Quantum Mpemba Effect in Random Circuits

Fuente: arXiv
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Main Authors: Turkeshi, Xhek, Calabrese, Pasquale, De Luca, Andrea
Format: Preprint
Published: 2024
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author Turkeshi, Xhek
Calabrese, Pasquale
De Luca, Andrea
author_facet Turkeshi, Xhek
Calabrese, Pasquale
De Luca, Andrea
contents The essence of the Mpemba effect is that non-equilibrium systems may relax faster the further they are from their equilibrium configuration. In the quantum realm, this phenomenon arises in the dynamics of closed systems, where it is witnessed by fundamental features such as symmetry and entanglement. Here, we study the quantum Mpemba effect in charge-preserving random circuits on qudits combining extensive numerical simulations and analytical arguments. We show that the more asymmetric certain classes of initial states (tilted ferromagnets) are, the faster they restore symmetry and reach the grand-canonical ensemble. Conversely, other classes of states (tilted antiferromagnets) do not show the Mpemba effect. We provide a simple and general mechanism underlying the effect, based on the spreading of nonconserved operators in terms of conserved densities. Our analysis is based on minimal principles -- locality, unitarity, and symmetry. Consequently, our results represent a significant advancement in clarifying the emergence of Mpemba physics in chaotic systems.
format Preprint
id arxiv_https___arxiv_org_abs_2405_14514
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum Mpemba Effect in Random Circuits
Turkeshi, Xhek
Calabrese, Pasquale
De Luca, Andrea
Quantum Physics
Statistical Mechanics
The essence of the Mpemba effect is that non-equilibrium systems may relax faster the further they are from their equilibrium configuration. In the quantum realm, this phenomenon arises in the dynamics of closed systems, where it is witnessed by fundamental features such as symmetry and entanglement. Here, we study the quantum Mpemba effect in charge-preserving random circuits on qudits combining extensive numerical simulations and analytical arguments. We show that the more asymmetric certain classes of initial states (tilted ferromagnets) are, the faster they restore symmetry and reach the grand-canonical ensemble. Conversely, other classes of states (tilted antiferromagnets) do not show the Mpemba effect. We provide a simple and general mechanism underlying the effect, based on the spreading of nonconserved operators in terms of conserved densities. Our analysis is based on minimal principles -- locality, unitarity, and symmetry. Consequently, our results represent a significant advancement in clarifying the emergence of Mpemba physics in chaotic systems.
title Quantum Mpemba Effect in Random Circuits
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2405.14514