Compact scalar field solutions in EiBI gravity
Abstract
We discuss exact scalar field solutions describing gravitating compact objects in the Eddingtoninspired BornInfeld (EiBI) gravity, a member of the class of (metricaffine formulated) Riccibased gravity (RBG) theories. We include a detailed account of the RBGs/GR correspondence exploited to analytically solve the field equations. The single parameter đťś– of the EiBI model defines two branches for the solution. The É› > 0 branch may be described as a â€śshell with no interiorâ€ť, and constitutes an illdefined, geodesically incomplete spacetime. The more interesting É› < 0 branch admits the interpretation of a â€śwormhole membraneâ€ť, an exotic horizonless compact object with the ability to transfer particles and light from any point on its surface (located slightly below the wouldbe Schwarzschild radius) to its antipodal point, in a vanishing fraction of proper time. This is a single example illustrating how the structural modifications introduced by the metricaffine formulation may lead to significant departures from General relativity (GR) even at astrophysically relevant scales, giving rise to physically plausible objects radically different from those we are used to think of in the metric approach, and that could act as a black hole mimickers whose shadows might present distinguishable signals.
 Publication:

International Journal of Modern Physics D
 Pub Date:
 2020
 DOI:
 10.1142/S0218271820410114
 arXiv:
 arXiv:2004.10795
 Bibcode:
 2020IJMPD..2941011A
 Keywords:

 Metricaffine gravity;
 compact objects;
 black hole mimickers;
 General Relativity and Quantum Cosmology
 EPrint:
 27 onecolumn pages, 4 figures, Contribution to Selected Papers of the Fifth Amazonian Symposium on Physics, Accepted in IJMPD