Cosmological Evolution of Quintessence and Phantom with a New Type of Interaction in Dark Sector

TL;DR

This paper introduces a novel interaction in the dark sector that changes sign during the universe's transition from deceleration to acceleration, affecting cosmological evolution and potentially addressing the coincidence problem.

Contribution

It proposes a new sign-changing interaction in dark energy models and analyzes its impact on cosmological dynamics and attractor solutions.

Findings

Identification of scaling attractors in the model

Interaction sign change correlates with universe's acceleration transition

Potential alleviation of the cosmological coincidence problem

Abstract

In the present work, motivated by the work of Cai and Su [Phys. Rev. D {\bf 81}, 103514 (2010)], we propose a new type of interaction in dark sector, which can change its sign when our universe changes from deceleration to acceleration. We consider the cosmological evolution of quintessence and phantom with this type of interaction, and find that there are some scaling attractors which can help to alleviate the cosmological coincidence problem. Our results also show that this new type of interaction can bring new features to cosmology.