes in their Bethe root distributions. We show that the Gaudin extraction method yields once again a Cauchy-type structure\, now\, perturbed by a matrix of rank equal to the number of holes. In this case\, the overlap factorizes into a pref actor that can be written in a product form\, similar to the case of the g round state\, multiplied by a finite determinant whose size is equal to th e number of holes n. In the thermodynamic limit\, we obtain an explicit ex pression for the overlap that depends on the anisotropy\, the boundary mag netic fields\, and the hole positions. The results presented here lay the groundwork for a broader analytical study of boundary-driven quenches in i ntegrable quantum systems through ABA techniques. \n\n \;\n\nJury : P. Baseilhac\, O. Castro-Alvaredo\, J. De Nardis\, N. Kitanine (co-directeur de thèse)\, K. Kozlowski\, V. Pasquier\, V. Terras (directrice de thèse ) CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1077@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251210T140000 DTEND;TZID=Europe/Paris:20251210T153000 DTSTAMP:20251204T094258Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-guido-giachetti-lpens/ SUMMARY:Informal Quantum Seminar: Guido Giachetti (LPENS) - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Déc 25 14:00 DESCRIPTION:Integrable Dynamics and Thermalization in the Quantum O(n) Mode l at Large-n  \nGuido Giachetti (LPENS)\n \;\n\nThe quantum O(n) mode l has long served as a valuable framework for studying both equilibrium an d dynamical properties of quantum many-body systems. In this talk\, we inv estigate its non-equilibrium dynamics following a quantum quench in the la rge-n limit. While the model is known to be tractable in this regime\, we show that it is in fact integrable - with integrals of motions stemming fr om that of the classical Neumann model - thus enabling a complete analytic al solution of its dynamics. This integrability reveals a synchronization mechanism that gives rise to persistent oscillations\, interpretable as Hi ggs modes localized at the edge of the spectral band. We further demonstra te that the long-time behavior is governed by a Generalized Gibbs Ensemble (GGE)\, in contrast to previous expectations\, and we obtain exact critic al exponents differing from those commonly reported. Remarkably\, integrab ility persists even in the presence of long-range couplings\, allowing us to explore the crossover between mean-field and genuinely many-body regime s in terms of parametric Floquet resonances of the microscopic degrees of freedom. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1064@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251212T110000 DTEND;TZID=Europe/Paris:20251212T120000 DTSTAMP:20251210T134253Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-valerio-sorichetti/ SUMMARY:Physics-Biology Interface seminar: Valerio Sorichetti - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Déc 25 11:0 0 DESCRIPTION:Charged for attraction: How biomolecular condensates pull chrom osomes together\nValerio Sorichetti (IST Austria)\nThe coacervation of cha rged polymers is an important driver for the formation of biomolecular con densates. Recent experiments suggest that this mechanism also controls the clustering of eukaryotic chromosomes during the late stages of cell divis ion [1\,2]. In this process\, inter-chromosome attraction is driven by the condensation of cytoplasmic RNA and Ki-67\, a charged intrinsically disor dered protein that coats the chromosomes as a brush. Attraction between ch romosomes has been shown to be specifically promoted by a localized charge d patch on Ki-67\, although the physical mechanism remains unclear [2]. To elucidate this process\, we combine coarse-grained simulations and analyt ical theory to study the RNA-mediated interaction between charged polymer brushes on the chromosome surfaces [3]. We find that the charged patch on Ki-67 leads to inter-chromosome attraction via RNA bridging between the tw o brushes\, whereby the RNA preferentially interacts with the charged patc hes\, leading to stable\, long-range forces. By contrast\, if the brush is uniformly charged\, bridging is basically absent due to complete adsorpti on of RNA onto the brush. Moreover\, the RNA dynamics becomes caged in pre sence of the charged patch\, while remaining diffusive when the charge is uniform. Our findings suggest that cells could control the forces exerted by biomolecular condensates by adjusting the way charges are distributed o n proteins\, providing a potential strategy for regulating biological orga nization.\n\n S. Cuylen-Haering\, M. Petrovic\, A. Hernandez-Armendariz\, M. W. Schneider\, M. Samwer\, C. Blaukopf\, L. J. Holt\, and D. W. Gerlic h\, Nature 587\, 285 (2020)\n A. Hernandez-Armendariz\, V. Sorichetti\, Y . Hayashi\, Z. Koskova\, A. Brunner\, J. Ellenberg\, A. Šarić\, and S. C uylen-Haering\, Molecular Cell 84\, 3254 (2024).\n V. Sorichetti\, P. Rob in\, I. Palaia\, A. Hernandez-Armendariz\, S. Cuylen-Haering\, A. Šarić\ , Charge distribution of coating brush drives inter-chromosome attraction\ , PRX Life 3\, 033010 (2025).\n\n\nThe seminar will be broadcasted over Zo om:\nhttps://cnrs.zoom.us/j/91724933601?pwd=Ip6PR9IZO9SGoXIpLBC9qwZTaIlCEz .1\nID de réunion: 917 2493 3601\nCode secret: 15aMuZ CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1079@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251212T160000 DTEND;TZID=Europe/Paris:20251212T170000 DTSTAMP:20251204T093309Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mlpp-seminars-gia nluca-manzan-paris-saclay-university/ SUMMARY:MLP@P seminars : Gianluca Manzan (LISN) - LISN\, bat 660 salle 201 4 (2° étage) - 12 Déc 25 16:00 DESCRIPTION:From Hopfield Inference to Federated Learning: challenges and s olutions in Teacher–Student models\nGianluca Manzan\nLISN\, Paris Saclay University\n\nSeminar of the Series MLP@P (Machine Learning Physics @ Pla teau)\, joint with LISN and IPhT.\nWhere: LISN\, bat 660 salle 2014 (2° étage)\n\nIn this work\, we investigate inference in neural networks thro ugh the teacher–student framework\, which provides a controlled setting to quantify how a student model learns the underlying signal from data gen erated by a teacher. Beginning with the Hopfield model\, interpreted as a dual formulation of associative memory\, we characterize the transition be tween non-informative and learning phases as a function of dataset size\, noise level\, and temperature. Extending the analysis to Restricted Boltzm ann Machines\, we show how choices in unit priors and regularization shape the emergence of the signal-retrieval phase and thus determine learning e fficiency.\nWe then address the limitations of the single-student scenario by introducing a collective learning strategy in which multiple student n etworks are coupled during inference. Recent advances in statistical-physi cs of learning show that interactions among students enhance generalizatio n\, thereby facilitating the teacher recovery. Our analysis of y-interacti ng Hopfield students confirms this cooperative effect\, demonstrating that coupling expands the region of successful inference by lowering data requ irements.\nThis collective perspective has a natural application to federa ted learning (FL)\, a decentralized paradigm where multiple clients collab oratively train local models without sharing their private data. In FL\, e ach client performs local updates based on its own dataset and communicate s only through model parameters. The cooperative mechanism observed in cou pled teacher–student systems provides a theoretical analogue to this fra mework: just as interacting students benefit from mutual alignment\, feder ated clients collectively enrich the global solution while retaining data locality. CATEGORIES:MLP@P LOCATION:LISN\, bat 660 salle 2014 (2° étage)\, 660 Av. des Sciences\, 9 1190 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=660 Av. des Sciences\, 911 90 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France;X-APPLE-RADI US=100;X-TITLE=LISN\, bat 660 salle 2014 (2° étage):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1066@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20251216T110000 DTEND;TZID=Europe/Paris:20251216T120000 DTSTAMP:20251211T151823Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-thibault-congy-northumbria-university-newcastle-uk/ SUMMARY:Séminaire du LPTMS : Thibault Congy (Northumbria University\, Newc astle\, UK) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 16 Déc 25 11:00 DESCRIPTION:Soliton gas description of modulational instability \nThibault Congy (Northumbria University\, Newcastle\, UK)\n\n \nSoliton gases are i nfinite random ensembles of interacting solitons whose large-scale dynamic s are governed by the elementary two-soliton collisions. By applying the s pectral theory of soliton gases to the focusing nonlinear Schrödinger equ ation (fNLSE)\, we can describe the statistically stationary and spatially homogeneous integrable turbulence that emerges at large times from the sp ontaneous (noise-induced) modulational instability of the plane-wave and t he elliptic “dn” solutions.\n\nI will show that a special\, critically dense soliton gas—the bound-state soliton condensate—provides an accu rate model for the asymptotic state of both plane-wave and elliptic integr able turbulence. Moreover\, certain statistical moments of the resulting t urbulence can be computed analytically\, allowing us to assess deviations from Gaussianity. These analytical predictions demonstrate excellent agree ment with direct numerical simulations of the fNLSE.\n\nThe talk is based on the recent works:\n- “Statistics of Extreme Events in Integrable Turb ulence”\, T. Congy\, G. A. El\, G. Roberti\, A. Tovbis\, S. Randoux\, an d P. Suret\, Phys. Rev. Lett. 132\, 207201 (2024).\n- “Spontaneous modul ational instability of elliptic periodic waves: The soliton condensate mod el”\, D. S. Agafontsev\, T. Congy\, G. A. El\, S. Randoux\, G. Roberti\, and P. Suret\, Physica D 134956 (2025).\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1092@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260109T110000 DTEND;TZID=Europe/Paris:20260109T120000 DTSTAMP:20260105T105836Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-arthur-molines/ SUMMARY:Physics-Biology interface seminar: Arthur Molines - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Jan 26 11:00 DESCRIPTION:Arthur Molines (I2BC Gif-sur-Yvette)\nEffect of viscosity and c rowding on cytoskeleton dynamics: an in vitro and in vivo exploration\nThe cytoplasm is a crowded\, viscoelastic environment whose physical properti es change according to physiological or developmental states. The physical properties of the cytoplasm\, which impact cellular functions in vivo\, r emain poorly understood. Here\, we probe the effects of cytoplasmic concen tration on microtubules by applying osmotic shifts to fission yeast\, moss \, and mammalian cells. We demonstrate that the rates of both microtubule polymerization and depolymerization scale linearly and inversely with cyto plasmic concentration. An increase in cytoplasmic concentration proportion ally decreases the rates of microtubule polymerization and depolymerizatio n\, whereas a decrease in cytoplasmic concentration leads to the opposite effect. Numerous lines of evidence indicate that these effects are due to changes in cytoplasmic viscosity rather than cellular stress responses or macromolecular crowding per se. We reconstituted these effects on microtub ules in vitro by tuning viscosity. Our findings indicate that\, even in no rmal conditions\, the viscosity of the cytoplasm modulates the reactions t hat underlie microtubule dynamic behaviors. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1086@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260109T140000 DTEND;TZID=Europe/Paris:20260109T150000 DTSTAMP:20260106T120826Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-francesco-mori-harvard/ SUMMARY:Séminaire du LPTMS : Francesco Mori (Harvard) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Jan 26 14:00 DESCRIPTION: Dynamics and Control Out of Equilibrium: From Active to Learn ing Systems\, Francesco Mori (Harvard University)\n \;\n\nAbstract: No nequilibrium systems are ubiquitous\, from swarms of living organisms to m achine learning algorithms. While much of statistical physics has focused on predicting emergent behavior from microscopic rules\, a growing questio n is the inverse problem: how can we guide a nonequilibrium system toward a desired state? This challenge becomes particularly daunting in high-dime nsional or complex systems\, where classical control approaches often brea k down. In this talk\, I will integrate methods from optimal control theor y with techniques from statistical physics to tackle this problem in two b road classes of nonequilibrium systems: active matter—focusing on multim odal strategies in animal navigation and mechanical confinement of active fluids—and learning systems\, where I will apply control theory to ident ify optimal learning principles for neural networks. Together\, these appr oaches point toward a general framework for controlling nonequilibrium dyn amics across systems and scales.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1093@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260109T160000 DTEND;TZID=Europe/Paris:20260109T170000 DTSTAMP:20260105T094922Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/mlpp-seminars-cyr il-furtlehner-lisn-2/ SUMMARY:MLP@P seminars : Cyril Furtlehner (LISN) - LISN\, bat 660 salle 20 14 (2° étage) - 9 Jan 26 16:00 DESCRIPTION:Learning in low dimensional space: the case of physics informed neural networks\nCyril Furtlehner\nLISN\, Paris Saclay University\n\nSemi nar of the Series MLP@P (Machine Learning Physics @ Plateau)\, joint with LISN and IPhT.\nWhere: LISN\, bat 660 salle 2014 (2° étage)\n\nIn this t alk we will introduce physics informed neural networks (PINNs) which are n eural networks designed to solve PDE. We will discuss some of their specif icity related to the low-dimensionality of the input data and a strong sp ectral bias issue which require to identify and address separately optimi zation and learning shortcomings.\nThe analysis of the geometric structure of the NN tangent space will lead us to propose state of the art optimiza tion\nalgorithms to these problem and to design a principled active learni ng strategy.\n CATEGORIES:MLP@P LOCATION:LISN\, bat 660 salle 2014 (2° étage)\, 660 Av. des Sciences\, 9 1190 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=660 Av. des Sciences\, 911 90 Gif-sur-Yvette\, France\, Gif-sur-Yvette\, 91190 \, France;X-APPLE-RADI US=100;X-TITLE=LISN\, bat 660 salle 2014 (2° étage):geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1081@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260116T110000 DTEND;TZID=Europe/Paris:20260116T123000 DTSTAMP:20260112T124352Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-leo-mangeolle-technische-universitaet-muenchen/ SUMMARY:Informal Quantum Seminar: Léo Mangeolle (Technische Universitaet M uenchen) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n °530 - 16 Jan 26 11:00 DESCRIPTION: Thermal Hall conductivity in quantum magnets from the kinetic equation\nLéo Mangeolle (Technische Universitaet Muenchen)\n \;\n\nTh ermal Hall conductivity has recently emerged as an experimentally accessib le property of insulating materials. Theoretical understanding thereof has remained a challenge\, in particular since the breaking of time-reversal symmetry by neutral particles is nontrivial and can emerge from multiple m echanisms (intrinsic semiclassical dynamics\, skew-scattering\, disorder s ide-jump effects\, etc). In this seminar\, I will show that many of these effects can be studied together within a kinetic (Boltzmann-like) formalis m. First\, I will briefly discuss inelastic skew-scattering of energy-car rying bosons by other collective excitations\, with applications to phonon -magnon interactions in antiferromagnets. Second\, I will present how anom alous contributions to the semiclassical dynamics of carriers can be incor porated in a rigorous way\, yielding the intrinsic thermal Hall effect of chiral bosons (e.g. magnons in frustrated magnets). Finally\, I will discu ss side-jump phenomena\, a mixed effect of disorder scattering and semicla ssical dynamics that may explain some puzzling experimental facts.  CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1067@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260120T110000 DTEND;TZID=Europe/Paris:20260120T120000 DTSTAMP:20260115T115122Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-luca-giacomelli-universite-paris-sud/ SUMMARY:Séminaire du LPTMS : Luca Giacomelli (Université Paris Sud) - Sal le des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Jan 26 11:00 DESCRIPTION:Emergent quantum phase transition of Josephson junction coupled to a high-impedance multimode resonator Luca Giacomelli (Laboratoire MPQ\ , Université Paris)\n\nABSTRACT:\nThe physics of a single Josephson junct ion coupled to a resistive environment is a long-standing fundamental prob lem at the center of an intense debate about the existence and properties of the superconducting to insulating Schmid-Bulgadaev transition. To circu mvent the potential subtleties in the original derivation\, we investigate the emergent criticality of a junction coupled to a multimode resonator w hen the number of modes is increased [1]. By solving the system via exact diagonalization\, we show that at the transition point the spectrum displa ys universality (scale invariance) not only at low frequencies. This refle cts in finite-frequency spectral signatures of the phase transition\, in a greement with recent experiments. The spectrum at the critical point is su ccessfully compared with analytical and numerical results obtained in the past [2]. Finally\, we prove a low-energy exact self-duality of the model\ , that emerges from two different finite-size circuits with different cons erved quantities [3]. This confirms and generalizes the approximate self d uality that is usually invoked\, and proves the independence of the transi tion point on the ratio of Josephson to charging energy.\n\n[1] Giacomelli L.\, Ciuti C. (2024) "Emergent quantum phase transition of a Josephson ju nction coupled to a high impedance multimode resonator".Nature Communicati ons\, 15(1)\, 5455.\n[2] Paris\, Giacomelli\, Daviet\, Ciuti\, Dupuis\, Mo ra (2025) "Resilience of the quantum critical line in the Schmid transitio n". Physical Review B\, 111(6)\, 064509.\n[3] Giacomelli L.\, Devoret M. H .\, Ciuti C. (2025) "Exact Duality at Low Energy in a Josephson Tunnel Jun ction Coupled to a Transmission Line". arXiv:2504.14651.\n CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1060@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260123T110000 DTEND;TZID=Europe/Paris:20260123T120000 DTSTAMP:20260119T091553Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-alexander-bershadsky/ SUMMARY:Physics-Biology Interface seminar: Alexander Bershadsky - Salle pol yvalente de l'Institut Curie\, bâtiment 111 - 23 Jan 26 11:00 DESCRIPTION:Integrin mediated cell-matrix adhesions and their regulation by microtubules\nAlexander D. Bershadsky (Natl. U. of Singapore &\; Weizm ann Institute)\n\nMind the unusual location\; unlike the the plateau cante en the one near Curie is functional!\n\nThe seminar will exceptionally be broadcasted over Zoom:\nhttps://cnrs.zoom.us/j/99232320872?pwd=PXHM7HB0jJc ksEL8AD6PjcFcifMDck.1\nMeeting ID: 992 3232 0872\nPasscode: Mg0F5N\n\n\nWe discuss here two major types of cell-matrix adhesions mediated by transme mbrane receptors of integrin family - focal adhesions\, formed by cells on locally flat surfaces coated with extracellular matrix proteins (integrin ligands)\, and fibrillar adhesions\, associated with cell-derived fibrils containing protein fibronectin. Focal adhesions are linked with actin fil ament bundles and probing the matrix stiffness by transmitting and sensing forces. Activation/inactivation of myosin-II contractility trigger assemb ly/disassembly of focal adhesions\, respectively. Unlike focal adhesions\, fibrillar adhesions associate with sparse actin network and do not disass emble upon myosin-II inhibition. Moreover\, specific nano-topographical cu es – nanofibers or nanogrooves – trigger formation of fibrillar adhesi ons in a myosin-II-independent fashion\, while excessive activation of myo sin II\, or increase of membrane tension\, trigger the disassembly of fibr illar adhesions. Theoretical modelling and experimental data suggest that formation of fibrillar adhesions along nano-topographical cues can be expl ained by a special shape of adhesion receptors\, preferably connecting the cell and substrate surfaces tilted relatively to each other. The shape of α5β1 integrin\, the only one found in fibrillar adhesions\, satisfies t o this condition. Microtubules are targeted to focal and fibrillar adhesio ns via KANK family proteins. Using genetic depletion and optogenetic tools \, we deciphered mechanism of microtubule-driven adhesion regulation. Disc onnecting microtubules from integrin adhesions triggers the release of mic rotubule-associated Rho activator GEF-H1\, subsequent activation of Rho an d assembly of myosin II filaments\, which then remodel the focal and fibri llar adhesions in a differential manner\, as described above. Thus\, micro tubules function as signaling structures locally regulating myosin II cont ractility in response to their interactions with integrin adhesions.\n\nFu rther reading\n\nRafiq NBM\, … Bershadsky AD. A mechano-signalling netwo rk linking microtubules\, myosin IIA filaments and integrin-based adhesion s. Nat Mater. 2019\;18(6):638-649.\nAureille J\, … Bershadsky AD. Focal adhesions are controlled by microtubules through local contractility regul ation. EMBO J. 2024\; 43(13):2715-2732.\nFarrugia AJ ... Bershadsky AD. Fi brillar adhesions are the primary integrin complexes shaped by matrix topo graphy. bioRxiv 2025\; 2025.11.26.690075.\n\n CATEGORIES:physbio,seminars LOCATION:Salle polyvalente de l'Institut Curie\, bâtiment 111\, 111\, Rue Jean-Dominique Cassini\, Bures-sur-Yvette\, 91440\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=111\, Rue Jean-Dominique Ca ssini\, Bures-sur-Yvette\, 91440\, France;X-APPLE-RADIUS=100;X-TITLE=Salle polyvalente de l'Institut Curie\, bâtiment 111:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1082@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260123T140000 DTEND;TZID=Europe/Paris:20260123T153000 DTSTAMP:20260120T080002Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-vincent-grison-lptmc-jussieu/ SUMMARY:Informal Quantum Seminar: Vincent Grison (LPTMC Jussieu) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 23 Jan 26 14 :00 DESCRIPTION:From Bose glass to Many-Body Localization in a one-dimensional disordered Bose gas\nVincent Grison (LPTMC Jussieu)\n \;\nOne-dimensio nal interacting bosons subjected to disorder are known to possess an insul ating ground state\, called the Bose glass. At finite temperature\, pertur bative computations advocate for a crossover to a non-disordered normal fl uid\, but an alternative scenario was also suggested\, arguing for the exi stence of a genuine phase transition. The resulting low-temperature insula ting phase is then akin to the Many-Body Localized (MBL) phase\, first int roduced for fermions.\nTo settle this debate\, we develop a field-theoreti cal approach leveraging the Functional Renormalization Group (FRG). At zer o temperature\, we find a new non-perturbative fixed point\, the approach to which contains information on the low-energy excitations of the system. We then turn to finite temperature effects\, discussing various crossover s to the normal fluid phase\, where disorder still plays an important role at finite length and time scales. Finally\, we point out how a modificati on of our approximations leads to a different scenario for the low-tempera ture physics of the system\, and put forward a hypothesis linking it to MB L. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1070@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260127T110000 DTEND;TZID=Europe/Paris:20260127T120000 DTSTAMP:20260122T070316Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-arthur-genton/ SUMMARY:Séminaire du LPTMS: Arthur Genthon/cancelled - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 27 Jan 26 11:00 DESCRIPTION:TBA Arthur Genton CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1087@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260202T110000 DTEND;TZID=Europe/Paris:20260202T120000 DTSTAMP:20260129T112618Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-fabian-aguirre-lopez/ SUMMARY:Postponed: Séminaire du LPTMS: Fabian Aguirre-Lopez - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Fév 26 11:00 DESCRIPTION:TBA Fabian Aguirre-Lopez (postponed to April) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1085@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260206T110000 DTEND;TZID=Europe/Paris:20260206T120000 DTSTAMP:20260201T203302Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-arthur-alexandre/ SUMMARY:Physics-Biology Interface seminar: Arthur Alexandre - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 6 Fév 26 11:00 DESCRIPTION:From transport in channels to population evolution: how heterog eneities shape dynamics\nArthur Alexandre (EPFL &\; Swiss Institute of Bioinformatics\, Switzerland)\nIn this seminar\, I will discuss two proble ms where effective descriptions capture the essential mechanisms at play: one from hydrodynamics and one from population genetics.\nIn hydrodynamics \, Taylor dispersion describes the enhanced spreading of particles in a fl uid due to the combined effects of diffusion and flow. We show how this ph enomenon can be understood in tortuous\, highly corrugated channels using an effective model that captures the main transport properties\, providing insight into flows in porous media.\nIn population genetics\, the gut mic robiota presents extensive genetic diversity shaped by its flow-dominated environment. Using a minimal model [2] incorporating flow\, diffusion\, an d microbial growth that we extend to non-neutral mutations\, we show how s patial structure and advection influence the fixation of beneficial mutant s. This illustrates the interplay between flow\, growth\, and spatial hete rogeneity in shaping microbial evolution.\n\nAlexandre\, A.\, Guérin\, T. &\; Dean\, D. S. Effective description of taylor dispersion in strongl y corrugated channels. Physical Review E 111\, 064124 (2025).\nLabavić\, D.\, Loverdo\, C. &\; Bitbol\, A.-F. Hydrodynamic flow and concentratio n gradients in the gut enhance neutral bacterial diversity. Proceedings of the National Academy of Sciences 119\, e2108671119 (2022).\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-1083@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260210T110000 DTEND;TZID=Europe/Paris:20260210T120000 DTSTAMP:20260129T112822Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-mylene-maida/ SUMMARY:Séminaire du LPTMS: Mylène Maïda - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Fév 26 11:00 DESCRIPTION:Thermodynamic limit and DLR equations for superstable Bose gas at any temperature and activity\, Mylène Maïda (Université Lille 1)\n\n We construct a thermodynamic limit for the grand canonical Bose gas in  d imension  $d \\geq 1$ (in its Feynman-Kac representation) with superstabl e interaction at any inverse temperature  and any chemical potential. Ou r infinite volume model is naturally a distribution over configurations of finite loops and possibly interlacements. We prove the limiting process t o solve a new class of DLR equations involving random permutations and Bro wnian paths.\n(joint work with Guillaume Bellot and David Dereudre (Univer sité de Lille)) \n \;\n\n \;\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1084@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260213T140000 DTEND;TZID=Europe/Paris:20260213T151500 DTSTAMP:20260206T091418Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-anna-delmonte-college-de-france/ SUMMARY:Informal quantum seminar: Anna Delmonte (Collège de France) - Sall e des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Fév 26 14:00 DESCRIPTION:Measurement-induced phase transition in interacting bosons from the most likely quantum trajectory\nAnna Delmonte (Collège de France)\n& nbsp\;\nWhen quantum many-body systems are continuously monitored during t heir time evolution\, the interplay between unitary dynamics and the stoch astic nature of quantum measurements\, represented by quantum trajectories \, can give rise to novel phenomena such as measurement-induced phase tran sitions. The study of such dynamics is\, however\, particularly complex bo th theoretically and experimentally\, due to the combination of many-body complexity and the stochastic nature of quantum measurements.\nIn this sem inar\, we will briefly introduce these concepts and explore a new methodol ogy to overcome this complexity and study monitored many-body bosonic syst ems by using solely the most likely quantum trajectory. We will show how t his method works exactly in the case of free bosons and yields a good appr oximation for studying interacting models\, such as the Sine-Gordon model. This approach allows us to observe a previously inaccessible measurement- induced phase transition in an interacting bosonic system. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1095@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260217T110000 DTEND;TZID=Europe/Paris:20260217T120000 DTSTAMP:20260211T104402Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-federica-ferretti-u-chicago/ SUMMARY:Séminaire du LPTMS: Federica Ferretti (U Chicago) - Salle des sém inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Fév 26 11:00 DESCRIPTION:Modeling emergent phenomena in adaptive immunity: from stereoty ped immunodominance to 'implicit regularization’ in antibody evolution: Federica Ferretti ( NITMB\, Chicago)\n\n\nAbstract: The immune system is a complex\, self-organized\, very dynamic biological system\, which must op erate reliably and reproducibly to protect organisms from threats. This ro bustness is mediated by the statistical and biophysical aspects of the var ious processes of interest: in this sense\, it can be seen as an emergent property. In this talk\, I will focus on two aspects of antibody evolution where quantitative approaches based on statistical and dynamical modeling can provide a useful description\, and help establish a link between micr oscopic mechanisms and emergent biological function.\nI will first introdu ce the problem of antibody immunodominance\, and propose a new quantitativ e framework to characterize the phenomenon. This framework is based on a s imple population dynamics model\, which can be mapped to a parabolic Ander son model on structured landscapes.\nI will then briefly discuss the theor etical study of a mechanism of `implicit regularization’ in population d ynamics\, inspired by antibody evolution in heterogeneous lymph-node envir onments. This mechanism is abstracted into an 'annealed population heterog eneity’\, which can be thought of as a population-wide implementation of the mini-batching strategy used in machine learning. Like in ML\, this pr oduces an inductive bias that favors the selection of generalist antibodie s—a major goal in the design of immunization strategies and development of therapeutic antibodies. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1100@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260219T110000 DTEND;TZID=Europe/Paris:20260219T120000 DTSTAMP:20260206T104051Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-stefano-villa/ SUMMARY:Physics-Biology Interface seminar: Stefano Villa - Petit Amphi\, Bu ilding 510\, Université Paris-Sud Orsay - 19 Fév 26 11:00 DESCRIPTION:Inferring system properties quantifying the dynamics: from coll oidal dynamics to cell tissues\nStefano Villa (Max-Planck Institut Göttin gen)\nObserving dynamics at the microscopic scale is a preferential way of gathering information on the systems under investigation\, ranging from p assive systems of isolated particles to out-of-equilibrium ones where acti ve components interact with each other. In this talk\, I will present two examples that I have explored during my research.\n\nFirst\, I will presen t results on the thermal dynamics of colloidal particles in the vicinity o f an air-water interface. The proximity to the interface affects the dynam ics via boundary conditions. The measured diffusivities dramatically devia te from the theoretical predictions\, thus revealing the presence of addit ional agents affecting the colloidal dynamics.\n\nIn a second example\, a confluent monolayer of epithelial cells is investigated. There\, internal stresses trigger the formation of 3D structures (‘domes’). Quantitativ e analysis of cellular dynamics and domes evolution provides a deeper unde rstanding of the interplay between stresses\, cell motility\, and tissue r emodeling. This simple in vitro system demonstrated to be a valuable model for improving our understanding of the relationship between cell migratio n and morphogenesis in living tissues.\n CATEGORIES:physbio,seminars LOCATION:Petit Amphi\, Building 510\, Université Paris-Sud Orsay\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.699116;2.179468 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Petit Amphi\, Building 510\, Un iversité Paris-Sud Orsay:geo:48.699116,2.179468 END:VEVENT BEGIN:VEVENT UID:0-1089@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260220T110000 DTEND;TZID=Europe/Paris:20260220T120000 DTSTAMP:20260209T135825Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-gergo-gogl/ SUMMARY:Physics-Biology Interface seminar: Gergö Gógl - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Fév 26 11:00 DESCRIPTION:Interactomics 2.0: From partially mapped qualitative protein-pr otein interaction graphs to biophysically characterized interaction networ ks\nGergö Gógl (U. Nice Côte-d'Azur)\nFor decades\, the study of the hu man protein-protein interaction networks\, a.k.a. the interactome has been dominated by qualitative "discovery" methods. While these tools have prov ided invaluable maps of cellular organization\, they often lack the biophy sical resolution required to understand the true dynamics of the cell and often miss weak and transient interactions that make up the bulk fabric of molecular interaction networks. We recently developed new generation inte ractomic tools\, such as the native holdup approach\, that allows us to sh ift from asking who interacts with whom to quantifying how strong is the d riving force of each interaction and under what conditions they form. Our approach offer a high-throughput solution for the biophysical characteriza tion of large-scale systems that\, unlike traditional approaches\, allows the direct measurement of equilibrium dissociation constants at proteome s cales within complex cellular lysates taking into consideration indirect i nteractions\, post-translational modifications and other biological mechan isms. Most importantly\, we can finally study weak and transient complexes that were hiding in the blind spot of conventional interactomics for deca des. We will discuss the technical implementation of nHU on large scale\, the challenges of scaling quantitative measurements\, and how this "bottom -up" biophysical data provides a more predictive framework for understandi ng cellular signaling and disease-state perturbations. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1097@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260220T140000 DTEND;TZID=Europe/Paris:20260220T153000 DTSTAMP:20260212T083243Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-sara-murciano-lptms/ SUMMARY:Informal quantum seminar: Sara Murciano (LPTMS) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Fév 26 14:00 DESCRIPTION:Experimental observation of conformal field theory spectra\nSar a Murciano (LPTMS)\n \;\n\nConformal field theories (CFTs) feature pro minently in high-energy physics\, and condensed matter. For example\, CFTs govern emergent universal properties of systems tuned to quantum phase tr ansitions\, including their entanglement or correlations. Much of the rich structure predicted by CFTs nevertheless remains unobserved in experiment . In this talk\, I will present direct observations of the energy excitati on spectra of emergent CFTs at quantum phase transitions\, recovering univ ersal energy ratios characteristic of the underlying field theories. By us ing a variant of the modulation technique\, we furthermore study the dynam ical structure factor of the critical system\, which is closely related to the correlation of an underlying Ising conformal field. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1114@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260224T110000 DTEND;TZID=Europe/Paris:20260224T120000 DTSTAMP:20260219T131152Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-pav el-orlov-university-of-ljubljana/ SUMMARY:LPTMS Seminar: Pavel Orlov (University of Ljubljana ) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Fév 26 11:0 0 DESCRIPTION: Classical thermalization and the Eigenstate Thermalization Hy pothesis\nPavel Orlov (University of Ljubljana)\nAbstract:\n\nThermalizati on in isolated quantum systems is commonly understood through the Eigensta te Thermalization Hypothesis (ETH)\, which attributes thermal behavior to properties of individual eigenstates of the unitary time-evolution operato r. Classical dynamics is also governed by a unitary evolution via the Koop man operator. In this seminar\, I will explore whether an analogue of the ETH can be meaningfully formulated in the classical setting.\n\nBased on a rXiv:2602.02681 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1099@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260310T110000 DTEND;TZID=Europe/Paris:20260310T120000 DTSTAMP:20260226T101747Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-manuele-landini-university-of-innsbruck/ SUMMARY:LPTMS Seminar: Manuele Landini (University of Innsbruck) - Salle de s séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Mar 26 11 :00 DESCRIPTION:Probing ultracold 1D systems out of equilibrium\nManuele Landin i (University of Innsbruck)\n \;\n\nI will present the activities of o ur group\, going under the broad topic of out of equilibrium phenomena in ultracold 1D gases. In our experiment\, an ensemble of a few thousand effe ctively one dimensional ultracold Cs samples\, each containing 10 to 30 at oms is prepared and investigated. Careful control over the trapping potent ial\, temperature and interaction energy enables the investigation of coll ective quantum transport behavior of these systems and the preparation of out of equilibrium states with unusual statistical properties. The control over interaction strength in our Cs experiment allows us to perform topol ogical pumping experiments by cycling the value of the coupling constant. In each cycle\, the system is promoted to increasingly more energetic many -body states\, stabilized by approximate integrability. These states are c haracterized by the presence of fractional Fermi seas (FFS) resulting from effective “hyperfermionic” statistics\, where each particle occupies more than one quantum state. The creation of the FFS is inferred in the ex periment by the direct observation of Friedel oscillations in the g1 corre lation function of the gas [1\,2]. Introducing spin impurities with variab le speed in the 1D gas\, we were able to characterize their relaxation dyn amics and infer the formation of a polaron\, resulting in finite long-time velocity of the impurity\, even though the system is not in a standard su perfluid state [3]. By slowly accelerating the impurity across the polaron ic dispersion\, we could observe its momentum distribution\, revealing a c ross-over in the effective statistical behavior of the system from bosonic to fermionic\, passing from the anyonic intermediate statistics as a func tion of the injected momentum [4].\n\n[1] Realization of fractional Fermi seas\, Y. Zeng\, A. Bastianello\, S. Dhar\, Z. Wang\, X. Yu\, M. Horvath\, G. E. Astrakharchik\, Y. Guo\, H.-C. Nägerl\, M. Landini\, arXiv:2602.17 657 (2026).\n\n[2] Exotic critical states as fractional Fermi seas in the one-dimensional Bose gas\, A. Bastianello\, Y. Zeng\, S. Dhar\, Z. Wang\, X. Yu\, M. Horvath\, G. E. Astrakharchik\, Y. Guo\, H.-C. Nägerl\, M. Lan dini\, arXiv:2602.17656 (2026).\n\n[3] Observing dissipationless flow of a n impurity in a strongly repulsive quantum fluid\, M. Horvath\, S. Dhar\, E. Wybo\, D. Trypogeorgos\, Y. Guo\, M. B. Zvonarev\, M. Knap\, M. Landini \, H.-C. Nägerl\, arXiv:2602.12320 (2026).\n\n[4] Observing anyonization of bosons in a quantum gas\, S. Dhar\, B. Wang\, M. Horvath\, A. Vashisht\ , Y. Zeng\, M. B. Zvonarev\, N. Goldman\, Y. Guo\, M. Landini\, H.-C. Näg erl\, Nature\, 642\, 53–57 (2025). CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1116@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260313T140000 DTEND;TZID=Europe/Paris:20260313T150000 DTSTAMP:20260225T085323Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-martina-giachello-gssi-laquila/ SUMMARY:Informal Quantum Seminar: Martina Giachello (GSSI\, L'Aquila) - Sal le des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 13 Mar 26 14:00 DESCRIPTION:Localization and "classical entanglement" in the discrete non-l inear Schrödinger equation\nMartina Giachello (GSSI\, L'Aquila)\n \;\ nIn this talk we present a detailed numerical study of the very peculiar t hermodynamic properties of the localized high-energy phase of the Discrete Non-Linear Schrödinger Equation (DNLSE). A numerical ampling of the micr ocanonical ensemble done by means of Hamiltonian dynamics reveals a new an d subtle relation between the presence of the localized phase and a proper ty of the system that we have called "classical entanglement". Our main fi nding is that a quantity defined for our classical system in perfect analo gy with the entanglement entropy of quantum ones\, and that we have theref orecalled Sent\, grows with the system size N in the localized phase as Se nt(N) ~ log(N)\, therefore revealing the presence of subtle non-local corr elations between any finite portion of the system and the rest of it. This manifestation of "classical entanglement" beautifully captures the lack o f system separability in the DNLSE localized phase\, revealing how statist ical correlations specific to the microcanonical ensemble and non-reproduc ible in the canonical one\, may concur to determine a property totally ana logous to the one produced by non-local quantum correlations. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1096@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260317T110000 DTEND;TZID=Europe/Paris:20260317T120000 DTSTAMP:20260309T151121Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-jerome-dubailuniversite-de-strasbourg-cnrs/ SUMMARY:LPTMS Seminar: Jérôme Dubail (CESQ &\; ISIS\, Strasbourg) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Mar 26 11:00 DESCRIPTION:Limit shapes in measured many-particle quantum states in the la rge deviation regime\nJérôme Dubail (CESQ &\; ISIS\, Strasbourg)\n&nb sp\;\n\nMotivated by the possibility of imaging density profiles of ultrac old quantum gases with high resolution\, e.g. at the single-atom level wit h quantum gas microscopes\, we investigate the effect of measuring the num ber of particles in an extended subsystem\, and of post-selecting those ra re measurements outcomes where the subsystem particle number differs signi ficantly from its mean value. In a gas of non-interacting bosons\, the eff ect of that protocol is clear: the measured state is a tensor product of t he equilibrium state at the measured density inside the subsystem\, and at the complementary density (so that the total number of particles in the f ull system is conserved) in its complement. The natural expectation about interacting systems would then be that this picture would be mildly modifi ed only in a small region around the interface between the subsystem and i ts complement. However\, this expectation turns out to be completely wrong \, and the density profiles are drastically different even in simple syste ms like the ground state of non-interacting fermions. I will discuss a few examples combining analytical techniques and results from quantum Monte C arlo\, and argue that the emergence of limit shapes in the density profile of such measured systems is a generic phenomenon. I will also discuss cor relations in such measured quantum states\, and their relation with 'symme try-resolved entanglement entropy' and argue that 'entanglement equipartit ion'\, generically expected in the regime of small deviations\, breaks dow n and is replaced by an area law in the large deviation regime. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1091@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260320T110000 DTEND;TZID=Europe/Paris:20260320T120000 DTSTAMP:20251219T164552Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-saikat-saha/ SUMMARY:Physics-Biology Interface seminar: Saikat Saha - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 20 Mar 26 11:00 DESCRIPTION:Probing properties of fluid interfaces at the scale of picolitr e droplets and Genetically-encoded interfaces\nSaikat Saha (ENS\, Paris)\n The mechanical properties of complex fluid interfaces dictate how the emer gent behaviours of\nthe microstructure manifest as functional properties. I will briefly discuss my previous work\non utilising acoustic-driven bubb le oscillations to interrogate the broad-spectrum deformation\nbehaviour o f complex interfaces. Next\, I will describe my current efforts in develop ing an\nexperimental microfluidic framework to characterise interfacial vi scoelasticities for picolitre\nvolume droplets\, particularly useful for p recious quantities. Fundamentally\, it offers a simple\napproach to probe mechanical properties in regimes of length-scales and time-scales where\ni nformation from conventional macroscopic rheometric methods cannot always be\nextrapolated to. Finally\, I will describe our exploratory work on pro grammable soft materials\nwherein a system is provided with a synthetic ge nome in which all the properties of the soft\nmaterial could virtually be encoded. This combined with cell-free expression of interfacially-\nactive proteins enables the control of surface tension and interfacial elasticit y at a genetic level.\nIn effect\, it permits a closed system – of fixed composition\, with the same starting raw materials\n– to dynamically ev olve its own interfacial properties to have autonomous spatio-temporal\nef fects. This has allowed us to program dynamic surface tension profiles as well as create fluid\npropulsion at the macroscale\, which to our knowledg e\, is the first example of genetically-driven\nsurface tension regulation and fluid transport.\n\nKeywords: viscoelastic interfaces\, microfluidics \, programmable soft matter\, DNA CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1101@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260324T110000 DTEND;TZID=Europe/Paris:20260324T120000 DTSTAMP:20260316T101958Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-thi bault-bonnemain-lptm-cergy-pontoise/ SUMMARY:LPTMS Seminar: Thibault Bonnemain (LPTM\, Cergy-Pontoise) - Salle d es séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 24 Mar 26 1 1:00 DESCRIPTION:Introduction to soliton gas theory and generalised hydrodynamic s\nThibault Bonnemain (LPTM\, Cergy-Pontoise)\n \;\n\nGeneralised Hydr odynamics (GHD) is a rather recent theory that provides a framework for st udying a wide family of many-body integrable and nearly integrable systems out of equilibrium. I will introduce the notion of soliton gas\, associat ed with the Korteweg-de Vries (KdV) equation among others\, and use it as a paradigmatic example for the GHD of integrable\, classical field theorie s. In particular\, by way of a heuristic argument based on the analogy bet ween solitons and classical particles\, I will construct the thermodynamic s of the KdV soliton gas (free energy\, entropy\, static covariance...)\, as well as the Euler-scale hydrodynamic equations describing the evolution of weakly inhomogeneous gases. The results thus produced agree with numer ical simulations\; moreover they are consistent with and supplement the mo re rigorous\, albeit less transparent\, construction pioneered by Gennady El\, based on the so-called thermodynamic spectral limit of finite-gap sol utions.\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1102@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260331T110000 DTEND;TZID=Europe/Paris:20260331T120000 DTSTAMP:20260319T170058Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-oli vier-martin-ips2-gif-sur-yvette/ SUMMARY:LPTMS Seminar: Olivier Martin (IPS2\, Gif-sur-Yvette) - Salle des s éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 31 Mar 26 11:00 DESCRIPTION:Inferring drivers-to-target interactions from time-series data using random forests\nOlivier Martin (IPS2\, Gif-sur-Yvette)\n \;\n\nA lthough co-expression networks are often used to provide clues about genet ic interactions\, the study of longitudinal (time-dependent) data offers t he possibility of extracting causal interactions from drivers to any candi date target. I will first present and benchmark our improved algorithm tha t builds on dynGENIE3 using random forests for regressions. I will then ap ply this approach to study the early stages of lateral root formation in A rabidopsis. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1090@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260403T110000 DTEND;TZID=Europe/Paris:20260403T120000 DTSTAMP:20260401T183556Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-anja-bockmann/ SUMMARY:Physics-Biology Interface seminar: Anja Böckmann - Moyen Amphi\, B uilding 510\, Université Paris-Saclay Orsay - 3 Avr 26 11:00 DESCRIPTION:Solid-state NMR of protein fibrils\nAnja Böckmann (Molecular M icrobiology and Structural Biochemistry Institute (MMSB) - CNRS/Lyon Unive rsity)\nSolid-state NMR was the first high-resolution structural biology a pproach to provide insights into the molecular organization of protein fib rils. Fibrils are best known for their role in neurodegenerative diseases such as Alzheimer’s and Parkinson’s\, but they are actually far more w idespread and functionally diverse\, as they are also found in connection with bacterial and viral infections\, among other things. A characteristic feature of many protein fibrils is that they violate the Anfinsen dogma\, according to which the native structure is determined exclusively by the protein’s amino acid sequence. I will introduce the concepts of structur al biology\, solid-state NMR\, and the solid-state NMR linewidth\, which p rovides access to the diverse states in protein fibrils and serves as a me asure of the static and dynamic disorder exhibited by biological objects a t the atomic level. I will illustrate these concepts with examples of crys talline\, fibrillar\, and membrane-bound proteins.\n\nThe seminar will be accessible remotely: https://rendez-vous.renater.fr/PhysBio_Seminar_April3 _015e07-79620f-34760d\n CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-1106@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260407T110000 DTEND;TZID=Europe/Paris:20260407T120000 DTSTAMP:20260330T174152Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-osc ar-bouverot-dupuis-alice-marche-lptms-orsay/ SUMMARY:LPTMS Seminar: Oscar Bouverot-Dupuis &\; Alice Marché (LPTMS\, Orsay) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°5 30 - 7 Avr 26 11:00 DESCRIPTION:Effect of dissipation on the one-dimensional Mott transition\nO scar Bouverot-Dupuis (LPTMS\, Orsay)\n \;\n\nIn one-dimensional quantu m systems\, the Mott transition is a well-understood superfluid-to-insulat or transition separating a perfectly conducting Luttinger liquid (LL) from a Mott insulator (MI). In this talk\, I will explore how this transition is modified when the system is coupled to local dissipative baths. Using a Caldeira-Leggett description of the environment and bosonization techniqu es\, the problem can be mapped onto an effective (1+1)D field theory with non-Markovian interactions induced by dissipation. As a starting point\, I will revisit the dissipation-free case and show how physical insights all ow to design efficient Monte Carlo algorithms. These algorithms are then u sed on the dissipative problem to establish its full phase diagram. This r eveals that dissipation qualitatively alters the transition: the direct LL -MI transition is avoided by the appearance of a intermediate dissipation- induced phase.\n\n \;\nObserving weakly broken conservation laws in a dipolar Rydberg quantum spin chain\nAlice Marché (LPTMS\, Orsay)\n \; \n\nIntegrability\, one of the main technical theoretical tools for the an alysis of models of physical setups\, is not just a mathematical property: it has deep physical consequences. Integrable and non-integrable setups d isplay qualitative different physical behaviours\, related to the presence (or absence) of families of extensive conservation laws. In the presence of weak perturbations\, a well-known dilemma takes place: is the system ak in to a thoroughly non-integrable setup\, or does it carry memory that int egrability has been only weakly broken? In this theoretical and experiment al collaboration we show that the weak breaking of conservation laws leave s a clear experimental fingerprint in a one-dimensional quantum spin chain of as few as 14 Rydberg atoms. Weak integrability breaking from resonant dipole-dipole interactions is directly detectable within experimentally ac cessible times in the dynamics of non-local observables. In particular\, m agnetization fluctuations are highly sensitive to the breaking of fragile conservation laws and exhibit anomalous growth\, which we observe experime ntally\; similar signatures appear in a semilocal string observable. We es tablish Rydberg-atom arrays as a platform to test perturbative description s of quantum many-body dynamics with weak integrability breaking. Based o n: https://arxiv.org/abs/2602.02251 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1112@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260410T140000 DTEND;TZID=Europe/Paris:20260410T153000 DTSTAMP:20260402T105131Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-alvise-bastianello-universite-dauphine/ SUMMARY:Informal Quantum Seminar: Alvise Bastianello (Universite Dauphine) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Avr 26 14:00 DESCRIPTION:New states in one-dimensional ultracold bosons with varying int eractions\nAlvise Bastianello (Université Dauphine)\n \;\nQuantum sta tistics governs ultracold matter: bosons can condense and are generally un stable when interactions are attractive. In contrast\, fermions form Fermi seas and avoid collapse when attractive via the Pauli principle exclusion s. In one dimension\, interactions and statistics intertwine\, blurring th is distinction\, and approximate integrability stabilizes novel phases.\nI n this talk\, I present recent experimental and theoretical results on ult racold bosons driven out of equilibrium by time-dependent interactions. In the first experiment\, we realized  Fermi sea-like states with fractiona l occupancy\, which we dub fractional Fermi seas (FFS). These FFS showcase prominent Friedel oscillations in the one-particle correlator detected in the experiment\, and bear clear signatures of criticality beyond the Lutt inger Liquid paradigm.\nIn the second experiment\, we gently swipe interac tions from the repulsive to the attractive regime\, promoting the formatio n of a gas of stable bound states called Bethe strings\, whose binding ene rgy leaves a clear signature in the experimentally observed momentum distr ibution.\nExperimental data are in quantitative agreement with theoretical predictions from Generalized Hydrodynamics\, which provide a comprehensiv e characterization of these exotic nonequilibrium states. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1104@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260414T110000 DTEND;TZID=Europe/Paris:20260414T120000 DTSTAMP:20260403T094013Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-nic olas-cherroret-lkb-paris/ SUMMARY:LPTMS Seminar: Nicolas Cherroret (LKB\, Paris) - Salle des séminai res du FAST et du LPTMS\, bâtiment Pascal n°530 - 14 Avr 26 11:00 DESCRIPTION:The Dynamical Condensation Phase Transition\nNicolas Cherroret (LKB\, Paris)\n \;\n\nFollowing a quantum quench\, local observables i n non-integrable many-body systems typically thermalize. In certain cases\ , however\, this process can be critically slowed down: the system first e xhibits universal dynamical scaling laws with strongly non-thermal propert ies\, before eventually reaching thermal equilibrium on a longer time scal e. This behavior has been referred to as a non-thermal fixed point. In thi s talk\, I will discuss the far-from-equilibrium dynamics of 3D Bose gases suddenly quenched across their condensation transition. I will show that this dynamics gives rise to distinct (non)-thermal fixed points\, dependin g on whether the quench is performed above\, at or below the critical poin t. In particular\, quenches below the critical point generally involve a t ransient regime of weak turbulence\, followed at later times by a coarseni ng dynamics associated with the slow recombination of vortex lines. Quench es at the critical point\, on the other hand\, lead to a universal dynamic s presumably without vortices but involving the diffusion of critical fluc tuations. If time permits\, I will also discuss how this universal dynamic s is destabilized in the presence of perturbations\, specifically external drive and disorder. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1088@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260417T110000 DTEND;TZID=Europe/Paris:20260417T120000 DTSTAMP:20260402T140155Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-nicolas-dray/ SUMMARY:Physics-Biology Interface seminar: Nicolas Dray - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Avr 26 11:00 DESCRIPTION:From stem cell interactions to tissue homeostasis: a multiscale approach\nNicolas Dray (Institut Pasteur)\nTissue homeostasis relies on t he coordinated regulation of stem cell (SC) behaviors\, including self-ren ewal\, differentiation\, and quiescence. Yet how stem cell fate decisions are coordinated across space and time to sustain long-term tissue stabilit y remains largely unknown.\nWe hypothesize that local cell-cell communicat ion through Notch signaling\, coupled with tissue geometry and spatial org anization\, gives rise to self-sustained emergent properties at the tissue scale. To investigate this question\, we combine experiments\, spatial st atistics\, and multiscale modeling in the adult zebrafish pallium\, a rela tively simple and accessible system for studying neural stem cell in vivo. \nUsing multiplexed smFISH\, immunohistochemistry\, morphometric analysis\ , and intravital imaging\, we quantify cell states\, fate transitions\, an d tissue geometry at single-cell resolution. We are now developing methods to infer causal Notch gene regulatory networks from these data and to cha racterize stem cell interactions across scales using spatial statistical a pproaches.\nI will present our recent progress and discuss our strategy to integrate these results into a multiscale model aimed at understanding ho w tissue homeostasis and multistability emerge from the interplay between cell-cell signaling\, tissue topology\, and cell fate decisions. CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1109@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260417T140000 DTEND;TZID=Europe/Paris:20260417T153000 DTSTAMP:20260409T135022Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-angelo-russotto-sissa/ SUMMARY:Informal Quantum Seminar: Angelo Russotto (SISSA) - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 17 Avr 26 14:00 DESCRIPTION:Diffusive entanglement spreading in the $\nu = 1$ QSSEP model\n Angelo Russotto (SISSA)\n \;\n\nWe discuss the $\nu=1$ Quantum Symmetr ic Simple Exclusion Process\, a one-dimensional system of free fermions wi th time-dependent\, spatially uniform stochastic hopping amplitudes.\nWe investigate the out-of-equilibrium entanglement spreading following both global and inhomogeneous quantum quenches. For global quenches\, we develo p a diffusive quasiparticle picture that captures the full-time probabilit y distribution of the entanglement entropy. For inhomogeneous quenches\, w e extend the framework of quantum generalized hydrodynamics to account for the underlying stochastic dynamics of the local quasiparticle occupation function. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1119@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260421T110000 DTEND;TZID=Europe/Paris:20260421T120000 DTSTAMP:20260416T101205Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-alb erto-bassanoni-universite-de-parme/ SUMMARY:LPTMS Seminar: Alberto Bassanoni (Université de Parme) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 21 Avr 26 11: 00 DESCRIPTION:Rare events and single big jump effects in stochastic processes \nAlberto Bassanoni (Université de Parme)\n \;\n\nRare events in stoc hastic processes are typically described within large deviation theory (LD T)\, where atypical fluctuations arise from the accumulation of many small contributions. In systems with sub-exponential statistics\, however\, rar e events can instead be dominated by a single large fluctuation\, as presc ribed by the big jump principle (BJP). In this talk\, I will discuss this alternative mechanism and its interplay with standard large deviation beha vior across different classes of stochastic processes. I will first focus on power-law dynamics\, such as Lévy processes\, where single big jump ef fects control extreme value statistics and first-passage properties\, incl uding the behavior of the fastest trajectories in multi-particle settings\ , in particular their mean exit time from a bounded domain. I will then tu rn to processes with stretched-exponential statistics\, with particular em phasis on the Ornstein–Uhlenbeck process. Using a renewal representation \, one can identify a crossover between a regime of typical fluctuations d escribed by LDT and a rare-event regime governed by the BJP\, providing a physical interpretation of previously observed anomalous solutions in term s of single big jump effects. Finally\, I will briefly discuss a perturbat ive approach that allows one to access intermediate regimes of moderate de viations\, interpolating between these two limits.\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1123@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260430T140000 DTEND;TZID=Europe/Paris:20260430T153000 DTSTAMP:20260421T104757Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-stefano-scopa-ens/ SUMMARY:Informal Quantum Seminar: Stefano Scopa (ENS) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 30 Avr 26 14:00 DESCRIPTION:Large deviations of current in noisy many-body quantum systems: classical emergence and quantum corrections\nStefano Scopa (ENS)\n \; \nIn this talk I discuss the fluctuation statistics of currents in stochas tic quantum chains at mesoscopic scales. The models considered are the QSS EP/QSSIP: quadratic fermionic or bosonic chains with stochastic nearest-ne ighbor hopping and boundary coupling to deterministic reservoirs. For thes e systems\, the fluctuation statistics can be computed exactly. At large s cales\, the transport fluctuations coincide with those of the correspondin g classical exclusion/inclusion processes. However\, genuinely quantum eff ects persist as subleading corrections in the large-scale expansion of the fluctuation statistics. These quantum corrections are amenable to direct experimental or numerical verification\, provided sufficient control over the noise realizations can be achieved. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1107@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260505T110000 DTEND;TZID=Europe/Paris:20260505T120000 DTSTAMP:20260420T143655Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-pie tro-caracciolo-di-torella-florent-ferro-lptms-orsay/ SUMMARY:LPTMS Seminar: Pietro Caracciolo Di Torella &\; Florent Ferro (L PTMS\, Orsay) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pasc al n°530 - 5 Mai 26 11:00 DESCRIPTION:Anisotropic decomposition: a compass and a map to design patchy particles interactions\nPietro Caracciolo Di Torella (LPTMS\, Orsay)\n&nb sp\;\n\nSelf-assembly is the process by which individual building blocks s pontaneously organize into larger aggregates. A widely used approach to mo del this process relies on patchy particles\, where anisotropic interactio ns are encoded through patches on the particle surface and the structures that emerge are determined by which pairs of patches attract or repel one another. A natural parametrization of particle interactions assigns an ind ependent interaction energy to each distinct patch–patch contact. Howeve r\, translating many local patch–patch rules into global structural outc omes is far from intuitive\, and becomes increasingly challenging as the n umber of patch types grows. Here we introduce a class of two- and three-di mensional lattice models of patchy particles for which\, using tools from group theory\, the full interaction matrix can be analytically decomposed into a set of anisotropic modes\, each possessing well-defined symmetry pr operties. We then show that each anisotropic mode has a distinct and inter pretable effect on the macroscopic properties of the assembled structure. By rewriting the interactions in this way\, we can both understand why a g iven set of interactions produces a particular aggregate and design intera ctions that target desired structural outcomes.\n\n \;\n\n \;\nBre aking of clustering and macroscopic quantum coherence out of equilibrium\n Florent Ferro (LPTMS\, Orsay)\n \;\n\nWe investigate the dynamics of s ymmetry-breaking states under both non-interacting [1] and interacting [2] Hamiltonians following a local quench. We show that such states exhibit a breakdown of clustering properties at ballistic scales\, resulting in ano malously large fluctuations of extensive order parameters. Using the Quant um Fisher Information (QFI)\, we show that this setting is an ideal framew ork for the emergence of macroscopic quantum coherence. Specifically\, we show that the breaking of clustering allows the system to develop coherenc e at scales proportional to the time after the quench. Our findings presen ts this scenario as one of the most natural ways to develop cat-like state s from product states through simple local interactions.\n[1]: F Ferro and M Fagotti\, arxiv.org/abs/2503.21905\n[2]: F Ferro\, arxiv.org/abs/2602.1 5969 CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1103@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260512T110000 DTEND;TZID=Europe/Paris:20260512T120000 DTSTAMP:20260507T075939Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-had rien-kurkjian-lptmc-paris/ SUMMARY:LPTMS Seminar: Hadrien Kurkjian (LPTMC\, Paris) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Mai 26 11:00 DESCRIPTION:Hamiltonian renormalization\, Fermi liquid theory and hydrodyna mic transport in ultracold Fermi gases\nHadrien Kurkjian (LPTMC\, Paris)\n  \;\n\nI will derive the Navier-Stokes equations that describe the hyd rodynamic behavior of a gas of spin-1/2 fermions at low temperatures. The difficult part of the derivation is to obtain accurate expressions of the transport coefficients (viscosity\, thermal conductivity and spin diffusiv ity) that control the dissipative terms of the Navier-Stokes system. For t his\, I will introduce a low-energy effective theory that extends Fermi li quid theory to account for the quasiparticle collision amplitudes in all d irections. This results in an exact expansion of the transport coefficient s in power of the s-wave scattering length a\, which one can view as the e quivalent for transport of the Lee-Huang-Yang expansion of the equation of state. I will confront our results to existing measurements of the viscos ity and spin diffusivity of ultracold Fermi gases. If time permits\, I wil l also discuss how our effective theory applies to the superfluid phase\, and in particular to two-fluid hydrodynamics. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1111@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260519T110000 DTEND;TZID=Europe/Paris:20260519T120000 DTSTAMP:20260512T150408Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-thi bault-scoquart-lpt-toulouse/ SUMMARY:LPTMS Seminar: Thibault Scoquart (LPT\, Toulouse) - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Mai 26 11:00 DESCRIPTION:Many-body localization through imbalance statistics: transition scaling and rare resonances\nThibault Scoquart (LPT\, Toulouse)\n \;\ n\nMany-body localization (MBL) is a remarkable phenomenon where interacti ng quantum systems fail to thermalize due to disorder. Despite two decades of intense theoretical and numerical work\, there is still no clear conse nsus on whether a true 1D MBL phase exists in the thermodynamic limit\, or whether it eventually gives way to slow thermalization.\n\nAfter a broad introduction to the current open questions surrounding MBL\, I will explai n why the fate of the localized regime is\, at its core\, controlled by th e system's ability to form resonances across the exponentially large many- body Hilbert space -- pairs of configurations close in energy and coupled by interactions. A growing consensus in the literature is that the relevan t resonances are rare events\, both in real space and in Fock space\, whic h is why disorder-averaged quantities can be misleading: the physics of MB L hides in the fluctuations and distributions of dynamical observables.\n\ nI will illustrate this through recent work on the imbalance\, a standard dynamical probe of the memory of an initial state in MBL experiments\, exa mined at two complementary levels. Across a family of disordered spin mode ls with different Fock-space correlation structures [1]\, I will first sho w how the scaling of the MBL crossover with system size is faithfully trac ked by the quantum and mesoscopic fluctuations of a "generalized" imbalanc e\, yielding finite-size phase diagrams and transition widths in agreement with spectral observables [2]. I will then turn to the deep localized reg ime\, where we recently showed that the standard\, site-averaged imbalance hides a much richer microscopic structure: the full distribution of site- resolved imbalances exhibits direct fingerprints of rare local resonances between a few neighboring spins\, quantitatively captured by a simple anal ytical toy model [3].\n\n[1] T. Scoquart\, I. Gornyi and A. Mirlin\, Phys. Rev. B 109\, 214203 (2024)\n[2] T. Scoquart\, I. Gornyi and A. Mirlin\, P hys. Rev. B 112\, 064203 (2025)\n[3] A. Haldar\, T. Scoquart\, F. Alet and N. Laflorencie\, arXiv:2601.05177 (2026) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1110@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260526T110000 DTEND;TZID=Europe/Paris:20260526T120000 DTSTAMP:20260209T122823Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-pie rfrancesco-urbani-ipht-gif-sur-yvette/ SUMMARY:LPTMS Seminar: Pierfrancesco Urbani (IPhT\, Gif-sur-Yvette) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Mai 26 11:00 DESCRIPTION:TBA\nPierfrancesco Urbani (IPhT\, Gif-sur-Yvette)\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1115@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260529T110000 DTEND;TZID=Europe/Paris:20260529T120000 DTSTAMP:20260220T141104Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-mathis-gueneau/ SUMMARY:Physics-Biology Interface seminar: Mathis Guéneau - Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay - 29 Mai 26 11:00 DESCRIPTION:Mathis Guéneau (MPIPKS Dresden) CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-1125@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260529T140000 DTEND;TZID=Europe/Paris:20260529T150000 DTSTAMP:20260428T142437Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-dmi try-starkov-skoltech-moscow/ SUMMARY:LPTMS Seminar: Dmitry Starkov (Skoltech\, Moscow) - Salle des sémi naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Mai 26 14:00 DESCRIPTION:Short-scale analytical theory shows cohesin actively extrudes l oops as a single motor\nDmitry Starkov (Skoltech\, Moscow)\n \;\n\nCoh esin-dependent loop extrusion is a key active mechanism of DNA organizatio n\, yet it remains unclear whether chromatin loops in living cells are gen erated primarily by individual cohesin motors or by higher-order structure s. To fill this major gap\, we build an analytical\, protocol-aware polyme r-physics model that extracts a missing parameter - the linear density of loops - directly from Hi-C data. We focus on short genomic distances\, whe re contact statistics simplify and chromatin can be described as an ideal polymer folded by quenched disorder of cohesin-mediated loops. In this reg ime\, the Hi-C signal is governed by the interplay between loop-induced po lymer compaction and a finite-resolution contact-detection process\, which can be described by an effective Gaussian detection kernel. This results in a perturbative expression for the contact probability of a looped chain under a finite contact-detection radius. Our theory recapitulates a chara cteristic dip in the logarithmic derivative of the contact probability tha t is broadly observed in experiments. By fitting this minimal model to a d iverse range of mammalian Hi-C datasets\, we infer approximately six loops per megabase. Independent imaging and mass spectrometry measurements of c ohesin density are consistent with our inferred loop density\, supporting the monomeric mode of cohesin-mediated DNA loop extrusion. CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1105@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260602T110000 DTEND;TZID=Europe/Paris:20260602T120000 DTSTAMP:20260206T144833Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-xia ngyu-cao-lpens-paris/ SUMMARY:LPTMS Seminar: Xiangyu Cao (LPENS\, Paris) - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Juin 26 11:00 DESCRIPTION:TBA\nXiangyu Cao (LPENS\, Paris)\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1121@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260609T110000 DTEND;TZID=Europe/Paris:20260609T120000 DTSTAMP:20260409T072203Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-ole g-evnin-chulalongkorn-university-bangkok/ SUMMARY:LPTMS Seminar: Oleg Evnin (Chulalongkorn University\, Bangkok) - Sa lle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 9 Juin 26 11:00 DESCRIPTION:TBA\nOleg Evnin (Chulalongkorn University\, Bangkok)\n \;\n \n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1098@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260612T110000 DTEND;TZID=Europe/Paris:20260612T120000 DTSTAMP:20260330T134454Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-tatiana-morozova/ SUMMARY:Physics-Biology Interface seminar: Tatiana Morozova - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Juin 26 11:00 DESCRIPTION:Tatiana Morozova (ENS Lyon) CATEGORIES:physbio,seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1113@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260623T110000 DTEND;TZID=Europe/Paris:20260623T120000 DTSTAMP:20260217T145144Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-jea n-marie-stephan-ens-lyon/ SUMMARY:LPTMS Seminar: Jean-Marie Stéphan (ENS\, Lyon) - Salle des sémina ires du FAST et du LPTMS\, bâtiment Pascal n°530 - 23 Juin 26 11:00 DESCRIPTION:TBA\nJean-Marie Stéphan (ENS\, Lyon) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1117@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260624T140000 DTEND;TZID=Europe/Paris:20260624T173000 DTSTAMP:20260403T133149Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-de-ivan-burenev/ SUMMARY:Soutenance de thèse de Ivan Burenev - Salle des séminaires du FAS T et du LPTMS\, bâtiment Pascal n°530 - 24 Juin 26 14:00 DESCRIPTION:Jury : Roberto Artuso\, Olivier Bénichou\, Denis Grebenkov (ra pporteur)\, Michael Kearney (invité)\, Satya Majumdar (directeur de thès e)\, Cécile Monthus\, Clément Sire (rapporteur) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1094@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260626T110000 DTEND;TZID=Europe/Paris:20260626T120000 DTSTAMP:20260107T170538Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-luca-barberi/ SUMMARY:Physics-Biology interface seminar: Luca Barberi - Moyen Amphi\, Bui lding 510\, Université Paris-Saclay Orsay - 26 Juin 26 11:00 DESCRIPTION:Luca Barberi (Medicines for Malaria Venture\, Geneva) CATEGORIES:physbio,seminars LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R ue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un iversité Paris-Saclay Orsay:geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-1124@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260626T110000 DTEND;TZID=Europe/Paris:20260626T123000 DTSTAMP:20260505T081528Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/informal-quantum- seminar-giacomo-bracci-testasecca/ SUMMARY:Informal Quantum Seminar: Giacomo Bracci Testasecca - Salle des sé minaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 26 Juin 26 11:00 DESCRIPTION:Giacomo Bracci Testasecca (SISSA) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1120@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260702T100000 DTEND;TZID=Europe/Paris:20260702T100000 DTSTAMP:20260403T132903Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the se-alice-marche/ SUMMARY:Soutenance de thèse : Alice Marché - Grand amphi\, bâtiment Pasc al n° 530 - 2 Juil 26 10:00 DESCRIPTION:Jury : Jérôme Dubail (rapporteur)\, Hosho Katsura (invité)\ , Zala Lenarčič (rapporteur)\, Leonardo Mazza (directeur de thèse)\, Gr égoire Misguich\, Pierre Nataf. CATEGORIES:seminars LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors ay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca l n° 530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1127@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260915T110000 DTEND;TZID=Europe/Paris:20260915T120000 DTSTAMP:20260505T125659Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-gui llaume-roux-lptms-orsay/ SUMMARY:LPTMS Seminar: Guillaume Roux (LPTMS\, Orsay) - Salle des séminair es du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 Sep 26 11:00 DESCRIPTION:TBA\nGuillaume Roux (LPTMS\, Orsay)\n \;\n\n \; CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1122@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260924T090000 DTEND;TZID=Europe/Paris:20260925T173000 DTSTAMP:20260414T130623Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/conference-en-lho nneur-de-mark-oliver-goerbig/ SUMMARY:Conférence en l'honneur de Mark-Oliver Goerbig - Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtiment 510) - 24 Sep 26 09:0 0 DESCRIPTION:“Topological quantum matter — a conference in memory of Mar k Oliver Goerbig”.\nhttps://markgoerbigconf.sciencesconf.org/\n\nORATEUR S (tous confirmés)\nKang Yang* (Westlake university\, Hangzhou)\nLih-King Lim (Zhejiang University\, Hangzhou)\nZlatko Papic (Leeds)\nXin Lu* (Shan ghaiTech University)\nFlorian Simon* (Münich)\nSilke Biermann (X)\nLeonar do Mazza (LPTMS)\nNicolas Regnault (NY\, Simons\, Flatiron)\nRoderich Moes sner (MPIPKS Dresden)\nDavid Carpentier (Lyon)\nCristiane Morais-Smith (Ut recht)\nLara Benfatto (Rome)\nMilan Orlita (Grenoble)\nEmmanuel Baudin* (E NS Paris)\nMiguel Monteverde* (LPS Orsay)\nMarc Gabay (LPS Orsay)\nGilles Montambaux* (LPS Orsay)\n(*) Présentations courtes.\n\nL’organisation e st assurée par des membres du groupe Théorie du Laboratoire de Physique des Solides (LPS). CATEGORIES:seminars LOCATION:Amphi BLANDIN du LPS de la Faculté des Sciences d’Orsay (Bâtim ent 510)\, 15 Rue Georges Clemenceau\, orsay\, France GEO:48.698187;2.181768 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\, orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Amphi BLANDIN du LPS de la Facu lté des Sciences d’Orsay (Bâtiment 510):geo:48.698187,2.181768 END:VEVENT BEGIN:VEVENT UID:0-1118@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260929T110000 DTEND;TZID=Europe/Paris:20260929T120000 DTSTAMP:20260504T095719Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-ser gio-ciliberto-ens-lyon/ SUMMARY:LPTMS Seminar: Sergio Ciliberto (ENS\, Lyon) - Salle des séminaire s du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Sep 26 11:00 DESCRIPTION:TBA\nSergio Ciliberto (ENS\, Lyon) CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VEVENT UID:0-1126@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20261002T080000 DTEND;TZID=Europe/Paris:20261002T180000 DTSTAMP:20260505T071817Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/fete-de-la-scienc e-lptms-fast/ SUMMARY:Fête de la Science LPTMS - FAST - Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 2 Oct 26 08:00 DESCRIPTION:Fête de la Science LPTMS - FAST CATEGORIES:seminars LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53 0\, rue André Riviere\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\ , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°530:geo:0,0 END:VEVENT BEGIN:VTIMEZONE TZID:Europe/Paris X-LIC-LOCATION:Europe/Paris BEGIN:STANDARD DTSTART:20181028T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20190331T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20191027T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20200329T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20201025T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20210328T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20211031T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20220327T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20221030T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20230326T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20231029T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20240331T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20241027T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20250330T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20251026T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD BEGIN:DAYLIGHT DTSTART:20260329T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT END:VTIMEZONE END:VCALENDAR