Inhomogeneous cosmology using general relativistic smoothed particle hydrodynamics coupled to numerical relativity

Abstract

We perform three-dimensional simulations of homogeneous and inhomogeneous cosmologies via the coupling of the einstein toolkit numerical relativity code for spacetime evolution to the phantom smoothed particle hydrodynamics code. Evolution of a flat dust and radiation-dominated Friedmann-Lemaître-Roberston-Walker (FLRW) spacetime shows an agreement of exact solutions with residuals on the order 10-6 and 10-3 respectively, even at low grid resolutions. We demonstrate evolution of linear perturbations of density, velocity and metric quantities to the FLRW with residuals of ≈10-2 compared to exact solutions. Finally, we demonstrate the evolution of nonlinear density perturbations past shell cro..