Couplings between holographic dark energy and dark matter

TL;DR

This paper explores a new model of interaction between dark matter and dark energy within holographic dark energy frameworks, analyzing cosmic evolution and constraining the model with recent observational data.

Contribution

It introduces a physically plausible interaction form proportional to the product of dark matter and dark energy densities, including the novel concept of 'incoupling' at late times.

Findings

Interaction proportional to the first power product fits data well.

Dark energy decouples from dark matter at late times.

Dark matter may become coupled to dark energy at late times.

Abstract

We consider the interaction between dark matter and dark energy in the framework of holographic dark energy, and propose a natural and physically plausible form of interaction, in which the interacting term is proportional to the product of the powers of the dark matter and dark energy densities. We investigate the cosmic evolution in such models. The impact of the coupling on the dark matter and dark energy components may be asymmetric. While the dark energy decouples from the dark matter at late time, just as other components of the cosmic fluid become decoupled as the universe expands, interestingly, the dark matter may actually become coupled to the dark energy at late time. We shall name such a phenomenon as "incoupling". We use the latest type Ia supernovae data from the SCP team, baryon acoustics oscillation data from SDSS and 2dF surveys, and the position of the first peak of the CMB angular power spectrum to constrain the model. We find that the interaction term which is proportional to the the first power product of the dark energy and dark matter densities gives excellent fit to the current data.