2013

Invariant $\beta$-Wishart ensembles, crossover densities and asymptotic corrections to the Marchenko-Pastur law

Romain Allez 1, Jean-Philippe Bouchaud 2, Satya N. Majumdar 3, Pierpaolo Vivo 3 Journal of Physics A: Mathematical and Theoretical 46 (2013) 015001 We construct a diffusive matrix model for the $\beta$-Wishart (or Laguerre) ensemble for general continuous $\beta\in [0,2]$, which preserves invariance under the orthogonal/unitary group transformation. Scaling the Dyson index $\beta$ with the largest size $M$ of the data matrix as […]

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Hawking radiation in a two-component Bose-Einstein condensate

P. -É. Larré 1, N. Pavloff 1 EPL 103 (2013) 60001 We consider a simple realization of an event horizon in the flow of a one-dimensional two-component Bose-Einstein condensate. Such a condensate has two types of quasiparticles; In the system we study, one corresponds to density fluctuations and the other to polarization fluctuations. We treat the case where a

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Glassy Critical Points and Random Field Ising Model

Silvio Franz 1, Giorgio Parisi 2, Federico Ricci-Tersenghi 2 Journal of Statistical Mechanics (2013) L02001 We consider the critical properties of points of continuous glass transition as one can find in liquids in presence of constraints or in liquids in porous media. Through a one loop analysis we show that the critical Replica Field Theory describing these points can be mapped

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From elongated spanning trees to vicious random walks

A. Gorsky 1, S. Nechaev 2, 3, V. S. Poghosyan 4, V. B. Priezzhev 5 Nuclear Physics B 870 (2013) 55-77 Given a spanning forest on a large square lattice, we consider by combinatorial methods a correlation function of $k$ paths ($k$ is odd) along branches of trees or, equivalently, $k$ loop–erased random walks. Starting and ending points of the paths are grouped in

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Freezing Transitions in Liquids Characterized by a Favoured Local Structure

Pierre Ronceray 1, 2, Peter Harrowell 3 Physical Review E 87 (2013) 052313 The ordering transitions of a 2D lattice liquid characterized by a single favoured local structure (FLS) are studied using Monte Carlo simulations. All eight distinct geometries for the FLS are considered and we find a variety of ordering transitions – first order, continuous and multi-step transitions. Using

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Post-doc position: Analogue Hawking effect in BEC systems

Paris-Sud University (LPT and LPTMS) is offering a two-year post-doctoral fellowship starting 1st October 2013, in a joint project involving the LCF of Palaiseau and the LPN of Marcoussis. The post-doc will work on various theoretical aspects of experiments aimed at measuring quantum features associated with the analogue Hawking effect and related phenomena such as

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Flux-based classification of reactions reveals a functional bow-tie organization of complex metabolic networks

Shalini Singh 1, 2, Areejit Samal 1, 3, 4, Varun Giri 1, Sandeep Krishna 5, Nandula Raghuram 6, Sanjay Jain 1, 7, 8 Physical Review E 87 (2013) 052708 Unraveling the structure of complex biological networks and relating it to their functional role is an important task in systems biology. Here we attempt to characterize the functional organization of the large-scale metabolic networks of three microorganisms. We apply flux balance analysis to

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Fluctuations quantiques et effets non-linéaires dans les condensats de Bose-Einstein : des ondes de choc dispersives au rayonnement de Hawking acoustique

Pierre-Élie Larré 1 Université Paris Sud – Paris XI (20/09/2013), Nicolas Pavloff (Dir.) Cette thèse est dédiée à l’étude de l’analogue du rayonnement de Hawking dans les condensats de Bose-Einstein. Le premier chapitre présente de nouvelles configurations d’intérêt expérimental permettant de réaliser l’équivalent acoustique d’un trou noir gravitationnel dans l’écoulement d’un condensat atomique unidimensionnel. Nous donnons dans

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Finite-size critical fluctuations in microscopic models of mode-coupling theory

Silvio Franz 1, Mauro Sellitto 2 Journal of Statistical Mechanics (2013) P02025 Facilitated spin models on random graphs provide an ideal microscopic realization of the mode-coupling theory of supercooled liquids: they undergo a purely dynamic glass transition with no thermodynamic singularity. In this paper we study the fluctuations of dynamical heterogeneity and their finite-size scaling properties in the beta-relaxation

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