Rigorous bounds on greybody factors for various types of black holes

Abstract

One of the quantum effects of black holes is Hawking radiation. Scattering of Hawking radiation from a gravitational potential barrier, resulting from the curvature of spacetime, is analogous to the scattering of matter wave from a potential barrier in quantum mechanics. In the context of black hole radiation, the transmission probability is known as greybody factor. In this dissertation, rigorous bounds on greybody factors for non-rotating black holes, Kerr-Newman black holes, and dirty black holes are derived. For non-rotating black holes, including dirty black holes, calculations of rigorous bounds on the greybody factors are simple. However, for a Kerr-Newman black hole, which is a type of rotating black holes, the situations are more complicated since the rigorous bounds on the greybody factors depend on scalar angular momentum mode. Moreover, there is a new phenomenon called super-radiance that arises in rotating black holes, which is absent in the non-rotating black holes.