English
Related papers

Related papers: Some Inhomogeneous Magnetized Viscous Fluid Cosmol…

200 papers

We consider a unified dissipative dark fluid model. Our fluid contains an adiabatic part plus a bulk viscous one. The adiabatic part has the ability to asymptote between two power laws and so can interpolate between the dust and dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-16 Esraa Elkhateeb

The analytic properties of the energy density rho(t) of the cosmic fluid, and the Hubble parameter H(t), are investigated near to the future singularity t=t_s assuming different forms for the equation of state. First, it is shown that the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 I. Brevik , O. Gorbunova

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

In this work, we introduce an effective model for both ideal and viscous fluid dynamics within the framework of kinetic field theory (KFT). The main application we have in mind is cosmic structure formation where gaseous components need to…

Statistical Mechanics · Physics 2018-11-01 C. Viermann , J. T. Schneider , R. Lilow , F. Fabis , C. Littek , E. Kozlikin , M. Bartelmann

This work explores the influence of viscous fluids on cosmological dynamics within the framework of General Relativity. We introduce a novel time-dependent parametrization for the bulk viscosity coefficient, given by \(\zeta = \zeta_0 (t -…

General Relativity and Quantum Cosmology · Physics 2025-04-30 Rajdeep Mazumdar , Mrinnoy M. Gohain , Kalyan Bhuyan

Barber's second self creation theory with bulk viscous fluid source for an LRS Bianchi type-I metric is considered by using deceleration parameter to be constant where the metric potentials are taken as function of $x$ and $t$. The…

General Relativity and Quantum Cosmology · Physics 2009-11-07 A. Pradhan , H. R. Pandey

The observational behavior of spherically symmetric inhomogeneous cosmological models is studied, which consist of inner and outer homogeneous regions connected by a shell or an intermediate self-similar region. It is assumed that the…

Astrophysics · Physics 2009-10-31 Kenji Tomita

General hyperbolic systems of balance laws with inhomogeneity in space and time in all constitutive functions are studied in the context of relative entropy. A framework is developed in this setting that contributes to a measure-valued weak…

Analysis of PDEs · Mathematics 2022-06-02 Cleopatra Christoforou

The holographic principle in a radiation dominated universe is extended to incorporate the case of a bulk-viscous cosmic fluid. This corresponds to a nonconformally invariant theory. Generalization of the Cardy-Verlinde entropy formula to…

General Relativity and Quantum Cosmology · Physics 2009-01-14 Iver Brevik

The expressions for average densities of currents and charges induced by a weak electromagnetic field in spatially inhomogeneous systems are obtained. The case of finite temperatures is considered. It is shown that average values are…

Mesoscale and Nanoscale Physics · Physics 2016-08-31 I. G. Lang , L. I. Korovin , S. T. Pavlov

We analyze gravitational waves propagating in an isotropic cosmic fluid endowed with a bulk viscosity $\zeta$ and a shear viscosity $\eta$, assuming these coefficients to vary with fluid density $\rho$ as $\rho^\lambda$, with $\lambda=1/2$…

General Relativity and Quantum Cosmology · Physics 2019-07-16 Iver Brevik , Shin'ichi Nojiri

Cylindrically symmetric inhomogeneous string cosmological model of the universe in presence of electromagnetic field is investigated. We have assumed that F_{12} is the only non-vanishing component of electromagnetic field tensor F_{ij}.…

General Relativity and Quantum Cosmology · Physics 2014-05-06 Anirudh Pradhan , S. K. Singh , L. J. S. Yadav

A Bianchi type -I metric of Kasner form is considered, when the space is filled with a viscous fluid. Whereas an ideal (nonviscous) fluid permits the Kasner metric to be anisotropic provided that the fluid satisfies the Zel'dovich equation…

General Relativity and Quantum Cosmology · Physics 2009-01-14 I. Brevik , S. V. Pettersen

We present and constrain a cosmological model where the only 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 bulk viscosity…

General Relativity and Quantum Cosmology · Physics 2009-01-05 Arturo Avelino , Ulises Nucamendi

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

We consider a low-dimensional model of convection in a horizontally magnetized layer of a viscous fluid heated from below. We analyze in detail the stability of hydromagnetic convection for a wide range of two control parameters. Namely,…

Chaotic Dynamics · Physics 2014-03-26 Wieslaw M. Macek , Marek Strumik

We consider the inflation produced by two coupled fluids in the flat Friedmann-Robertson-Walker universe. Different cosmological models for describing inflation by use of an inhomogeneous equation of state for the fluid are investigated.…

General Relativity and Quantum Cosmology · Physics 2016-05-12 I. Brevik , A. V. Timoshkin

Plane symmetric bulk viscous string cosmological models with strange quark matter are investigated. We have incorporated bulk viscous pressure to study its affect on the properties of the model. Assuming an anisotropic relationship among…

General Relativity and Quantum Cosmology · Physics 2014-10-08 K. L. Mahanta , S. K. Tripathy

In this paper we consider dissipative effects in $\Lambda$CDM model, i.e., we consider a universe with cosmological constant having viscous matter. We assume the most general form for bulk viscous coefficient,…

General Relativity and Quantum Cosmology · Physics 2024-08-14 Athira Sasidharan , Titus K Mathew

Based on the assumption that the dark energy possessing bulk viscosity is homogenously and isotropically permeated in the universe, we propose three new viscous dark energy (VDE) models to characterize the accelerating universe. By…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-30 Deng Wang , Yang-Jie Yan , Xin-He Meng