New Interaction between Dark Energy and Dark Matter Changes Sign during Cosmological Evolution

TL;DR

This paper proposes a new model of dark energy and dark matter interaction that changes sign during cosmic evolution, aligning with thermodynamics and observational data, and explores its stability properties.

Contribution

It introduces a novel interaction form between dark energy and dark matter that transitions from negative to positive, providing a better fit to cosmological observations.

Findings

Interaction changes sign from negative to positive during evolution

Model is consistent with thermodynamics laws

Compatible with observational constraints

Abstract

It is found by Cai and Su that the interaction between dark energy and cold dark matter is likely to change the sign during the cosmological evolution. Motivated by this, we suggest a new form of interaction between dark energy and dark matter, which changes from negative to positive as the expansion of our universe changes from decelerated to accelerated. We find that the interacting model is consistent with the second law of thermodynamics and the observational constraints. And, we also discuss the unified adiabatic-squared sound speed of the model.