Oscillating phases in Bianchi type IX anisotropic universes are obtained as linearized solutions of Einstein-Cartan theory of gravity.Instead of making use of Weyssenhoff spinning fluids we addopt axionic torsion matter where the torsion tensor is totally skew-symmetric as in Kalb-Rammond type theories.Spin-torsion,metric and matter density oscillate at different phases. An upper bound oscillat...

In this work we consider particle creation by the expansion of universe, using two Bianchi type I anisotropic models. The particles studied are spin 0 and 1/2. cosmological models have rotational symmetry, which allows us to solve exactly equations motion. number density created is calculated with method Bogolubov transformations.

Cosmological solutions are obtained in an anisotropic Kantowski-Sachs (KS) and Bianchi Type-I universes considering a cosmological constant with Skyrme fluid. Interestingly, the here both KS Bianchi-I found isotropize at late time due to presence of fluid even absence $\Lambda$ term or any inflationary mechanism involving inflaton field. A comparative study models carried out that universe admi...

Some Bianchi type I viscous fluid cosmological models with a variable cosmological constant are investigated in which the expansion is considered only in two direction i.e. one of the Hubble parameter (H1 = A4 A ) is zero. The viscosity coefficient of bulk viscous fluid is assumed to be a power function of mass density whereas the coefficient of shear viscosity is considered as constant in firs...

Bianchi Type IX Cosmological Model with Varying Lambda Term R.K. Tiwari*, Devendra Kumar Tiwari *, C.Chauhan** *Dept. of Mathematics, Govt. Model Science College, Rewa-486001 (M.P.), India **Dept. of Mathematics, I.E.T. DAVV Indore (M.P.), India __________________________________________________________________________________________ Abstract: We have investigated Bianchi type IX space time in...

In this paper we will study the qualitative behavior of three anisotropic and homogeneous models: Kantowski-Sachs, Bianchi I and Bianchi III universes, with pressureless and cosmological constant. We conclude stating that, this models undergo isotropisation, except for the KantowskiSachs model (Ωk0 > 0) with ΩΛ0 < ΩΛM and for the Bianchi III (Ωk0 < 0) with ΩΛ0 < ΩΛM . To appear in Proceedings o...

We present a study of Bianchi class A tilted cosmological models admitting a proper homothetic vector field together with the restrictions, both at the geometrical and dynamical level, imposed by the existence of the simply transitive similarity group. The general solution of the symmetry equations and the form of the homothetic vector field are given in terms of a set of arbitrary integration ...