Analytical growth functions for cosmic structures in a ΛCDM Universe

The cosmological fluid equations describe the early gravitational dynamics of cold dark matter (CDM), exposed to a uniform component energy, constant $\Lambda$. Perturbative predictions for typically assume that impact $\Lambda$ on CDM can be encapsulated by refined growing mode $D$ linear density fluctuations. Here we solve, arbitrary high perturbative orders, nonlinear with an {\it Ansatz} variables in increasing powers $D$. We show begins populate solutions starting at fifth order this strict $D$-expansion. By applying suitable resummation techniques, recast these standard series where not $D$, but essentially initial potential serves as bookkeeping parameter within expansion. Then, using growth functions second and third perturbation theory, determine power spectrum one-loop accuracy well leading-order contribution bispectrum. find employing our impacts total power- bispectra precision is below one percent late times. However, spectrum, characteristic scale-dependent suppression fairly similar what observed massive neutrino cosmologies. Therefore, recommend reduce theoretical uncertainties analysing data related pipelines.