Interaction quenches in the 1D Bose gas

TL;DR

This paper investigates the non-equilibrium dynamics of the 1D Bose gas after an interaction quench, showing that integrability causes deviations from traditional thermalization predictions.

Contribution

It provides the first analytic results for interaction quenches in a non-quadratic integrable continuum system, the Lieb-Liniger model.

Findings

Local correlators computed for non-interacting initial states

Two-point functions analyzed for quenches to the Tonks-Girardeau regime

Deviations from grand canonical ensemble predictions in the long-time limit

Abstract

The non-equilibrium dynamics of integrable systems are special: there is substantial evidence that after a quantum quench they do not thermalize but their asymptotic steady state can be described by a Generalized Gibbs Ensemble (GGE). Most of the studies on the GGE so far have focused on models that can be mapped to quadratic systems while analytic treatment in non-quadratic systems remained elusive. We obtain results on interaction quenches in a non-quadratic continuum system, the 1D Bose gas described by the integrable Lieb-Liniger model. We compute local correlators for a non-interacting initial state and arbitrary final interactions as well as two-point functions for quenches to the Tonks-Girardeau regime. We show that in the long time limit integrability leads to significant deviations from the predictions of the grand canonical ensemble.