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Related papers: Qualitative Viscous Cosmology

200 papers

Perfect fluid Friedmann-Robertson-Walker quantum cosmological models for an arbitrary barotropic equation of state $p = \alpha\rho$ are constructed using Schutz's variational formalism. In this approach the notion of time can be recovered.…

General Relativity and Quantum Cosmology · Physics 2021-10-20 F. G. Alvarenga , J. C. Fabris , N. A. Lemos , G. A. Monerat

We consider the dynamics of a viscous cosmological fluid in the generalized Randall-Sundrum model for an anisotropic, Bianchi type I brane. To describe the dissipative effects we use the Israel-Hiscock-Stewart full causal thermodynamic…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. Harko , M. K. Mak

In the context of dark energy solutions, we consider a Friedmann-Robertson-Walker spacetime filled with a non-interacting mixture of dust and a viscous fluid, whose bulk viscosity is governed by the nonlinear model proposed in [15]. Through…

General Relativity and Quantum Cosmology · Physics 2015-06-19 G. Acquaviva , A. Beesham

Based on the conservation-dissipation formalism proposed by Zhu and collaborators we formulate a general version of the Israel-Stewart theory for relativistic fluid dynamics with bulk viscosity. Our generalization consists in allowing for a…

Analysis of PDEs · Mathematics 2022-03-14 Heiner Olbermann

The Einstein field equation as an equation of state of a thermodynamical system of spacetime is reconsidered in the present Letter. We argue that a consistent interpretation leads us to identify scalar curvature and cosmological constant…

General Relativity and Quantum Cosmology · Physics 2007-05-29 S. C. Tiwari

We study a full causal bulk viscous cosmological model with flat FRW symmetries and where the ``constants'' $G,c$ and $\Lambda $ vary. We take into account the possible effects of a $c-$variable into the curvature tensor in order to outline…

General Relativity and Quantum Cosmology · Physics 2016-08-16 J. A. Belinchón

In this paper, we have presented bulk viscous cosmological model of the universe in the modified gravity theory in which the Lagragian of the gravitational action contains a general function $f(R, T) $, where $R$ and $T$ denote the…

General Relativity and Quantum Cosmology · Physics 2019-07-05 Partha Sarathi Debnath

We present a class of relativistic fluid models for cold and dense matter with bulk viscosity, whose equilibrium equation of state is polytropic. These models reduce to Israel-Stewart theory for small values of the viscous stress $\Pi$.…

General Relativity and Quantum Cosmology · Physics 2025-04-10 Lorenzo Gavassino

A spatially homogeneous and locally rotationally symmetric Bianchi type-II cosmological model under the influence of both shear and bulk viscosity has been studied. Exact solutions are obtained with a barotropic equation of state between…

General Relativity and Quantum Cosmology · Physics 2021-05-11 A. Banerjee , S. B. Duttachoudhury , Abhik Kumar Sanyal

The Misner and Sharp approach to the study of gravitational collapse is extended to the viscous dissipative case in, both, the streaming out and the diffusion approximations. The dynamical equation is then coupled to causal transport…

General Relativity and Quantum Cosmology · Physics 2009-03-24 L. Herrera , A. Di Prisco , E. Fuenmayor , O. Troconis

In this paper, we discuss the phase space analysis of locally rotationally symmetric Bianchi type I universe model by taking a noninteracting mixture of dust like and viscous radiation like fluid whose viscous pressure satisfies a nonlinear…

General Relativity and Quantum Cosmology · Physics 2019-05-29 M. Sharif , Saadia Mumtaz

Some properties of cosmological models with a time variable bulk viscous coefficient in presence of adiabatic mater creation and G, c, Lambda variables are investigated in the framework of flat FRW line element. We trivially find a set of…

General Relativity and Quantum Cosmology · Physics 2015-06-25 J. A. Belinchon

In this paper, we investigate Bianchi type$-V$ cosmological models with bulk viscous fluid and time varying cosmological $\Lambda$ and Newtonian $G$ parameters. The Einstein's field equations have been transformed into a coupling…

We consider a Friedmann-Robertson-Walker spacetime filled with both viscous radiation and nonviscous dust. The former has a bulk viscosity which is proportional to an arbitrary power of the energy density, i.e. $\zeta \propto \rho_v^{\nu}$,…

General Relativity and Quantum Cosmology · Physics 2015-05-11 Giovanni Acquaviva , Aroonkumar Beesham

A new class of exact solutions of Einstein's field equations with a perfect fluid source, variable gravitational coupling $G$ and cosmological term $\Lambda$ for FRW spacetime is obtained by considering variable deceleration parameter…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Anirudh Pradhan , Ajay Kumar Singh , Saeed Otarod

In this paper, we explore a theoretical and observational study of the presence of viscosity in the Unimodular Gravity formalism, a pioneering approach that, to the best of our knowledge, has not been previously explored in this context.…

General Relativity and Quantum Cosmology · Physics 2026-01-27 Norman Cruz , Esteban González

We establish a general thermodynamic scheme for cosmic fluids with internal self-interactions and discuss equilibrium and non-equilibrium aspects of such systems in connection with (generalized) symmetry properties of the cosmological…

Astrophysics · Physics 2009-10-31 Winfried Zimdahl , Alexander B. Balakin

Combining the equivalence between cosmological particle creation and an effective viscous fluid pressure with the fact that the latter represents a dynamical degree of freedom within the second-order Israel-Stewart theory for imperfect…

Astrophysics · Physics 2009-10-31 Winfried Zimdahl

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 analyze the effect of higher order viscosity corrections in a spatially homogeneous and isotropic universe. The viscous effects are modeled by introducing a second-order term to the energy density in the equation of state and on the…

General Relativity and Quantum Cosmology · Physics 2025-09-19 A. G. Cesar , Mario Novello