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In this paper we study the evolution of a LRS Bianchi I Universe, filled with a bulk viscous cosmological fluid in the presence of time varying constants "but" taking into account the effects of a c-variable into the curvature tensor. We…

General Relativity and Quantum Cosmology · Physics 2009-11-10 J. A. Belinchón

We consider anisotropic cosmological models with an universe of dimension 4 or more, factorized into n>1 Ricci-flat spaces, containing an m-component perfect fluid of m non-interacting homogeneous minimally coupled scalar fields under…

General Relativity and Quantum Cosmology · Physics 2015-06-25 U. Kasper , M. Rainer , A. Zhuk

In the present work, we study the dynamical evolution of an homogeneous and anisotropic, noncommutative (NC) Bianchi I (BI) model coupled to a radiation perfect fluid. Our first motivation is determining if the present model tends to an…

General Relativity and Quantum Cosmology · Physics 2024-03-07 G. Oliveira-Neto , T. M. Abreu

We study the cosmological evolution of scalar fields with arbitrary potentials in the presence of a barotropic fluid (matter or radiation) without making any assumption on which term dominates. We determine what kind of potentials V(phi)…

High Energy Physics - Phenomenology · Physics 2013-05-29 A. de la Macorra , G. Piccinelli

Self-similar, spherically symmetric cosmological models with a perfect fluid and a scalar field with an exponential potential are investigated. New variables are defined which lead to a compact state space, and dynamical systems methods are…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Alan Coley , Martin Goliath

We have found exact constant solutions for the cosmological density parameter using a generalization of general relativity that incorporates a cosmic time-variation of the velocity of light in vacuum and the Newtonian gravitation constant.…

Astrophysics · Physics 2009-10-31 Luis P. Chimento , Alejandro S. Jakubi

A cylindrically symmetric perfect fluid spacetime with no curvature singularity is shown. The equation of state for the perfect fluid is that of a stiff fluid. The metric is diagonal and non-separable in comoving coordinates for the fluid.…

General Relativity and Quantum Cosmology · Physics 2009-11-10 L. Fernandez-Jambrina

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

We consider a Bianchi type-I Polytropic bulk viscous fluid cosmological model with variable G and {\Lambda}. To get a deterministic model, we assume some conditions of A, B, C, and polytropic relation to find the results. physical…

General Physics · Physics 2014-03-11 Rishi Kumar Tiwari , Mukesh Sharma , Sonia Sharma

Cosmological models of Bianchi type V and I containing a perfect fluid with a linear equation of state plus cosmological constant are investigated using a tetrad approach where our variables are the Riemann tensor, the Ricci rotation…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Michael Bradley , Daniel Eriksson

The dynamics of cosmological models with isotropic matter sources (perfect fluids) is extensively studied in the literature; in comparison, the dynamics of cosmological models with anisotropic matter sources is not. In this paper we…

General Relativity and Quantum Cosmology · Physics 2011-02-16 Simone Calogero , J. Mark Heinzle

A cosmological model describing the evolution of n Ricci-flat spaces (n>1) in the presence of 1-component perfect-fluid and minimally coupled scalar field is considered. When the pressures in all spaces are proportional to the density, the…

High Energy Physics - Theory · Physics 2009-09-25 V. D. Ivashchuk , V. N. Melnikov

We present a cosmological model constituted by three perfect fluids, cold dark matter, vacuum energy and radiation, which interacting with each other lead to an equivalent model of three self-preserved fluids that can be identified with the…

General Relativity and Quantum Cosmology · Physics 2018-01-25 Mónica Forte

We study cosmological implications of bigravity and massive gravity solutions with non-simultaneously diagonal metrics by considering the generalized Gordon and Kerr-Schild ansatzes. The scenario that we obtain is equivalent to that of…

General Relativity and Quantum Cosmology · Physics 2016-12-21 Carlos García-García , Antonio L. Maroto , Prado Martín-Moruno

We study the anisotropic Bianchi type-I cosmological model at late times, taking into account quantum gravitational corrections in the formalism of the exact renormalization group flow of the effective average action for gravity. The…

General Relativity and Quantum Cosmology · Physics 2020-02-24 Rituparna Mandal , Sunandan Gangopadhyay , Amitabha Lahiri

In this paper, we have investigated an anisotropic cosmological model in $f(Q)$ gravity with string fluid in LRS Bianchi type-I universe. We have considered the arbitrary function $f(Q)=Q+\alpha\sqrt{~Q}+2\Lambda$ where $\alpha$ is model…

General Relativity and Quantum Cosmology · Physics 2023-03-02 Dinesh Chandra Maurya , Archana Dixit , Anirudh Pradhan

In this paper, we investigate Bianchi type$-V$ cosmological models with bulk viscous fluid and time varying cosmological $\Lambda$ and Newtonian $G$ parameters. The Einstein's field equations have been transformed into a coupling…

We use the S\'aez-Ballester theory on anisotropic Bianchi I cosmological model, with barotropic fluid and cosmological constant. We obtain the classical solution by using the Hamilton-Jacobi approach. Also the quantum regime is constructed…

General Relativity and Quantum Cosmology · Physics 2016-08-14 J. Socorro , M. Sabido , M. A. Sánchez G. , M. G. Frías Palos

The asymptotic properties of the Bianchi type II cosmological model in the Brane-world scenario are investigated. The matter content is assumed to be a combination of a perfect fluid and a minimimally coupled scalar field that is restricted…

General Relativity and Quantum Cosmology · Physics 2009-11-07 R. J. van den Hoogen , J. Ibanez

In this work, we have studied the Brans-Dicke (BD) cosmology in anisotropic models. We present three dimensional dynamical system describing the evolution of anisotropic models containing perfect fluid and BD scalar field with…

General Physics · Physics 2011-12-30 Jhumpa Bhadra , Shuvendu Chakraborty , Ujjal Debnath