Cosmology of fermionic dark energy coupled to curvature

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 - xi/6 ((psi) over bar psi)(-l), the possibility for a late time interaction emerges. In that way, the early universe agrees with ACDM model, but for the late universe the new integrating term dominates. (c) 2023 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP(3).