Quasinormal modes of accelerating spacetime

TL;DR

This paper computes exact quasinormal frequencies for massless perturbations in pure accelerating spacetime, revealing spin-independent, purely imaginary spectra that relate to acceleration modes and are consistent with de Sitter results.

Contribution

It provides the first exact calculation of quasinormal modes in pure accelerating spacetime using hypergeometric equations, showing their independence from spin and connection to acceleration modes.

Findings

Spectra are purely imaginary and spin-independent.

Spectra match acceleration modes of accelerating black holes in Minkowski limit.

Method verified by comparing with de Sitter perturbation results.

Abstract

We calculate the exact values of the quasinormal frequencies for massless perturbations with spin $s\leq2$ moving in pure accelerating spacetime. We use two different methods to transfer the perturbation equations into the form of hypergeometric differential equations and obtain the same quasinormal frequencies. These purely imaginary spectra are shown to be independent of the spin of the perturbation and match those of the so-called acceleration modes of accelerating black holes after taking the Minkowski limit. This implies that the acceleration modes actually originate from the pure accelerating spacetime and the appearance of black holes would deform the spectra. In addition, we calculate the quasinormal frequencies of scalar, electromagnetic and gravitational perturbations of $D$-dimensional de Sitter spacetime and compare them with previous results to verify the validity of our method.