Quasi-normal modes of AdS black holes: a superpotential approach

A novel method, based on superpotentials is proposed for obtaining the quas inormal modes of anti-de Sitter black holes. This is inspired by the case o f the three-dimensional BTZ black hole, where the quasi-normal modes can be obtained exactly and are proportional to the surface gravity. Using this a pproach, the quasi-normal modes of the five-dimensional Schwarzschild anti- de Sitter black hole are computed numerically. The modes again seem to be p roportional to the surface gravity for very small and very large black hole s. They reflect the well known instability of small black holes in anti-de Sitter space.