Seminarium Teorii Względności i Grawitacji

I will present a systematic and robust approach to nonlinear gravitational perturbations of vacuum spacetimes. In particular, I will show that at each order of perturbation expansion, the system of perturbative Einstein equations can be reduced to two (for each gravitational mode in 3+1 dimensions on which the study will be focused) scalar wave equations, and the metric perturbations can be explicitly obtained, once the solutions to these scalar wave equations are known. The talk will be based on a recent paper Phys. Rev. D96, 124026 [https://journals.aps.org/prd/abstract/10.1103/PhysRevD.96.124026], [http://arxiv.org/abs/1705.02258].