Interacting cosmic fluids and phase transitions under a holographic modeling for dark energy

TL;DR

This paper explores how sign changes in energy transfer between dark energy and dark matter, modeled holographically with a linear equation of state, lead to phase transitions and temperature changes consistent with thermodynamic laws.

Contribution

It introduces a holographic model of dark energy with a linear equation of state to analyze the effects of sign changes in energy transfer on thermodynamics and phase transitions.

Findings

Sign changes in the $Q$-function affect dark energy and dark matter temperatures.

Phase transitions occur at specific cosmic epochs due to heat capacity sign changes.

Thermodynamic constraints restrict the evolution of dark energy and dark matter.

Abstract

We discuss the consequences of possible sign changes of the $Q$-function which measures the energy transference between dark energy and dark matter. We investigate this scenario from a holographic perspective to modeling the dark energy by a linear-parametrization of the equation of state parameter denoted by $\omega$. By imposing the strong constraint of the second law of thermodynamics, we show that sign changes of $Q$ due to the cosmic evolution imply changes in the temperatures of dark energy and dark matter, respectively. We also discuss the phase transitions, in the past and future, experienced by dark energy and dark matter (or, equivalently, the sign changes of their heat capacities).