Free hyperboloidal evolution of the Einstein–Maxwell–Klein–Gordon system

We present simulations of the Einstein–Maxwell–Klein–Gordon system on compactified hyperboloidal slices. To the best of our knowledge, these are the first hyperboloidal evolutions of this system that employ a common formulation like BSSN/Z4. Hyperboloidal slices smoothly reach future null infinity, the only location in spacetime where radiation (such as gravitational waves) is unambiguously defined. We are thus able to reach null infinity and extract signals there. We showcase the capabilities of our implementation in spherical symmetry with the evolution of a charged scalar field perturbing a regular spacetime and near an electrically charged black hole. We also present the collapse of a charged scalar field into a Reissner–Nördstrom black hole. Here we show sample evolutions and validation tests for these setups.