Dynamical thermalization in Bose-Hubbard systems

TL;DR

This paper demonstrates that moderate interactions in a finite Bose-Hubbard ring lead to dynamical thermalization, with eigenstates well described by Bose-Einstein distribution, linking quantum chaos and ergodicity.

Contribution

It provides numerical evidence that dynamical thermalization occurs in finite Bose-Hubbard systems with disorder and interactions, supporting the thermalization conjecture.

Findings

Eigenstates follow Bose-Einstein distribution at various temperatures

Thermalization occurs at positive and negative temperatures

Connections to quantum chaos and ergodicity are discussed

Abstract

We numerically study a Bose-Hubbard ring of finite size with disorder containing a finite number of bosons that are subject to an on-site two-body interaction. Our results show that moderate interactions induce dynamical thermalization in this isolated system. In this regime the individual many-body eigenstates are well described by the standard thermal Bose-Einstein distribution for well-defined values of the temperature and the chemical potential which depend on the eigenstate under consideration. We show that the dynamical thermalization conjecture works well both at positive and negative temperatures. The relations to quantum chaos, quantum ergodicity and to the Aberg criterion are also discussed.