{
  "abstract": "In quasi-Hermitian mixed-state quenches, the initial and final Hamiltonians generally possess different positive-definite metrics, so post-quench evolution is not quasi-unitary in the initial physical space. Choosing the preparation/measurement space as reference, we derive from first principles a normalized mixed-state Loschmidt amplitude using metric-compatible purifications. The resulting biorthogonal trace representation contains a normalization factor given by the norm of the evolved purification in the initial metric; this factor is essential for comparing states from different physical Hilbert spaces and directly encodes the metric mismatch. We prove that this normalization function is strictly positive on the real-time axis, so real-time criticality arises solely from destructive interference in the dynamical overlap. In complex time, zeros of the normalization factor generate branch singularities distinct from Fisher zeros. For a general two-level system, we derive analytic expressions for the Fisher and normalization zeros and analyze exceptional-point scaling together with the temperature- and quasi-Hermiticity-dependent DQPT critical times in two solvable quench protocols. In contrast to metric-stationary quenches, where non-Hermitian effects may be absorbed into an equivalent Hermitian description, the metric mismatch here produces genuine non-Hermitian dynamics: a time-dependent normalization factor and complex-time branch structure that cannot be removed by any global similarity transformation.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.20016",
  "author_total": 3,
  "authors": [
    {
      "name": "Xu-Yang Hou"
    },
    {
      "name": "Jia-Chen Tang"
    },
    {
      "name": "Hao Guo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bwvy5jbsqqmz9.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.20016",
  "fulltext_url": null,
  "id": "bwvy5jbsqqmz9",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.20016",
  "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 Mechanics and Non-Hermitian Physics"
    ]
  ],
  "openalex": "W7222206558",
  "pdf_url": "https://arxiv.org/pdf/2610.20016",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bwvy5jbsqqmz9.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:31Z",
      "native_id": "2610.20016",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.20016"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Metric-Changing Quasi-Hermitian Quenches: Normalized Loschmidt Amplitude and Complex-Time Zeros",
  "title_text": "Metric-Changing Quasi-Hermitian Quenches: Normalized Loschmidt Amplitude and Complex-Time Zeros",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:31Z",
  "url": "https://research.draconitic.com/paper/bwvy5jbsqqmz9",
  "venue": "arXiv",
  "versions": []
}