Physics Seminar
Date: Tuesday, 03 October 2023
Time: 03:30 PM
Venue: Lecture Hall 03
Black holes and their QNMs in degenerate EGB gravity
Suvikranth Gera
BITS Pilani, Goa Campus.
03-10-23

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Abstract

In recent years, there has been a renewed interest in lovelock theorems and Gauss Bonnet(GB) terms in four dimensions. In the context of first-order formulation of gravity, Sengupta [JCAP 02(2022)02] provided a gravity framework with dynamical imprints of GB density. Unlike the earlier approaches, this framework does not rely on singular rescaling nor introduces any new dynamical fields. Instead, this is achieved from a degenerate metric.

In this talk, I will briefly introduce the framework of degenerate gravity theories while emphasising degenerate Einstein Gauss-Bonnet (dEGB) in particular. Then, we explore the static spherically symmetric solutions in this framework. These solutions also have two branches, akin to the Einstein Gauss-Bonnet(EBG) gravity. However, unlike the EBG solutions, both the branches of dEGB are well-defined asymptotically. The negative branches from both theories can be identified for the asymptotically flat case. We observe black holes for specific ranges of the Gauss-Bonnet coupling parameter and perform a stability analysis by calculating the quasinormal modes (QNMs) under scalar wave propagation. Finally, the ringdown spectrums of our black holes are compared with their GR counterparts.