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Related papers: Anisotropic cosmological solutions in $R + R^2$ gr…

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We perform a detailed dynamical analysis of anisotropic scalar-field cosmologies, and in particular of the most significant Kantowski-Sachs, Locally Rotationally Symmetric (LRS) Bianchi I and LRS Bianchi III cases. We follow the new and…

General Relativity and Quantum Cosmology · Physics 2014-03-18 Carlos R. Fadragas , Genly Leon , Emmanuel N. Saridakis

In the present work, we study the dynamical evolution of an homogeneous and anisotropic KS cosmological model, considering general relativity as the gravitational theory, such that there are three different perfect fluids in the matter…

General Relativity and Quantum Cosmology · Physics 2022-06-15 G. Oliveira-Neto , D. L. Canedo , G. A. Monerat

We investigate the evolution of anisotropies in Einstein-Gauss-Bonnet theory with a scalar field coupled to the Gauss-Bonnet term. Specifically, we examine the simplest scenario in which the scalar field lacks a kinetic term, and its…

General Relativity and Quantum Cosmology · Physics 2025-03-13 Alex Giacomini , Andronikos Paliathanasis , Alexey Toporensky

In this paper, we consider the Bianchi type-I space-time with perfect fluid as matter content of the Universe in the framework of $f(Q)$ gravity (where $% Q$ is the non-metricity scalar) recently proposed by Jim\'{e}nez et al. (Phys. Rev. D…

General Relativity and Quantum Cosmology · Physics 2022-08-18 M. Koussour , S. H. Shekh , M. Bennai

In this paper, we discuss the phase space analysis of locally rotationally symmetric Bianchi type I universe model by taking a noninteracting mixture of dust like and viscous radiation like fluid whose viscous pressure satisfies a nonlinear…

General Relativity and Quantum Cosmology · Physics 2019-05-29 M. Sharif , Saadia Mumtaz

We write down an anisotropic solution for a flat 5+1 dimensional Universe in Gauss-Bonnet gravity. In the model under investigation this solution replaces the generalized Kasner solution near a cosmological singularity.

General Relativity and Quantum Cosmology · Physics 2008-11-26 A. Toporensky , P. Tretyakov

The possible anisotropic nature in the early phases of the Universe is one of the interesting aspects of study in cosmology. We investigate the evolution of the Universe in terms of few cosmological parameters considering an anisotropic…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Pranjal Sarmah , Avik De , Umananda Dev Goswami

In this article, we have discussed the results of our investigation. We consider an anisotropic viscous cosmological model of (LRS) Bianchi type I spacetime universe filled with a viscous fluid under $f(Q)$ gravity. We have studied the…

General Relativity and Quantum Cosmology · Physics 2024-08-14 Anirudh Pradhan , Archana Dixit , Dinesh Chandra Maurya

Stability analysis of the Bianchi type I universe in pure gravity theory is studied in details. We first derive the non-redundant field equation of the system by introducing the generalized Bianchi type I metric. This non-redundant equation…

High Energy Physics - Theory · Physics 2009-11-07 W. F. Kao

We consider a self-consistent system of Bianchi type-I (BI) gravitational field and a binary mixture of perfect fluid and dark energy. The perfect fluid is taken to be the one obeying the usual equation of state, i.e., $p = \zeta \ve$, with…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha

We examine the anisotropy originated from a first-order vacuum phase transitions through three-dimensional numerical simulations. We apply Bianchi Type-I metric to our model that has one scalar field minimally coupled to the gravity. We…

General Relativity and Quantum Cosmology · Physics 2023-08-01 A. Savaş Arapoğlu , A. Emrah Yükselci

The "improved dynamics" of loop quantum cosmology is extended to include anisotropies of the Bianchi I model. As in the isotropic case, a massless scalar field serves as a relational time parameter. However, the extension is non-trivial…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Abhay Ashtekar , Edward Wilson-Ewing

We investigate the dynamics of spatially homogeneous solutions of the Einstein-Vlasov equations with Bianchi type I symmetry by using dynamical systems methods. All models are forever expanding and isotropize toward the future; toward the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 J. Mark Heinzle , Claes Uggla

$f(T)$ gravity offers an alternative context in which to consider gravitational interactions where torsion, rather than curvature, is the mechanism by which gravitation is communicated. We investigate the stability of the Kasner solution…

General Relativity and Quantum Cosmology · Physics 2018-02-14 Andronikos Paliathanasis , Jackson Levi Said , John D. Barrow

We investigate the classical and quantum behavior of a Bianchi I model in the presence of a stiff matter contribution when the Vilenkin interpretation of the wave function of the Universe is taken into account. We study its evolution in the…

General Relativity and Quantum Cosmology · Physics 2017-08-02 Riccardo Moriconi , Giovanni Montani

This thesis has considered the existence of anisotropic exact vacuum solutions in the context of higher order gravities. The investigated models generally are a function of three scalars R, $R_{\alpha\beta}R^{\alpha\beta}$ and…

General Relativity and Quantum Cosmology · Physics 2013-09-11 Hamid Shabani

We study the locally rotational symmetry Bianchi type-I dark energy model in the framework of $f(T)$ theory of gravity, where $T$ denotes the torsion scalar. A viable cosmological model is undertaken and the isotropization of this latter is…

General Relativity and Quantum Cosmology · Physics 2014-01-13 M. E. Rodrigues , I. G. Salako , M. J. S. Houndjo , J. Tossa

We show under the assumption of small data that solutions to the Einstein-Vlasov system with a pure magnetic field and Bianchi I symmetry isotropise and tend to dust solutions. We also obtain the decay rates for the main variables. This…

General Relativity and Quantum Cosmology · Physics 2024-06-18 Ho Lee , Ernesto Nungesser

In this paper we study the evolution of spatially homogeneous and anisotropic Bianchi type-I Universe models with the cosmological constant, \Lambda, and filled with nonlinear viscous fluid. The dynamical equations for these models are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Nouraddin Mostafapoor , Oyvind Gron

We present an exact solution of Einstein equations that describes a Bianchi type III spacetime with conformal expansion. The matter content is given by an anisotropic scalar field and two perfect fluids representing dust and isotropic…

General Relativity and Quantum Cosmology · Physics 2013-11-11 Saulo Carneiro , Guillermo A. Mena Marugan
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