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In this manuscript, we analyze the viscous fluid cosmological model in the framework of recently proposed $f(Q)$ gravity by assuming three different forms of bulk viscosity coefficients, specifically, $(i)\zeta =\zeta_{0}+\zeta_{1}\left(…

General Relativity and Quantum Cosmology · Physics 2023-05-02 Raja Solanki , Dheeraj Singh Rana , Sanjay Mandal , P. K. Sahoo

In the present work, we study a cosmological model composed of a viscous dark matter interacting with decaying vacuum energy in a spatially flat Universe. In the first part, we find the analytical solution of different cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-27 Vinita Khatri , C. P. Singh , Milan Srivastava

We investigate the out-of-equilibrium dynamics of viscous fluids in a spatially flat Friedmann-Lema\^itre-Robertson-Walker cosmology using the most general causal and stable viscous energy-momentum tensor defined at first order in spacetime…

General Relativity and Quantum Cosmology · Physics 2023-07-31 Fábio S. Bemfica , Marcelo M. Disconzi , Jorge Noronha , Robert J. Scherrer

Evolution of the bulk viscous matter dominated universe has been analysed using the full causal, Israel-Stewart theory for the evolution of bulk viscous pressure in the context of recent acceleration of the universe. The form of bulk…

General Relativity and Quantum Cosmology · Physics 2018-04-23 Jerin Mohan N D , Athira Sasidharan , Titus K Mathew

In this paper, bulk viscosity is introduced in new holographic dark energy (HDE) to describe the effects of cosmic non-perfect fluid on the evolution of the universe in modified $f(R,T)$ gravity. Assuming $f(R,T)=R+\lambda T$, where $R$ is…

General Relativity and Quantum Cosmology · Physics 2018-04-17 C P Singh , Milan Srivastava

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

The objective of the present work is to study a cosmological model for a spatially flat Universe whose constituents are a dark energy field and a matter field which includes baryons and dark matter. The constituents are supposed to be in…

General Relativity and Quantum Cosmology · Physics 2013-09-13 Gilberto M. Kremer , Octavio A. S. Sobreiro

We consider the evolution of a flat, isotropic and homogeneous Friedmann-Robertson-Walker Universe, filled with a causal bulk viscous cosmological fluid, that can be characterized by an ultra-relativistic equation of state and bulk…

General Relativity and Quantum Cosmology · Physics 2011-10-05 A. Tawfik , M. Wahba , H. Mansour , T. Harko

We explore flat {\Lambda}CDM models with bulk viscosity, and study the role of the bulk viscosity in the evolution of these universe models. The dynamical equations for these models are obtained and solved for some cases of bulk viscosity.…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-04 Nouraddin Mostafapoor , Oyvind Gron

We study the late acceleration of the universe by incorporating bulk viscous matter with the running vacuum. The vacuum energy density varies as the squares of the Hubble parameter ($\rho_{\Lambda}\propto H^2$), and the coefficient of bulk…

General Relativity and Quantum Cosmology · Physics 2022-04-27 Sarath N , Jerin Mohan N D , Titus K Mathew

Bulk viscosity is the only viscous influence that can change the background dynamics in a homogeneous and isotropic universe. In the present work, we analyze the bulk viscous cosmological model with the bulk viscosity coefficient of the…

General Relativity and Quantum Cosmology · Physics 2021-12-13 Gaurav Gadbail , Simran Arora , P. K. Sahoo

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

In this paper, we investigate the effects of varying bulk viscosity coefficients $\zeta(t)=\zeta_{0}+\zeta_{1}H$ on cosmic evolution within the framework of $f(T)$ teleparallel gravity. We focus on two cases: (i) $\zeta_{1} \neq0$ and (ii)…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Kairat Myrzakulov , O. Donmez , M. Koussour , S. Muminov , E. Davletov , J. Rayimbaev

Isotropic and spatially homogeneous viscous fluid cosmological models are investigated using the truncated Israel-Stewart theory of irreversible thermodynamics to model the bulk viscous pressure. The governing system of differential…

General Relativity and Quantum Cosmology · Physics 2010-04-06 A A Coley , R J van den Hoogen

In this article we have presented FRW cosmological model in the framework of Brans-Dicke theory. This paper deals with a new proposed form of deceleration parameter and cosmological constant. The effect of bulk viscosity is also studied in…

General Relativity and Quantum Cosmology · Physics 2017-07-27 G. P. Singh , Binaya K. Bishi

Some cylindrically symmetric inhomogeneous viscous fluid cosmological models with electro-magnetic field are obtained. To get a solution a supplementary condition between metric potentials is used. The viscosity coefficient of bulk viscous…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Anirudh Pradhan , Sudhir Kumar Srivastav , Kanti R. Jotania

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

We consider the evolution of a flat Friedmann-Robertson-Walker Universe, filled with a causal bulk viscous cosmological fluid, in the presence of variable gravitational and cosmological constants. The basic equation for the Hubble…

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

In this paper we have considered a flat FLRW universe with bulk viscous Zel'dovich as the cosmic component. Being considered the bulk viscosity as per the Eckart formalism, we have analyzed the evolution of the Hubble parameter and…

General Relativity and Quantum Cosmology · Physics 2015-08-21 Rajagopalan Nair K. , Titus K. Mathew

We have studied bulk viscosity in the modified $f(Q, T)$ gravity theory formalism, where $Q$ represents the non-metricity and $T$ denotes the trace of energy-momentum tensor within a flat Friedmann-Lema\^{i}tre-Robertson-Walker metric…

General Relativity and Quantum Cosmology · Physics 2021-12-01 Simran Arora , S. K. J. Pacif , Abhishek Parida , P. K. Sahoo
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