Irreversible processes and the accelerated-decelerated phases of the Universe

TL;DR

This paper proposes a cosmological model where the Universe's evolution includes distinct accelerated and decelerated phases driven by irreversible energy transfer from gravity to matter, simulating the Universe's dynamic history.

Contribution

It introduces a novel model incorporating irreversible particle production to explain the Universe's phases, unifying acceleration and deceleration periods within a scalar-matter field framework.

Findings

The model reproduces the three key phases of the Universe's evolution.

Irreversible energy transfer influences the transition between phases.

Scalar field dominance correlates with accelerated expansion.

Abstract

A model for the Universe is proposed where it is considered as a mixture of scalar and matter fields. The particle production is due to an irreversible transfer of energy from the gravitational field to the matter field and represented by a non-equilibrium pressure. This model can simulate three distinct periods of the Universe: (a) an accelerated epoch where the energy density of the scalar field prevails over the matter field, (b) a past decelerated period where the energy density of the matter field becomes more predominant than the scalar energy density, and (c) a present acceleration phase where the scalar energy density overcomes the energy density of the matter field.