Cosmology with Interaction between Phantom Dark Energy and Dark Matter and the Coincidence Problem

TL;DR

This paper explores a cosmological model where phantom dark energy interacts with dark matter through a phenomenological coupling, affecting universe evolution, lifetime, and the coincidence problem.

Contribution

It introduces a coupled term parameterized by a dimensionless function, analyzing its impact on cosmological dynamics and the coincidence problem.

Findings

Interaction causes significant deviations from non-interacting models.

The coupling influences the universe's total lifetime.

Interaction affects the duration of the coincidence state.

Abstract

We study a cosmological model in which phantom dark energy is coupled to dark matter by phenomenologically introducing a coupled term to the equations of motion of dark energy and dark matter. This term is parameterized by a dimensionless coupling function $\delta$, Hubble parameter and the energy density of dark matter, and it describes an energy flow between the dark energy and dark matter. We discuss two cases: one is the case where the equation-of-state $\omega_e$ of the dark energy is a constant; the other is that the dimensionless coupling function $\delta$ is a constant. We investigate the effect of the interaction on the evolution of the universe, the total lifetime of the universe, and the ratio of the period when the universe is in the coincidence state to its total lifetime. It turns out that the interaction will produce significant deviation from the case without the interaction.