Tests of Cosmic Censorship in the Ernst Spacetime

TL;DR

This paper investigates cosmic censorship in the Ernst spacetime, showing that while weak censorship holds, strong censorship may be violated due to potential inner horizon stability in certain parameter ranges.

Contribution

It provides the first analysis of cosmic censorship in the Ernst spacetime, demonstrating the stability of the event horizon and potential violation of strong censorship.

Findings

Weak cosmic censorship is upheld as the event horizon remains intact.

Strong cosmic censorship may be violated due to inner horizon stability.

Inner horizon stability depends on specific parameter ranges.

Abstract

The Ernst spacetime is a solution of the Einstein-Maxwell equations describing two charged black holes accelerating apart in a uniform electric (or magnetic) field. As the field approaches a critical value, the black hole horizon appears to touch the acceleration horizon. We show that weak cosmic censorship cannot be violated by increasing the field past this critical value: The event horizon remains intact. On the other hand, strong cosmic censorship does appear to be violated in this spacetime: For a certain range of parameters, we find evidence that the inner horizon is classically stable.