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We study some properties of exact cosmological solutions for a flat multidimensional anisotropic Universe in Lovelock gravity. A particular attention is paid to some features of solution in a general Lovelock gravity which have no their…

广义相对论与量子宇宙学 · 物理学 2014-06-11 S. Pavluchenko , A. Toporensky

It was shown recently that a very simple nonlocal de Sitter gravity model contains exact vacuum cosmological solution which mimics dark energy and dark matter in flat space. Some other interesting solutions have been also found. In this…

广义相对论与量子宇宙学 · 物理学 2023-07-04 Ivan Dimitrijevic

In this article we give a full description of the dynamics of the flat anisotropic (4+1)-dimensional cosmological model in the presence of both Gauss-Bonnet and Einstein contributions. This is the first complete description of this model…

广义相对论与量子宇宙学 · 物理学 2010-12-13 S. A. Pavluchenko

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…

广义相对论与量子宇宙学 · 物理学 2016-03-16 A. A. Kobtsev , V. D. Ivashchuk , K. K. Ernazarov

In this paper, we investigate the exact solution of an anisotropic space-time in the context of $f(Q)$ gravity, where $f\left( Q\right) $ is the arbitrary function of the non-metricity scalar $Q$. Here, we consider a specific power-law form…

广义相对论与量子宇宙学 · 物理学 2022-12-01 M. Koussour , M. Bennai

We uncover the solution space of a five dimensional geometry which we deem it as the direct counterpart of the Bianchi Type V cosmological model. We kinematically reduce the scale factor matrix and then, with an appropriate scaling and…

广义相对论与量子宇宙学 · 物理学 2025-04-01 Homa Shababi , Theophanes Grammenos , Nikolaos Dimakis , Andronikos Paliathanasis , Theodosios Christodoulakis

A solution for the Einstein gravity coupled with non linear electrodynamics is introduced in 2+1 dimensions. Especially, in the case with a non-vanishing cosmological constant, we obtain a novel black hole solution. To find fundamental…

广义相对论与量子宇宙学 · 物理学 2013-12-11 M. Kuniyasu

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"…

广义相对论与量子宇宙学 · 物理学 2011-04-20 V. D. Ivashchuk

In this paper we study the properties of Kasner cosmological solutions in Lovelock gravity. Recent progress in the investigation of flat cosmological models in Lovelock gravity unveiled the fact that in quadratic (Gauss--Bonnet) and cubic…

广义相对论与量子宇宙学 · 物理学 2026-01-06 Sergey Pavluchenko

In this paper we investigate the past evolution of an anisotropic Bianchi I universe in $R+R^2$ gravity. Using the dynamical system approach we show that there exists a new two-parameters set of solutions that includes both an isotropic…

广义相对论与量子宇宙学 · 物理学 2018-05-09 Daniel Müller , Angelo Ricciardone , Alexei A. Starobinsky , Aleksey Toporensky

Anisotropic exponential cosmological solutions for a space of arbitrary dimension filled with ordinary matter in the 4th and 5th orders of Lovelock gravity are obtained. Also we have supposed a generalization of such solutions on an…

广义相对论与量子宇宙学 · 物理学 2017-02-24 Ilya V. Kirnos

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…

广义相对论与量子宇宙学 · 物理学 2014-12-17 Dmitry Chirkov , Sergey A. Pavluchenko , Alexey Toporensky

We show that in Gauss-Bonnet gravity with negative Gauss-Bonnet coefficient and without a cosmological constant, one can explain the acceleration of the expanding Universe. We first introduce a solution of the Gauss-Bonnet gravity with…

高能物理 - 理论 · 物理学 2009-11-10 M. H. Dehghani

We consider 5-dimensional spacetimes of constant 3-dimensional spatial curvature in the presence of a bulk cosmological constant. We find the general solution of such a configuration in the presence of a Gauss-Bonnet term. Two classes of…

高能物理 - 理论 · 物理学 2009-11-07 Christos Charmousis , Jean-Francois Dufaux

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…

广义相对论与量子宇宙学 · 物理学 2025-03-13 Alex Giacomini , Andronikos Paliathanasis , Alexey Toporensky

It is known that Gauss-Bonnet terms in higher dimensional gravity can produce an effective cosmological constant. We add extra examples to this picture by presenting explicitly two branches of accelerating vacuum solutions to the…

广义相对论与量子宇宙学 · 物理学 2015-05-30 Liu Zhao , Kun Meng

In this paper, we study anisotropic universe using Noether symmetries in modified gravity. In particular, we choose locally rotationally symmetric Bianchi type-$I$ universe for the analysis in $f(R,\mathcal{G})$ gravity, where $R$ is the…

广义相对论与量子宇宙学 · 物理学 2017-05-18 M. Farasat Shamir , Fiza Kanwal

We study a possibility of anisotropic scale invariant cosmology. It is shown that within the conventional Einstein gravity, the violation of the null energy condition is necessary. We construct an example based on a ghost condensation model…

高能物理 - 理论 · 物理学 2011-03-04 Yu Nakayama

We investigate the cosmological reconstruction in anisotropic universe for both homogeneous and inhomogeneous content of the universe. Special attention is attached to three interesting cases: Bianchi type-I, Bianchi type-III and…

广义相对论与量子宇宙学 · 物理学 2012-11-29 M. E. Rodrigues , M. J. S. Houndjo , D. Saez-Gomez , F. Rahaman

We present a brief review of the modified Brans-Dicke theory (MBDT) in arbitrary dimensions, whereby the ($N+1$)-dimensional field equations reduce to the $N$-dimensional $(ND)$ configuration with sources and an effective induced scalar…

广义相对论与量子宇宙学 · 物理学 2014-05-27 S. M. M. Rasouli