Cosmological bounces, cyclic universes, and effective cosmological constant in EinsteinCartanDiracMaxwell theory
Abstract
EinsteinCartan theory is an extension of the standard formulation of general relativity characterized by a nonvanishing torsion. The latter is sourced by the matter fields via the spin tensor, and its effects are expected to be important at very high spin densities. In this work, we analyze in detail the physics of EinsteinCartan theory with Dirac and Maxwell fields minimally coupled to the spacetime torsion. This breaks the U (1 ) gauge symmetry, which is suggested by the possibility of a torsioninduced phase transition in the early Universe. The resulting Diraclike and Maxwelllike equations are nonlinear with selfinteractions as well as having fermionboson nonminimal couplings. We discuss several cosmological aspects of this theory under the assumption of randomly oriented spin densities (unpolarized matter), including bounces, acceleration phases, and matterantimatter asymmetry in the torsion era, as well as latetime effects such as the generation of an effective cosmological constant, dark energy, and future bounces within cyclic solutions.
 Publication:

Physical Review D
 Pub Date:
 October 2020
 DOI:
 10.1103/PhysRevD.102.083509
 arXiv:
 arXiv:2003.07463
 Bibcode:
 2020PhRvD.102h3509C
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Theory
 EPrint:
 20 pages, 4 figures