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The loop quantum cosmology of the Bianchi type II string cosmological model in the presence of a homogeneous magnetic field is studied. We present the effective equations which provide modifications to the classical equations of motion due…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Victor Rikhvitsky , Bijan Saha , Mihai Visinescu

In this paper we study the effect of the magnetic field in string cosmology for a spatially homogenous and anisotropic Bianchi type -V space-time model. In order to study the effect of magnetic field, the standard form of the energy…

General Relativity and Quantum Cosmology · Physics 2013-05-07 C. P. Singh , Vijay Singh

A Bianchi type-I cosmological model in the presence of a magnetic flux along a cosmic string is investigated. A nonlinear spinor field is used to simulate the cosmological cloud of strings. It is shown that the spinor field simulation offer…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha , Mihai Visinescu

A Bianchi type-VI cosmological model in the presence of a magnetic flux together with a cloud of cosmic strings is considered. In general, the presence of a magnetic field imposes severe restrictions regarding the consistency of the field…

General Relativity and Quantum Cosmology · Physics 2012-06-01 Bijan Saha , Mihai Visinescu

Here, we have investigated the interaction of Bianchi type I anisotropic cloud string cosmological model universe with electromagnetic field in the context of general relativity. In this paper, the energy momentum tensor is assumed to be…

General Relativity and Quantum Cosmology · Physics 2019-10-21 Kangujam Priyokumar Singh , Mahbubur Rahman Mollah , Rajshekhar Roy Baruah , Meher Daimary

Cylindrically symmetric inhomogeneous magnetized string cosmological model is investigated with cosmological term $\Lambda$ varying with time. To get the deterministic solution, it has been assumed that the expansion ($\theta$) in the model…

General Relativity and Quantum Cosmology · Physics 2014-05-06 Anirudh Pradhan

Exact solutions of the Einstein field equations with cosmic string and space varying cosmological constant, viz., $\Lambda= \Lambda(r)$, in the energy-momentum tensors are presented. Three cases have been studied: where variable…

Astrophysics · Physics 2009-07-22 Saibal Ray , Farook Rahaman , Utpal Mukhopadhyay

In this paper, we have investigated some features of anisotropic accelerating Bianchi type-I cosmological model in the presence of two non-interacting fluids, i.e. one usual string and other dark energy fluid towards the gravitational field…

General Physics · Physics 2020-04-20 S. H. Shekh , V. R. Chirde

Bianchi type V bulk viscous fluid cosmological models are investigated with dynamic cosmological term $\Lambda(t)$. Using a generation technique (Camci {\it et al.}, 2001), it is shown that the Einstein's field equations are solvable for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Anirudh Pradhan , Kanti Jotania , Anju Rai

The present study deals with spatially homogeneous and totally anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with variable $G$ and $\Lambda$ in presence of imperfect fluid. To get the deterministic model…

General Physics · Physics 2012-01-17 Anil Kumar Yadav , Anirudh Pradhan , Ajay Kumar Singh

In this paper we study the evolution of a LRS Bianchi I Universe, filled with a bulk viscous cosmological fluid in the presence of time varying constants "but" taking into account the effects of a c-variable into the curvature tensor. We…

General Relativity and Quantum Cosmology · Physics 2009-11-10 J. A. Belinchón

Bianchi type I massive string cosmological model with magnetic field of barotropic perfect fluid distribution through the techniques used by Latelier and Stachel, is investigated. To get the deterministic model of the universe, it is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Raj Bali , Umesh Kumar Pareek , Anirudh Pradhan

Bianchi type I magnetized cosmological models in the presence of a bulk viscous fluid are investigated. The source of the magnetic field is due to an electric current produced along x-axis. The distribution consists of an electrically…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Anirudh Pradhan , Om Prakash Pandey

We describe exact cosmological solutions with rotation and expansion in the low-energy effective string theory. These models are spatially homogeneous (closed Bianchi type IX) and they belong to the family of shear-free metrics which are…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Yuri N. Obukhov , Thoralf Chrobok , Mike Scherfner

Aspects of string cosmology for critical and non-critical strings are discussed emphasizing the necessity to account for the dilaton dynamics for a proper incorporation of ``large - small" duality. This drastically modifies the intuition…

High Energy Physics - Theory · Physics 2009-09-17 A. A. Tseytlin , C. Vafa

We investigate some classical aspects of fundamental strings via numerical experiments. In particular, we study the thermodynamics of a string network within a toroidal universe, as a function of string energy density and space…

High Energy Physics - Theory · Physics 2009-10-28 Mairi Sakellariadou

The asymptotic behaviour of two classes of scalar field cosmological models are studied using the theory of dynamical systems: general relativistic Bianchi models containing matter and a scalar field with an exponential potential and a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Andrew P. Billyard

With no free parameter (except the string scale $M_S$), dynamical flux compactification in Type IIB string theory determines both the cosmological constant (vacuum energy density) $\Lambda$ and the Planck mass $M_P$ in terms of $M_S$, thus…

High Energy Physics - Theory · Physics 2018-03-19 S. -H. Henry Tye

Bianchi-type string cosmology involves generalizations of the FRW backgrounds with three transitive spacelike Killing symmetries, but without any a priori assumption of isotropy in the 3D sections of homogeneity. With emphasis on those…

High Energy Physics - Theory · Physics 2009-10-28 N. A. Batakis

LRS Bianchi type-I models have been studied in the cosmological theory based on Lyra's geometry. A new class of exact solutions has been obtained by considering a time dependent displacement field for variable deceleration parameter models…

General Relativity and Quantum Cosmology · Physics 2010-05-28 Anirudh Pradhan , D. S. Chauhan