Kantowski-Sachs String Cosmological Model with Bulk Viscosity in General Scalar Tensor Theory of Gravitation

V U M Rao,D Neelima

doi:10.1155/2013/759274

Abstract

A new class of spatially homogeneous Kantowski-Sachs string cosmological models with bulk viscosity in Nordtvedt (1970) general scalar-tensor theory of gravitation with the help of a special case proposed by Schwinger (1970) is obtained. In this paper we have presented anisotropic as well as isotropic cosmological models. Some important features of the models, thus obtained, have been discussed. These exact models are new and more general and represent not only the early stages of evolution but also the present universe.

Highlights

Nordtvedt [1] proposed a general class of scalar-tensor gravitational theories in which the parameter ω of the BD theory is allowed to be an arbitrary function of the scalar field [ω → ω(φ)]
Motivated by the above investigations, we study spatially homogeneous and anisotropic Kantowski-Sachs string cosmological model with bulk viscosity in Nordtvedt [1] general scalar-tensor theory with the help of a special case proposed by Schwinger [21], that is, 3 + 2ω(φ) = 1/λφ, where λ is a constant
We obtain string cosmological model with bulk viscosity in Nordtvedt’s general scalar-tensor theory with the help of a special case proposed by Schwinger [21] in the form 3 + 2ω (φ) = 1, λφ λ = constant

Summary

Introduction

Nordtvedt [1] proposed a general class of scalar-tensor gravitational theories in which the parameter ω of the BD theory is allowed to be an arbitrary (positive definite) function of the scalar field [ω → ω(φ)]. Rao et al [18] and Rao and Sireesha [19] have obtained Bianchi types II, VIII, and IX string cosmological models with bulk viscosity in Lyra [20] and Brans and Dicke [3] theory of gravitation, respectively. Motivated by the above investigations, we study spatially homogeneous and anisotropic Kantowski-Sachs string cosmological model with bulk viscosity in Nordtvedt [1] general scalar-tensor theory with the help of a special case proposed by Schwinger [21], that is, 3 + 2ω(φ) = 1/λφ, where λ is a constant

Metric and Energy Momentum Tensor

Solution of the Field Equations

Some Important Features of the Model

Conclusions