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The behavior of magnetic field in plane symmetric inhomogeneous cosmological models for bulk viscous distribution is investigated. The coefficient of bulk viscosity is assumed to be a power function of mass density $(\xi =\xi_{0}\rho^{n})$.…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Anirudh Pradhan , Purnima Pandey

The irrotational Bianchi V cosmological model under the influence of both shear and bulk viscosity, together with heat flux, has been studied. Exact solutions for the model are obtained with three physically viable assumptions. The first…

General Relativity and Quantum Cosmology · Physics 2019-12-09 A. Banerjee , Abhik Kumar Sanyal

The bulk viscosity is introduced to model unified dark matter. The viscous unified model assumes the universe is filled with a single fluid with the bulk viscosity. We review the general framework of the viscous cosmology. The Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Xu Dou , Xin-He Meng

The nature of cosmological solutions for a homogeneous, anisotropic Universe given by a Bianchi type-I (BI) model in the presence of a Cosmological constant $\Lambda$ is investigated by taking into account dissipative process due to…

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

In this work we consider particle creation by the expansion of the universe, using two Bianchi type I anisotropic models. The particles studied are of spin 0 and 1/2. The cosmological models have rotational symmetry, which allows us to…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Luis O. Pimentel , Flavio Pineda

The main purpose of the present paper is to investigate LRS Bianchi type I metric in the presence of perfect fluid and dark energy. In order to obtain a deterministic solution of the field equations we have assumed that, the two sources of…

General Relativity and Quantum Cosmology · Physics 2020-03-06 Y. S. Solanke , D. D. Pawar , V. J. Dagwal

Bianchi type V viscous fluid cosmological model for barotropic fluid distribution with varying cosmological term $\Lambda$ is investigated. We have examined a cosmological scenario proposing a variation law for Hubble parameter $H$ in the…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Raj Bali , Pratibha Singh , J. P. Singh

We investigate diagonal Bianchi-I spacetimes in the presence of viscous fluids by using the shear and the anisotropic pressure components as the basic variables, where the viscosity is driven by the (second-order) causal thermodynamics. A…

General Relativity and Quantum Cosmology · Physics 2017-02-13 Eduardo Bittencourt , Leandro G. Gomes , Renato Klippert

We study the evolution of a flat Friedmann-Robertson- Walker Universe, filled with a bulk viscous cosmological fluid, in the presence of variable gravitational and cosmological constants. The dimensional analysis of the model suggest a…

General Relativity and Quantum Cosmology · Physics 2009-09-25 J. A. Belinchon , T. Harko , M. K. Mak

A simple model of uniformly expanding, homogeneous Universe with a bulk viscosity is studied wherein the inflationary density decays due to viscous dissipation during the expansion phase of the Universe. The model is shown to generate the…

General Relativity and Quantum Cosmology · Physics 2020-10-14 Sanved Kolekar , S. Shankaranarayanan , S. M. Chitre

Bulk viscosity in cold dark matter is an appealing feature that introduces distinctive phenomenological effects in the cosmological setting as compared to the $\Lambda$CDM model. Under this view, we propose a general parametrization of the…

General Relativity and Quantum Cosmology · Physics 2023-08-24 Gabriel Gómez , Guillermo Palma , Ángel Rincón , Norman Cruz , Esteban González

We study the evolution of a homogeneous, anisotropic Universe given by a Bianchi type-I cosmological model filled with viscous fluid, in the presence of a cosmological constant $\Lambda$. The role of viscous fluid and $\Lambda$ term in the…

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

The unified dark energy and dark matter model within the framework of a model of a continuous medium with bulk viscosity (dark fluid) is considered. It is supposed that the bulk viscosity coefficient is an arbitrary function of the Hubble…

Astrophysics · Physics 2009-06-23 V. Folomeev , V. Gurovich

In this paper, we explore an axially symmetric Bianchi type-I model of the universe with bulk viscous fluid as a source of gravitational field under the framework of Einstein's field equations by assuming barotropic bulk viscous pressure as…

General Relativity and Quantum Cosmology · Physics 2025-04-29 G. K. Goswami , Anirudh Pradhan , Vipin Chandra Dubey

The standard formulation of general relativity fails to describe some recent interests in the universe. It impels us to go beyond the standard formulation of gravity. The $f(Q)$ gravity theory is an interesting modified theory of gravity,…

General Relativity and Quantum Cosmology · Physics 2022-04-14 Sanjay Mandal , Abhishek Parida , P. K. Sahoo

We study particle creation in the presence of bulk viscosity of cosmic fluid in the early universe within the framework of open thermodynamical systems. Since the first-order theory of non-equilibrium thermodynamics is non-causal and…

General Relativity and Quantum Cosmology · Physics 2015-04-30 Mehdi Eshaghi , Nematollah Riazi , Ahmad Kiasatpour

In this work, we investigate the dynamics of bulk viscous models with decaying vacuum energy density (VED) in a spatially homogeneous and isotropic flat Friedmann-Lema\^{i}tre- Robertson-walker (FLRW) spacetime. We particularly are…

General Relativity and Quantum Cosmology · Physics 2024-01-10 C. P. Singh , Vinita Khatri

In a viscous Bianchi type I metric of the Kasner form, it is well known that it is not possible to describe an anisotropic physical model of the universe, which satisfies the second law of thermodynamics and the dominant energy condition…

General Relativity and Quantum Cosmology · Physics 2009-10-31 M. Cataldo , S. del Campo , P. Salgado

In this paper, we investigate the evolution of cosmological perturbations within the context of Bianchi Type$-I$ spacetimes. We consider models containing viscous fluids with evolving cosmological (\LL) and Newtonian gravitational (G)…

General Relativity and Quantum Cosmology · Physics 2023-11-08 Alnadhief H. A. Alfedeel , Maye Elmardi , Amare abebe

Multidimensional cosmological model describing the evolution of a fluid with shear and bulk viscosity in $n$ Ricci-flat spaces is investigated. The barotropic equation of state for the density and the pressure in each space is assumed. The…

General Relativity and Quantum Cosmology · Physics 2010-04-30 V. R. Gavrilov , V. N. Melnikov , Roland Triay