Radiating black holes in general relativity need not be singular

TL;DR

This paper demonstrates that charged black holes formed through collapse and Hawking radiation can avoid singularities and Cauchy horizons due to electromagnetic repulsion and energy condition violations.

Contribution

It challenges the common view by showing that black holes need not contain singularities or Cauchy horizons under certain conditions involving Hawking radiation.

Findings

Electromagnetic repulsion can prevent singularity formation.

Hawking radiation-induced energy condition violations are sufficient.

Similar mechanisms may apply to astrophysical rotating black holes.

Abstract

It is common knowledge that black holes necessarily contain a region where general relativity breaks down, due to the inevitable formation of either a curvature singularity or a Cauchy horizon. In this work we challenge this view by analyzing a charged spherically symmetric black hole formed through gravitational collapse and evaporating via Hawking radiation. We show that the electromagnetic repulsion and the violation of energy conditions due to the presence of Hawking radiation are be sufficient to avoid the formation of both a singularity and a Cauchy horizon. We argue that a similar mechanism may apply to astrophysical black holes in which the role of the electric charge is replaced by the angular momentum.