On the Creation of Scalar Particles in a Flat Robertson-Walker Space-time

TL;DR

This paper investigates scalar particle creation in a flat Robertson-Walker universe, providing exact solutions to the Klein-Gordon equation, calculating pair creation probabilities, and analyzing specific cosmological models.

Contribution

It introduces exact solutions for the Klein-Gordon equation in this context and applies the Bogoliubov transformation to quantify particle creation in different cosmological scenarios.

Findings

Pair creation probabilities are computed for various models.

Vacuum to vacuum transition probabilities are established.

The imaginary part of the effective action is derived.

Abstract

The problem of particle creation from vacuum in a flat Robertson-Walker space-time is studied. Two sets of exact solutions for the Klein Gordon equation are given. Then the canonical method based on Bogoliubov transformation is applied to calculate the pair creation probability and the density number of created particles. Some particular cosmological models such as radiation dominated universe and Milne universe are discussed. For the both cases the vacuum to vacuum transition probability is calculated and the imaginary part of the effective action is extracted.