Prethermal memory loss in interacting quantum systems coupled to thermal baths

TL;DR

This paper investigates how interacting quantum systems coupled to thermal baths exhibit prethermal memory loss, characterized by a peak in entropy before reaching thermal equilibrium, linked to localization effects in Wannier-Stark systems.

Contribution

It reveals a novel prethermal memory loss phenomenon in quantum many-body systems with Wannier-Stark localization coupled to thermal baths, highlighting the role of localization in dissipative dynamics.

Findings

Entropy peaks before thermalization at large field gradients.

System exhibits simple scaling behavior during entropy peak.

Localization in Wannier-Stark systems influences dissipative coupling.

Abstract

We study the relaxation dynamics of an extended Fermi-Hubbard chain with a strong Wannier-Stark potential tilt coupled to a bath. When the system is subjected to dephasing noise, starting from a pure initial state the system's total von Neumann entropy is found to grow monotonously. The scenario becomes rather different when the system is coupled to a thermal bath of finite temperature. Here, for sufficiently large field gradients and initial energies, the entropy peaks in time and almost reaches its largest possible value (corresponding to the maximally mixed state), long before the system relaxes to thermal equilibrium. This entropy peak signals a prethermal memory loss and, relative to the time where it occurs, the system is found to exhibit a simple scaling behavior in space and time. By comparing the system's dynamics to that of a simplified model, the underlying mechanism is found to be related to the localization property of the Wannier-Stark system, which favors dissipative coupling between eigenstates that are close in energy.