Exact cosmological solutions of models with an interacting dark sector

TL;DR

This paper derives exact cosmological solutions for models with interacting dark energy and dark matter, revealing scenarios with early deceleration and late acceleration, including dark matter or dark energy dominance, and purely accelerating universes.

Contribution

It extends the first order formalism to include interactions between fermionic and scalar fields, providing new exact solutions for complex dark sector interactions.

Findings

Identified solutions with early deceleration and late acceleration phases.

Found models where dark matter dominates in the past and dark energy in the future.

Obtained exclusively accelerating cosmological solutions.

Abstract

In this work we extend the first order formalism for cosmological models that present an interaction between a fermionic and a scalar field. Cosmological exact solutions describing universes filled with interacting dark energy and dark matter have been obtained. Viable cosmological solutions with an early period of decelerated expansion followed by late acceleration have been found, notably one which presents a dark matter component dominating in the past and a dark energy component dominating in the future. In another one, the dark energy alone is the responsible for both periods, similar to a Chaplygin gas case. Exclusively accelerating solutions have also been obtained.