2013/12/31 by Hyeong-Chan Kim · 1 citation
Mathematics · Physics and Astronomy · #Astrophysics #Black Holes and Theoretical Physics #Classical mechanics #Cosmology and Gravitation Theories #Curvature #Equation of state #Geometry #Gravitation #Gravitational singularity #Mathematical physics #Mathematics #Physics #Polytropic process #Quantum mechanics #Scalar curvature #Singularity #Solar and Space Plasma Dynamics #Stars #Surface (topology) #Surface gravity #astro-ph.SR #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.89.064001
published as Phys. Rev. D 89, 064001 (2014) · 7 pages, Comments are added for negative curvatures
arxiv created 2014/01/04 · openalex publication_date 2014/03/04 · arxiv updated 2014/06/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study phenomena happening at the surface of a star in Eddington-inspired Born-Infeld (EiBI) gravity. The star is made of particles, which are effectively described by a polytropic fluid. The EiBI theory was known to have a pathology that singularities happen at a star surface. We suggest that the gravitational backreaction on the particles cures the problem. Strong tidal forces near the (surface) singularity modify the effective equation of state of the particles or make the surface be unstable depending on its matter contents. The geodesic deviation equations take after Hooke's law, where its frequency squared is proportional to the scalar curvature at the surface. For a positive curvature, a particle collides with a probing wall more often and increases the pressure. With the increased pressure, the surface is no longer singular. For a negative curvature, the matters around the surface experience repulsions with infinite accelerations. Therefore, the EiBI gravity is saved from the pathology of a surface singularity.