Inflaton field governed universe from NKK theory of gravity: stochastic approach

Anabitarte, Mariano; Aguilar, José Edgar Madriz; Bellini, Mauricio

doi:10.1140/epjc/s2005-02404-9

Cited by 10 publications

(6 citation statements)

References 20 publications

(19 reference statements)

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“…However, as it has been shown in [23,24], depending on the metric background and considering separable scalar fields such an identification is valid.…”

Section: The Effective Four-dimensional Modified Brans-dicke Theorymentioning

confidence: 91%

“…At this point we would like to call attention for the fact that in the formalism developed in the present paper a potential exhibiting the mentioned property can be geometrically induced due to the presence of the fifth coordinate, avoiding ipso facto its introduction as "by hand". In fact, the idea of inducing 4D scalar potentials V (ϕ) geometrically from a 5D space-time has already been introduced in [23,24], in the context of inflationary models. Let us now develop a formalism which, in a way, generalizes the induced-matter approach and which leads to a slightly modified BD theory in four dimensions, these modifications being caused essentially by the presence of the scalar potential.…”

Section: The Effective Four-dimensional Modified Brans-dicke Theorymentioning

confidence: 99%

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Modified Brans–Dicke theory of gravity from five-dimensional vacuum

2007

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We investigate, in the context of five-dimensional (5D) Brans-Dicke theory of gravity, the idea that macroscopic matter configurations can be generated from pure vacuum in five dimensions, an approach first proposed by Wesson and collaborators in the framework of 5D general relativity. We show that the 5D Brans-Dicke vacuum equations when reduced to four dimensions (4D) lead to a modified version of Brans-Dicke theory in 4D. As an application of the formalism, we obtain two 5D extensions of 4D O'Hanlon and Tupper vacuum solution and show that they lead two different cosmological scenarios in 4D.

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“…However, as it has been shown in [23,24], depending on the metric background and considering separable scalar fields such an identification is valid.…”

Section: The Effective Four-dimensional Modified Brans-dicke Theorymentioning

confidence: 91%

Section: The Effective Four-dimensional Modified Brans-dicke Theorymentioning

confidence: 99%

Modified Brans–Dicke theory of gravity from five-dimensional vacuum

2007

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“…Such an identification has been claimed [46,47] to be valid depending on metric background and considering separable scalar fields. However, this definition is different from what has been used in Ref.…”

Section: Modified Brans-dicke Theory From Five-dimensional Vacuummentioning

confidence: 97%

“…Real solutions of relation (53) dictate that (n + 3) 2 + 6ω(n + 1) ≥ 0. By substituting solutions (45)- (47) in the WEC (23) or (24), we get…”

Section: Power-law Solutionsmentioning

confidence: 99%

FRW cosmology from five dimensional vacuum Brans–Dicke theory

2010

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We follow the approach of induced-matter theory for a five-dimensional (5D) vacuum Brans-Dicke theory and introduce induced-matter and induced potential in four dimensional (4D) hypersurfaces, and then employ a generalized FRW type solution. We confine ourselves to the scalar field and scale factors be functions of the cosmic time. This makes the induced potential, by its definition, vanishes, but the model is capable to expose variety of states for the universe. In general situations, in which the scale factor of the fifth dimension and scalar field are not constants, the 5D equations, for any kind of geometry, admit a power-law relation between the scalar field and scale factor of the fifth dimension. Hence, the procedure exhibits that 5D vacuum FRW-like equations are equivalent, in general, to the corresponding 4D vacuum ones with the same spatial scale factor but a new scalar field and a new coupling constant,ω. We show that the 5D vacuum FRW-like equations, or its equivalent 4D vacuum ones, admit accelerated solutions. For a constant scalar field, the equations reduce to the usual FRW equations with a typical radiation dominated universe. For this situation, we obtain dynamics of scale factors of the ordinary and extra dimensions for any kind of geometry without any priori assumption among them. For nonconstant scalar fields and spatially flat geometries, solutions are found to be in the form of power-law and exponential ones. We also employ the weak energy condition for the induced-matter, that gives two constraints with negative or positive pressures. All types of solutions fulfill the weak energy condition in different ranges. The 123 848 A. F. Bahrehbakhsh et al.power-law solutions with either negative or positive pressures admit both decelerating and accelerating ones. Some solutions accept a shrinking extra dimension. By considering non-ghost scalar fields and appealing the recent observational measurements, the solutions are more restricted. We illustrate that the accelerating power-law solutions, which satisfy the weak energy condition and have non-ghost scalar fields, are compatible with the recent observations in ranges −4/3 < ω ≤ −1.3151 for the coupling constant and 1.5208 ≤ n < 1.9583 for dependence of the fifth dimension scale factor with the usual scale factor. These ranges also fulfill the conditionω > −3/2 which prevents ghost scalar fields in the equivalent 4D vacuum Brans-Dicke equations. The results are presented in a few tables and figures.

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“…Furthermore, the quantum fluctuations of the short-wavelength field, give place to cosmological density perturbations that could be the origin of the structure of the universe [2]. The coarsegraining representation of the inflaton field has played an important role in 4D standard inflationary cosmology [3], in 5D inflationary cosmology from modern Kaluza-Klein theory [4], and in extensions to vectorial fields more recently implemented in the framework of Gravitoelectromagnetic Inflation [5].…”

Section: Introductionmentioning

confidence: 99%

Stochastic emergence of inflaton fluctuations in a SdS primordial universe with large-scale repulsive gravity from a 5D vacuum

Reyes¹,

Aguilar²,

Bellini³

2011

Eur. Phys. J. Plus

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We develop a stochastic approach to study scalar field fluctuations of the inflaton field in an early inflationary universe with a black-hole (BH), which is described by an effective 4D Schwarzschildde Sitter (SdS) metric. This effective 4D metric is the induced metric on a 4D hypersurface, here representing our universe, which is obtained from a 5D Ricci-flat SdS static metric, after implement a planar coordinate transformation. On this background we found that at the end of inflation, the squared fluctuations of the inflaton field are not exactly scale independent and result sensitive to the mass of the BH.

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Inflaton field governed universe from NKK theory of gravity: stochastic approach

Cited by 10 publications

References 20 publications

Modified Brans–Dicke theory of gravity from five-dimensional vacuum

Modified Brans–Dicke theory of gravity from five-dimensional vacuum

FRW cosmology from five dimensional vacuum Brans–Dicke theory

Stochastic emergence of inflaton fluctuations in a SdS primordial universe with large-scale repulsive gravity from a 5D vacuum

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