Hot Big Bang from inflation without the inflaton reheating

TL;DR

This paper proposes that a non-conformal quantum field theory's nonequilibrium dynamics during inflation can generate a hot, thermal universe without the need for inflaton coupling, challenging traditional reheating mechanisms.

Contribution

It introduces a novel reheating mechanism where a non-conformal QFT produces a hot plasma during inflation without inflaton coupling.

Findings

Reheating temperature can reach the inflationary Hubble scale.

Hot quark-gluon plasma can form without inflaton interactions.

Challenges standard inflaton-based reheating models.

Abstract

According to the standard lore, a prolonged inflation leaves a quantum field theory in a cold, low entropy state. Thus, some mechanism is needed to reheat this post-inflationary state, leaving a hot, thermal, radiation-dominated Universe. Typically, reheating is achieved coupling the inflaton field to the QFT degrees of freedom. We argue that the nonequilibrium dynamics of a non-conformal QFT in (post-)inflationary background space-time can produce hot quark-gluon plasma with the reheating temperature of order the inflationary Hubble scale, without the inflaton coupling.