Scalar-Fluid interacting dark energy: cosmological dynamics beyond the exponential potential

TL;DR

This paper extends the analysis of scalar-fluid interacting dark energy models to include non-exponential potentials, revealing similar late-time acceleration and scaling solutions, thus broadening the understanding of dark energy dynamics.

Contribution

It introduces a comprehensive dynamical systems analysis for scalar-fluid models with power-law and hyperbolic potentials, beyond the exponential case, highlighting their cosmological implications.

Findings

Existence of late-time accelerated attractors.

Transitions from dark matter to dark energy domination.

Presence of accelerated scaling solutions addressing the cosmic coincidence problem.

Abstract

We extend the dynamical systems analysis of Scalar-Fluid interacting dark energy models performed in C. G. Boehmer et al, Phys. Rev. D 91, 123002 (2015), by considering scalar field potentials beyond the exponential type. The properties and stability of critical points are examined using a combination of linear analysis, computational methods and advanced mathematical techniques, such as centre manifold theory. We show that the interesting results obtained with an exponential potential can generally be recovered also for more complicated scalar field potentials. In particular, employing power-law and hyperbolic potentials as examples, we find late time accelerated attractors, transitions from dark matter to dark energy domination with specific distinguishing features, and accelerated scaling solutions capable of solving the cosmic coincidence problem.