Location: The London Relativity and Cosmology Seminar, QMUL
In this talk I will illustrate the results obtained with the first fully relativistic cosmological simulations in numerical relativity. These simulations represent the fully nonlinear GR evolution of perturbations in a Einstein de Sitter background, and show that: 1) voids expansion rate is significantly higher than that of the background and close to that of an open universe; 2) over-densities can reach turn-around much earlier than predicted by the standard top-hat mode; 3) back-reaction effects on the overall expansion of the model seems to be tiny. However, at this stage we can’t conclude that the contribution of back-reaction to the overall expansion is entirely negligible. I will conclude with an outline of future work that is needed to establish the real significance of these results.