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Condensation transition and ensemble inequivalence in the discrete nonlinear Schrödinger equation
Giacomo Gradenigo1, Stefano Iubini2,3, Roberto Livi2,3,4
1Gran Sasso Science Institute, Viale F. Crispi 7, 67100, L'Aquila, Italy. giacomo.gradenigo@gssi.it.
Abstract:
The thermodynamics of the discrete nonlinear Schrödinger equation in the vicinity of infinite temperature is explicitly solved in the microcanonical ensemble by means of large-deviation techniques. A first-order phase transition between a thermalized phase and a condensed (localized) one occurs at the infinite-temperature line. Inequivalence between statistical ensembles characterizes the condensed phase, where the grand-canonical representation does not apply. The control over finite-size corrections of the microcanonical partition function allows to design an experimental test of delocalized negative-temperature states in lattices of cold atoms.
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