Dynamics of dark energy with a coupling to dark matter

TL;DR

This paper explores how a new, physically motivated coupling between dark energy and dark matter affects the universe's evolution, using exponential quintessence models and analyzing their complex dynamical behavior.

Contribution

It introduces a novel form of dark sector coupling with improved physical motivation and analyzes its impact on cosmological dynamics.

Findings

New coupling leads to richer dynamical phase space.

Coupling models compatible with observational constraints.

Enhanced understanding of dark energy-dark matter interactions.

Abstract

Dark energy and dark matter are the dominant sources in the evolution of the late universe. They are currently only indirectly detected via their gravitational effects, and there could be a coupling between them without violating observational constraints. We investigate the background dynamics when dark energy is modelled as exponential quintessence, and is coupled to dark matter via simple models of energy exchange. We introduce a new form of dark sector coupling, which leads to a more complicated dynamical phase space and has a better physical motivation than previous mathematically similar couplings.