نتایج جستجو برای: anisotropic bianchi type i universe

تعداد نتایج: 2280375  

Journal: :Pramana 2022

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...

Journal: :General Relativity and Gravitation 2021

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.

Journal: :Physical review. D, Particles and fields 1990
Huang

The one-loop effective potential for φ theory on a Bianchi type-I universe is evaluated in the adiabatic approximation. It is used to see the quantum-field effects on symmetry breaking and restoration in anisotropic spacetimes. The results show that the fate of symmetry will not be changed in the cases of conformal coupling or a vanishing scale curvature, and only for some suitable values of sc...

1993
J. M. Aguirregabiria

We obtain a general exact solution of the Einstein field equations for the anisotropic Bianchi type I universes filled with an exponential-potential scalar field and study their dynamics. It is shown, in agreement with previous studies, that for a wide range of initial conditions the late-time behaviour of the models is that of a power-law inflating FRW universe. This property, does not hold, i...

2004
B. C. Paul

The Cosmic no hair theorem is studied in anisotropic Bianchi brane models which admit power law inflation with a scalar field. We note that all Bianchi models except Bianchi type IX transit to an inflationary regime and the anisotropy washes out at a later epoch. It is found that in the brane world, the anisotropic universe approaches the isotropic phase via inflation much faster than that in t...

D Neelima, V U M Rao,

Bianchi type-VI0 space time with strange quark matter attached to string cloud in Nordtvedt [1] general scalar tensor theory of gravitation with the help of a special case proposed by Schwinger [2] is obtained. The field equations have been solved by using the anisotropy feature of the universe in the Bianchi type-VI0 space time. Some important features of the model, thus obtained, have been di...

Journal: :Modern Physics Letters A 2005

Journal: :Journal of Cosmology and Astroparticle Physics 2008

2001
Chiang-Mei Chen T. Harko M. K. Mak

An anisotropic ~Bianchi type I! cosmology is considered in the four-dimensional Neveu-Schwarz–NeveuSchwarz ~NS–NS! sector of low-energy effective string theory coupled to a dilaton and an axionlike H field within a de Sitter–Einstein frame background. The general solution of the gravitational field equations can be expressed in an exact parametric form in both Einstein and string frames. The st...

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