Cosmology seminar: Black hole binaries in higher derivative scalar-tensor theories of gravity

 In this talk I will present some work on black hole binary simulations in higher derivative theories of gravity. We shall consider Horndeski theories and the most general scalar tensor theory of gravity up to four derivatives of the fields. Contrary to the majority of the previous work, we shall treat these theories fully non-linearly. I will discus the challenges in doing so and I will present a new  formulation which is well-posed in the regime of validity of effective field theory. Treating these theories fully non-linearly is crucial to capture their unique non-perturbative physics and compute, from first principles, waveforms that can distinguish these theories from general relativity in gravitational wave observations in present and future detectors.