{
  "abstract": "This paper studies homogeneous \\Godel-type geometries in a gravitational model where local Lorentz symmetry is spontaneously broken by the vacuum expectation value of an antisymmetric Kalb-Ramond two-form. We consider the Einstein-Hilbert action supplemented by two independent nonminimal curvature couplings: a Ricci-tensor coupling of the form $B_{a}{}^{c}B_{bc}R^{ab}$ and a Riemann-tensor coupling of the form $B^{ab}B^{cd}R_{abcd}$. In the homogeneous vacuum sector, where the Kalb-Ramond field strength and the first derivatives of the symmetry-breaking potential vanish, the field equations reduce to a closed algebraic system in the tetrad frame of the \\Godel-type metric. We derive the curvature tensors, the reduced metric equations, and the Kalb-Ramond consistency equations for several inequivalent orientations of the vacuum two-form. Particular attention is given to the pseudo-magnetic background $B_{12}=b$, because it preserves the symmetry of the rotation plane and yields a transparent deformation of the usual bumblebee result. For this sector the Kalb-Ramond equation fixes $\\frac{m^2}{ω^2}=\\frac{2(ξ_1+3ξ_2)}{ξ_1+2ξ_2}$, where $ξ_1$ and $ξ_2$ are the Ricci and Riemann couplings. The Ricci coupling alone reproduces the noncausal \\Godel value $m^2=2ω^2$, while the Riemann coupling shifts the chronology bound and allows the critical causal value $m^2=4ω^2$ for $ξ_2=-ξ_1$. We also show that the Riemann coupling can move the critical radius for closed timelike curves, but ordinary positive-energy matter severely restricts completely causal solutions. Finally, we discuss perfect fluid, scalar field, and electromagnetic sources.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.26472",
  "author_total": 1,
  "authors": [
    {
      "name": "Fernando M. Belchior"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2nb0tn5x5t31r.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.26472",
  "fulltext_url": null,
  "id": "2nb0tn5x5t31r",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.26472",
  "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"
    ],
    [
      "openalex",
      "3109|Noncommutative and Quantum Gravity Theories"
    ]
  ],
  "openalex": "W7204543862",
  "pdf_url": "https://arxiv.org/pdf/2608.26472",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-31",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2nb0tn5x5t31r.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:41Z",
      "native_id": "2608.26472",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.26472"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Gödel-type universes in Lorentz-violating Kalb-Ramond gravity with Ricci- and Riemann-tensor nonminimal couplings",
  "title_text": "Gödel-type universes in Lorentz-violating Kalb-Ramond gravity with Ricci- and Riemann-tensor nonminimal couplings",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:41Z",
  "url": "https://research.draconitic.com/paper/2nb0tn5x5t31r",
  "venue": "arXiv",
  "versions": []
}