Remarks on non-singular black holes

TL;DR

This paper examines non-singular black hole models, focusing on their properties, radiation emission, and the challenges of ensuring their self-consistency, especially regarding information retrieval and the mass inflation problem.

Contribution

It analyzes the radiation behavior of non-singular evaporating black holes and discusses potential solutions to the mass inflation issue.

Findings

Quantum radiation can be exponentially large in certain models.

Including a non-trivial redshift function can suppress radiation.

Self-consistency remains challenging due to the mass inflation problem.

Abstract

We briefly discuss non-singular black hole models, with the main focus on the properties of non-singular evaporating black holes. Such black holes possess an apparent horizon, however the event horizon may be absent. In such a case, the information from the black hole interior may reach the external observer after the complete evaporation of the black hole. This model might be used for the resolution of the information loss puzzle. However, as we demonstrate, in a general case the quantum radiation emitted from the black hole interior, calculated in the given black hole background, is very large. This outburst of the radiation is exponentially large for models with the redshift function $\alpha=1$. We show that it can be suppressed by including a non-trivial redshift function. However, even this suppression is not enough to guarantee self-consistency of the model. This problem is a manifestation of a general problem, known as the "mass inflation". We briefly comment on possible ways to overcome this problem in the models of non-singular evaporating black holes.