Non-linear Power Spectrum including Massive Neutrinos: the Time-RG Flow Approach

TL;DR

This paper develops a non-linear power spectrum calculation for LambdaCDM models with massive neutrinos using the Time-RG flow approach, improving accuracy over traditional methods and aiding future large-scale structure observations.

Contribution

It introduces the Time-RG flow method for computing the non-linear power spectrum with massive neutrinos, surpassing one-loop perturbation theory in accuracy.

Findings

Time-RG method better fits N-body data than one-loop theory.

Accurately predicts suppression of power spectrum due to neutrino mass.

Provides a tool for precise forecasts in large-scale structure surveys.

Abstract

Future large scale structure observations are expected to be sensitive to small neutrino masses, of the order of 0.05 eV or more. However, forecasts are based on the assumption that by the time at which these datasets will be available, the non-linear spectrum in presence of neutrino mass will be predicted with an accuracy at least equal to the neutrino mass effect itself, i.e. about 3%. Motivated by these considerations, we present the computation of the non-linear power spectrum of LambdaCDM models in the presence of massive neutrinos using the Renormalization Group time-flow approach, which amounts to a resummation of perturbative corrections to the matter power spectrum to all orders. We compare our results with those obtained with other methods, i.e. linear theory, one-loop perturbation theory and N-body simulations and show that the time-RG method improves the one-loop method in fitting the N-body data, especially in determining the suppression of the matter power spectrum when neutrino are massive with respect to the linear power spectrum.