Evolution of the Density Contrast with Particle Production in a Gauge-Invariant Formalism

TL;DR

This paper develops a gauge-invariant formalism to analyze how particle production influences the evolution of density contrast in cosmology, providing solutions and conditions relevant for structure formation.

Contribution

It introduces a covariant approach to study density contrast evolution with particle production, including a generalized Prigogine model and conditions for non-linear regime onset.

Findings

Derived evolution equations for density contrast with particle production

Provided solutions for specific particle production models

Established conditions for the transition to non-linear structure formation

Abstract

In this work we derive the evolution equation for the density contrast considering open system cosmology, where the influence of adiabatic particle production process on the dynamic of a homogeneous and isotropic is investigated within a manifestly covariant formulation. As application we derive the solution for two sources, one of them is a generalization of Prigogine's model. Then we establish the condition for the reach of the non-linear regime for the density contrast which turns out to be a necessary condition for the structure formation.