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In this paper, we introduce bulk viscosity in the formalism of modified gravity theory in which the gravitational action contains a general function $f(R,T)$, where $R$ and $T$ denote the curvature scalar and the trace of the…

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

We discuss a spatially homogeneous and anisotropic Bianchi type-I space-time with two fluids as the content of the Universe: matter and holographic dark energy in the framework of general relativity. To get the exact solutions of Einstein's…

General Relativity and Quantum Cosmology · Physics 2023-02-03 M. Koussour , M. Bennai

Cosmic Microwave Background anomalies suggest that the Universe is slightly anisotropic, so a Cosmological Model that does not satisfy the Cosmological Principle is necessary. Anisotropic Bianchi models have been studied given that they…

General Relativity and Quantum Cosmology · Physics 2017-02-07 Ericsson López , Mario Llerena

Bianchi cosmologies are ``natural'' anisotropic extensions of the Friedmann universes and they have long been used to investigate the cosmological implications of anisotropy. The latter introduces new ingredients to the standard scenarios,…

General Relativity and Quantum Cosmology · Physics 2024-09-13 Amalia Tzartinoglou , Christos G. Tsagas

We have developed a Bianchi I cosmological model of the universe in $f(R,T)$ gravity theory which fit good with the present day scenario of accelerating universe. The model displays transition from deceleration in the past to the…

General Relativity and Quantum Cosmology · Physics 2023-05-25 Anirudh Pradhan , Gopikant Goswami , Syamala Krishnannair

A generally parameterized equation of state (EOS) is investigated in the cosmological evolution with bulk viscosity media modelled as dark fluid, which can be regarded as a unification of dark energy and dark matter. Compared with the case…

Astrophysics · Physics 2009-11-13 J. Ren , 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 propose an analytical parametrization of the comoving distance and Hubble parameter to study the cosmic expansion history beyond the vanilla $\Lambda$CDM model. The parametrization is generalized enough to include the contribution of…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-22 Bikash R. Dinda

The present study deals with spatially homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with dominance of dark energy. To get the deterministic model of Universe, we assume that the shear…

General Physics · Physics 2012-01-24 Anil Kumar Yadav , Bijan Saha

The intention of this paper is mainly two-fold. \textit{First}, we point out a striking numerical agreement between the bulk viscosity in the lepton era calculated by Husdal (2016) and our own calculations of the present-day bulk viscosity…

General Relativity and Quantum Cosmology · Physics 2020-07-08 Iver Brevik , Ben David Normann

Bianchi type V string cosmological models with bulk viscosity for massive string are investigated. The bulk viscosity is assumed to vary with time in such a manner that it is related to simple power function of the energy density. Using…

General Relativity and Quantum Cosmology · Physics 2011-09-28 Anil Kumar Yadav

In this paper, we have examined the viability of the Bianchi type-V universe in Brans-Dicke (BD) theory of gravitation. We have discussed the interacting and non-interacting scenarios between dark matter (DM) and dark energy (DE) of the…

General Relativity and Quantum Cosmology · Physics 2023-02-22 Vinod Kumar Bhardwaj , Archana Dixit , Anirudh Pradhan

In this paper, we examine the accelerated expansion of the Universe at late-time in the framework of $f\left( Q\right) $ gravity theory in which the non-metricity scalar $Q$ describes the gravitational interaction. To this, we propose a new…

General Relativity and Quantum Cosmology · Physics 2023-02-21 M. Koussour , S. K. J. Pacif , M. Bennai , P. K. Sahoo

A spatially homogeneous and anisotropic Bianchi type V cosmological model of the universe for perfect fluid within the framework of Scale covariant theory of gravitation proposed by Canuto et al., is studied in view of a variable…

General Physics · Physics 2017-04-13 Mohd. Zeyauddin , C. V. Rao

We use the expansion-normalized variables approach to study the dynamics of a non-tilted Bianchi Type I cosmological model with both a homogeneous magnetic field and a viscous fluid. In our model the perfect magnetohydrodynamic…

General Relativity and Quantum Cosmology · Physics 2014-02-26 Ikjyot Singh Kohli , Michael C. Haslam

We have studied the locally rotationally symmetric (LRS) Bianchi type-I cosmological model in $f(R,T)$ gravity ($R$ is the Ricci scalar and $T$ is the trace of the stress energy tensor) with Bulk viscous fluid as matter content. The model…

General Relativity and Quantum Cosmology · Physics 2018-03-29 Parbati Sahoo , Raghavender Reddy

The Universe is modeled as consisting of pressureless baryonic matter and a bulk viscous fluid which is supposed to represent a unified description of the dark sector. In the homogeneous and isotropic background the \textit{total} energy…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-22 W. Zimdahl , H. E. S. Velten , W. S. Hipólito-Ricaldi

In this paper, we show that the expansion history of the Universe in power-law cosmology essentially depends on two crucial parameters, namely the Hubble constant $H_{0}$ and deceleration parameter $q$. We find the constraints on these…

General Relativity and Quantum Cosmology · Physics 2014-08-27 Suresh Kumar

In this work, we have studied how incorporating viscous fluids leads to exact bounce cosmological solutions in general relativity (GR) framework. Specifically, we propose a novel parameterization of bulk viscosity coefficient of the form…

General Relativity and Quantum Cosmology · Physics 2024-07-23 Rajdeep Mazumdar , Mrinnoy M. Gohain , Kalyan Bhuyan

We investigate a late-time cosmological model for a homogeneous and isotropic space-time in the Rastall theory. We explore the observational constraints on the Hubble parameter by using the latest cosmological datasets such as cosmic…

General Relativity and Quantum Cosmology · Physics 2026-01-01 Vinod Kumar Bhardwaj , Saibal Ray , Kazuharu Bamba , Akram Ali
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