Fresh inflation and decoherence of super Hubble fluctuations

TL;DR

This paper investigates how super Hubble fluctuations in a fresh inflation model become decoherent due to thermal and dissipative effects, differing from supercooled inflation scenarios that require rapid expansion.

Contribution

It introduces a stochastic approach to fresh inflation and demonstrates decoherence of super Hubble fluctuations without rapid scale factor expansion.

Findings

Decoherence occurs at the end of fresh inflation due to damping of interference.

Thermal and dissipative effects contribute to loss of coherence.

Decoherence mechanism differs from supercooled inflation scenarios.

Abstract

I study a stochastic approach to the recently introduced fresh inflation model for super Hubble scales. I find that the state loses its coherence at the end of the fresh inflationary period as a consequence of the damping of the interference function in the reduced density matrix. This fact should be a consequence of a) the relative evolutions of both the scale factor and the horizon and b) the additional thermal and dissipative effects. This implies a relevant difference with respect to supercooled inflationary scenarios which require a very rapid expansion of the scale factor to give the decoherence of super Hubble fluctuations.