Fermionic and bosonic fields in the Einstein–Cartan theory

Abstract

A cosmological model with a fermionic field and a massive bosonic field within the framework of the Einstein–Cartan theory is developed. The spacetime curvature is due to the matter-energy of the gravitational sources, whereas the torsion of the spacetime manifold follows from the spin density. From the numerical simulations it is shown that the fermionic spin density and the bosonic constituent answer for the transition from a decelerated to an accelerated era. The massive bosonic field behaves as dark energy, as it promotes the final accelerated period. During the initial decelerated era both constituents contribute, and the transition occurs as the torsion effect decreases with time. The exchange of energy between the constituents occurs via the gravitational field.