Quintessence with quadratic coupling to dark matter

TL;DR

This paper proposes a novel quadratic coupling between dark energy and dark matter, analyzing its impact on cosmic evolution and identifying conditions for late-time acceleration and matter era compatibility.

Contribution

It introduces a new quadratic coupling model between dark energy and dark matter and studies its background dynamics and cosmological implications.

Findings

All coupling types admit late-time accelerating solutions.

Two coupling types support a matter era before acceleration.

One coupling type does not allow a suitable matter era.

Abstract

We introduce a new form of coupling between dark energy and dark matter that is quadratic in their energy densities. Then we investigate the background dynamics when dark energy is in the form of exponential quintessence. The three types of quadratic coupling all admit late-time accelerating critical points, but these are not scaling solutions. We also show that two types of coupling allow for a suitable matter era at early times and acceleration at late times, while the third type of coupling does not admit a suitable matter era.