Weak Cosmic Censorship with spinning particles in Kerr-(A)dS spacetimes

TL;DR

This paper examines whether spinning particles can overspin extremal Kerr-(A)dS black holes, finding that such particles cannot violate the weak cosmic censorship conjecture in these spacetimes.

Contribution

It extends previous analyses of the weak cosmic censorship conjecture to include spinning particles in Kerr-(A)dS spacetimes, considering the effects of a non-zero cosmological constant.

Findings

Particles captured by the black hole do not overspin it beyond extremality.

The weak cosmic censorship conjecture holds for spinning particles in both de Sitter and anti-de Sitter Kerr spacetimes.

Analysis accounts for the subtleties of the point particle approximation in AdS spacetime.

Abstract

We investigate the weak cosmic censorship conjecture by analyzing the dynamics of spinning timelike particles dropped along the rotational axis of an extremal Kerr (anti)de Sitter black hole. This idea was first considered in a seminal paper by Wald and later by Needham but both analyses were restricted to asymptotically flat spacetimes. We generalize these studies, involving spinning particles, to rotating spacetimes with non vanishing cosmological constant. We examine whether the absorption of such particles can overspin the black hole beyond extremality, potentially leading to the formation of a naked singularity. In asymptotically de Sitter spacetime, we find that particles that are captured cannot overspin the black hole. Similar conclusions hold also with anti-de Sitter asymptotics, but the analysis is more subtle, requiring careful consideration of the point particle approximation.