%0 Generic
%A Vollmer, Adrian
%D 2014
%F heidok:17736
%R 10.11588/heidok.00017736
%T Efficient computation of nonlinear corrections to the matter power spectrum using the time renormalization group
%U https://archiv.ub.uni-heidelberg.de/volltextserver/17736/
%X We develop a new technique to compute the nonlinear matter power spectrum up to BAO scales at present time using the Time Renormalization Group. The great advantage of our method is a significant decrease in runtime. Overall, our numerical implementation yields a speedup of a factor of 50 when compared to similar implementations, leading to a runtime that is as little as six seconds.      As a first application, we investigate how sensitive the constraints obtained from the Fisher matrix are to the source of nonlinear corrections.  The results from these sources may agree, but because the Fisher matrix depends on derivatives it is not immediately obvious that we can expect agreement here as well. We find hints that there may be substantial differences.      Unrelated to this, we perform a weak lensing Fisher matrix analysis on the anisotropic stress eta = -Phi/Psi in a completely model-independent way. We cover different cases where we, among others, allow \eta to vary with time and scale and where it takes the Horndeski parameterization.  We find that, in the best case, eta can be constrained by future Euclid-like surveys together with supernovae data to within 1%, and to within 60% or better in the Horndeski case.