Speaker: Alex Vañó-Viñuales (University of the Balearic Islands)
Title: Numerical hyperboloidal compactification: waves on FLRW and neutron star initial data
Abstract: Both parts of this talk involve numerical descriptions on compactified hyperboloidal slices reaching future null infinity -- the "location" in spacetime where electromagnetic and gravitational radiation arrives and where global properties of spacetimes can be measured. The first part, presenting joint work with Flavio Rossetti, focuses on the asymptotic decay of the linear wave equation on flat and hyperbolic FLRW spacetimes with a time-dependent scale factor. I will describe the hyperboloidal setup, which allows us to recover decay rates obtained from evolutions on usual truncated Cauchy slices, and also consider solutions of a non-linear wave with self-interactions. The second part will describe the construction of initial data for a neutron star on a hyperboloidal slice, involving spherical symmetry and a polytropic-like equation of state. Constraint-satisfying compactified hyperboloidal initial data are obtained for a single neutron star and for a combination of a neutron star with a small black hole in its center. To the best of my knowledge, this is the first time that full hyperboloidal slices including a neutron star are constructed.
Room: Sala de Reuniões e Seminários (2-8.3, 2nd Floor of Physics Building)