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Related papers: A Dark Energy Model in Lyra Manifold

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In this paper, we study a triad of inhomogeneous scalar fields, known as "solid", as a source of homogeneous but anisotropic dark energy. By using a dynamical system approach, we find that anisotropic accelerated solutions can be realized…

General Relativity and Quantum Cosmology · Physics 2021-04-22 J. Motoa-Manzano , J. Bayron Orjuela-Quintana , Thiago S. Pereira , César A. Valenzuela-Toledo

In this study, we examine the role of a scalar field in the evolution of the Universe within the framework of a Bianchi type-I cosmological model with Lyra's geometry. Previous research has explored the nonlinear spinor field in various…

General Relativity and Quantum Cosmology · Physics 2026-03-20 Evgeny Petuhov , Bijan Saha

We have investigated the evolution of a homogeneous isotropic background of the Universe and inhomogeneous subhorizon matter density perturbations in viable $f(R)$ models of present dark energy and cosmic acceleration analytically and…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-05 Hayato Motohashi , Alexei A. Starobinsky , Jun'ichi Yokoyama

The current standard cosmological model is constructed within the framework of general relativity with a cosmological constant $\Lambda$, which is often associated with dark energy, and phenomenologically explains the accelerated cosmic…

General Relativity and Quantum Cosmology · Physics 2023-06-27 Jiamin Hou , Julian Bautista , Maria Berti , Carolina Cuesta-Lazaro , César Hernández-Aguayo , Tilman Tröster , Jinglan Zheng

In this paper we consider a universe filled with barotropic dark matter and Ricci dark energy in Lyra geometry with varying Lambda. We assume two different kinds of interactions between dark matter and dark energy. Then, by using numerical…

General Relativity and Quantum Cosmology · Physics 2015-05-12 M. Khurshudyan , J. Sadeghi , A. Pasqua , S. Chattopadhyay , R. Myrzakulov , H. Farahani

The present study deals with Lyra's geometry in plane symmetric metric discussed in the presence of bulk viscous fluid and one dimensional strings are assumed to be loaded with particles and the particle energy density. The variation of…

General Relativity and Quantum Cosmology · Physics 2023-06-21 M Krishna , SobhanBabu Kappala , R Santhikumar

In this paper, we obtained a new class of axially symmetric cosmological mesonic stiff fluid models in the context of Lyra's geometry. Expressions for the energy, pressure and the massless scalar field are derived by considering the time…

General Relativity and Quantum Cosmology · Physics 2015-05-14 Ragab M. Gad

We suggest the possibility that the mysterious dark energy component driving the acceleration of the Universe is the leading term, in the de Sitter temperature, of the free energy density of space-time seen as a quantum gravity coherent…

General Relativity and Quantum Cosmology · Physics 2014-04-03 Luciano Vanzo

In this essay, I present an alternative explanation for the cosmic acceleration which appears as a consequence of recent high redshift Supernova data. In the usual interpretation, this cosmic acceleration is explained by the presence of a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. -F. Pascual-Sánchez

We explore the possibility that the present stage of accelerated expansion of the universe is due to the presence of a cosmic vector field. We show that vector theories allow for the generation of an accelerated phase without the…

Astrophysics · Physics 2008-07-17 Jose Beltran Jimenez , Antonio L. Maroto

In view to scrutinize the idea that nonlocal modifications of General Relativity could dynamically address the dark energy problem, we investigate the evolution of the Universe at infrared scales as an Infinite Derivative Gravity model of…

General Relativity and Quantum Cosmology · Physics 2024-05-03 Salvatore Capozziello , Anupam Mazumdar , Giuseppe Meluccio

General Relativistic Entropic Acceleration (GREA) theory provides a covariant formalism for out-of-equilibrium phenomena in GR, extending the Einstein equations with an entropic force that behaves like bulk viscosity with a negative…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-28 Juan Garcia-Bellido

An oscillating, homogeneous and isotropic Universe which arises from Scalar-Tensor gravity is discussed in the linearized approach, showing that some observative evidences like the Hubble Law and the Cosmological Redshift are in agreement…

Astrophysics · Physics 2010-01-24 Christian Corda

In this paper, a stable flat cosmological model has been constructed and the evolution of dark energy has been investigated in the framework of the recently suggested $\kappa(R,T)$ gravity. The empirical approach we adopt in the current…

General Relativity and Quantum Cosmology · Physics 2020-02-11 Nasr Ahmed , Anirudh Pradhan

Recently, a new alternative vector theory of gravity has been proposed which assumes that universe has fixed background Euclidean geometry and gravity is a vector field that alters this geometry [Phys. Scr. 92, 125001 (2017)]. It has been…

General Physics · Physics 2019-05-28 Anatoly A. Svidzinsky

We consider scalar tensor theories of gravity assuming that the scalar field is non minimally coupled with gravity. We use this theory to study evolution of a flat homogeneous and isotropic universe. In this case the dynamical equations can…

Astrophysics · Physics 2012-07-13 M. Demianski , E. Piedipalumbo , C. Rubano , C. Tortora

We have investigated an inhomogeneous Bianchi type-I cosmological model with electromagnetic field based on Lyra geometry. A new class of exact solutions have been obtained by considering the potentials of metric and displacement field are…

General Relativity and Quantum Cosmology · Physics 2014-11-24 M. Abdel-Megied , Ragab M. Gad , E. A. Hegazy

We consider a cosmology with a non-compact nonlinear sigma model.The target space is of de-Sitter type and four scalar fields are introduced.The potential is absent but cosmological constant term $\Lambda$ is added. One of the scalar fields…

General Relativity and Quantum Cosmology · Physics 2009-10-19 Joohan Lee , Tae Hoon Lee , Taeyoon Moon , Phillial Oh

We study a dark energy scenario in the presence of a tachyon field $\phi$ with potential $V(\phi)$ and a barotropic perfect fluid. The cosmological dynamics crucially depends on the asymptotic behavior of the quantity…

High Energy Physics - Theory · Physics 2008-11-26 Edmund J. Copeland , Mohammad R. Garousi , M. Sami , Shinji Tsujikawa

Modeling of matter bounce in $f(R,T)$ gravity has been presented with no violation of the null energy condition. Only a closed universe with negative pressure is allowed in good agreement with some recent observations which favor a universe…

General Relativity and Quantum Cosmology · Physics 2022-06-22 Vinod Kumar Bhardwaj , Anirudh Pradhan , Nasr Ahmed , A. A. Shaker