Non-Perturbative Instabilities as a Solution of the Cosmological Moduli Problem

TL;DR

The paper proposes a non-perturbative decay mechanism via parametric resonance to resolve the cosmological moduli problem, enabling early decay of moduli fields and preserving nucleosynthesis predictions.

Contribution

It introduces a new non-perturbative decay channel for moduli oscillations driven by parametric resonance, offering a solution to the cosmological moduli problem.

Findings

Moduli decay can be enhanced through parametric resonance.

The decay occurs before nucleosynthesis, avoiding cosmological issues.

A net negative mass term triggers the non-perturbative decay channel.

Abstract

It is widely accepted that moduli in the mass range 10eV - $10^4$GeV which start to oscillate with an amplitude of the order of the Planck scale either jeopardize successful predictions of nucleosynthesis or overclose the Universe. It is shown that the moduli problem can be relaxed by making use of parametric resonance. A new non-perturbative decay channel for moduli oscillations is discussed. This channel becomes effective when the oscillating field results in a net negative mass term for the decay products. This scenario allows for the decay of the moduli much before nucleosynthesis and, therefore, leads to a complete solution of the cosmological moduli problem.