Quasi normal modes and the area spectrum of a near extremal de Sitter black hole with conformally coupled scalar field

Abstract

In this paper we have studied a black hole in de Sitter space which has a conformally coupled scalar field in the background. This black hole is also known as the $MTZ$ black hole. We have obtained exact values for the quasi normal mode frequencies under massless scalar field perturbations. We have demonstrated that when the black hole is near-extremal, that the wave equation for the massless scalar field simplifies to a Schr$\ddot{o}$dinger type equation with the well known P$\ddot{o}$shler-Teller potential. We have also used 6th order WKB approximation to compute quasinormal mode frequencies to compare with exact values obtained via the P$\ddot{o}$shler-Tell method for comparison. As an application, we have obtained the area spectrum using modified Hods approach and show that it is equally spaced.