The Coyote Universe I: Precision Determination of the Nonlinear Matter Power Spectrum

TL;DR

This paper demonstrates that with careful control and large-scale N-body simulations, the nonlinear matter power spectrum can be predicted with 1% accuracy up to certain scales, supporting upcoming cosmological surveys.

Contribution

It shows that high-accuracy nonlinear matter power spectrum predictions are achievable with controlled N-body simulations, addressing a key challenge for dark energy research.

Findings

Achieved 1% accuracy in nonlinear matter power spectrum predictions up to k~1 h/Mpc.

Identified key simulation components: precise initial conditions, large volumes, and accurate time stepping.

Validated simulation convergence and robustness for future cosmological applications.

Abstract

Near-future cosmological observations targeted at investigations of dark energy pose stringent requirements on the accuracy of theoretical predictions for the clustering of matter. Currently, N-body simulations comprise the only viable approach to this problem. In this paper we demonstrate that N-body simulations can indeed be sufficiently controlled to fulfill these requirements for the needs of ongoing and near-future weak lensing surveys. By performing a large suite of cosmological simulation comparison and convergence tests we show that results for the nonlinear matter power spectrum can be obtained at 1% accuracy out to k~1 h/Mpc. The key components of these high accuracy simulations are: precise initial conditions, very large simulation volumes, sufficient mass resolution, and accurate time stepping. This paper is the first in a series of three, with the final aim to provide a high-accuracy prediction scheme for the nonlinear matter power spectrum.