<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mi>R</mml:mi></mml:math>multidimensional gravity with form-fields: Stabilization of extra dimensions, cosmic acceleration, and domain walls

Saidov, Tamerlan; Zhuk, Alexander

doi:10.1103/physrevd.75.084037

Cited by 6 publications

(7 citation statements)

References 43 publications

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“…In a scale-invariant realization of the theory, a scalar potential acquires two flat regions in such a way that both inflation and dark energy may emerge [50,51]. Forms, being intrinsically anisotropic, could also be relevant for a dynamical origin of the four large dimensions [52,53,54], modeling violation of the Lorenz invariance [55,56,57,58,59,60], the observed CMB anomalies [61,62,63,64,65] or testable late-time anisotropic phenomenology [66,67,68,69,70].…”

Section: Introductionmentioning

confidence: 99%

Inflation and dark energy from three-forms

Koivisto¹,

Nunes²

2009

Phys. Rev. D

188

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Three-forms can give rise to viable cosmological scenarios of inflation and dark energy with potentially observable signatures distinct from standard single scalar field models. In this study, the background dynamics and linear perturbations of self-interacting three-form cosmology are investigated. The phase space of cosmological solutions possesses (super)-inflating attractors and saddle points which can describe three-form driven inflation or dark energy. The quantum generation and the classical evolution of perturbations is considered. The scalar and tensor spectra from a three-form inflation and the impact from the presence of a three-form on matter perturbations are computed. Stability properties and equivalence of the model with alternative formulations are discussed.Comment: 19 pages, 8 figures, 2 tables, uses RevTeX; v2: Typos fixed, refs added, reflects the PRD version but with some extra material in Section V and appendice

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Section: Introductionmentioning

confidence: 99%

Inflation and dark energy from three-forms

Koivisto¹,

Nunes²

2009

Phys. Rev. D

188

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“…It is indeed appealing to study models which combine both approaches, in other words, to consider nonlinear f (R) models in multidimensional space-time. As regards the cosmological aspects, such models were investigated in [12][13][14][15][16][17][18], where the authors focused mainly on the problems of internal space stabilization, early and late time accelerated expansion of the Universe and dark matter in the form of gravexcitons/radions. To be viable candidates, these models are required to satisfy the gravitational tests carried out in the Solar system, viz., the deflection of light, time delay of radar echoes and perihelion shift.…”

Section: Introductionmentioning

confidence: 99%

Effects of nonlinearity of f(R) gravity and perfect fluid in Kaluza–Klein models with spherical compactification

2020

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We study the effects associated with nonlinearity of f(R) gravity and of the background perfect fluid manifested in the Kaluza–Klein model with spherical compactification. The background space-time is perturbed by a massive gravitating source which is pressureless in the external space but has an arbitrary equation of state (EoS) parameter in the internal space. As characteristics of a nonlinear perfect fluid, the squared speeds of sound are not equal to the background EoS parameters in the external and internal spaces. In this setting, we find exact solutions to the linearized Einstein equations for the perturbed metric coefficients. For nonlinear models with $$f^{\prime \prime }(R_0)\ne 0$$f″(R0)≠0, we show that these coefficients acquire correction terms in the form of two summed Yukawa potentials and that in the degenerated case, the solutions are reduced to a single Yukawa potential with some “corrupted” prefactor (in front of the exponential function), which, in addition to the standard 1/r term, contains a contribution independent of the three-dimensional distance r. In the linear $$f''(R)=0$$f′′(R)=0 model, we generalize the previous studies to the case of an arbitrary nonlinear perfect fluid. We also investigate the particular case of the nonlinear background perfect fluid with zero speed of sound in the external space and demonstrate that a non-trivial solution exists only in the case of $$f''(R_0)=0$$f′′(R0)=0.

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“…Such modification of gravity may result in the late-time acceleration of our Universe [12]. Nonlinear models with polynomial as well as R −1 -type correction terms have also been generalized to the multidimensional case (see e.g., [10,11,[13][14][15][16][17][18]).…”

Section: Introductionmentioning

confidence: 99%

Bouncing inflation in nonlinear $R^2+R^4$ gravitational model

Saidov,

Zhuk

2010

Preprint

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We study a gravitational model with curvature-squared R 2 and curvature-quartic R 4 nonlinearities. The effective scalar degree of freedom φ (scalaron) has a multi-valued potential U (φ) consisting of a number of branches. These branches are fitted with each other in the branching and monotonic points. In the case of four-dimensional space-time, we show that the monotonic points are penetrable for scalaron while in the vicinity of the branching points scalaron has the bouncing behavior and cannot cross these points. Moreover, there are branching points where scalaron bounces an infinite number of times with decreasing amplitude and the Universe asymptotically approaches the de Sitter stage. Such accelerating behavior we call bouncing inflation. For this accelerating expansion there is no need for original potential U (φ) to have a minimum or to check the slow-roll conditions. A necessary condition for such inflation is the existence of the branching points. This is a new type of inflation. We show that bouncing inflation takes place both in the Einstein and Brans-Dicke frames.

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1/Rmultidimensional gravity with form-fields: Stabilization of extra dimensions, cosmic acceleration, and domain walls

Cited by 6 publications

References 43 publications

Inflation and dark energy from three-forms

Inflation and dark energy from three-forms

Effects of nonlinearity of f(R) gravity and perfect fluid in Kaluza–Klein models with spherical compactification

Bouncing inflation in nonlinear $R^2+R^4$ gravitational model

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