Aspects of Black Hole Scattering

We discuss various aspects of black hole scattering. Firstly, we consider nonextremal rotating black branes. We solve the wave equation for a massless scalar field and calculate the absorption cross section. We obtain a function of two temperature parameters once we move away from extremality, which is similar to the case of Kerr- Newman black holes. We discuss the implications of this result to the AdS/CFT correspondence. Secondly, we study a system of maximally-charged slowly-moving black holes and take the limit of a continuous self-interacting matter distribution (black string). We quantize the system by using the path integral method. We show that a careful implementation of the Faddeev-Popov gauge-fixing procedure leads to a Hamiltonian possessing a well-defined vacuum. The Hamiltonian consists of a kinetic energy term and a potential which is the generator of special conformal transformations. We obtain an explicit expression for the Hamiltonian of a ring-shaped formation and show that it is equivalent to a harmonic oscillator in the non-relativistic limit. Thirdly, we investigate quasinormal modes. We develop a perturbative method of calculating quasinormal frequencies in the high temperature limit of AdS Schwarzschild spacetimes of varying dimensionality. In 2+1 dimensions, exact expressions involving hypergeometric functions have been obtained. We discuss the (4+1)-dimensional case in detail. In this case, the calculation of quasinormal modes amounts to solving Heun’s equation. Higher dimensions are also considered. Our analytical results are in agreement with numerical results for the low-lying frequencies. iii