A Relativistic Gas of Inflatons as an Initial State for Inflation

TL;DR

This paper investigates whether inflation can begin under unfavorable initial conditions by modeling the inflaton as a relativistic gas near black body spectrum, showing potential energy suppression impacts inflation onset.

Contribution

It extends previous work by analyzing how a relativistic gas initial state affects the likelihood of inflation starting, especially under conditions below the self-reproduction threshold.

Findings

Initial potential energy is suppressed in a relativistic gas environment.

Rare regions with favorable conditions can dominate late-time universe if above self-reproduction threshold.

Inflation resilience depends on initial state properties of the inflaton field.

Abstract

The possibility of the resilience of the beginning of inflation under unfavorable conditions is examined by considering the initial state of the inflaton field to be in the form of a relativistic gas with some of its properties in close proximity to the black body spectrum. It is demonstrated that the initial potential energy budget in such an environment is suppressed beyond the minimal value required for inflation. This is the extension of our earlier work, where we have shown that the rare regions which happen to host favorable initial conditions for the beginning of inflation could come to dominate the late-time Universe only if they started out from above the so-called self-reproduction threshold.