Quantum phase transitions of the Cavity Heisenberg spin-chain
Abstract
The interplay between quantum criticality and ergodicity breaking constitutes a central challenge in complex quantum many-body systems. Here, we investigate ground-state quantum phase transitions (QPTs) and excited-state quantum phase transitions (ESQPTs), as well as ergodic-nonergodic transition in the cavity Heisenberg spin-chain (CHS) model. By combining quantum information measures with semiclassical fixed-point analysis, we identify a deformed phase that interpolates between the normal and superradiant phases, featuring a logarithmic nonanalyticity in the density of states (DoS) and two additional jump discontinuities. We further elucidate the spectral-structure mechanism underlying the connection between ESQPTs and the ergodic--nonergodic transition (ENET) via level statistics, participation ratios, and multifractal analysis. Our results provide a general framework for characterizing phase structures and spectral features in light--matter quantum many-body systems.
Related
- Field-driven quantum phase transitions in a spin-1/2 Heisenberg antiferromagnet on an extended Lieb lattice
- Dynamical Phase Transitions as Properties of the Stationary State: Analytic Results after Quantum Quenches in the Spin-1/2 XXZ Chain
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- Quantum phase transitions and quantum-information characterization of a non-Hermitian XY chain with staggered Dzyaloshinskii--Moriya interactions
BibTeX
@misc{gong2026quantum,
title = {{Quantum phase transitions of the Cavity Heisenberg spin-chain}},
author = {Lv-Ting Gong and Shao-Fan He and Fu-Quan Dou},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01340},
eprint = {2609.01340},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01340},
}
RIS
TY - UNPB
TI - Quantum phase transitions of the Cavity Heisenberg spin-chain
AU - Lv-Ting Gong
AU - Shao-Fan He
AU - Fu-Quan Dou
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.01340
UR - https://arxiv.org/abs/2609.01340
AB - The interplay between quantum criticality and ergodicity breaking constitutes a central challenge in complex quantum many-body systems. Here, we investigate ground-state quantum phase transitions (QPTs) and excited-state quantum phase transitions (ESQPTs), as well as ergodic-nonergodic transition in the cavity Heisenberg spin-chain (CHS) model. By combining quantum information measures with semiclassical fixed-point analysis, we identify a deformed phase that interpolates between the normal and superradiant phases, featuring a logarithmic nonanalyticity in the density of states (DoS) and two additional jump discontinuities. We further elucidate the spectral-structure mechanism underlying the connection between ESQPTs and the ergodic--nonergodic transition (ENET) via level statistics, participation ratios, and multifractal analysis. Our results provide a general framework for characterizing phase structures and spectral features in light--matter quantum many-body systems.
ER -