Failure of the GGE hypothesis for integrable models with bound states

TL;DR

This paper investigates the limitations of the Generalized Gibbs Ensemble (GGE) in describing long-term dynamics of integrable one-dimensional models with bound states, showing it often fails for various initial states.

Contribution

It demonstrates the failure of GGE in integrable models with bound states, providing calculations for the Lieb-Liniger gas and XXZ magnet.

Findings

GGE fails for most initial states including eigenstates

Results obtained for Lieb-Liniger gas and XXZ magnet

Failure likely extends to other similar models

Abstract

In this work we study the applicability of the GGE to integrable one dimensional systems with bound states. We find that the GGE fails to describe the long time dynamics for most initial states including eigenstates. We present our calculations studying the attractive Lieb-Liniger gas and the XXZ magnet, though similar results may be obtained for other models.