We use holography in order to study the entanglement entropy for a spherical entangling surface FRW background with an arbitrary time dependence of scale factor. The calculation is done various dimensions, allowing nonzero spatial curvature. CFT at temperature this also considered. Our approach based on coordinate transformations that relate extremization problem one static background, careful ...

We study the late time evolution of positively curved FRW models with a scalar field which arises in the conformal frame of the R + αR 2 theory. The resulted three-dimensional dynamical system has two equilibrium solutions corresponding to a de Sitter space and an ever expanding closed universe. We analyze the structure of the first equilibrium with the methods of the center manifold theory and...

In a Friedmann-Robertson-Walker (FRW) cosmological model with zero spatial curvature, we consider the interaction of the gravitational waves with the plasma in the presence of a weak magnetic field. Using the relativistic hydromagnetic equations it is verified that large amplitude magnetosonic waves are excited, assuming that both, the gravitational field and the weak magnetic field do not brea...

Using the AdS/CFT correspondence we study the holographic principle and the CFT/FRW relations in the near-horizon AdS 5 × S 5 geometry with a probe D3-brane playing the rôle of the boundary to this space. The motion of the probe D3-brane in the bulk, induces a cosmological evolution on the brane. As the brane crosses the horizon of the bulk black hole, it probes the holography of the dual CFT. ...

We investigate the motion of a spinning test particle in a spatially-flat FRW-type space-time in the framework of the Einstein-Cartan theory. The space-time has a torsion arising from a spinning fluid filling the space-time. We show that for spinning particles with nonzero transverse spin components, the torsion induces a precession of particle spin around the direction of the fluid spin. We al...

The tunneling rate, with exact prefactor, is calculated to first order in h̄ for a closed FRW universe filled with perfect fluid violating the strong energy condition. The calculations are performed by applying the dilute-instanton approximation on the corresponding Duru-Kleinert path integral. It is shown that a closed FRW universe filled with a perfect fluid with small violation of strong ener...

I show that all FRW models (four dimensional pseudo-Riemannian manifolds with maximally symmetric space) can be embedded in a flat Minkowski manifold with 5 dimensions. The pseudo Riemannian metric of space-time is induced by the flat metric. This generalizes the usual embedding widely used for the de Sitter models. I give the coordinate transformations for the embedding. Taking into account th...