paper

Cosmic structure from the path integral of classical mechanics and its comparison to standard perturbation theory

arXiv:2507.02692 · doi:10.1103/3mwp-26wz

Abstract

We investigate cosmic structure formation in the framework of a path-integral formulation of an -particle ensemble in phase space, dubbed Resummed Kinetic Field Theory (RKFT), up to one-loop perturbative order. In particular, we compute power spectra of the density contrast, the divergence and curl of the momentum density and arbitrary -point cumulants of the stress tensor. In contrast to earlier works, we propose a different method of sampling initial conditions, with a Gaussian initial phase-space density. Doing so, we exactly reproduce the corresponding results from Eulerian standard perturbation theory (SPT) at one-loop order, showing that formerly found deviations can be fully attributed to inconsistencies in the previous sampling method. Since, in contrast to SPT, the full phase-space description does not assume a truncation of the Vlasov hierarchy, our findings suggest that nonperturbative techniques are required to accurately capture the physics of cosmic structure formation.

16 pages, 2 figures; minor improvements, results and conclusions unchanged

References in corpus (36)

Cited by in corpus (1)