{
  "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.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.01340",
  "author_total": 3,
  "authors": [
    {
      "name": "Lv-Ting Gong"
    },
    {
      "name": "Shao-Fan He"
    },
    {
      "name": "Fu-Quan Dou"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ce2wvr5tbsn43.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.01340",
  "fulltext_url": null,
  "id": "ce2wvr5tbsn43",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.01340",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "3107|Quantum many-body systems"
    ]
  ],
  "openalex": "W7206180019",
  "pdf_url": "https://arxiv.org/pdf/2609.01340",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ce2wvr5tbsn43.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:00Z",
      "native_id": "2609.01340",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.01340"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Quantum phase transitions of the Cavity Heisenberg spin-chain",
  "title_text": "Quantum phase transitions of the Cavity Heisenberg spin-chain",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:00Z",
  "url": "https://research.draconitic.com/paper/ce2wvr5tbsn43",
  "venue": "arXiv",
  "versions": []
}