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Related papers: Note on bulk viscosity as an alternative to dark e…

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The full causal M\"uller-Israel-Stewart (MIS) theory of dissipative processes in relativistic fluids is applied to a flat, homogeneous and isotropic universe with bulk viscosity. It is clarified in which sense the so called truncated…

Astrophysics · Physics 2008-11-26 Winfried Zimdahl

In this paper, we study the cosmological evolution of a viscous dark energy model within the framework of $f(Q, C)$ gravity, utilizing a two-fluid approach. The model incorporates non-metricity and boundary contributions to the total…

General Relativity and Quantum Cosmology · Physics 2025-10-15 N. Myrzakulov , Anirudh Pradhan , S. H. Shekh

In this work we explore the thermodynamic aspects of dark energy for late future time universe in two different scenarios: as a perfect fluid with constant and variable equation of state parameter; and as dissipative fluid described by a…

General Relativity and Quantum Cosmology · Physics 2022-03-03 David Tamayo

In a recent Letter [Phys. Rev. Lett. 114 091301 (2105)] the cause of the acceleration of the present Universe has been identified with the shear viscosity of an imperfect relativistic fluid even in the absence of any bulk viscous…

General Relativity and Quantum Cosmology · Physics 2015-05-04 Massimo Giovannini

We have studied the effect of nonzero bulk viscosity with peak near the lattice QCD predicted crossover temperature $T_{co}\sim 175 MeV$ on charged particle transverse momentum spectra and elliptic flow. The Israel-Stewart theory of 2nd…

Nuclear Theory · Physics 2013-05-30 Victor Roy , A. K. Chaudhuri

We derive a general formalism for bulk viscous solutions of the energy-conservation-equation for $\rho(a,\zeta)$, both for a single-component and a multicomponent fluid in the Friedmann universe. For our purposes these general solutions…

General Relativity and Quantum Cosmology · Physics 2016-06-03 Ben David Normann , Iver Brevik

Phantom dark energy is a proposal that explains the current observations that mildly favor the equation of state of dark energy $\omega^{de}$ crossing -1 at 68% confidence level. However, phantom fields are generally ruled out by…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-09 Hassan Amirhashchi

In this work we perform some studies related to dark energy. Firstly, we propose a dynamical approach to explain the dark energy content of the universe. We assume that a massless scalar field couples to the Hubble parameter with some…

High Energy Physics - Phenomenology · Physics 2009-01-07 Fei Wang , Jin Min Yang

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

We show explicitly, by using astrophysical data plus reasonable assumptions for the bulk viscosity in the cosmic fluid, how the magnitude of this viscosity may be high enough to drive the fluid from its position in the quintessence region…

General Relativity and Quantum Cosmology · Physics 2015-09-15 Iver Brevik

We propose a scenario in which the dark components of the Universe are manifestations of a single bulk viscous fluid. Using dynamical system methods, a qualitative study of the homogeneous, isotropic background scenario is performed in…

Astrophysics · Physics 2008-12-18 R. Colistete , J. C. Fabris , J. Tossa , W. Zimdahl

Dissipative features of dark matter affect its clustering properties and could lead to observable consequences for the evolution of large--scale structure. We analyse the evolution of cold dark matter density perturbations allowing for the…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-21 Giovanni Acquaviva , Anslyn John , Aurélie Pénin

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

In a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker universe, we investigate a unified cosmic fluid scenario endowed with bulk viscosity in which the coefficient of the bulk viscosity has a power law evolution. The power law in the…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-20 Weiqiang Yang , Supriya Pan , Eleonora Di Valentino , Andronikos Paliathanasis , Jianbo Lu

We consider a cosmological model dominated by bulk viscous matter with total bulk viscosity coefficient proportional to the velocity and acceleration of the expansion of the universe in such a way that…

General Relativity and Quantum Cosmology · Physics 2016-04-28 Athira Sasidharan , Titus K. Mathew

Microscopic black holes explode with their temperature varying inversely as their mass. Such explosions would lead to the highest temperatures in the present universe, all the way to the Planck energy. Whether or not a quasi-stationary…

Astrophysics · Physics 2008-11-26 J. I. Kapusta

In this paper, we investigate the fluid/gravity correspondence in the framework of massive Einstein gravity. Treating the gravitational mass terms as an effective energy-momentum tensor and utilizing the Petrov-like boundary condition on a…

High Energy Physics - Theory · Physics 2016-11-18 Wen-Jian Pan , Yong-Chang Huang

This paper is the fourth in a series exploring the physical consequences of the solidity of highly viscous liquids. It is argued that the two basic characteristics of a flow event (a jump between two energy minima in configuration space)…

Soft Condensed Matter · Physics 2007-05-23 Jeppe C. Dyre

The cosmological constant is the most economical candidate for dark energy. No other approach really alleviates the difficulties faced by the cosmological constant because, in all other attempts to model the dark energy, one still has to…

General Relativity and Quantum Cosmology · Physics 2014-11-18 T. Padmanabhan

The non-linear bubble dynamics equations in a compressible liquid have been modified considering the effects of compressibility of both the liquid and the gas at the bubble interface. A new bubble boundary equation has been derived, which…

Fluid Dynamics · Physics 2009-11-10 Ahmad Moshaii , Rasool Sadighi-Bonabi , Mohammad Taeibi-Rahni
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