Cosmology of fermionic dark energy coupled to curvature

TL;DR

This paper explores a cosmological model where fermionic fields coupled to curvature influence universe evolution, aligning with standard models early on but introducing new effects at late times.

Contribution

It introduces a novel fermion-curvature coupling in cosmology, providing a unified framework for early universe behavior and late-time acceleration.

Findings

Early universe matches $ ext{ extLambda}$CDM model

Late-time dynamics dominated by new interaction term

Potential explanation for dark energy phenomena

Abstract

A formulation of cosmology driven by fermions $\psi $ is studied. Assumption that the expectation value of the fermion bilinear is non-zero simplifies the homogeneous solution of the Dirac equations and connects the spinor field with the scale parameter of the universe. With coupling between the Einstein term and spinor field $1 - \frac{\xi }{6} (\bar{\psi }\psi )^{-l}$, the possibility for a late time interaction emerges. In that way, the early universe agrees with $\Lambda $CDM model, but for the late universe the new integrating term dominates.