Julian Adamek - November 15, 2017
Using numerical simulations to study relativistic effects
The Newtonian approximation which is usually invoked in N-body simulations of cosmic
large scale structure relies on the assumptions that gravitational fields are weak
and that they are only sourced by nonrelativistic matter. The latter constitutes an
implicit assumption about the nature of the "dark" components of the Universe (dark
matter and dark energy), thereby precluding a serious assessment of some potentially
interesting models. I will present N-body simulations of cosmic structure formation
based on a weak field approximation to General Relativity, taking into account all
six degrees of freedom of the metric. The geodesic equations are solved consistently
also for relativistic particles, such as massive neutrinos. The approach is very
general and can be applied to various settings where the Newtonian approximation
would be unreliable or inconsistent, for instance some models of dynamical dark
energy or modified gravity.