Nonlinear, noniterative treatment of EFT-motivated gravity

We study a higher derivative extension to General Relativity and present a fully nonlinear/non-perturbative treatment to construct initial data and study its dynamical behavior in spherical symmetry when coupled to a massless scalar field. For initial data, we compare the obtained solutions with those from alternative treatments that rely on a perturbative (or iterative) approach. For the future evolution of such data, we implement a recently introduced approach which addresses mathematical pathologies brought in by the higher derivatives. Our solutions demonstrate the presence of unexpected phenomena-when seen from the lens of General Relativity, as well as departures from General Relativity in the quasinormal mode behavior of the scalar field scattering off the black hole.