发表机构
College of Physics and Electronic Engineering, Northwest Normal University; Gansu Provincial Research Center for Basic Disciplines of Quantum Physics（西北师范大学物理与电子工程学院; 甘肃省量子物理基础学科研究中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文针对腔海森堡自旋链模型，结合量子信息度量与半经典不动点分析，识别出介于正常相与超辐射相之间的形变相，阐明了激发态量子相变与遍历-非遍历相变的谱结构机制，为光-物质量子多体系统的相结构表征提供通用框架。
AI 中文摘要
量子临界性与遍历性破缺之间的相互作用是复杂量子多体系统中的核心挑战。本文研究腔海森堡自旋链（CHS）模型中的基态量子相变（QPT）、激发态量子相变（ESQPT）以及遍历-非遍历相变。通过将量子信息度量与半经典不动点分析相结合，我们识别出一个介于正常相和超辐射相之间的形变相，其态密度（DoS）具有对数非解析性，且存在两个额外的跳变不连续性。我们进一步通过能级统计、参与比和多重分形分析阐明了ESQPT与遍历-非遍历相变（ENET）之间关联的谱结构机制。我们的结果为表征光-物质量子多体系统中的相结构和谱特征提供了通用框架。
英文摘要
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.
Comments14 pages,9 figures
