Extended anisotropic models in noncompact Kaluza–Klein theory

Rasouli, S. M. M.; Moniz, Paulo Vargas

doi:10.1088/1361-6382/ab0987

Cited by 11 publications

(12 citation statements)

References 61 publications

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“…It has been shown that the classical tests of general relativity and the experimental limits on violation of the equivalence principle do not disqualify any higher dimensional theories of gravity [5][6][7]. Concerning astrophysical/cosmological applications, such induced sectors or their extensions can play the role of either ordinary matter, dark matter or dark energy [7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Late time cosmic acceleration in modified Sáez–Ballester theory

Rasouli

Pacheco

Sakellariadou

et al. 2020

Physics of the Dark Universe

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We establish an extended version of the modified Sáez-Ballester (SB) scalar-tensor theory in arbitrary dimensions whose energy momentum tensor as well as potential are pure geometrical quantities. This scenario emerges by means of two scalar fields (one is present in the SB theory and the other is associated with the extra dimension) which widens the scope of the induced-matter theory. Moreover, it bears a close resemblance to the standard Sáez-Ballester scalar-tensor theory, as well as other alternative theories to general relativity, whose construction includes either a minimally or a non-minimally coupled scalar field. However, contrary to those theories, in our framework the energy momentum tensor and the scalar potential are not added by hand, but instead are dictated from the geometry. Concerning cosmological applications, our herein contribution brings a new perspective. We firstly show that the dark energy sector can be naturally retrieved within a strictly geometric perspective, and we subsequently analyze it. Moreover, our framework may provide a hint to understand the physics of lower gravity theories.

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Section: Introductionmentioning

confidence: 99%

Late time cosmic acceleration in modified Sáez–Ballester theory

Rasouli

Pacheco

Sakellariadou

et al. 2020

Physics of the Dark Universe

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“…Yet, involving extra spatial dimensions may be good place for looking for such possibilities as it was shown that it is possible to make BD theory (massive or massless) consistent with the gravitational tests (including solar system tests) for |ω| = O(1) in the presence of extra dimensions [127]. Noticing the presence of extra dimensions as part of string theories and the dynamical extra dimensions (internal space) contribute to the evolution of the four dimensional anisotropic spacetime like an anisotropic stress in a similar way that the Jordan field does in BD theory make this option more appealing and interesting [161][162][163][164][165]. This shows one of the many possibilities of rich behaviors which could be worthwhile to investigate in future studies on the extensions of the standard ΛCDM model wherein the expansion anisotropy exhibits non-trivial behaviors that may have interesting cosmological consequences.…”

Section: Discussionmentioning

confidence: 99%

Anisotropic massive Brans–Dicke gravity extension of the standard $$\Lambda $$CDM model

et al. 2020

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We present an explicit detailed theoretical and observational investigation of an anisotropic massive Brans-Dicke (BD) gravity extension of the standard ΛCDM model, wherein the extension is characterized by two additional degrees of freedom; the BD parameter, ω, and the present day density parameter corresponding to the shear scalar, Ω σ 2 ,0 . The BD parameter, determining the deviation from general relativity (GR), by alone characterizes both the dynamics of the effective dark energy (DE) and the redshift dependence of the shear scalar. These two affect each other depending on ω, namely, the shear scalar contributes to the dynamics of the effective DE, and its anisotropic stress -which does not exist in scalar field models of DE within GR-controls the dynamics of the shear scalar deviating from the usual ∝ (1 + z) 6 form in GR. We mainly confine the current work to non-negative ω values as it is the right sign -theoretically and observationally-for investigating the model as a correction to the ΛCDM. By considering the current cosmological observations, we find that ω 250, Ω σ 2 ,0 10 −23 and the contribution of the anisotropy of the effective DE to this value is insignificant. We conclude that the simplest anisotropic massive BD gravity extension of the standard ΛCDM model exhibits no significant deviations from it all the way to the Big Bang Nucleosynthesis. We also point out the interesting features of the model in the case of negative ω values; for instance, the constraints on Ω σ 2 ,0 could be relaxed considerably, the values of ω ∼ −1 (relevant to string theories) predict dramatically different dynamics for the expansion anisotropy.

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“…In this section, let us first review the MSBT in arbitrary dimensions [38,16], and then investigate the GD equation in this framework.…”

Section: Gd Equation In the Context Of The Msbtmentioning

confidence: 99%

“…it has then been shown that the effective EMT as well as an induced scalar potential emerge intrinsically from the geometry of the extra dimension (for more detail, see [38,16]). In (139), l denotes a non-compact coordinate along the extra dimension; the scalar field ψ depends on all coordinates and = ±1.…”

Section: Gd Equation In the Context Of The Msbtmentioning

confidence: 99%

“…As the particular case of MSBT, by considering a five-dimensional manifold (empty of ordinary matter), this yields an effective framework on a four-dimensional hypersurface, in which the usual right hand side of the field equations is explained solely in terms of the whole geometry. This effective framework is called the space-time matter theory or the induced-matter theory (IMT) [26,27,28,29,30] (see also [15,16,31,32,33,34,35,36,37,38], as cosmological applications).…”

Section: Introductionmentioning

confidence: 99%

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Geodesic deviation in Saez-Ballester theory

Rasouli,

Sakellariadou,

Moniz

2022

Preprint

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We study the geodesic deviation (GD) equation in a generalized version of the Sáez-Ballester (SB) theory in arbitrary dimensions. We first establish a general formalism and then restrict to particular cases, where (i) the matter-energy distribution is that of a perfect fluid, and (ii) the spacetime geometry is described by a vanishing Weyl tensor. Furthermore, we consider the spatially flat FLRW universe as the background geometry. Based on this setup, we compute the GD equation as well as the convergence condition associated with fundamental observers and past directed null vector fields. Moreover, we extend that framework and extract the corresponding geodesic deviation in the modified Sáez-Ballester theory (MSBT), where the energy-momentum tensor and potential emerge strictly from the geometry of the extra dimensions. In order to examine our herein GD equations, we consider two novel cosmological models within the SB framework. Moreover, we discuss a few quintessential models and a suitable phantom dark energy scenario within the mentioned SB and MSBT frameworks. Noticing that our herein cosmological models can suitably include the present time of our Universe, we solve the GD equations analytically and/or numerically. By employing the correct energy conditions plus recent observational data, we consistently depict the behavior of the deviation vector η(z) and the observer area distance r 0 (z) for our models. Concerning the Hubble constant problem, we specifically focus on the observational data reported by the Planck collaboration and the SH0ES collaboration to depict η(z) and r 0 (z) for our herein phantom model. Subsequently, we contrast our results with those associated with the ΛCDM model. We argue that the MSBT can be considered as a fitting candidate for a proper description of the late evolution of the universe.

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Extended anisotropic models in noncompact Kaluza–Klein theory

Cited by 11 publications

References 61 publications

Late time cosmic acceleration in modified Sáez–Ballester theory

Late time cosmic acceleration in modified Sáez–Ballester theory

Anisotropic massive Brans–Dicke gravity extension of the standard $$\Lambda $$CDM model

Geodesic deviation in Saez-Ballester theory

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