Quantum Mpemba effect of Z2 symmetry restoration in the Dicke model
Abstract
We study a symmetry-restoration quantum Mpemba effect in the dissipative Dicke model as an example of a weakly ℤ2-symmetric open quantum system, where the full Liouvillian is parity covariant although individual quantum jumps connect the two Hilbert-space parity sectors. Using the entanglement-asymmetry (EA) diagnostic to monitor parity restoration, we compare coherent-product and cat-product initial states. Coherent-product states show conventional relaxation, with larger initial asymmetry decaying more slowly and no Mpemba crossing observed. Cat-product states, by contrast, can reverse this hierarchy over a finite region of initial-state space. This reversal is enabled by initial-state mode filtering: the cat-product superposition suppresses the contributions of the leading slow Liouvillian modes, allowing a more asymmetric state to restore parity through faster decay channels. Our results reveal that symmetry-restoration QME can arise even when parity is preserved only as a weak Liouvillian symmetry, with quantum jumps mixing the Hilbert-space parity sectors. The anomalous relaxation is governed by initial-state-dependent filtering of the leading slow Liouvillian modes, providing a mechanism for symmetry-restoration QME beyond strongly conserved symmetry sectors.
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BibTeX
@misc{chen2026quantum,
title = {{Quantum Mpemba effect of Z2 symmetry restoration in the Dicke model}},
author = {Dongni Chen and Wei Xiong and Peng-Cheng Li and Yee Sin Ang and Ching Hua Lee and Yi Qin},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00902},
eprint = {2611.00902},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00902},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Quantum Mpemba effect of Z2 symmetry restoration in the Dicke model
AU - Dongni Chen
AU - Wei Xiong
AU - Peng-Cheng Li
AU - Yee Sin Ang
AU - Ching Hua Lee
AU - Yi Qin
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00902
UR - https://arxiv.org/abs/2611.00902
AB - We study a symmetry-restoration quantum Mpemba effect in the dissipative Dicke model as an example of a weakly ℤ_2-symmetric open quantum system, where the full Liouvillian is parity covariant although individual quantum jumps connect the two Hilbert-space parity sectors. Using the entanglement-asymmetry (EA) diagnostic to monitor parity restoration, we compare coherent-product and cat-product initial states. Coherent-product states show conventional relaxation, with larger initial asymmetry decaying more slowly and no Mpemba crossing observed. Cat-product states, by contrast, can reverse this hierarchy over a finite region of initial-state space. This reversal is enabled by initial-state mode filtering: the cat-product superposition suppresses the contributions of the leading slow Liouvillian modes, allowing a more asymmetric state to restore parity through faster decay channels. Our results reveal that symmetry-restoration QME can arise even when parity is preserved only as a weak Liouvillian symmetry, with quantum jumps mixing the Hilbert-space parity sectors. The anomalous relaxation is governed by initial-state-dependent filtering of the leading slow Liouvillian modes, providing a mechanism for symmetry-restoration QME beyond strongly conserved symmetry sectors.
ER -