Higher order initial conditions with massive neutrinos

ABSTRACT The discovery that neutrinos have mass has important consequences for cosmology. main effect of massive is to suppress the growth cosmic structure on small scales. Such can be accurately modelled using cosmological N-body simulations, but doing so requires accurate initial conditions (ICs). There a trade-off, especially with first-order ICs, between truncation errors late starts and discreteness relativistic early starts. Errors minimized by starting simulations at times higher order ICs. In this paper, we show neutrino effects absorbed into scale-independent coefficients in Lagrangian perturbation theory (LPT). This clears way use ICs simulations. We demonstrate going substantially improves accuracy To match sensitivity surveys like DESI Euclid, matter power spectrum should well below $1{{\ \rm per\ cent}}$. However, find Zel’dovich lead much larger errors, even when as z = 127, exceeding cent}}$ 0 k > 0.5 Mpc?1 0.1 equilateral bispectrum our Ratios spectra different masses are more robust than absolute statistics, still depend choice For all statistics considered, obtain agreement 2LPT 3LPT 0.