Scalar perturbations of black holes in Jackiw-Teitelboim gravity

TL;DR

This paper analyzes scalar perturbations of black holes in 2D Jackiw-Teitelboim gravity, deriving quasinormal modes, Hawking spectra, and examining cosmic censorship, with both analytical and numerical methods.

Contribution

It provides exact quasinormal mode expressions for JT black holes, explores scalar wave equations in 2D Reissner-Nordström solutions, and investigates cosmic censorship in dimensionally reduced BTZ black holes.

Findings

Exact quasinormal mode frequencies for JT black holes derived

Hawking spectra computed using confluent Heun equation

Potential violation of strong cosmic censorship near extremality, mitigated by quantum effects

Abstract

We study linear scalar perturbations of black holes in two-dimensional (2D) gravity models with a particular emphasis on Jackiw-Teitelboim (JT) gravity. We obtain an exact expression of the quasinormal mode frequencies for single horizon black holes in JT gravity and then verify it numerically using the Horowitz-Hubeny method. For a 2D Reissner-Nordstr\"om like solution, we find that the massless scalar wave equation reduces to the confluent Heun equation using which we calculate the Hawking spectra. Finally, we consider the dimensionally reduced Ba\~nados-Teitelboim-Zanelli (BTZ) black hole and obtain the exterior and interior quasinormal modes. The dynamics of a scalar field near the Cauchy horizon mimics the behavior of the same for the usual BTZ black hole, indicating a possible violation of the strong cosmic censorship conjecture in the near extreme limit. However, quantum effects seem to rescue strong cosmic censorship.