Correspondence between grey-body factors and quasinormal frequencies for rotating black holes

TL;DR

This paper explores the intrinsic connection between grey-body factors and quasinormal modes in rotating black holes, extending previous results to more general black hole geometries and highlighting limitations related to superradiance.

Contribution

It demonstrates that the correspondence between grey-body factors and quasinormal modes applies to axially symmetric black holes, broadening the scope beyond spherically symmetric cases.

Findings

The correspondence extends to general axially symmetric black holes.

The connection is valid for non-superradiant waves.

The study clarifies limitations related to superradiance.

Abstract

Although the proper oscillation frequencies of black holes (quasinormal modes) and the grey-body factors, which determine the scattering properties of black holes, represent two distinct spectral problems with different boundary conditions, a recent study has revealed an intrinsic connection between these quantities. We have shown that the correspondence between grey-body factors and quasinormal modes, previously established for spherically symmetric and asymptotically flat black holes, also extends to general parametrized axially symmetric black holes. This correspondence is limited to non-superradiant waves.