Nonlinear spinor fields in LRS Bianchi type-I space-time: Theory and observation

Resumo

Within the scope of a LRS Bianchi type-I cosmological model we study the role of a nonlinear spinor field in the evolution of the Universe. In doing so, we consider a polynomial type of nonlinearity that describes different stages of the evolution. Finally, we use the observational data to fix the problem parameters that match best with the real picture of the evolution. An assessment of the age of the Universe in the case of a soft beginning of the expansion (initial speed of expansion at the singularity is zero), the age was found to be 15 billion years, whereas in the case of a hard beginning (nonzero initial speed) the Universe is found to be 13.7 billion years old. Values of the constants D₁ and X₁ that define the anisotropy of our model are also calculated.