Properties of Kaluza-Klein Black Holes

Abstract

We detail numerical methods to compute the geometry of static vacuum black holes in 6-dimensional gravity compactified on a circle. We calculate properties of these Kaluza-Klein black holes for varying mass, keeping the asymptotic compactification radius fixed. For increasing mass, the horizon deforms into a prolate ellipsoid, and the geometry near the horizon and axis decompactifies. We are able to find solutions with horizon radii approximately equal to the asymptotic compactification radius. Having chosen 6 dimensions, we may compare these solutions to those of non-uniform strings compactified on a circle of the same radius found in a previous numerical work. We find the black holes achieve larger masses and horizon volumes than most non-uniform strings. This sheds doubt on whether these solution branches can merge via a topology changing solution. Further work is required to resolve whether there is a maximum mass for the black holes, or whether the mass can become arbitrarily large.