Asymptotic quasinormal modes of string-theoretical $d$-dimensional black holes

TL;DR

This paper calculates the asymptotic quasinormal mode frequencies of string-theoretical black holes in higher dimensions, revealing differences from Einstein gravity for tensorial gravitational and scalar perturbations.

Contribution

It provides the first perturbative computation of quasinormal modes for string-corrected $d$-dimensional black holes, highlighting distinctions from classical Einstein gravity.

Findings

Distinct quasinormal mode spectra for gravitational and scalar perturbations.

Analytic computation of monodromies in the complex plane.

Differences from Einstein gravity in highly damped regimes.

Abstract

We compute the quasinormal frequencies of $d$-dimensional spherically symmetric black holes with leading string $\alpha'$ corrections for tensorial gravitational perturbations in the highly damped regime. We solve perturbatively the master differential equation and we compute the monodromies of the master perturbation variable (analytically continued to the complex plane) in different contours, in order to obtain the quasinormal mode spectra. We proceed analogously for the quasinormal modes of test scalar fields. Differently than in Einstein gravity, we obtain distinct results for the two cases.