Thermodynamics and emergent universe

TL;DR

This paper investigates thermodynamic models of the universe, showing that first order particle creation can lead to an emergent universe scenario even with non-zero chemical potential, unlike second order models.

Contribution

It demonstrates the conditions under which emergent universe solutions arise in different thermodynamic frameworks and establishes a correspondence with non-particle creation models.

Findings

First order thermodynamics allows emergent universe with non-zero chemical potential.

Second order non-equilibrium theory does not support emergent universe scenarios.

A correspondence is established between particle creation models and non-particle creation equations of state.

Abstract

We show that in the isentropic scenario the first order thermodynamical particle creation model gives an emergent universe solution even when the chemical potential is non-zero. However there exists no emergent universe scenario in the second order non-equilibrium theory for the particle creation model. We then point out a correspondence between the particle creation model with barotropic equation of state and the equation of state giving rise to an emergent universe without particle creation in spatially flat FRW cosmology.