On the Cosmological Models with Matter Creation

TL;DR

This paper revisits matter creation cosmological models, proposing a flat FRWL universe with a quasi-adiabatic process that explains late-time acceleration without dark energy, using thermodynamics and particle creation rates.

Contribution

It introduces a new matter creation model with a redefined creation pressure, allowing explicit solutions for universe evolution and a natural transition to acceleration without dark energy assumptions.

Findings

Models late-time acceleration without dark energy.

Establishes correspondence with quintessence models.

Provides explicit time-dependent variables including entropy.

Abstract

The matter creation model of Prigogine--G\'eh\'eniau--Gunzig--Nardone is revisited in terms of a redefined creation pressure which does not lead to irreversible adiabatic evolution at constant specific entropy. With the resulting freedom to choose a particular gas process, a flat FRWL cosmological model is proposed based on three input characteristics: (i) a perfect fluid comprising of an ideal gas, (ii) a quasi-adiabatic polytropic process, and (iii) a particular rate of particle creation. Such model leads to the description of the late-time acceleration of the expanding Universe with a natural transition from decelerating to accelerating regime. Only the Friedmann equations and the laws of thermodynamics are used and no assumptions of dark energy component is made. The model also allows the explicit determination as functions of time of all variables, including the entropy, the non-conserved specific entropy and the time the accelerating phase begins. A form of correspondence with the dark energy models (quintessence, in particular) is established via the $Om$ diagnostics. Parallels with the concordance cosmological $\Lambda$CDM model for the matter-dominated epoch and the present epoch of accelerated expansion are also established via slight modifications of both models.