Interacting dark sector: a dynamical system perspective

TL;DR

This paper analyzes the interaction between dark energy and dark matter using dynamical systems, classifying potentials and identifying late-time attractors, revealing that interactions tend to weaken over time and differ between quintessence and phantom fields.

Contribution

It provides a general dynamical system framework for interacting dark energy models, including both quintessence and phantom fields, and classifies potential late-time behaviors.

Findings

Dark energy domination as late-time attractors

Interaction weakens over time

Energy transfer direction varies between quintessence and phantom fields

Abstract

We investigate the interaction between the dark sectors from the point of view of a dynamical system analysis. A general setup for interacting dark energy models that incorporates both quintessence and phantom fields through a switch parameter, allowing an interaction in the dark sectors, has been considered. In the first part of our analysis, we have not assumed any specific form of the interaction, and in the second part, we invoked examples in a general framework of the interaction. The potentials of the scalar field are classified into two broad classes of potentials: exponential and non-exponential. We identify the potential late-time attractors of the system, which have a complete dark energy domination. From our analysis, it is evident there could be an interaction between the dark sector. The interaction, if any, weakens over time. We find for the quintessence field the transfer of energy from dark matter to dark energy can flip the direction, and on the contrary, for the phantom field, it is only from dark matter to dark energy.