Gravity Seminar: Dynamics in UV extensions of k-essence and scalar Gauss-Bonnet theory, Guillermo Lara, Albert Einstein Institute, Potsdam, Germany

In recent years there has been an increased interest in modelling the nonlinear dynamics in theories beyond general relativity. Recent work by different groups has provided new pathways towards performing numerical relativity simulations in such theories. In this talk, I summarise subset of these ideas and will illustrate them in the context of k-essence and scalar Gauss-Bonnet theory, both instances of the more general Horndeski theory. In particular, I will present and example where different extensions (or UV completions) of the theory allow for continuing the evolution past the Cauchy breakdown and address the issue of accurately reproducing the physics of the original theory.