Seminarium "High Energy, Cosmology and Astro-particle Physics (HECA)"

Asymptotic Safety is an approach to quantum gravity that solely relies on quantum field theory - it posits that gravity can be quantised by a nonperturbative fixed point of its renormalisation group flow. This rather simple idea is complicated by the fact that in quantum field theory, field redefinitions can be performed without changing physical predictions, encoded for example in scattering amplitudes. As a consequence, only so-called essential couplings need to show such a fixed point - these are the combinations of couplings that are invariant under such redefinitions.In this talk, after a general introduction to Asymptotic Safety, I will discuss recent developments in how to treat the freedom of field redefinitions within nonperturbative renormalisation group flows. In particular, I will show how we can wield this freedom to simplify computations enormously so that more refined approximations can be investigated, consequently improving the accuracy of predictions.