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TZID:Europe/Paris
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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 &amp\; 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
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