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We present the classical solutions to the Einstein field equations derived using the WKB-like and Hamilton procedures. The investigation is carried out in the commutative and noncommutative scenario for the Bianchi type I cosmological model…

General Relativity and Quantum Cosmology · Physics 2009-11-13 C. Ortiz , E. Mena-Barboza , M. Sabido , J. Socorro

We consider the classical evolution of the inflaton field $\phi(t)$ and the Hubble parameter $H(t)$ in homogeneous and isotropic single-field inflation models. Under an extremely broad assumption, we show that the universe generically…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 W. J. Handley , S. D. Brechet , A. N. Lasenby , M. P. Hobson

We investigate the phase-space of a flat FRW universe including both a scalar field, $\phi,$ coupled to matter, and radiation. The model is inspired in scalar-tensor theories of gravity, and thus, related with $F(R)$ theories through…

General Relativity and Quantum Cosmology · Physics 2010-09-06 Genly Leon , Pavel Silveira , Carlos R. Fadragas

This study presents a study of equilibrium points, periodic orbits, stabilities, and manifolds in a rotating plane symmetric potential field. It has been found that the dynamical behaviour near equilibrium points is completely determined by…

Earth and Planetary Astrophysics · Physics 2018-07-02 Yu Jiang , Hexi Baoyin , Xianyu Wang , Hengnian Li

This paper explores the dynamics of warm intermediate and logamediate inflationary models during weak dissipative regime with a general form of dissipative coefficient. We analyze these models within the framework of locally rotationally…

General Relativity and Quantum Cosmology · Physics 2016-03-23 M. Sharif , Rabia Saleem

The study of a self-consistent system of nonlinear spinor and Bianchi type I gravitational fields in presence of a viscous fluid and $\Lambda$ term with the spinor field nonlinearity being some arbitrary functions of the invariants $I$ an…

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

A self-consistent system of interacting nonlinear spinor and scalar fields within the scope of a Bianchi type-I cosmological model filled with perfect fluid is considered. Exact self-consistent solutions to the corresponding field equations…

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

In this work, we study a cosmological model of Bianchi type-I Universe in teleparallel gravity for a perfect fluid. To obtain the cosmological solution of the model, we assume that the deceleration parameter is a linear function of the…

General Relativity and Quantum Cosmology · Physics 2022-05-25 M. Koussour , M. Bennai

Einstein's field equations for stationary Bianchi type II models with a perfect fluid source are investigated. The field equations are rewritten as a system of autonomous first order differential equations. Dimensionless variables are…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Ulf S. Nilsson , C. Uggla

We investigate exact solutions of the Einstein field equations in higher-dimensional, spatially homogeneous Bianchi type-I spacetimes, introducing a real parameter $\lambda$ that correlates the expansion rates of external and internal…

General Relativity and Quantum Cosmology · Physics 2025-07-02 Nihan Katırcı

Understanding the early evolution of the universe requires models that incorporate possible quantum and anisotropic effects in its dynamics. In this work, we analyze the dynamical evolution of locally rotationally symmetric anisotropic…

General Relativity and Quantum Cosmology · Physics 2025-10-13 G. Oliveira-Neto , Y. Soncco Apaza

A perturbative expansion of Loop Quantum Cosmological transitions amplitudes of Bianchi I models is performed. Following the procedure outlined in [1,2] for isotropic models, it is shown that the resulting expansion can be written in the…

General Relativity and Quantum Cosmology · Physics 2010-11-12 Miguel Campiglia , Adam Henderson , William Nelson

We analyze the dynamics of a Taub cosmological model in the presence of a massless minimally coupled scalar field and a cosmological constant, in the limit when both the Universe volume and the scalar field live in a quasi-classical…

General Relativity and Quantum Cosmology · Physics 2020-06-05 Mariaveronica De Angelis , Giovanni Montani

We consider the Bianchi I geometry coupled to several species of comoving barotropic perfect fluids with a linear equation of state in the context of general relativity. The solution of the dynamics can be reduced to a quadrature, which can…

General Relativity and Quantum Cosmology · Physics 2024-10-29 David Brizuela , Sara F. Uria

We study the dynamical effects in the scale factors due to the scalar $\phi$-field at the early stages of a supposedly anisotropic Universe expansion in connection with the problem of the initial singularity in the scalar-tensor cosmology…

General Relativity and Quantum Cosmology · Physics 2007-05-23 H. N. Núñez-Yépez

Bianchi type V viscous fluid cosmological model for barotropic fluid distribution with varying cosmological term $\Lambda$ is investigated. We have examined a cosmological scenario proposing a variation law for Hubble parameter $H$ in the…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Raj Bali , Pratibha Singh , J. P. Singh

An LRS Bianchi I model is considered with constant deceleration parameter, $q=\alpha-1$, where $\alpha\geq0$ is a constant. The physical and kinematical behaviour of the models for $\alpha=0$ and $\alpha\neq0$ is studied in detail. The…

General Relativity and Quantum Cosmology · Physics 2019-12-13 Vijay Singh , Aroonkumar Beesham

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

Within the scope of Bianchi type-$II$ cosmological model we have studied the role of spinor field in the evolution of the Universe. It is found that in this case the components of energy-momentum tensor of spinor field along the principal…

General Physics · Physics 2023-02-21 Bijan Saha

In this work we present a phase space analysis of a quintessence field and a perfect fluid trapped in a Randall-Sundrum's Braneworld of type 2. We consider a homogeneous but anisotropic Bianchi I brane geometry. Moreover, we consider the…

General Relativity and Quantum Cosmology · Physics 2013-10-31 Dagoberto Escobar , Carlos R. Fadragas , Genly Leon , Yoelsy Leyva