Superradiant instability in AdS

TL;DR

This paper explores superradiant instability in asymptotically AdS spacetimes, analyzing its effects on stability and endpoint configurations, including black hole charge reduction and scalar condensates, with implications for cosmic censorship.

Contribution

It provides a detailed analysis of superradiant instability in Kerr-AdS and RN-AdS spacetimes, including boundary conditions and potential endpoint states.

Findings

Superradiant instability can lead to black hole charge reduction.

Charged scalar condensates can form around black holes.

Some outcomes suggest violations of cosmic censorship.

Abstract

The phenomenon of superradiance in the context of asymptotically global AdS spacetimes is investigated with particular accent on its effect on the stability of the systems under consideration. To this end, the concept of an asymptotically AdS spacetime is explained, together with its implications on the boundary conditions at $\mathcal{I}$, as well as the Newman-Penrose-Teukolsky formalism, whereby the Teukolsky master equation in a most general form for Kerr-AdS is given. Furthermore, work done in the cases of RN-AdS and Kerr-AdS is laid out in a concise manner, putting emphasis on the important steps taken in determining the endpoint of the superradiant instability in the two configurations. For the former this turns out to be a black hole with reduced charge and a static charged scalar condensate around it, whereas for the latter two of the more probable outcomes are presented, both of which imply a violation of one of the cosmic censorships.