We apply the Dirac procedure for constrained systems to Arnowitt-Deser-Misner formalism linearized around Bianchi I universe. discuss and employ basic concepts such as observables, brackets, gauge-fixing conditions, reduced phase space, physical Hamiltonian, canonical isomorphism between different surfaces spacetime reconstruction. relate this approach non-perturbative relativity. issue of prop...

We study gravitational waves propagating through an anisotropic Bianchi I dust–filled universe (containing the Einstein–de–Sitter universe as a special case). The waves are modeled as small perturbations of this background cosmological model and we choose a family of null hypersurfaces in this space–time to act as the histories of the wave– fronts of the radiation. We find that the perturbation...

We introduce the notion of topological fragility and briefly discuss some examples from the literature. An important example of this type of fragility is the way globally anisotropic Bianchi V generalisations of the FLRW k = −1 model result in a radical restriction on the allowed topology of spatial sections, thereby excluding compact cosmological models with negatively curved three-sections wi...

We examine homogeneous but anisotropic cosmologies in scalar-tensor gravity theories, including Brans-Dicke gravity. We present a method for deriving solutions for any isotropic perfect fluid with a barotropic equation of state (p ∝ ρ) in a spatially flat (Bianchi type I) cosmology. These models approach an isotropic, general relativistic solution as the expansion becomes dominated by the barot...

Abstract In this work, we study a cosmological model of Bianchi type-I Universe in teleparallel gravity for perfect fluid. To obtain the solution model, assume that deceleration parameter (DP) is linear function Hubble H i.e. q = ?1 + ?H (where ? as positive constant). Consequently, get our Universe, where it goes from initial phase to current acceleration. We have discussed some physical and g...

In this study, using the energy momentum definitions of Einstein, Møller, Bergmann-Thomson, Landau-Lifshitz and Papapetrou we compute the total energy-momentum distribution (due to matter and fields including gravitation) of the universe based on general Bianchi type I-III-V-V I0 spacetime and its transforms type I, III, V, V I0 metrics, respectively. The energy-momentum densities are found exa...