Interacting spinor and scalar fields in a Bianchi type-I Universe: Oscillatory solutions

TL;DR

This paper investigates a self-consistent system involving spinor, scalar, and gravitational fields in a Bianchi type-I universe, revealing conditions under which the universe exhibits oscillatory expansion modes.

Contribution

It provides exact solutions to the coupled field equations and demonstrates the existence of oscillatory universe solutions depending on interaction parameters and the cosmological constant.

Findings

Exact solutions in terms of volume scale are obtained.

Oscillatory expansion modes are identified for certain parameter ranges.

Positive cosmological constant and specific interaction terms enable oscillatory universe behavior.

Abstract

Self-consistent system of spinor, scalar and BI gravitational fields is considered. Exact solutions to the field equations in terms of volume scale of the BI metric are obtained. Einstein field equations in account of the cosmological constant $\Lambda$ and perfect fluid are studied. Oscillatory mode of expansion of the universe is obtained. It is shown that for the interaction term being a power function of the invariants of bilinear spinor forms and $\Lambda > 0$ and given other parameters, e.g., coupling constant, spinor mass etc., there exists a finite range of integration constant which generates oscillatory mode of evolution.