English
Related papers

Related papers: Stable exponential cosmological solutions with two…

200 papers

A D-dimensional gravitational model with Gauss-Bonnet and cosmological term is considered. When ansatz with diagonal cosmological metrics is adopted, we overview recent solutions for zero cosmological term and find new examples of solutions…

General Relativity and Quantum Cosmology · Physics 2016-03-16 A. A. Kobtsev , V. D. Ivashchuk , K. K. Ernazarov

We explore the possibility of a consistent cosmology based on the gauge-fixing independent running of the gravitational and cosmological constants ($G$ and $\Lambda$) in the framework of effective quantum gravity. In particular, their…

General Relativity and Quantum Cosmology · Physics 2024-04-30 Nicolas R. Bertini , Davi C. Rodrigues , Ilya L. Shapiro

In this paper we are looking for the exponential solutions (i.e. the solutions with the scale factors change exponentially over time) in the Einstein-Gauss-Bonnet gravity. We argue that we found all possible non-constant-volume solutions…

General Relativity and Quantum Cosmology · Physics 2014-08-19 Dmitry Chirkov , Sergey Pavluchenko , Alexey Toporensky

In this work, we analyze the Einstein-scalar-Gauss-Bonnet (EsGB) theory of gravity in a cosmological context using the formalism of dynamical systems. We obtain the equations of motion of the theory and introduce an appropriate set of…

General Relativity and Quantum Cosmology · Physics 2025-09-23 Miguel A. S. Pinto , João Luís Rosa

A new set of field equations for a space-time dependent Newton's constant $G(x)$ and cosmological constant $\Lambda(x)$ in the presence of matter is presented. We prove that it represents the most general mathematically consistent,…

General Relativity and Quantum Cosmology · Physics 2021-05-19 Alfio Bonanno , Georgios Kofinas , Vasilios Zarikas

In this paper we investigate the constant volume exponential solutions (i.e. the solutions with the scale factors change exponentially over time so that the comoving volume remains the same) in the Einstein-Gauss-Bonnet gravity. We find…

General Relativity and Quantum Cosmology · Physics 2014-12-17 Dmitry Chirkov , Sergey A. Pavluchenko , Alexey Toporensky

We study Einstein's equation in $(m+n)D$ and $(1+n)D$ warped spaces $(\bar{M},\bar{g})$ and classify all such spaces satisfying Einstein equations $\bar{G}=-\bar{\Lambda}\bar{g}$. We show that the warping function not only can determine the…

Differential Geometry · Mathematics 2017-05-16 Morteza Faghfouri , Ali Haji Badali , Fatemeh Gholami

The conditions for the existence and stability of cosmological power-law scaling solutions are established when the Einstein-Hilbert action is modified by the inclusion of a function of the Gauss-Bonnet curvature invariant. The general form…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Kotub Uddin , James E. Lidsey , Reza Tavakol

In this paper we perform stability analysis for exponential solutions in Einstein-Gauss-Bonnet and cubic Lovelock gravity. We report our findings, provide areas on parameters space and discuss familiarities and differences between cases.…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Sergey A. Pavluchenko

We report the results of a study on the dynamical compactification of spatially flat cosmological models in Einstein-Gauss-Bonnet gravity. The analysis was performed in the arbitrary dimension in order to be more general. We consider both…

High Energy Physics - Theory · Physics 2018-03-08 Sergey Pavluchenko

In this work, the cosmic solutions, particularly the well-known $\Lambda$CDM model, are investigated in the framework of the Gauss-Bonnet gravity, where the gravitational action incorporates the Gauss-Bonnet invariant function. We utilize a…

General Relativity and Quantum Cosmology · Physics 2024-09-26 N. Myrzakulov , Anirudh Pradhan , Archana Dixit , S. H. Shekh

We reconcile seemingly conflicting statements in the literature about the behavior of cosmological solutions in modified theories of gravity where the Einstein-Hilbert Lagrangian for gravity is modified by the addition of a function of the…

Astrophysics · Physics 2008-11-26 Ignacy Sawicki , Wayne Hu

We present a model in which the cosmological constant emerges as a purely geometric effect from the four-dimensional compactification of five-dimensional Einstein-Chern-Simons gravity. The compactification of the extra dimension generates…

General Relativity and Quantum Cosmology · Physics 2026-04-03 M. Cataldo , S. Lepe , C. Riquelme , P. Salgado

We study the homogeneous but anisotropic Bianchi type-V cosmological model with time-dependent gravitational and cosmological "constants". Exact solutions of the Einstein field equations (EFEs) are presented in terms of adjustable…

General Relativity and Quantum Cosmology · Physics 2018-07-30 Alnadhief H. A. Alfedeel , Amare Abebe , Hussam M. Gubara

We establish the existence of $1$-parameter families of $\epsilon$-dependent solutions to the Einstein-Euler equations with a positive cosmological constant $\Lambda >0$ and a linear equation of state $p=\epsilon^2 K \rho$, $0<K\leq 1/3$,…

General Relativity and Quantum Cosmology · Physics 2018-07-27 Chao Liu , Todd A. Oliynyk

The properties of the Melvin-type spacetime with a positive cosmological constant $\Lambda$ in $d$-dimensional Einstein--Maxwell gravity is studied. The solution is parametrised in terms of the `de Sitter radius' $\ell\propto\Lambda^{-1/2}$…

General Relativity and Quantum Cosmology · Physics 2025-09-03 Yu-Xuan Toh , Yun-Ten Chin , Ethan Quanrun Wu , Yen-Kheng Lim

Solutions of Einstein's equations are found for global defects in a higher-dimensional spacetime with a nonzero cosmological constant Lambda. The defect has a (p-1)-dimensional core (brane) and a `hedgehog' scalar field configuration in the…

High Energy Physics - Theory · Physics 2010-04-06 Itsaso Olasagasti , Alexander Vilenkin

We introduce a new kind of super warped product spaces $\bar{M}_{_{(I)}}=\textbf{I}^{1|0}\times_f M^{m|n}$, $\bar{M}_{_{(II)}}=\textbf{I}^{0|1}\times_{f} M^{m|n}$, and $\bar{M}_{_{(III)}}=\textbf{I}^{1|1}\times_{f} M^{m|n}$, where $M^{m|n}$…

General Relativity and Quantum Cosmology · Physics 2021-08-27 F. Gholami , F. Darabi , M. Mohammadi , S. Varsaie , M. Roshande

We study gravitational theories with a cosmological constant and the Gauss-Bonnet curvature squared term and analyze the possibility of de Sitter expanding spacetime with a constant internal space. We find that there are two branches of the…

High Energy Physics - Theory · Physics 2015-06-19 Kei-ichi Maeda , Nobuyoshi Ohta

We study the cosmological model based on Einstein-Gauss-Bonnet gravity with non-minimal coupling of a scalar field to a Gauss-Bonnet term in 4D Friedmann universe. We show how constructing the exact solutions by the method based on a…

General Relativity and Quantum Cosmology · Physics 2017-07-26 Igor V. Fomin , Sergey V. Chervon