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Related papers: Dynamics of a self--gravitating magnetized source

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We investigate the behaviour of the skewness parameters for an anisotropic universe in the framework of General Relativity. Non interacting dark energy is considered in presence of electromagnetic field. A time varying deceleration…

General Physics · Physics 2022-07-19 B. Mishra , Pratik P Ray , S. K. Tripathy , Kazuharu Bamba

In this paper we study the equilibrium configurations of anisotropic self-gravitating fermions, by extending to general relativity the solutions obtained in a previous paper. This treatment also generalizes to anisotropic systems the…

Astrophysics of Galaxies · Physics 2015-07-23 Marco Merafina , Giuseppe Alberti

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

A system of self-gravitating massive fermions is studied in the framework of the general-relativistic Thomas-Fermi model. We study the properties of the free energy functional and its relation to Einstein's field equations. A…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Neven Bilic , Raoul D. Viollier

In this paper, we study the model of the late universe with the homogeneous, isotropic and flat Friedmann-Robertson-Walker metric, where the source of the gravitational field is based on the fermion and boson field, with the Maxwell term…

General Relativity and Quantum Cosmology · Physics 2020-07-13 O. Razina , P. Tsyba , B. Meirbekov , R. Myrzakulov

By using Bianchi I type of homogenous and anisotropic background metric having cylindrical symmetry in $x$ direction of a local cartesian coordinates system, we solve metric field equations for a non-minimally coupled Einstein-Maxwell…

General Relativity and Quantum Cosmology · Physics 2020-12-08 Hossein Ghaffarnejad , Hoda Gholipour

In this work we investigate a model for the early Universe in a Bianchi type-I metric, where the sources of the gravitational field are a fermionic and a bosonic field, interacting through a Yukawa potential, following the standard model of…

General Relativity and Quantum Cosmology · Physics 2016-02-23 M. O. Ribas , L. L. Samojeden , F. P. Devecchi , G. M. Kremer

Static spherically symmetric anisotropic source has been studied for the Einstein-Maxwell field equations assuming the erstwhile cosmological constant $ \Lambda $ to be a space-variable scalar, viz., $ \Lambda = \Lambda(r) $. Two cases have…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Saibal Ray , Sumana Bhadra , Anand S. Sengupta

We study Bianchi cosmologies in the ghost-free bigravity theory assuming both metrics to be homogeneous and anisotropic, of the Bianchi class A, which includes types I,II,VI$_0$,VII$_0$,VIII, and IX. We assume the universe to contain a…

High Energy Physics - Theory · Physics 2013-11-08 Kei-ichi Maeda , Mikhail S. Volkov

We explore the possibility that part of what we call dark matter may be the mark of a preferred frame, revealing a breakdown of diffeomorphism invariance. In the non-relativistic limit this appears as a deviant matter source capable of…

General Relativity and Quantum Cosmology · Physics 2025-05-08 Raymond Isichei , Joao Magueijo

We investigate an electromagnetic instability in two-dimensional materials arising from an anisotropy of the Fermi surface, utilizing a kinetic model accounting for the effects of the values of temperature, chemical potential and anisotropy…

Materials Science · Physics 2025-06-27 Diogo Simões , Hugo Terças , Jorge Ferreira

In this manuscript, we investigate the oscillatory behaviour of the anisotropy in the diagonal Bianchi-I spacetimes. Our starting point is a simplification of Einstein's equations using only observable or physical variables. As a…

General Relativity and Quantum Cosmology · Physics 2021-04-02 Leandro G Gomes , Bruno B. Bizarria , Gabriel A. de Souza Silva , William O. Clavijo

Methods of dynamical systems analysis are used to show rigorously that the presence of a magnetic field orthogonal to the two commuting Killing vector fields in any spatially homogeneous Bianchi type VI_0 vacuum solution to Einstein's…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Marsha Weaver

Some new exact solutions of Einstein's field equations have come forth within the scope of a spatially homogeneous and anisotropic Bianchi type-III space-time filled with barotropic fluid and dark energy by considering a variable…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-20 Hassan Amirhashchi , Anirudh Pradhan , Rekha Jaiswal

We investigate the evolution of cosmological anisotropies within the framework of $f\left(G\right)$-gravity. Specifically, we consider a locally rotationally symmetric geometry in four-dimensional spacetime that describes the Bianchi I,…

General Relativity and Quantum Cosmology · Physics 2025-12-25 R. Bogadi , A. Giacomini , M. Govender , C. Hansraj , G. Leon , A. Paliathanasis

We present a dynamical analysis in terms of new expansion-normalized variables for homogeneous and anisotropic Bianchi-I spacetimes in $f(R)$ gravity in the presence of anisotropic matter. With a suitable choice of the evolution parameter,…

General Relativity and Quantum Cosmology · Physics 2019-03-29 Saikat Chakraborty , Kazuharu Bamba , Alberto Saa

We study the dynamical evolution of an $f(R)$ model of gravity in a viscous and anisotropic background which is given by a Bianchi type-I model of the Universe. We find viable forms of $f(R)$ gravity in which one is exactly the Einsteinian…

General Physics · Physics 2014-01-20 Kh. Saaidi , A. Aghamohammadi , H. Hossienkhani

We consider an anisotropic brane world with Bianchi type I and V geometries where the mechanism of confining the matter on the brane is through the use of a confining potential. The resulting equations on the anisotropic brane are modified…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Heydari-Fard , H. R. Sepangi

Motivated by the structure of one-loop vacuum polarization effects in curved spacetime we discuss a non-minimal extension of the Einstein-Maxwell equations. This formalism is applied to Bianchi I models with magnetic field. We obtain…

Astrophysics · Physics 2016-08-30 Alexander B. Balakin , Winfried Zimdahl

The behaviour of magnetic field in anisotropic Bianchi type I cosmological model for bulk viscous distribution is investigated. The distribution consists of an electrically neutral viscous fluid with an infinite electrical conductivity. It…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Anirudh Pradhan , Sanjay Kumar Singh