{
  "abstract": "Pressure anisotropy in relativistic stars is commonly prescribed through a phenomenological closure, obscuring its microscopic origin and relation to stress-energy conservation. Here it is derived directly from the minimally coupled Einstein-complex-Proca theory. For spherical Proca stars, the principal-pressure difference admits an exact on-shell form whose sign is controlled solely by the local mass-shell threshold. The stress is radially dominated in the core, reverses on a surface of fixed gravitational redshift, and becomes tangentially dominated in the envelope. At the first mass maximum, the fractional anisotropy reaches about 21% near the density maximum, whilst the region beyond the reversal contains about 9% of the mass. Its exact atmospheric limit is approximately 24%, equal in magnitude and opposite in sign to the scalar-boson-star limit. Because the usual local fluid variables remain non-zero at the crossing, no sign-definite closure constructed from them can reproduce the profile. These results identify an intrinsically vectorial stress reversal, generated without additional interactions, and provide a first-principles benchmark for anisotropic bosonic compact objects.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Physics Letters B, October 2026, 40940, Volume 881",
  "arxiv": "2609.12773",
  "author_total": 1,
  "authors": [
    {
      "name": "Ilídio Lopes"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dk7gatrx9acjw.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.12773",
  "fulltext_url": null,
  "id": "dk7gatrx9acjw",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.12773",
  "language": null,
  "licence": "CC0-1.0",
  "licence_label": "CC0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/publicdomain/zero/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "hep-th"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.12773",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-11",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dk7gatrx9acjw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2609.12773",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.12773"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Intrinsic pressure anisotropy in spherical Proca stars",
  "title_text": "Intrinsic pressure anisotropy in spherical Proca stars",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:41Z",
  "url": "https://research.draconitic.com/paper/dk7gatrx9acjw",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1016/j.physletb.2026.140940",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}