Cosmological solutions with gravitational particle production and non-zero curvature

TL;DR

This paper investigates how gravitational particle production influences the evolution of a homogeneous, isotropic universe with non-zero spatial curvature, revealing solutions that connect pre-inflationary conditions to de Sitter expansion.

Contribution

It derives a nonlinear differential equation governing universe dynamics with particle production and analyzes solutions considering curvature effects and additional fluids.

Findings

Curvature effects dominate early universe dynamics.

Analytic solutions depend on particle creation rates.

Negative curvature can lead to de Sitter expansion.

Abstract

In a homogeneous and isotropic universe with non-zero spatial curvature we consider the effects of gravitational particle production in the dynamics of the universe. We show that the dynamics of the universe in such a background is characterized by a single nonlinear differential equation which is significantly dependent on the rate of particle creation and whose solutions can be dominated by the curvature effects at early times. For different particle creation rates we apply the singularity test in order to find the analytic solutions of the background dynamics. We describe the behavior of the cosmological solutions for both open and closed universes. We also show how the effects of curvature can be produced by the presence of a second perfect fluid with an appropriate equation of state. By combining that results with the analysis of the critical points we find that our consideration can be related with the pre-inflationary era. Specifically we find that for negative spatial curvature small changes of the Milne spacetime leads to a de Sitter universe.