# First order QED effects on a spatially flat FLRW spacetime with a Milne-type scale factor

## TL;DR

This paper investigates first-order QED effects in a flat FLRW universe with a Milne-type scale factor, focusing on pair creation probabilities and their angular behavior.

## Contribution

It provides a detailed analysis of first-order QED effects on a Milne-type FLRW spacetime, refining the understanding of pair creation amplitudes.

## Key findings

- Revised transition rate definitions for pair creation
- Angular behavior of pair creation probability clarified
- First-order QED effects characterized in Milne-type spacetime

## Abstract

The quantum electrodynamics (QED) on a spatially flat $(1+3)$-dimensional Friedmann-Lema\^ itre-Robertson-Walker (FLRW) spacetime with a Milne-type scale factor is outlined focusing on the amplitudes of the allowed effects in the first order of perturbations. The definition of the transition rates is reconsidered obtaining an appropriate angular behavior of the probability of the pair creation from a photon.