{
  "abstract": "We investigate the domain in which a semiclassical gravitational WKB flow can serve as a quantitatively controlled temporal reference for subordinate quantum degrees of freedom. Rather than introducing WKB time at the outset, we formulate the Born--Oppenheimer adiabatic condition directly on gravitational configuration space using the Hamilton--Jacobi vector field. This separates adiabatic control from the local WKB validity of the gravitational branch and from the sharpness of the candidate reference against quantum fluctuations. For a single selected semiclassical branch, these requirements define the validity domain $D_t = D_{\\mathrm{WKB}} \\cap D_{\\mathrm{ad}} \\cap D_{\\mathrm{sharp}}$, with an additional decoherence condition when coherent branches coexist.In a closed Friedmann--Robertson--Walker minisuperspace coupled to a homogeneous massive scalar mode, the distinction is explicit: approaching the gravitational turning point from the oscillatory region, the ordinary WKB control parameter diverges while the configuration-space adiabatic parameter tends to zero. A uniform Airy treatment of the turning point removes the formal WKB divergence while preserving the inequivalence: the corresponding local control parameter remains of order unity, whereas the configuration-space adiabatic parameter is parametrically suppressed as $O(M^{-1/3})$.Thus Born--Oppenheimer adiabaticity and gravitational WKB validity define inequivalent domains even within the simplest minisuperspace model. We conclude that the existence of an oscillatory semiclassical branch is not sufficient for a reliable WKB temporal description: semiclassical temporal reliability is instead determined by the overlap of the validity domains supporting the reference flow.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.37696",
  "author_total": 2,
  "authors": [
    {
      "name": "Gianpaolo Rosati"
    },
    {
      "name": "Sergio L. Cacciatori"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dcaff9sjg9m32.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.37696",
  "fulltext_url": null,
  "id": "dcaff9sjg9m32",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.37696",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "arxiv",
      "hep-th"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.37696",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dcaff9sjg9m32.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:22Z",
      "native_id": "2610.37696",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.37696"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-th",
      "subfield": "high-energy"
    }
  ],
  "title": "Validity Domains for Semiclassical Time in Quantum Cosmology",
  "title_text": "Validity Domains for Semiclassical Time in Quantum Cosmology",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:44Z",
  "url": "https://research.draconitic.com/paper/dcaff9sjg9m32",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1103/w7zp-vz6k",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}