Physical constraints on interacting dark energy models

TL;DR

This paper investigates physical and observational constraints on models where dark energy interacts with dark matter, deriving bounds on model parameters using thermodynamics and cosmological data.

Contribution

It introduces a framework combining thermodynamic principles with observational data to restrict interacting dark energy models.

Findings

Thermodynamic limits impose bounds on dark energy equation-of-state parameters.

Observational data further tighten constraints on dark matter-dark energy interaction.

Derived general expression for dark energy density evolution in interacting models.

Abstract

Physical limits on the equation-of-state (EoS) parameter of a dark energy component non-minimally coupled with the dark matter field are examined in light of the second law of thermodynamics and the positiveness of entropy. Such constraints are combined with observational data sets of type Ia supernovae, baryon acoustic oscillations and the angular acoustic scale of the cosmic microwave background to impose restrictions on the behaviour of the dark matter/dark energy interaction. Considering two EoS parameterisations of the type $w = w_0 + w_a\zeta(z)$, we derive a general expression for the evolution of the dark energy density and show that the combination of thermodynamic limits and observational data provide tight bounds on the $w_0 - w_a$ parameter space.