Embedding regular black holes and black bounces in a cloud of strings

TL;DR

This paper investigates how a cloud of strings affects the regularity, energy conditions, and thermodynamics of Bardeen and Simpson--Visser black hole solutions in general relativity, revealing that the cloud can alter their singularity and energy properties.

Contribution

It introduces the analysis of a cloud of strings around regular black hole solutions, showing how it impacts their regularity, energy conditions, and thermodynamic behavior.

Findings

The cloud of strings can make the energy density positive in some cases.

The Bardeen solution becomes singular with a cloud of strings.

The Simpson--Visser solution remains regular despite the cloud.

Abstract

A string is the one-dimensional generalization of a point particle. In this sense, the analog of a cloud of dust would be a cloud of strings. In this work, we consider a cloud of strings around a regular solution in general gelativity. We consider the Bardeen solution and the Simpson--Visser solution, analyzing the consequences of the cloud in the regularity and in the energy conditions. Actually, the presence of the cloud could make the energy density positive when compared to the Simpson--Visser case. We verify that the usual Bardeen solution becomes singular in the presence of the cloud of string while the Simpson--Visser solution is still regular, violating the energy conditions, as the usual solution. We also calculate some thermodynamic quantities to evaluate how a cloud of strings influences the thermodynamics of the solutions.