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Related papers: Viscous Dark Energy in $f(T)$ Gravity

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We present a discussion of the effects induced by the bulk viscosity on the very early Universe stability. The matter filling the cosmological (isotropic and homogeneous) background is described by a viscous fluid having an…

General Relativity and Quantum Cosmology · Physics 2009-03-24 Nakia Carlevaro , Giovanni Montani

In this paper, we examine the acceleration of the Universe's expansion in $F(R,T)$ gravity, where $R$ denotes the Ricci scalar and $T$ the trace of energy-momentum tensor. Indeed, the unknown nature of the source controlling this…

General Relativity and Quantum Cosmology · Physics 2024-04-25 Ahmed Errahmani , Amine Bouali , Safae Dahmani , Imad El Bojaddaini , Taoufik Ouali

The incorporation of bulk viscosity process to General Relativity leads to the appearance of nonsingular backgrounds that, at early and late times, depict an accelerated universe. These backgrounds could be analytically calculated and…

General Relativity and Quantum Cosmology · Physics 2017-12-20 Jaume Haro , Supriya Pan

The effect of bulk viscisity on the evolution of the homogeneous and isotropic cosmological models is considered. Solutions are found, with a barotropic equation of state, and a viscosity coefficient that is proportional to a power of the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Pimentel L O , Diaz-Rivera L M

In this article, we considered the bulk viscous fluid in the formalism of modified gravity in which the general form of a gravitational action is $f(R, T)$ function, where $R$ is the curvature scalar and $T$ is the trace of the energy…

General Relativity and Quantum Cosmology · Physics 2017-08-02 G. C. Samanta , R. Myrzakulov

A general equation of state is used to model unified dark matter and dark energy (dark fluid), and it has been proved that this model is equivalent to a single fluid with time-dependent bulk viscosity. In this paper, we investigate scalar…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-31 Xu Dou , Xin-He Meng

In this article, we investigate the observed cosmic acceleration in the framework of a cosmological $f(R,L_m)$ model dominated by bulk viscous matter in an anisotropic background. We consider the LRS Bianchi type I metric and derive the…

General Relativity and Quantum Cosmology · Physics 2023-06-14 Raja Solanki , Bina Patel , Lakhan V. Jaybhaye , P. K. Sahoo

In this paper, viscous generalized Chaplygin gas as a model of dark energy considered. We assume non-constant bulk viscous coefficient and study dark energy density. We consider several cases of density-dependent viscosities. We find that,…

General Relativity and Quantum Cosmology · Physics 2014-03-10 H. Saadat , B. Pourhassan

The universe media is considered as a non-perfect fluid with bulk viscosity and described by a more general equation of state. We assume the bulk viscosity is a linear combination of the two terms: one is constant, and the other is…

Astrophysics · Physics 2009-03-19 Xin-He Meng , Jie Ren , Ming-Guang Hu

We study the behavior of dark energy (DE) in the scope of anisotropic Bianchi type V (BV) space-time. First we derive Friedmann-Like Equations, then we compare the dark energy equation of state (EoS) parameter for viscous and non-viscous…

General Physics · Physics 2017-12-13 Hassan Amirhashchi

In this paper, the dynamical behavior of the accelerated expansion of the universe is studied within the framework of $f(T)$ gravity by considering a well-motivated functional form of $f(T)$. A specific form of the Hubble parameter is…

General Relativity and Quantum Cosmology · Physics 2026-03-20 Khomesh R. Patle , G. P. Singh

Extended teleparallel gravity, characterized by $F(Q)$ function where $Q$ is the non-metricity scalar, is one of the most promising approaches to general relativity. In this paper, we reexamine a specific dynamical dark energy model, which…

General Relativity and Quantum Cosmology · Physics 2024-08-14 Omar Enkhili , Safae Dahmani , Dalale Mhamdi , Taoufik Ouali , Ahmed Errahmani

It is shown that a present acceleration with a past deceleration is a possible solution of the Friedmann equation by considering the Universe as a mixture of a scalar with a matter field and by including a non-equilibrium pressure term in…

General Relativity and Quantum Cosmology · Physics 2009-11-07 G. M. Kremer , F. P. Devecchi

It is proposed that dark energy may become dominant over standard matter due to universe expansion (curvature decrease). Two models: non-linear gravity-matter system and modified gravity may provide the effective phantom or effective…

Astrophysics · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

In this paper, we have presented an FLRW universe containing two-fluids (baryonic and dark energy) with a deceleration parameter (DP) having a transition from past decelerating to the present accelerating universe. In this model, dark…

General Physics · Physics 2021-08-03 Anirudh Pradhan , G. K. Goswami , A. Beesham , Archana Dixit

We propose a bulk viscous unified dark matter scenario based on a nonlinear extension of the full causal Israel-Stewart theory. This framework allows the viscous fluid to remain far from equilibrium, an essential feature for a physically…

General Relativity and Quantum Cosmology · Physics 2025-12-16 Guillermo Palma , Gabriel Gomez

We discuss the dynamical effects of bulk viscosity and particle creation on the early evolution of the Friedmann -Robertson -Walker model in the framework of open thermodynamical systems. We consider bulk viscosity and Particle creation as…

General Relativity and Quantum Cosmology · Physics 2015-03-02 C. P. Singh

Our universe is observed to be accelerating due to the dominant dark energy with negative pressure. The dark energy equation of state (w) holds a key to understanding the ultimate fate of the universe. The cosmic voids behave like bubbles…

Astrophysics · Physics 2011-02-11 Jounghun Lee , Daeseong Park

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 evolution of a flat, isotropic and homogeneous universe is studied. The background geometry in the early phases of the universe is conjectured to be filled with causal bulk viscous cosmological fluid and dark energy. The energy density…

General Relativity and Quantum Cosmology · Physics 2012-04-23 A. Tawfik
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