$\nu\scriptstyle{\rm CO}N{\rm CEPT}$: Cosmological neutrino simulations from the non-linear Boltzmann hierarchy

TL;DR

This paper introduces a new simulation method for modeling the non-linear effects of massive neutrinos on cosmic structures, achieving high accuracy and minimal error in matter power spectrum predictions.

Contribution

It presents a novel approach to simulate non-linear neutrino effects by solving the Boltzmann hierarchy with a grid-based N-body method, improving precision over previous models.

Findings

Accurately simulates non-linear neutrino power spectrum

Negligible error in matter power spectrum predictions

Suitable for future high-precision cosmological observations

Abstract

In this paper the non-linear effect of massive neutrinos on cosmological structures is studied in a conceptually new way. We have solved the non-linear continuity and Euler equations for the neutrinos on a grid in real space in $N$-body simulations, and closed the Boltzmann hierarchy at the non-linear Euler equation using the stress and pressure perturbations from linear theory. By comparing with state-of-the art cosmological neutrino simulations, we are able to simulate the non-linear neutrino power spectrum very accurately. This translates into a negligible error in the matter power spectrum, and so our $\scriptstyle{\rm CO}N{\rm CEPT}$ code is ideally suited for extracting the neutrino mass from future high precision non-linear observational probes such as Euclid.