Strong Cosmic Censorship and Eigenvalue Repulsions for rotating de Sitter black holes in higher-dimensions

TL;DR

This paper investigates the validity of Strong Cosmic Censorship in higher-dimensional rotating de Sitter black holes, showing it holds in certain cases and analyzing scalar field quasinormal modes revealing eigenvalue repulsions.

Contribution

It demonstrates SCC preservation in odd-dimensional Myers-Perry-de Sitter black holes and explores their quasinormal mode spectra, including eigenvalue repulsions, extending previous four-dimensional results.

Findings

SCC is respected by odd-dimensional Myers-Perry-de Sitter black holes.

Eigenvalue repulsions are observed in the QNM spectra, similar to asymptotically flat Kerr-Newman black holes.

QNM spectra typically consist of two main families for non-axisymmetric modes.

Abstract

It has been established that Christodoulou's formulation of Strong Cosmic Censorship (SCC) is violated by Reissner-Nordstr\"om-de Sitter black holes, but holds in four-dimensional Kerr-de Sitter black holes. We show that SCC is also respected by equal angular momenta (cohomogeneity-1) Myers-Perry-de Sitter (MP-dS) in odd $d \ge 5$ spacetime dimensions. This suggests that the preservation of SCC in rotating backgrounds might be a universal property of Einstein gravity and not limited to the d = 4 Kerr-dS background. As required to discuss SCC in de Sitter spacetimes, we also study important aspects of the scalar field quasinormal mode (QNM) spectra of MP-dS. In particular, we find eigenvalue repulsions similar to those recently observed in the QNM spectra of asymptotically flat Kerr-Newman black holes. For axisymmetric modes (i.e. with azimuthal quantum number m = 0) there are three distinct families of QNM (de Sitter, photon sphere and near-horizon). However, typically, for non-axisymmetric ($m \ne 0$) QNMs, we find that the entire spectra can be described by just two families of QNM (since several overtone sections of the photon sphere and near-horizon families merge). For completeness, we also study the full scalar field QNM spectra of higher-dimensional Schwarzschild-de Sitter black holes.