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In this paper a cosmological solution of polynomial type $H \approx ( t + const.)^{-1}$ for the causal thermodynamical approach of Isarel-Stewart, found in \cite{MCruz:2017, Cruz2017}, is constrained using the joint of the latest…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-17 Norman Cruz , A. Hernández-Almada , Octavio Cornejo-Pérez

We investigate the cosmological applications of fluids having an equation of state which is the analog to the one related to the isotropic deformation of crystalline solids, that is containing logarithmic terms of the energy density,…

General Relativity and Quantum Cosmology · Physics 2018-11-14 S. D. Odintsov , V. K. Oikonomou , A. V. Timoshkin , Emmanuel N. Saridakis , R. Myrzakulov

Observations of distant supernovae indicate that the Universe is now in a phase of accelerated expansion the physical cause of which is a mystery. Formally, this requires the inclusion of a term acting as a negative pressure in the…

We investigate the entropy production within dissipative hydrodynamics in the Israel-Stewart (IS) and Navier-Stokes theory (NS) for relativistic heavy ion physics applications. In particular we focus on the initial condition in a 0+1D…

High Energy Physics - Phenomenology · Physics 2015-05-28 Stefano Mattiello

In this article, we have investigated the role of bulk viscosity to study the accelerated expansion of the universe in the framework of modified $f(Q)$ gravity. The gravitational action in this modified gravity theory has the form $f(Q)$,…

General Relativity and Quantum Cosmology · Physics 2022-07-20 Raja Solanki , S. K. J. Pacif , Abhishek Parida , P. K. Sahoo

We investigate what current cosmological data tells us about the cosmological expansion rate in a model independent way. Specifically, we study if the expansion was decelerating at high redshifts and is accelerating now, without referring…

Astrophysics · Physics 2009-11-13 Edvard Mortsell , Chris Clarkson

Boyle's 1662 observation that the volume of a gas is, at constant temperature, inversely proportional to pressure, offered a prototypical example of how an equation of state (EoS) can succinctly capture key properties of a many-particle…

Motivated by the increasing evidence for the need of a geometry that resembles Bianchi morphology to explain the observed anisotropy in the WMAP data, we have discussed some features of the Bianchi type-$VI_{0}$ universes in the presence of…

General Physics · Physics 2015-06-11 Anirudh Pradhan

We investigate the evolution of a flat Emergent Universe obtained with a non-linear equation of state (nEoS) in Einstein's general theory of Relativity. The nEoS is equivalent to three different types of barotropic cosmic fluids, which are…

General Relativity and Quantum Cosmology · Physics 2024-01-08 Bikash Chandra Roy , Anirban Chanda , Bikash Chandra Paul

There is introduced a class of barotropic equations of state (EOS) which become polytropic of index $n = 5$ at low pressure. One then studies asymptotically flat solutions of the static Einstein equations coupled to perfect fluids having…

General Relativity and Quantum Cosmology · Physics 2009-10-31 R. Beig , M. Karadi

This paper investigates the global well-posedness and large-time behavior of solutions for a coupled fluid model in $\mathbb{R}^3$ consisting of the isothermal compressible Euler-Poisson system and incompressible Navier-Stokes equations…

Analysis of PDEs · Mathematics 2024-05-29 Young-Pil Choi , Houzhi Tang , Weiyuan Zou

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

We present new viscosity and equation of state (EoS) results extending to high pressures for o-terphenyl, salol, and dibutylphthalate. Using these and data from the literature, we show that the three liquids all conform to density scaling;…

Soft Condensed Matter · Physics 2016-08-24 R. Casalini , S. S. Bair , C. M. Roland

We test a cosmological model which the only component is a pressureless fluid with a constant bulk viscosity as an explanation for the present accelerated expansion of the universe. We classify all the possible scenarios for the universe…

General Relativity and Quantum Cosmology · Physics 2009-04-17 Arturo Avelino , Ulises Nucamendi

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 revisit a cosmological model where dark matter (DM) and dark energy (DE) follow barotropic equations of state, allowing deviations from the standard $\Lambda$CDM framework (i.e. $w_{dm} \neq 0$, $w_{de} \neq -1$), considering both flat…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-24 Dorian Araya , Cristian Castillo , Genly Leon , Juan Magaña , Angie Barr Domínguez , Miguel A. García-Aspeitia

In this article, the bulk viscosity is introduced in a modified gravity model. The gravitational action has a general $f(R,T)$ form, where $R$ and $ T $ are the curvature scalar and the trace of energy momentum tensor respectively. An…

General Relativity and Quantum Cosmology · Physics 2020-10-02 Simran Arora , Xin-he Meng , S. K. J. Pacif , P. K. Sahoo

The Full (non--truncated) Israel--Stewart theory of bulk viscosity is applied to dissipative FRW spacetimes. Dimensionless variables and dimensionless equations of state are used to write the Einstein--thermodynamic equations as a plane…

General Relativity and Quantum Cosmology · Physics 2009-10-28 A. A. Coley , R. J. van den Hoogen , R. Maartens

A new method of solving the Einstein-Friedmann dynamical equations of a spatially homogeneous and isotropic universe is presented. The method is applicable when the equation of state of the material content assumes the form P=(g -1) rho, g…

Classical Physics · Physics 2009-10-31 Valerio Faraoni

In the framework of the KIDS generalized energy density functional (EDF), the nuclear equation of state (EoS) is expressed as an expansion in powers of the Fermi momentum or the cubic root of the density ($\rho^{1/3}$). Although an optimal…

Nuclear Theory · Physics 2019-07-24 Hana Gil , Young-Min Kim , Chang Ho Hyun , Panagiota Papakonstantinou , Yongseok Oh
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