Maxwell-Dirac system in cosmology

TL;DR

This paper investigates how interacting spinor and electromagnetic fields influence the evolution of a Bianchi type-I universe, revealing that such interactions allow for more general solutions than previously possible with pure fields.

Contribution

It demonstrates that in a Bianchi type-I cosmology, the interaction between spinor and electromagnetic fields relaxes restrictions on the spacetime and field configurations, enabling nonlinear, massive spinor fields to persist.

Findings

Interacting fields reduce restrictions on spacetime geometry.

Nonlinear, massive spinor fields can exist in general Bianchi I models.

Electromagnetic field nonlinearity influences metric and vector potential components.

Abstract

Within the scope of a Bianchi type-I (BI) cosmological model we study the interacting system of spinor and electromagnetic fields and its role in the evolution of the Universe. In some earlier studies it was found that in case of a pure spinor field the presence of nontrivial non-diagonal components of EMT leads to some severe restrictions both on the spacetime geometry and/or spinor field itself, whereas in case of electromagnetic field with induced nonlinearity such components impose severe restrictions on metric functions and the components of the vector potential. It is shown that in case of interacting spinor and electromagnetic fields restrictions are not as severe as in other cases and in this case a nonlinear and massive spinor field with different components of vector potential can survive in a general Bianchi type-I spacetime.