Phase-space analysis of interacting phantom cosmology

TL;DR

This paper analyzes interacting phantom cosmological models using phase-space methods to identify late-time attractors and assess their ability to address the coincidence problem.

Contribution

It provides a comprehensive phase-space analysis of interacting phantom models, highlighting their limitations in solving the coincidence problem without fine-tuning.

Findings

Stable late-time accelerated solutions exist.

Models do not naturally solve the coincidence problem.

Fine-tuning is required for models to match observations.

Abstract

We perform a detailed phase-space analysis of various phantom cosmological models, where the dark energy sector interacts with the dark matter one. We examine whether there exist late-time scaling attractors, corresponding to an accelerating universe and possessing dark energy and dark matter densities of the same order. We find that all the examined models, although accepting stable late-time accelerated solutions, cannot alleviate the coincidence problem, unless one imposes a form of fine-tuning in the model parameters. It seems that interacting phantom cosmology cannot fulfill the basic requirement that led to its construction.