## Exact out-of-equilibrium steady states in the semiclassical limit of the interacting Bose gas

Giuseppe Del Vecchio Del Vecchio, Alvise Bastianello, Andrea De Luca, Giuseppe Mussardo

SciPost Phys. 9, 002 (2020) · published 6 July 2020

- doi: 10.21468/SciPostPhys.9.1.002
- Submissions/Reports

### Abstract

We study the out-of-equilibrium properties of a classical integrable non-relativistic theory, with a time evolution initially prepared with a finite energy density in the thermodynamic limit. The theory considered here is the Non-Linear Schrodinger equation which describes the dynamics of the one-dimensional interacting Bose gas in the regime of high occupation numbers. The main emphasis is on the determination of the late-time Generalised Gibbs Ensemble (GGE), which can be efficiently semi-numerically computed on arbitrary initial states, completely solving the famous quench problem in the classical regime. We take advantage of known results in the quantum model and the semiclassical limit to achieve new exact results for the momenta of the density operator on arbitrary GGEs, which we successfully compare with ab-initio numerical simulations. Furthermore, we determine the whole probability distribution of the density operator (full counting statistics), whose exact expression is still out of reach in the quantum model.

### Cited by 18

### Authors / Affiliations: mappings to Contributors and Organizations

See all Organizations.-
^{1}Giuseppe del Vecchio del Vecchio, -
^{2}Alvise Bastianello, -
^{3}Andrea De Luca, -
^{4}Giuseppe Mussardo

^{1}King's College London [KCL]^{2}Institute of Physics, University of Amsterdam [IoP, UvA]^{3}CY Cergy Paris Université / CY Cergy Paris University^{4}Istituto Nazionale di Fisica Nucleare (presso la SISSA) / National Institute of Nuclear Physics (at SISSA) [INFN at SISSA]