On the quasi-stationary expansion in gravity

After shortly commenting and reviewing the quasi stationary (or adiabatic) approximation/expansion in general, Dieter Van den Bleeken (Physics Department, Bogazici University, Bebek, Istanbul, Turkey) will discuss some recent applications of it to GR. First, he will discuss how in the setting of GR inside a finite spatial volume, the Einstein equations in the quasi-stationary limit can be re-expressed as geodesic equations on the (infinite dimensional) group of boundary diffeomorphisms. Secondly, he will explain how the quasi-stationary expansion is related to the strong field non relativistic expansion of GR (also referred to as the 1/c expansion). Finally, he will mention some work in progress where the quasi-stationary expansion is used concretely to find an (approximate) solution for a time dependent (i.e. dynamic) black hole in an evolving de Sitter background.