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Related papers: Analysing dissipative effects in the $\Lambda$CDM …

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The evolution of an homogeneous and isotropic dissipative fluid is analyzed using dynamical systems techniques. The dissipation is driven by bulk viscous pressure and the truncated Israel-Stewart theory is used. Although almost all…

General Relativity and Quantum Cosmology · Physics 2008-11-26 A. Di Prisco , L. Herrera , J. Ibanez

We present a novel extended version of the $\Lambda$CDM model that provides analytical solution for Hubble parameter uniting all epochs of cosmic evolution starting from inflation to late-acceleration, with intermediate radiation and…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-31 Vishnu A Pai , Titus K Mathew

We consider a cosmological model with bulk viscosity ($\eta$) and variable cosmological $(\Lambda\propto \rho^{-\alpha}, \alpha=\rm const.$) and gravitational ($G$) constants. The model exhibits many interesting cosmological features.…

High Energy Physics - Theory · Physics 2008-11-26 Arbab I. Arbab

Decaying dark matter models provide a physically motivated way of channeling energy between the matter and radiation sectors. In principle, this could affect the predicted value of the Hubble constant in such a way as to accommodate the…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-04 Emil Brinch Holm , Thomas Tram , Steen Hannestad

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

Thermodynamic analyses of dark energy as a relativistic fluid indicates that this intriguing component of the universe mimics a bulk viscous pressure when the parameter of its barotropic equation of state varies with time. Since in…

General Relativity and Quantum Cosmology · Physics 2025-03-04 José Medeiros da Costa Netto , Heydson Henrique Brito da Silva

We Consider a cosmological model based on a generalization of the equation of state proposed by Nojiri and Odintsov [46] and \v{S}tefan\v{c}i'c [47], [48]. We argue that this model works as a dark fluid model which can interpolate between…

General Relativity and Quantum Cosmology · Physics 2023-02-17 Esraa Elkhateeb

We analyze a model for Dark Energy - Dark Matter interaction, based on a decaying process of the former into the latter. The dynamical equations are constructed following a kinetic formulation, which separates the interacting fluctuations…

General Relativity and Quantum Cosmology · Physics 2025-02-24 Giovanni Montani , Nakia Carlevaro , Luis A. Escamilla , Eleonora Di Valentino

The aim of this paper is to investigate the dynamical aspects of charged viscous cylindrical source by using Misner approach. To this end, we have considered the more general charged dissipative fluid enclosed by the cylindrical symmetric…

General Relativity and Quantum Cosmology · Physics 2018-01-24 S. M. Shah , G. Abbas

We discuss the ability of a dark fluid becoming relevant around the time of matter radiation equality to significantly relieve the tension between local measurements of the Hubble constant and CMB inference, within the $\Lambda$CDM model.…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-31 Meng-Xiang Lin , Giampaolo Benevento , Wayne Hu , Marco Raveri

A generalized dynamical equation for the scale factor of the universe is proposed to describe the cosmological evolution, of which the $\Lambda$CDM model is a special case. It also provides a general example to show the equivalence of the…

Astrophysics · Physics 2009-11-11 J. Ren , X. H. Meng

The tensions between the values of Hubble constant obtained from the early and the late Universe data pose a significant challenge to modern cosmology. Possible modifications of the flat homogeneous isotropic cosmological {\Lambda}CDM model…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-14 S. L. Parnovsky

We examine linear perturbation theory to evaluate the contribution of viscosity coefficient in the growing of dark matter perturbations in the context of the bulk viscous dark energy model inspired by thermodynamical dissipative phenomena…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-12 B. Mostaghel , H. Moshafi , S. M. S. Movahed

It is performed a detailed dynamical analysis for a bulk viscosity model in the full Israel-Stewart formalism for a spatially flat Friedmann-Robertson-Walker Universe. In our study we have considered the total cosmic fluid constituted by…

General Relativity and Quantum Cosmology · Physics 2017-08-02 Samuel Lepe , Giovanni Otalora , Joel Saavedra

In this work, we study the extended viscous dark energy models in the context of matter perturbations. To do this, we assume an alternative interpretation of the flat Friedmann-Lema\^itre-Robertson-Walker Universe, through the nonadditive…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-13 W. J. C. da Silva , R. Silva

We discuss influences of bulk viscosity on the Early Universe, which is modeled by Friedmann-Robertson-Walker metric and Einstein field equations. We assume that the matter filling the isotropic and homogeneous background is relativistic…

General Relativity and Quantum Cosmology · Physics 2009-12-02 A. Tawfik , H. Mansour , M. Wahba

We consider an effective viscous pressure as the result of a backreaction of inhomogeneities within Buchert's formalism. The use of an effective metric with a time-dependent curvature radius allows us to calculate the luminosity distance of…

General Relativity and Quantum Cosmology · Physics 2016-04-13 Rodrigo M. Barbosa , G. Eddy , I. Chirinos , Winfried Zimdahl , Oliver F. Piattella

The generalized Chaplygin gas, which interpolates between a high density relativistic era and a non-relativistic matter phase, is a popular dark energy candidate. We consider a generalization of the Chaplygin gas model, by assuming the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 C. S. J. Pun , L. Á. Gergely , M. K. Mak , Z. Kovács , G. M. Szabó , T. Harko

We examine the decay vacuum model with a parameter $\epsilon$ that indicates the vacuum energy decay rate. By constraining this model with cosmic microwave background radiation, baryon acoustic oscillation, type Ia supernovae and 30 H(z)…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-04 Yang-Jie Yan , Deng Wang , Xin-He Meng

We investigate Dark Energy by associating it with vacuum energy or Cosmological constant ${\Lambda}$ which is taken to be dynamic in nature. Our approach is phenomenological and falls within the domain of variable-$\Lambda$ Cosmology.…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-08 Arkajit Aich
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