Fermion production by a dependent of time electric field in de Sitter universe

TL;DR

This paper investigates fermion pair production in a de Sitter universe under a time-dependent electric field, revealing non-conservation of momentum and helicity, with implications for early universe particle generation.

Contribution

It provides a detailed calculation of pair production amplitudes and probabilities in a de Sitter universe with a dynamic electric field, highlighting effects on momentum and helicity conservation.

Findings

Momentum conservation is broken during fermion production.

Helicity is not conserved in the process.

Pair production rate is significant during early universe expansion.

Abstract

Fermion production by the electric field of a charge on de Sitter expanding universe is analyzed. The amplitude and probability of pair production are computed. We obtain from our calculations that the modulus of the momentum is no longer conserved and that there are probabilities for production processes where the helicity is no longer conserved. The rate of pair production in an electric field is found to be important in the early universe when the expansion factor was large comparatively with the particle mass.