An automatically generated code for relativistic inhomogeneous cosmologies

TL;DR

This paper introduces a new computational infrastructure for simulating inhomogeneous dust cosmologies using numerical relativity, enabling detailed studies of nonlinear effects on cosmic expansion.

Contribution

It presents a novel, open-source code built on the Einstein Toolkit for modeling inhomogeneous cosmologies with high parallel efficiency.

Findings

Code correctly reproduces known cosmological scenarios

Demonstrates scalability on large computational grids

Provides new insights into nonlinear inhomogeneity effects

Abstract

The applications of numerical relativity to cosmology are on the rise, contributing insight into such cosmological problems as structure formation, primordial phase transitions, gravitational-wave generation, and inflation. In this paper, I present the infrastructure for the computation of inhomogeneous dust cosmologies which was used recently to measure the effect of nonlinear inhomogeneity on the cosmic expansion rate. I illustrate the code's architecture, provide evidence for its correctness in a number of familiar cosmological settings, and evaluate its parallel performance for grids of up to several billion points. The code, which is available as free software, is based on the Einstein Toolkit infrastructure, and in particular leverages the automated-code-generation capabilities provided by its component Kranc.