On stable exponential cosmological solutions in the EGB model with a cosmological constant in dimensions D = 5, 6, 7, 8

Chirkov, Dmitry; Toporensky, A. V.

doi:10.1134/s0202289317040077

Cited by 17 publications

(7 citation statements)

References 34 publications

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“…we start from a totally anisotropic configuration. Since we are interesting only in stable solutions we require that the sum of initial values of the hubble parameters is positive [29][30][31].…”

Section: A Stage 1: Splitting Of Flat Space Onto Isotropic Subspacesmentioning

confidence: 99%

Anisotropic cosmological dynamics in Einstein–Gauss–Bonnet gravity: an example of dynamical compactification in $$7+1$$ dimensions

2020

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We consider a particular example of dynamical compactification of an anisotropic 7+1 dimensional Universe in Einstein -Gauss -Bonnet gravity. Starting from rather general totally anisotropic initial conditions a Universe in question evolves towards a product of two isotropic subspaces. The first subspace expands isotropically, the second represents an "inner" isotropic subspace with stabilized size. The dynamical evolution does not require finetuning of initial conditions, though it is possible for a particular range of coupling constants. The corresponding condition have been found analytically and have been confirmed using numerical integration of equations of motion.

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Section: A Stage 1: Splitting Of Flat Space Onto Isotropic Subspacesmentioning

confidence: 99%

Anisotropic cosmological dynamics in Einstein–Gauss–Bonnet gravity: an example of dynamical compactification in $$7+1$$ dimensions

2020

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“…As it is well-known, the Gauss-Bonnet term appeared in (super)string theory in the next to leading order correction (in slope parameter) to the effective action [1]- [3]. Currently, the EGB model and its extensions, see [4]- [19] and references therein, are under a wide studying in cosmology aimed at possible explanation of accelerating expansion of the Universe (i.e. in a context of the so-called dark energy problem) [20,21,22].…”

Section: Introductionmentioning

confidence: 99%

Examples of Stable Exponential Cosmological Solutions with Three Factor Spaces in EGB Model with a Λ-Term

Ernazarov

Ivashchuk

2019

Gravit. Cosmol.

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We deal with Einstein-Gauss-Bonnet model in dimension D with a Λ-term. We obtain three stable cosmological solutions with exponential behavior (in time) of three scale factors corresponding to subspaces of dimensions (l 0 , l 1 , l 2 ) = (3, 4, 4), (3, 3, 2), (3, 4, 3) and D = 12, 9, 11, respectively. Any solution may describe an exponential expansion of 3-dimensional subspace governed by Hubble parameter H. Two of them may also describe a small enough variation of the effective gravitational constant G (in Jordan frame) for certain values of Λ.

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“…To study this possibility, first we need get results on stability of these solutions. The analysis of [17][18][19] indicate that solutions with no one-dimensional subspaces are locally stable when sum of Hubble-like parameters is positive, except for some special discrete sets of coupling constant. However, local stability is not enough to claim that these solutions are natural attractors for general anisotropic initial conditions.…”

Section: Introductionmentioning

confidence: 99%

Splitting Into Two Isotropic Subspaces as a Result of Cosmological Evolution in Einstein—Gauss—Bonnet Gravity

Chirkov

Toporensky

2019

Gravit. Cosmol.

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We consider numerically dynamics of a flat anisotropic Universe in Einstein-Gauss-Bonnet gravity with positive Λ in dimensionalities 5+1 and 6+1. We identify three possible outcomes of the evolution, one singular and two nonsingular. First nonsingular outcome is oscillatory. Second is the known exponential solution. The simplest version of it is the isotropic de Sitter solution. In Gauss-Bonnet cosmology there exist also anisotropic exponential solutions. When an exponential solution being an outcome of cosmological evolution has two different Hubble parameters, the evolution leads from initially totally anisotropic stage to a warped product of two isotropic subspaces. We show that such type of evolution is rather typical and possible even in the case when de Sitter solution also exists.

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On stable exponential cosmological solutions in the EGB model with a cosmological constant in dimensions D = 5, 6, 7, 8

Cited by 17 publications

References 34 publications

Anisotropic cosmological dynamics in Einstein–Gauss–Bonnet gravity: an example of dynamical compactification in $$7+1$$ dimensions

Anisotropic cosmological dynamics in Einstein–Gauss–Bonnet gravity: an example of dynamical compactification in $$7+1$$ dimensions

Examples of Stable Exponential Cosmological Solutions with Three Factor Spaces in EGB Model with a Λ-Term

Splitting Into Two Isotropic Subspaces as a Result of Cosmological Evolution in Einstein—Gauss—Bonnet Gravity

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