Regular black holes in de Sitter universe: scalar field perturbations and quasinormal modes

TL;DR

This paper investigates the quasinormal modes of regular black holes in de Sitter space under scalar perturbations, analyzing how various parameters affect the frequencies and employing analytical and approximation methods.

Contribution

It provides a detailed analysis of QNM frequencies for regular de Sitter black holes, including analytical proofs and approximation techniques like Pöschl-Teller potential.

Findings

QNM frequencies vary with black hole parameters.

The $l=0$ mode reaches a constant at late times.

Exact frequencies are obtained using Pöschl-Teller potential approximation.

Abstract

The purpose of this paper is to study quasinormal modes (QNM) of a regular black hole with a cosmological constant due to scalar perturbations. A detailed study of the QNM frequencies for the massless scalar field were done by varying the parameters of the theory such as the mass, magnetic charge, cosmological constant, and the spherical harmonic index. We have employed the sixth order WKB approximation to compute the QNM frequencies. We have also proved analytically that the $l=0$ mode for the massless field reach a constant value at late times. We have approximated the near-extreme regular-de Sitter black hole potential with the P$\ddot{o}$schl-Teller potential to obtain exact frequencies. The null geodesics of the regular-de Sitter black hole is employed to describe the QNM frequencies at the eikonal limit ($ l >>1$).