FLRW metric f(R) cosmology with a perfect fluid by generating integrals of motion

Quadratic quantum cosmology with Schutz’ perfect fluid

We study the classical and quantum models of a Friedmann-Robertson-Walker (FRW) cosmology coupled to a perfect fluid in the context of f(R) gravity. We use the Schutz’ variational formalism for the perfect fluid and show that it leads to a time parameter for the corresponding dynamical system. This formalism gives rise to a Schrödinger-Wheeler-DeWitt (SWD) equation for the quantum cosmology of ...

Symmetrized Gravitational Formulism in Perfect-fluid Cosmology

We investigate the model of magnetized cosmology, and simplify the exact solutions on the perfect-fluid. We show that large-scale magnetic components of cosmological fields have mathematical connection to the angular-momentum. In the general case where cosmologies are generalized by magnetic components, it introduces some mathematical solutions for gravitational fields in a manner similar to Di...

Tilt Classifications in Perfect Fluid Cosmology

Multidimensional perfect fluid cosmology with stable compactified internal dimensions

Multidimensional cosmological models in the presence of a bare cosmological constant and a perfect fluid are investigated under dimensional reduction to D0 = 4 dimensional effective models. Stable compactification of the internal spaces is achieved for a special class of perfect fluids. The external space behaves in accordance with the standard Friedmann model. Necessary restrictions on the par...

Long-wavelength approximation for string cosmology with barotropic perfect fluid

The field equations derived from the low energy string effective action with a matter tensor describing a perfect fluid with a barotropic equation of state are solved iteratively using the long-wavelength approximation, i.e. the field equations are expanded by the number of spatial gradients. In the zero order, a quasi-isotropic solution is presented and compared with the general solution of th...