Skip to main content

Research Repository

Advanced Search

An optimal non-linear method for simulating relic neutrinos

Elbers, Willem; Frenk, Carlos S; Jenkins, Adrian; Li, Baojiu; Pascoli, Silvia

An optimal non-linear method for simulating relic neutrinos Thumbnail


Profile Image

Willem Elbers
Postdoctoral Research Associate


Cosmology places the strongest current limits on the sum of neutrino masses. Future observations will further improve the sensitivity and this will require accurate cosmological simulations to quantify possible systematic uncertainties and to make predictions for non-linear scales, where much information resides. However, shot noise arising from neutrino thermal motions limits the accuracy of simulations. In this paper, we introduce a new method for simulating large-scale structure formation with neutrinos that accurately resolves the neutrinos down to small scales and significantly reduces the shot noise. The method works by tracking perturbations to the neutrino phase-space distribution with particles and reduces shot noise in the power spectrum by a factor of O(102) at z = 0 for minimal neutrino masses and significantly more at higher redshifts, without neglecting the back-reaction caused by neutrino clustering. We prove that the method is part of a family of optimal methods that minimize shot noise subject to a maximum deviation from the non-linear solution. Compared to other methods, we find per mille level agreement in the matter power spectrum and per cent level agreement in the large-scale neutrino bias, but large differences in the neutrino component on small scales. A basic version of the method can easily be implemented in existing N-body codes and allows neutrino simulations with significantly reduced particle load. Further gains are possible by constructing background models based on perturbation theory. A major advantage of this technique is that it works well for all masses, enabling a consistent exploration of the full neutrino parameter space.

Journal Article Type Article
Acceptance Date Jul 24, 2021
Online Publication Date Aug 6, 2021
Publication Date 2021-10
Deposit Date Oct 8, 2021
Publicly Available Date Oct 8, 2021
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 507
Issue 2
Pages 2614-2631
Public URL


Published Journal Article (2.6 Mb)

Publisher Licence URL

Copyright Statement
The Author(s) 2021.
Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium,
provided the original work is properly cited.

You might also like

Downloadable Citations