On the Reliability of the Langevin Pertubative Solution in Stochastic Inflation

TL;DR

This paper presents a method to assess the reliability of perturbative solutions to the stochastic inflationary Langevin equation, showing that such approaches are generally dependable except near the end of inflation.

Contribution

The paper introduces a new method for evaluating the accuracy of perturbative solutions in stochastic inflation models, applicable across various inflationary scenarios.

Findings

Perturbative solutions are reliable during most of inflation.

Breakdown of perturbation theory occurs only near the end of inflation.

Method is applicable to large field, small field, and running mass models.

Abstract

A method to estimate the reliability of a perturbative expansion of the stochastic inflationary Langevin equation is presented and discussed. The method is applied to various inflationary scenarios, as large field, small field and running mass models. It is demonstrated that the perturbative approach is more reliable than could be naively suspected and, in general, only breaks down at the very end of inflation.