Superradiant instability of Kerr-de Sitter black holes in scalar-tensor theory

TL;DR

This paper analyzes the superradiant instability of Kerr-de Sitter black holes within scalar-tensor gravity, exploring the conditions for instability and implications for astrophysical black holes with a cosmological constant.

Contribution

It provides a detailed examination of superradiance mechanisms and identifies conditions for scalarization in de Sitter backgrounds, advancing understanding of black hole stability in scalar-tensor theories.

Findings

Superradiant instability can occur in Kerr-de Sitter black holes within scalar-tensor gravity.

Spontaneous scalarization is possible in spherical de Sitter configurations under certain conditions.

Results offer insights into testing scalar-tensor gravity with astrophysical black holes.

Abstract

We investigate in detail the mechanism of superradiance to render the instability of Kerr-de Sitter black holes in scalar-tensor gravity. Our results provide more clues to examine the scalar-tensor gravity in the astrophysical black holes in the universe with cosmological constant. We also discuss the spontaneous scalarization in the de Sitter background and find that this instability can also happen in the spherical de Sitter configuration in a special style.