Nonsingular black holes in Palatini extensions of General Relativity

TL;DR

This paper explores extended gravity theories in Palatini formalism, showing that they can replace black hole singularities with wormholes, resulting in geodesically complete, non-singular spacetimes through specific models.

Contribution

It demonstrates how Palatini extensions of General Relativity can resolve black hole singularities by replacing them with wormhole structures in spherically symmetric, charged configurations.

Findings

Central singularities are replaced by wormholes in these theories.

The resulting spacetime is geodesically complete and non-singular.

Two models, quadratic $f(R)$ and Born-Infeld gravity, illustrate these properties.

Abstract

An introduction to extended theories of gravity formulated in metric-affine (or Palatini) spaces is presented. Focusing on spherically symmetric configurations with electric fields, we will see that in these theories the central singularity present in General Relativity is generically replaced by a wormhole structure. The resulting space-time becomes geodesically complete and, therefore, can be regarded as non-singular. We illustrate these properties considering two different models, namely, a quadratic $f(R)$ theory and a Born-Infeld like gravity theory.