Entanglement prethermalization: Locally thermal but non-locally non-thermal states in a one-dimensional Bose gas

TL;DR

This paper investigates how a one-dimensional Bose gas exhibits prethermalization, where subsystems reach thermal states individually, but the entire system remains non-thermal due to quantum entanglement, supported by exact few-body calculations.

Contribution

It introduces the concept of entanglement prethermalization in a 1D Bose gas, showing subsystems thermalize locally while the whole system does not, based on exact few-body analysis.

Findings

Subsystems relax to Gibbs states

The entire system remains non-thermal due to entanglement

Predictions are testable with current ultracold atom experiments

Abstract

A well-isolated system often shows relaxation to a quasi-stationary state before reaching thermal equilibrium. Such a prethermalization has attracted considerable interest recently in association with closely related fundamental problems of relaxation and thermalization of isolated quantum systems. Motivated by the recent experiment in ultracold atoms, we study the dynamics of a one-dimensional Bose gas which is split into two subsystems, and find that individual subsystems relax to Gibbs states, yet the entire system does not due to quantum entanglement. In view of recent experimental realization on a small well-defined number of ultracold atoms, our prediction based on exact few-body calculations is amenable to experimental test.