Chiral fermions and torsion in the early Universe

Understand

Torsion arising from fermionic matter in the Einstein-Cartan formulation of general relativity is considered in the context of Robertson-Walker geometries and the early Universe.

• An ambiguity in the way torsion arising from hot fermionic matter in chiral models should be implemented is highlighted and discussed.
• In one interpretation, chemical potentials in chiral models can contribute to the Friedmann equation and give a negative contribution to the energy density.