A square-torsion modification of Einstein-Cartan theory

TL;DR

This paper explores a modified gravity theory incorporating both curvature and torsion with independent couplings, analyzing its effects on Dirac fields and cosmological models, revealing potential new physics at subatomic and cosmological scales.

Contribution

It introduces a square-torsion modification of Einstein-Cartan theory with independent coupling constants for curvature and torsion, and examines its implications for fermions and cosmology.

Findings

Dirac self-interactions depend on the torsion coupling constant.

Different applications emerge based on the parameter value, affecting subatomic physics.

The theory yields FLRW cosmological models with torsion effects.

Abstract

In the present paper we consider a theory of gravity in which not only curvature but also torsion is explicitly present in the Lagrangian, both with their own coupling constant. In particular, we discuss the couplings to Dirac fields and spin fluids: in the case of Dirac fields, we discuss how in our approach, the Dirac self-interactions depend on the coupling constant as a parameter that may even make these non-linearities manifest at subatomic scales, showing different applications according to the value of the parameter we have assigned; in the case of spin fluids, we discuss FLRW cosmological models arising from the proposed theory.