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Related papers: Inhomogeneous Bulk Viscous Fluid Universe with Ele…

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In this paper, we investigate inhomogeneous viscous fluid cosmology for inflation. Several toy models are presented in the attempt to analyze how inflation can be realized according with cosmological data by making use of an inhomogeneous…

General Relativity and Quantum Cosmology · Physics 2015-09-21 Ratbay Myrzakulov , Lorenzo Sebastiani

In this work, we have studied, for the first time, the impact of a realistic picture of a time dependent electric and magnetic field on the shear and bulk viscosities of the medium. Both the electric and magnetic fields are considered to be…

High Energy Physics - Phenomenology · Physics 2025-05-15 Debarshi Dey , Gowthama K K , Sadhana Dash , Basanta Kumar Nandi

We have analyzed a nonsingular model with a variable cosmological term following the Carvalho {\it et al}. ansatz. The model was shown to approximate to the model of Freese {\it et al}. in one direction and to the \"{O}zer-Taha in the…

General Relativity and Quantum Cosmology · Physics 2017-06-15 Arbab I. Arbab

This paper is devoted to study the phase space analysis of isotropic and homogenous universe model by taking a noninteracting mixture of electromagnetic and viscous radiating fluids whose viscous pressure satisfies a nonlinear version of…

General Relativity and Quantum Cosmology · Physics 2017-03-08 M. Sharif , Saadia Mumtaz

We investigate the late-time cosmic acceleration within the framework of viscous $f(T,L_m)$ gravity, where the gravitational action depends on both the torsion scalar $T$ and the matter Lagrangian $L_m$. In this context, the Universe is…

General Physics · Physics 2026-03-24 M. Koussour , Alnadhief H. A. Alfedeel , S. Muminov , J. Rayimbaev

A gauge invariant and hence physically meaningful definition of magnetic helicity density for random fields is proposed, using the Gauss linking formula, as the density of correlated field line linkages. This definition is applied to the…

Astrophysics · Physics 2011-02-11 Kandaswamy Subramanian , Axel Brandenburg

In order to provide a formally correct thermodynamical description of inhomogeneous fluids valid on all length scales down to the classical limit we postulate that all extensive quantities have locally extensive analogues. We derive local…

Statistical Mechanics · Physics 2016-08-14 Aljaž Godec , Janko Jamnik , Franci Merzel

Several isotropic, homogeneous cosmological models containing a self-interacting minimally coupled scalar field, a perfect fluid source and cosmological constant are solved. New exact, asymptotically stable solutions with an inflationary…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Luis P. Chimento , Alejandro S. Jakubi

We investigate a simple inhomogeneous anisotropic cosmology (plane symmetric $G_2$ model) filled with a tilted perfect fluid undergoing velocity diffusion on a scalar field. Considered are two types of fluid: dust and radiation. We solve…

General Relativity and Quantum Cosmology · Physics 2014-11-13 Dmitry Shogin , Sigbjorn Hervik

The presence of a bulk viscosity for the cosmic fluid on a single Randall-Sundrum brane is considered. The spatial curvature is assumed to be zero. The five-dimensional Friedmann equation is derived, together with the energy conservation…

General Relativity and Quantum Cosmology · Physics 2009-01-14 I. Brevik , A. Hallanger

So far all known singularity-free cosmological models are cylindrically symmetric. Here we present a new family of spherically symmetric non-singular models filled with imperfect fluid and radial heat flow, and satisfying the weak and…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Naresh Dadhich

Lord Kelvin believed that the electromagnetic aether must also generate gravity. Presently, we have no methods to determine the density of the electromagnetic aether, or we say the $\Omega(1)$ substratum. Thus, we also suppose that vacuum…

General Physics · Physics 2022-09-22 Xiao-Song Wang

The Einstein-Klein-Gordon field equations are solved in a inhomogeneous shear-free universe containing a material fluid, a self-interacting scalar field, a variable cosmological term, and a heat flux. A quintessence-dominated scenario…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Luis P. Chimento , Alejandro S. Jakubi , Diego Pavon

It has been recently proposed that the presence of a temporal electromagnetic field on cosmological scales could explain the phase of accelerated expansion that the universe is currently undergoing. The field contributes as a cosmological…

General Physics · Physics 2009-11-13 Jose Beltran Jimenez , Tomi S. Koivisto , Antonio L. Maroto , David F. Mota

The standard formulation of General Relativity Theory, in the absence of a cosmological constant, is unable to explain the responsible mechanism for the observed late-time cosmic acceleration. On the other hand, by inserting the…

General Relativity and Quantum Cosmology · Physics 2022-12-26 Raja Solanki , Simran Arora , P. K. Sahoo , P. H. R. S. Moraes

We investigate the bounce cosmology induced by inhomogeneous viscous fluids in FRW space-time (non necessarly flat), taking into account the early-time acceleration after the bounce. Different forms for the scale factor and several examples…

General Relativity and Quantum Cosmology · Physics 2015-09-21 Ratbay Myrzakulov , Lorenzo Sebastiani

Specific dark energy models with a linear inhomogeneous time-dependent equation of state, within the framework of 4d Friedman-Robertson-Walker (FRW) cosmology, are investigated. It is demonstrated that such 4d inhomogeneous fluid models may…

General Relativity and Quantum Cosmology · Physics 2014-01-28 I. Brevik , A. V. Timoshkin , Ye. Rabochaya , S. Zerbini

We present and constrain a cosmological model which component is a pressureless fluid with bulk viscosity as an explanation for the present accelerated expansion of the universe. We study the particular model of a constant bulk viscosity…

General Relativity and Quantum Cosmology · Physics 2009-03-24 Arturo Avelino , U. Nucamendi , F. S. Guzmán

We study evolution of a flat Friedmann-Robertson Walker universe filled with a bulk viscous cosmological fluid in a higher derivative theory of gravity in the presence of time varying gravitational and cosmological constant. Cosmological…

General Relativity and Quantum Cosmology · Physics 2015-03-13 B. C. Paul , P. S. Debnath

We have investigated a non-static and rotating model of the universe with an imperfect fluid distribution. It is found that the model is free from singularity and represents an ever expanding universe with shear and rotation vanishing for…

General Relativity and Quantum Cosmology · Physics 2011-12-16 G. K. Goswami , Mandwi Trivedi