Sound from extra dimension: quasinormal modes of thick brane

TL;DR

This paper studies the quasinormal modes of a thick brane system, revealing discrete decaying massive gravitons that reflect the brane's structure using analytical and numerical methods.

Contribution

It introduces a detailed analysis of quasinormal modes in thick branes, employing WKB and asymptotic iteration methods to solve the Schrödinger-like equation for tensor perturbations.

Findings

Identification of discrete quasinormal modes in the thick brane model

Quasinormal modes behave as decaying massive gravitons

Modes reflect the structure of the thick brane

Abstract

In this work, we investigate the quasinormal modes of a thick brane system. Considering the transverse-traceless tensor perturbation of the brane metric, we obtain the Schr\"odinger-like equation of the Kaluza-Klein modes of the tensor perturbation. Then we use the Wentzel-Kramers-Brillouin approximation and the asymptotic iteration method to solve this Schr\"odinger-like equation. We also study the numeric evolution of an initial wave packet against the thick brane. The results show that there is a set of discrete quasinormal modes in the thick brane model. These quasinormal modes appear as the decaying massive gravitons for a brane observer. They are characteristic modes of the thick brane and can reflect the structure of the thick brane.