Large-Scale Suppression from Stochastic Inflation

TL;DR

This paper demonstrates that self-interacting scalar fields in de Sitter space experience significant large-scale suppression of their power spectrum, resolving infra-red divergence issues and depending on coupling strength, e-folds, and expansion rate.

Contribution

It provides a non-perturbative analysis showing suppression of the scalar field power spectrum in de Sitter space, a novel insight into inflationary fluctuations.

Findings

Power spectrum is strongly suppressed on large scales.

Infra-red divergences are eliminated in the two-point correlation function.

Suppression scale depends on self-coupling, e-folds, and expansion rate.

Abstract

We show non-perturbatively that the power spectrum of a self-interacting scalar field in de Sitter space-time is strongly suppressed on large scales. The cut-off scale depends on the strength of the self-coupling, the number of e-folds of quasi-de Sitter evolution, and its expansion rate. As a consequence, the two-point correlation function of field fluctuations is free from infra-red divergencies.