Irreversible thermodynamic description of interacting dark energy - dark matter cosmological models

TL;DR

This paper explores the thermodynamic interactions between dark energy and dark matter in cosmology, incorporating matter creation effects and analyzing specific scalar field models through exact and numerical solutions.

Contribution

It generalizes dark energy-dark matter interaction theory by including decay pressures within the thermodynamics of open systems in cosmology.

Findings

Derived generalized interaction models with decay pressures.

Analyzed scalar field models with oscillations and constant potential.

Obtained exact and numerical solutions of the gravitational field equations.

Abstract

We investigate the interaction between dark energy and dark matter in the framework of irreversible thermodynamics of open systems with matter creation/annihilation. We consider dark energy and dark matter as an interacting two component (scalar field and "ordinary" dark matter) cosmological fluid in a homogeneous spatially flat and isotropic Friedmann-Robertson-Walker (FRW) Universe. The thermodynamics of open systems as applied together with the gravitational field equations to the two component cosmological fluid leads to a generalization of the elementary dark energy-dark mater interaction theory, in which the decay (creation) pressures are explicitly considered as parts of the cosmological fluid stress-energy tensor. Specific models describing coherently oscillating scalar waves, leading to a high particle production at the beginning of the oscillatory period, and models with a constant potential energy scalar field are considered. Furthermore, exact and numerical solutions of the gravitational field equations with dark energy-dark matter interaction are also obtained.