Seminarium Teorii Względności i Grawitacji

It is well known that gravitational waves interact in a non-linear way. This makes it difficult to describe them rigorously. The cleanest description is based on certain conformal properties of the Einstein equations — first discovered by R. Penrose, they were rigorously developed and used by H. Friedrich to prove several important global results for general relativistic space-times. The conformal field equations, which implement this conformal framework, provide various well-posed initial (boundary) value problems for use in many different situations. The talk will give a computational perspective on one particular application, the non-linear interaction of gravitational waves with an initially static (and spherically symmetric) black hole. We will show how to 'kick' the black hole and possibly how to spin it up.