English
Related papers

Related papers: Perturbations in Bianchi Type-I spacetimes with va…

200 papers

An LRS Bianchi type-V cosmological models representing a viscous fluid distribution with a time dependent cosmological term $\Lambda$ is investigated. To get a determinate solution, the viscosity coefficient of bulk viscous fluid is assumed…

General Relativity and Quantum Cosmology · Physics 2007-08-06 Anirudh Pradhan , J. P. Shahi , C. V. Singh

In this work, we study some physical aspects of unitary evolution of Bianchi-I model. In particular, we study the behavior of the volume and the scale factor as a function of time for the Bianchi-I universe with ultra-relativistic fluid…

General Relativity and Quantum Cosmology · Physics 2016-01-28 Sridip Pal

In this paper, we investigate Bianchi type-$VI$ cosmological model for the universe filled with dark energy and viscous fluid in the presence of cosmological constant. Also, we show accelerating expansion of the universe by drawing volume…

General Relativity and Quantum Cosmology · Physics 2013-08-29 J. Sadeghi , Ali R. Amani , N. Tahmasbi

Some Bianchi type IX viscous fluid cosmological models are investigated. To get a solution a supplementary condition between metric potentials is used. The viscosity coefficient of bulk viscous fluid is assumed to be a power function of…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Anirudh Pradhan , Sudhir Kumar Srivastav , Mahesh K. Yadav

The study of a self-consistent system of interacting spinor and scalar fields within the scope of a Bianchi type I (BI) gravitational field in presence of a viscous fluid and $\Lambda$ term has been carried out. The system of equations…

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

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

In this paper, we study the viscous fluid cosmological model that when certain conditions are invoked mimics the $\Lambda$CDM model. The background equations governing the evolution of viscous interacting fluids in a multifluid system are…

General Relativity and Quantum Cosmology · Physics 2024-12-09 BG Mbewe , RR Mekuria , S Sahlu , A Abebe

We consider the evolution of perturbed cosmological spacetime with multiple fluids and fields in Einstein gravity. Equations are presented in gauge-ready forms, and are presented in various forms using the curvature (\Phi or \phi_\chi) and…

Astrophysics · Physics 2010-05-28 J. Hwang , H. Noh

This study investigates the dynamics of a spatially homogeneous and anisotropic LRS Bianchi type-I universe with viscous fluid in the framework of $f(Q)$ symmetric teleparallel gravity. We assume a linear form for $f(Q)$ and introduce…

General Relativity and Quantum Cosmology · Physics 2024-04-16 M. Koussour , S. H. Shekh , M. Bennai , N. Myrzakulov

The dynamics and evolution of Bianchi type I space-times is considered in the framework of the four-dimensional truncation of a reduced theory obtained from the N=2,D=5 supergravity. The general solution of the gravitational field equations…

High Energy Physics - Theory · Physics 2009-10-31 Chiang-Mei Chen , T. Harko , M. K. Mak

Tilted Bianchi type I cosmological models filled with disordered radiation in presence of a bulk viscous fluid and heat flow are investigated. The coefficient of bulk viscosity is assumed to be a power function of mass density. Some…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Anirudh Pradhan , Abha Rai

According to standard cosmology, the universe is homogeneous and isotropic at large scales. However, some anisotropies can be observed at the local scale in the universe through various ways. Here we have studied the Bianchi type I model…

General Relativity and Quantum Cosmology · Physics 2022-09-12 Pranjal Sarmah , Umananda Dev Goswami

Spatially homogeneous and anisotropic Bianchi type V space-time with bulk viscous fluid source and time varying gravitational constant $G$ and cosmological term $\Lambda$ are considered. Coefficient of bulk viscosity $\zeta$ is assumed as a…

General Relativity and Quantum Cosmology · Physics 2012-05-25 Prashant S. Baghel , J. P. Singh

We have investigated an LRS Bianchi Type I models with bulk viscosity in the cosmological theory based on Lyra's geometry. A new class of exact solutions have been obtained by considering a time-dependent displacement field for a constant…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Anirudh Pradhan , Hare Ram Pandey

Anisotropic Bianchi-III cosmological model is investigated with variable gravitational and cosmological constants in the framework of Einstein's general relativity. The shear scalar is considered to be proportional to the expansion scalar.…

General Relativity and Quantum Cosmology · Physics 2015-06-23 S. K. Tripathy , D. Behera , T. R. Routray

Cosmic Microwave Background anomalies suggest that the Universe is slightly anisotropic, so a Cosmological Model that does not satisfy the Cosmological Principle is necessary. Anisotropic Bianchi models have been studied given that they…

General Relativity and Quantum Cosmology · Physics 2017-02-07 Ericsson López , Mario Llerena

We study several cosmological models with Bianchi \textrm{VI}$_{0}$ symmetries under the self-similar approach. In order to study how the \textquotedblleft constants\textquotedblright\ $G$ and $\Lambda$ may vary, we propose three scenarios…

General Relativity and Quantum Cosmology · Physics 2015-05-30 J. A. Belinchón

Bianchi type V matter filled universe with varying lambda in general relativity are investigated by using the law of variation for the generalized mean Hubble parameter. This yields the constant value of deceleration parameter and generates…

General Relativity and Quantum Cosmology · Physics 2013-01-15 Anil Kumar Yadav

We study Bianchi type-I space time with cosmological constant lambda using some conditions.

General Physics · Physics 2017-04-13 Mukesh Sharma , Sonia Sharma

In this work, we study the effect of a magnetic field on the growth of cosmological perturbations. We develop a mathematical consistent treatment in which a perfect fluid and a uniform magnetic field evolve together in a Bianchi I universe.…

General Relativity and Quantum Cosmology · Physics 2019-11-19 Federico Di Gioia , Giovanni Montani