Gravitational particle production in massive chaotic inflation and the moduli problem

TL;DR

This paper revisits particle production during inflation, addresses the moduli problem with light particles, and proposes a universal solution that ensures acceptable reheating temperatures by assuming moduli behave as non-relativistic matter post-inflation.

Contribution

It introduces a universal solution to the moduli problem in inflation, justified within massive chaotic inflation models, aligning particle evolution with matter-dominated behavior after inflation.

Findings

Revisits vacuum fluctuation particle production during inflation.

Identifies the moduli problem with light particles conflicting with nucleosynthesis constraints.

Proposes a universal solution ensuring reasonable reheating temperatures.

Abstract

Particle production from vacuum fluctuations during inflation is briefly revisited. The moduli problem occurring with light particles produced at the end of inflation is addressed, namely the fact that some results are in disagreement with nucleosynthesis constrains. A universal solution to this problem is found which leads to reasonable reheating temperatures in all cases. It invokes the assumption that, immediately after inflation, the moduli evolve like non-relativistic matter. The assumption is justified in the context of massive chaotic inflation were, at the end of inflation, the universe evolves as if it was matter-dominated.