The nature of cosmological metric perturbations in presence of gravitational particle production

Abstract

The present paper addresses the issue of cosmological metric perturbations in models of cosmology accompanied by gravitational particle production. The general structure of such theories is constructed and then the paper focusses on metric perturbations of the de Sitter space in the early Universe full of radiation, such spaces can occur in presence of gravitational particle production. The main focus of the calculations is on scalar metric perturbations. The paper briefly opines on vector and tensor perturbations of the de Sitter space in question. The results show that the metric perturbations can have finite instability in the short scale and these instabilities may produce the inhomogeneities in the early radiation dominated universe. The instabilities are in general finite and do not tend to blow up to infinity. The tensor perturbations do not show any instability in the present model.