Glimpses of Violation of Strong Cosmic Censorship in Rotating Black Holes

TL;DR

This paper investigates the stability of the Cauchy horizon in rotating black holes with a positive cosmological constant, providing evidence that the Strong Cosmic Censorship conjecture may be violated in such spacetimes.

Contribution

It offers the first evidence that the Strong Cosmic Censorship conjecture can be violated in four-dimensional rotating black holes by analyzing linear perturbations and quasinormal modes.

Findings

Existence of weak solutions across the Cauchy horizon in nearly-extremal Kerr-Newman-de Sitter black holes.

Evidence for potential violation of Strong Cosmic Censorship in rotating black hole spacetimes.

Analysis of scalar and fermion field perturbations supports these conclusions.

Abstract

Rotating and/or charged black hole spacetimes possess a Cauchy horizon, beyond which Einstein's equations of General Relativity cease to be deterministic. This led to the formulation of the Strong Cosmic Censorship conjecture that such horizons become irregular under field perturbations. We consider linear field perturbations of rotating and electrically-charged (Kerr-Newman-de Sitter) black holes in a universe with a positive cosmological constant. By calculating the quasinormal modes for scalar and fermion fields, we provide evidence for the existence of weak solutions to Einstein's equations across the Cauchy horizon in the nearly-extremal regime. We thus provide, for the first time, evidence for violation of Strong Cosmic Censorship in (4-dimensional) rotating black hole spacetimes.