Quasinormal modes of Dirac spinors in the background of rotating black holes in four and five dimensions

Abstract

We study the quasinormal modes of massive Dirac spinors in the background of rotating black holes. In particular, we consider the Kerr geometry as well as the five dimensional Myers–Perry spacetime with equal angular momenta. We decouple the equations using the standard methods from the literature. In the five dimensional Myers–Perry black hole the angular equation is solved analytically. Using the continued fraction method, we calculate the spectrum of quasinormal modes for the ground modes and first excited modes. For the case of the Kerr black hole we also study some features of the modes with high overtone number. We analyze, in a systematic way, its dependence on the different parameters of the black hole and fermionic field. We compare our values with previous results available in the literature for Kerr and for the static limit. The numerical results show several differences between the four and five dimensional cases. For instance, in five dimensions the symmetry between the positive and negative (real) frequency of the modes breaks down, which results in a richer spectrum.