Irreversible dynamics in quantum many-body systems

TL;DR

This paper investigates the intrinsic irreversibility of isolated quantum many-body systems by analyzing how observable echoes decay under imperfect time reversal, revealing exponential decay independent of perturbation strength.

Contribution

It provides a numerical demonstration that irreversibility in quantum many-body systems is intrinsic, with echoes decaying exponentially regardless of perturbation magnitude.

Findings

Observable echoes decay exponentially with a system-intrinsic rate.

Sensitivity to perturbations is inherent, indicating effective irreversibility.

Decay rate is independent of the perturbation strength.

Abstract

Irreversibility, despite being a necessary condition for thermalization, still lacks a sound understanding in the context of isolated quantum many-body systems. In this work we approach this question by studying the behavior of generic many-body systems under imperfect effective time reversal, where the imperfection is introduced as a perturbation of the many-body state at the point of time reversal. Based on numerical simulations of the full quantum dynamics we demonstrate that observable echos occurring in this setting decay exponentially with a rate that is independent of the perturbation; hence, the sensitivity to perturbations is intrinsic to the system meaning that the dynamics is effectively irreversible.