Testing the Cactus code on exact solutions of the Einstein field equations

TL;DR

This paper evaluates the Cactus numerical relativity code by testing it against exact Einstein solutions, demonstrating its stability and convergence in simulating various cosmological and matter-including models.

Contribution

It introduces a new 'thorn' for Cactus that enables evolving a range of exact solutions, enhancing its utility for numerical relativity testing.

Findings

Cactus code shows stable evolution of exact solutions

The code demonstrates good convergence properties

Applicable to cosmological models of the early universe

Abstract

The article presents a series of numerical simulations of exact solutions of the Einstein equations performed using the Cactus code, a complete 3-dimensional machinery for numerical relativity. We describe an application (``thorn'') for the Cactus code that can be used for evolving a variety of exact solutions, with and without matter, including solutions used in modern cosmology for modeling the early stages of the universe. Our main purpose has been to test the Cactus code on these well-known examples, focusing mainly on the stability and convergence of the code.