Quantum Mpemba effect without global symmetries

TL;DR

This paper demonstrates that the quantum Mpemba effect is common in generic non-integrable many-body systems without global symmetries, providing a unified framework connecting it with classical thermal relaxation.

Contribution

It shows that the quantum Mpemba effect occurs broadly in non-symmetric quantum systems and offers a unified understanding linking it to classical thermal relaxation.

Findings

QME is prevalent in non-integrable systems without global symmetries.

The effect can be explained via initial energy density and inverse participation ratio.

A unified framework connects QME with classical thermal relaxation.

Abstract

The Mpemba effect, where a system initially farther from equilibrium relaxes faster than one closer to equilibrium, has been extensively studied in classical systems and recently explored in quantum settings. While previous studies of the quantum Mpemba effect (QME) have largely focused on isolated systems with global symmetries, we argue that the QME is ubiquitous in generic, non-integrable many-body systems lacking such symmetries, including U(1) charge conservation, spatial symmetries, and even energy conservation. Using paradigmatic models such as the quantum Ising model with transverse and longitudinal fields, we show that the QME can be understood through the energy density of initial states and their inverse participation ratio in the energy eigenbasis. Our findings provide a unified framework for the QME, linking it with classical thermal relaxation.