{
  "abstract": "It has been shown that the thermodynamics of frame-invariant scalar-tensor gravity admits an Einstein-frame-like invariant representation, in which the scalar sector is minimally coupled and behaves as a perfect fluid with vanishing temperature. We show that this is not the only invariant thermodynamic organization available. Using instead the invariant matter metric, we construct a Jordan-frame-like invariant representation in which matter is minimally coupled and the gravitational action takes the Brans-Dicke-Bergmann-Wagoner form with invariant fields $Ψ=\\mathcal I_1^{-1}$, $\\mathcal U(Ψ)$, and $ω_{\\mathrm{inv}}(Ψ)$. In this representation the metric field equations retain the Hessian sector characteristic of Jordan-frame scalar-tensor gravity. A $1+3$ decomposition of the corresponding effective stress tensor yields nonvanishing heat flux and anisotropic stress in a generic congruence. In the $Ψ$-comoving frame, the usual first-order thermodynamic identifications are recovered in invariant form, including $K_{\\mathrm J}T_{\\mathrm J}=-\\dotΨ/(κ^2Ψ)$ and $η_{\\mathrm J}=\\dotΨ/(2κ^2Ψ)$, with the bulk channel obtained in homogeneous and isotropic sectors. Thus, frame-invariant scalar-tensor thermodynamics is not intrinsically restricted to an Einstein-frame-like perfect-fluid description: it also admits a Jordan-frame-like invariant formulation in which the effective imperfect-fluid interpretation is manifest.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.20189",
  "author_total": 2,
  "authors": [
    {
      "name": "David S. Pereira"
    },
    {
      "name": "José Pedro Mimoso"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/09h265zdd8vqg.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.20189",
  "fulltext_url": null,
  "id": "09h265zdd8vqg",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.20189",
  "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",
      "gr-qc"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.20189",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/09h265zdd8vqg.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:19Z",
      "native_id": "2609.20189",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.20189"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Jordan-like invariant representations of scalar-tensor gravity and the return of imperfect-fluid thermodynamics",
  "title_text": "Jordan-like invariant representations of scalar-tensor gravity and the return of imperfect-fluid thermodynamics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:19Z",
  "url": "https://research.draconitic.com/paper/09h265zdd8vqg",
  "venue": "arXiv",
  "versions": []
}