English

Static spacetimes with a Finsler angular sector

General Relativity and Quantum Cosmology 2026-02-18 v2

Abstract

We consider static spacetimes in spherical coordinates whose angular sector is described by a Finsler metric rather than the standard round metric on S2S^2. Our first contribution is kinematical: maintaining arbitrary lapse and radial factors eν(r)e^{\nu(r)}, eϑ(r)e^{\vartheta(r)}, and relying solely on Killing symmetries and the null constraint, we derive model--independent relations for circular photon orbits and the effective dynamics. By specializing the angular sector to Randers sphere of constant positive flag curvature, we obtain exact expressions for the conserved angular charge, the critical impact parameter and we quantify a Finslerian Sagnac--type effect. Our second contribution is dynamical: we examine the field equations used in the literature to determine (eν,eϑ)(e^{\nu},e^{\vartheta}). We revisit the family of hairy black holes in \cite{Nekouee2025}, demonstrating that the analysis therein neglects crucial non-reversible Finsler features. Furthermore, we show that the solutions presented as new reproduce previously known results in \cite{Ovalle2021}.

Keywords

Cite

@article{arxiv.2508.20658,
  title  = {Static spacetimes with a Finsler angular sector},
  author = {Erasmo Caponio},
  journal= {arXiv preprint arXiv:2508.20658},
  year   = {2026}
}

Comments

AMSLaTex, 13 pages, v2: Remarks 3.2 and 3.6 expanded, added Subsec. 3.3, Appendix in v1 is now Section 4

R2 v1 2026-07-01T05:10:01.260Z