Crossing the phantom divide with a classical Dirac field

TL;DR

This paper presents a cosmological model with a classical Dirac field that reproduces dark matter and dark energy behaviors, crossing the phantom divide, and can be constrained by observations.

Contribution

It introduces a modified $mbda$CDM model with a classical Dirac field to explain dark energy dynamics and the crossing of the phantom divide.

Findings

Identifies the scale factor where dark energy crosses the phantom divide.

Provides a parameter set compatible with current astrophysical observations.

Models effective dark matter and dark energy using a multifluid approach.

Abstract

In this paper we consider a spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with cosmological constant, containing a stiff fluid and a classical Dirac field. The proposed cosmological scenario describes the evolution of effective dark matter and dark energy components reproducing, with the help of that effective multifluid configuration, the quintessential behavior. We find the value of the scale factor where the effective dark energy component crosses the phantom divide. The model we introduce, which can be considered as a modified $\Lambda$CDM one, is characterized by a set of parameters which may be constrained by the astrophysical observations available up to date.