Stiff Fluid in Accelerated Universes with Torsion

Abstract EN

The flat Friedmann universes filled by stiff fluid and a nonminimally coupled material scalar field with polynomial potentials of the fourth degree are considered in the framework of the Einstein-Cartan theory.

Exact general solution is obtained for arbitrary positive values of the coupling constant ξ.

A comparative analysis of the cosmological models with and without stiff fluid is carried out.

Some effects of stiff fluid are elucidated.

It is shown that singular models with a de Sitter asymptotic and with the power-law (t4/3) asymptotic at late times are possible.

It is found that ξ=3/8 is a specific value of the coupling constant.

It is demonstrated that the bouncing models without the particle horizon and with an accelerated expansion by a de Sitter law of an evolution at late times are admissible.