Einstein-Cartan cosmology and the high-redshift Universe

TL;DR

This paper proposes that Einstein-Cartan cosmology, incorporating spacetime torsion and neutrino spin effects, can better reconcile high-redshift observations and the Hubble tension than standard models.

Contribution

It introduces a nonsingular Einstein-Cartan model with torsion parametrization, linking neutrino spin to cosmological phenomena and addressing observational tensions.

Findings

Improved fit to high-redshift data and Hubble tension.

Neutrino spin and torsion effects are significant in cosmology.

Heavy Majorana neutrinos as dark matter candidates.

Abstract

The Hubble tension, known as a discrepancy between the local measurements vs. the CMB, SNe and galaxy clustering fits of the Hubble constant, the first measurement of the 21-centimeter high-redshift signal by EDGES, the high-redshift galaxy halo number densities and the measurements of the ionizing photon mean free path represent a great challenge for the concordance cosmology. We show that the nonsingular Einstein-Cartan cosmological model with the simple parametrization of torsion of spacetime (angular momentum of the Universe) can substantially improve agreement with data. Light Majorana neutrinos are dominant source of the spin of matter coupled to torsion, while the heavy Majorana neutrinos represent cold dark matter particles fulfilling the Griest-Kamionkowski unitarity bound.