Small noise expansion of stochastic inflation
Cosmology and Nongalactic Astrophysics
2025-04-02 v2 General Relativity and Quantum Cosmology
Abstract
By introducing the small noise expansion techniques, we show that the fully nonlinear (non-Markovian) stochastic inflationary system, may be re-cast in terms of an infinite set of Wiener processes (stochastic equations with white noises). As a byproduct, we show that the Starobinsky test field approximation might only provide information about the linear regime of cosmological perturbations and scalar-feld non-Gaussianities might only appear at leading order in slow-roll parameters.
Keywords
Cite
@article{arxiv.2410.17987,
title = {Small noise expansion of stochastic inflation},
author = {Diego Cruces and Cristiano Germani and Amin Nassiri-Rad and Masahide Yamaguchi},
journal= {arXiv preprint arXiv:2410.17987},
year = {2025}
}
Comments
26 pages 2 appendices. This version corrects errors in the calculations of Section 5.2 from the previous draft (Section 6 in the current version). The main conclusions remain unchanged. Accepted for publication in JCAP