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In this study, we present an approach $ f(R, G) $ gravity incorporating power law in $ G $. To study the cosmic evolution of the universe given by the reconstruction of the Hubble parameter given by $ E(z) = \bigg(…

General Relativity and Quantum Cosmology · Physics 2024-09-30 Rita Rani , Shaily , G. K. Goswami , J. K. Singh

Static, spherically symmetric solutions with regular origin are investigated of the Einstein-Yang-Mills theory with a negative cosmological constant $\Lambda$. A combination of numerical and analytical methods leads to a clear picture of…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Peter Breitenlohner , Dieter Maison , George Lavrelashvili

A new class of exact solutions of Einstein's field equations with perfect fluid for an LRS Bianchi type-I spacetime is obtained by using a time dependent deceleration parameter. We have obtained a general solution of the field equations…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Anirudh Pradhan , S. Otarod

A type of exponential correction to General Relativity gives viable modified gravity model of dark energy. The model behaves as $R-2\Lambda$ at large curvature where an effective cosmological constant appears, but it becomes zero in flat…

General Relativity and Quantum Cosmology · Physics 2022-01-13 L. N. Granda

We present two new classes of magnetic brane solutions in Einstein-Maxwell-Gauss-Bonnet gravity with a negative cosmological constant. The first class of solutions yields an $(n+1)$-dimensional spacetime with a longitudinal magnetic field…

High Energy Physics - Theory · Physics 2009-11-10 M. H. Dehghani

The (n +1)-dimensional Einstein-Gauss-Bonnet (EGB) model is considered. For diagonal cosmological metrics, the equations of motion are written as a set of Lagrange equations with the effective Lagrangian containing two "minisuperspace"…

General Relativity and Quantum Cosmology · Physics 2011-04-20 V. D. Ivashchuk

The canonical structure of the Einstein-Hilbert Lagrange density $L=\sqrt{-g}R$ is examined in two spacetime dimensions, using the metric density $h^{\mu \nu}\equiv \sqrt{-g}g^{\mu \nu}$ and symmetric affine connection $\Gamma_{\sigma…

High Energy Physics - Theory · Physics 2009-11-11 N. Kiriushcheva , S. V. Kuzmin , D. G. C. McKeon

We investigate the $D\rightarrow 4$ limit of the $D$-dimensional Einstein-Gauss-Bonnet gravity, where the limit is taken with $\tilde{\alpha}=(D-4)\, \alpha$ kept fixed and $\alpha$ is the original Gauss-Bonnet coupling. Using the ADM…

General Relativity and Quantum Cosmology · Physics 2020-10-12 Katsuki Aoki , Mohammad Ali Gorji , Shinji Mukohyama

This manuscript is based on an investigation of bouncing cosmology in a 4D Einstein Gauss-Bonnet gravity. Various bouncing models such as symmetric bounce, matter bounce, super bounce, and oscillatory bounce have been examined. Expressions…

General Relativity and Quantum Cosmology · Physics 2023-06-16 M. Zubair , Mushayydha Farooq

In recent years, there has been a growing interest in stellar modelling in the framework of Einstein-Gauss-Bonnet gravity. In this paper, for a relativistic star in static equilibrium, we invoke the $5$ dimensional Einstein-Gauss-Bonnet…

General Relativity and Quantum Cosmology · Physics 2023-06-22 Soumik Bhattacharya , Suntharalingam Thirukkanesh , Ranjan Sharma

In this paper, we obtain higher dimensional topological black hole solutions of Einstein-$\Lambda$ gravity in the presence of a class of nonlinear electrodynamics. First, we calculate the conserved and thermodynamic quantities of…

General Relativity and Quantum Cosmology · Physics 2015-07-13 S. H. Hendi , M. Momennia

We study how the constants $G$ and $\Lambda$ may vary in different theoretical models (general relativity with a perfect fluid, scalar cosmological models (\textquotedblleft quintessence\textquotedblright) with and without interacting…

General Relativity and Quantum Cosmology · Physics 2012-04-06 José Antonio Belinchón

A finite quantum gravity theory is used to resolve the cosmological constant problem. A fundamental quantum gravity scale, \Lambda_G \leq 10^{-3} eV, is introduced above which the quantum corrections to the vacuum energy density coupled to…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. W. Moffat

We probe the cosmic expansion scenario within the framework of $f(R, L_{m})$ gravity by employing a well-motivated functional form of $f(R, L_{m}) = \frac{R}{2} + L_{m}^{\lambda}$. Specifically, we introduce three novel cosmological models…

General Relativity and Quantum Cosmology · Physics 2026-05-27 Khomesh R. Patle , G. P. Singh

We construct non-stationary exact solutions to five dimensional Einstein-Maxwell-Chern-Simons theory with positive cosmological constant. The solutions are based on four-dimensional Atiyah-Hitchin space. In asymptotic regions, the solutions…

High Energy Physics - Theory · Physics 2010-04-06 A. M. Ghezelbash

We construct an approximate solution to the cosmological perturbation theory around Einstein-de Sitter background up to the fourth-order perturbations. This could be done with the help of the specific symmetry condition imposed on the…

General Relativity and Quantum Cosmology · Physics 2021-03-17 Szymon Sikora , Krzysztof Głód

We consider cosmological dynamics in fourth order gravity with both $f(R)$ and $\Phi(\mathcal {G})$ correction to the Einstein gravity ($\mathcal{G}$ is the Gauss-Bonnet term). The particular case for which both terms are equally important…

General Relativity and Quantum Cosmology · Physics 2012-05-09 Mikhail M. Ivanov , Alexey V. Toporensky

The static, apparently cylindrically symmetric vacuum solution of Linet and Tian for the case of a positive cosmological constant $\Lambda$ is shown to have toroidal symmetry and, besides $\Lambda$, to include three arbitrary parameters. It…

General Relativity and Quantum Cosmology · Physics 2010-12-23 J. B. Griffiths , J. Podolsky

The idea here is to set the cosmical constant $\lambda$ proportional to the scalar of the stress-energy tensor of the ordinary matter. We investigate the evolution of the scale factor in a cosmological model in which the cosmological…

Astrophysics · Physics 2007-05-23 V. Majernik

It is shown that for every multidimensional metric in the multiply warped product form $\bar{M} = K\times_{f_1} M_1\times_{f_2}M_2$ with warp functions $f_1$, $f_2$, associated to the submanifolds $M_1$, $M_2$ of dimensions $n_1$, $n_2$…

General Relativity and Quantum Cosmology · Physics 2016-10-20 F. Gholami , F. Darabi , A. Haji-Badali
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