We investigate the dynamics of a Bianchi I brane Universe in the presence of a nonlocal anisotropic stress Pµν proportional to a " dark energy " U. Using this ansatz for the case U > 0 we prove that if a matter on a brane satisfies the equation of state p = (γ − 1)ρ with γ ≤ 4/3 then all such models isotropize. For γ > 4/3 anisotropic future asymptotic states are found. We also describe the pas...

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...

Motivated form recent string theoretic results, a tachyonic potential is constructed for a spatially homogeneous and anisotropic background cosmology.

In one-loop string effective action, we study a generality of non-singular cosmological solutions found in the isotropic and homogeneous case. We discuss Bianchi I and IX type spacetimes. We find that nonsingular solutions still exist in Bianchi I model around nonsingular flat Friedmann solutions. On the other hand, we cannot find any nonsingular solutions in Bianchi IX model. Non-existence of ...

We consider a procedure of elimination cosmological singularities similar to that suggested in the recent paper by Simpson and Visser for construction regular black holes. It is shown imposing nonsingular evolution with bounce flat Friedmann universe filled minimally coupled scalar field, we obtain transition between standard field its phantom counterpart. In this case, potential has nonanalyti...

Within the context of Saez-Ballester theory, we explored interaction a five-dimensional Bianchi type-I anisotropic cloud string cosmological model Universe with an electromagnetic field. With field, energy momentum tensor is assumed to be sum rest density and tension in this paper. We use average scale factor as integrating function time get exact answers equations. The dynamics importance mode...

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...