Quasinormal modes of the near extremal Schwarzschild-de Sitter black hole

TL;DR

This paper derives exact formulas for the quasinormal modes of various perturbations in near extremal Schwarzschild-de Sitter black holes, clarifying previous approximations and exploring implications for highly damped modes and quantum gravity parameters.

Contribution

It provides the first exact expressions for quasinormal modes in the near extremal Schwarzschild-de Sitter spacetime, confirming the validity of earlier approximations in this regime.

Findings

Exact quasinormal mode formulas for scalar, electromagnetic, and gravitational perturbations.

Asymptotic behavior of highly damped modes analyzed.

Insights into the relation between quasinormal modes and the Barbero-Immirzi parameter.

Abstract

We present an exact expression for the quasinormal modes of scalar, electromagnetic and gravitational perturbations of a near extremal Scwarzschild-de Sitter black hole and we show why a previous approximation holds exactly in this near extremal regime. In particular, our results give the asymptotic behavior of the quasinormal frequencies for highly damped modes, which as recently attracted much attention due to the proposed identification of its real part with the Barbero-Immirzi parameter.