Qualitative behavior of cosmological models combining various matter fields

TL;DR

This paper analyzes the qualitative behavior of cosmological models with a mixture of matter, dark matter, and scalar fields, using dynamical systems to understand the universe's accelerated expansion and evolution.

Contribution

It introduces a dynamical system framework for multi-fluid cosmological models, highlighting the role of effective equation of state in understanding cosmic acceleration.

Findings

Stability analysis identifies dominant fluids during different cosmic epochs.

The model explains transition phases between matter, dark matter, and dark energy dominance.

The approach links fluid domination to universe acceleration phases.

Abstract

The late time accelerated expansion of the universe can be realized using scalar fields with given self-interacting potentials. Here we consider a straightforward approach where a three cosmic fluid mixture is assumed. The fluids are standard matter perfect fluid, dark matter, and a scalar field with the role of dark energy. A dynamical system analysis is developed in this context. A central role is played by the equation of state $\omega_{eff}$ which determines the acceleration phase of the models. Determining the domination of a particular fluid at certain stages of the universe history by stability analysis allows, in principle, to establish the succession of the various cosmological eras.