Quasinormal modes and greybody factors of the novel four dimensional Gauss\u2013Bonnet black holes in asymptotically de Sitter space time: scalar, electromagnetic and Dirac perturbations

Saraswati Devi,Sayan Chakrabarti,Rittick Roy

doi:10.1140/epjc/s10052-020-8311-1

Abstract

We find the low lying quasinormal mode frequencies of the recently proposed novel four dimensional Gauss–Bonnet de Sitter black holes for scalar, electromagnetic and Dirac field perturbations using the third order WKB approximation as well as Padé approximation, as an improvement over WKB. We figure out the effect of the Gauss–Bonnet coupling alpha and the cosmological constant Lambda on the real and imaginary parts of the QNM frequencies. We also study the greybody factors and eikonal limits in the above background for all three different types of perturbations.

Highlights

The black hole parameters and despite the classical origin, it was found that quasinormal modes (QNMs) might provide a hint into the quantum nature of the black holes [5,6,7]
QNMs of black holes have already been observed in the ground based experiments [8,9] and they already present a plethora of information about black holes
It has been observed that the last stage of formation of the single BH or NS from the binary merger is dominated by the quasinormal ringing and this process corresponds to an extremely strong gravitational field which cannot be modeled using the help of post-Newtonian approximation

Summary

Introduction

The black hole parameters and despite the classical origin, it was found that QNMs might provide a hint into the quantum nature of the black holes [5,6,7]. It has been observed that the last stage of formation of the single BH or NS from the binary merger is dominated by the quasinormal ringing and this process corresponds to an extremely strong gravitational field which cannot be modeled using the help of post-Newtonian approximation It is this last stage of the merger process which carries the necessary imprint of the characteristics of a particular theory of gravity [10]. Studying various alternative theories of gravity in the strong field region still remains an active and interesting area of research in the context of gravitational wave signatures of black holes. One such alternative theory is the Einstein–Gauss–Bonnet (EGB) theory of gravity which consists of higher curvature corrections to the Einstein–Hilbert term in the gravitational action. Very recently a non-trivial extension of EGB theory of gravity has been proposed by Glavan and Lin [41] in four space time dimensions as D → 4 limit of the higher dimensional Gauss–

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