Coupled fields in external background with application to nonthermal production of gravitinos

TL;DR

This paper develops a formalism for quantizing coupled bosonic and fermionic fields in a time-dependent background and applies it to analyze nonthermal gravitino production, finding it to be strongly suppressed in a specific model.

Contribution

It introduces a generalized quantization method for coupled fields in dynamic backgrounds and applies it to gravitino production, revealing suppression effects.

Findings

Gravitino production is strongly suppressed in the considered model.

The formalism allows clear definition and computation of occupation numbers.

Weak coupling between inflation and supersymmetry-breaking sectors reduces particle production.

Abstract

We provide the formalism for the quantization of systems of coupled bosonic and fermionic fields in a time dependent classical background. The occupation numbers of the particle eigenstates can be clearly defined and computed, through a generalization of the standard procedure valid for a single field in which Bogolyubov coefficients are employed. We apply our formalism to the problem of nonthermal gravitino production in a two-fields model where supersymmetry is broken gravitationally in the vacuum. Our explicit calculations show that this production is strongly suppressed in the model considered, due to the weak coupling between the sector which drives inflation and the one responsible for supersymmetry breakdown.