Non-compact Kaluza-Klein Theory Research Articles

Extended anisotropic models in noncompact Kaluza–Klein theory

In this paper, new exact solutions for locally rotational symmetric (LRS) space-times are obtained within the modified Brans–Dicke theory (MBDT) (Rasouli et al 2014 Class. Quantum Grav. 31 115002). Specifically, extended five-dimensional (5D) versions of Kantowski–Sachs, LRS Bianchi type I and Bianchi type III are investigated in the context of the standard Brans–Dicke theory. We subsequently extract their corresponding dynamics on a 4D hypersurface. Our results are discussed regarding others obtained in the standard Brans–Dicke theory, induced-matter theory and general relativity. Moreover, we comment on the evolution of the scale factor of the extra spatial dimension, which is of interest in Kaluza–Klein frameworks.

Gravitational waves during inflation from a 5D large-scale repulsive gravity model

We investigate, in the transverse traceless (TT) gauge, the generation of the relic background of gravitational waves, generated during the early inflationary stage, on the framework of a large-scale repulsive gravity model. We calculate the spectrum of the tensor metric fluctuations of an effective 4D Schwarzschild–de Sitter metric on cosmological scales. This metric is obtained after implementing a planar coordinate transformation on a 5D Ricci-flat metric solution, in the context of a non-compact Kaluza–Klein theory of gravity. We found that the spectrum is nearly scale invariant under certain conditions. One interesting aspect of this model is that it is possible to derive the dynamical field equations for the tensor metric fluctuations, valid not just at cosmological scales, but also at astrophysical scales, from the same theoretical model. The astrophysical and cosmological scales are determined by the gravity–antigravity radius, which is a natural length scale of the model, that indicates when gravity becomes repulsive in nature.

Inflaton and metric fluctuations in the early universe from a 5D vacuum state

In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza–Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that 〈δρ〉/ρb depends on the coupling of Φ with δφ and the spectral index of its spectrum is 0.9483<n1<1.

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

We study a nonperturbative single field (inflaton) governed cosmological model from a 5D Noncompact Kaluza-Klein (NKK) theory of gravity. The inflaton field fluctuations are estimated for different epochs of the evolution of the universe. We conclude that the inflaton field has been sliding down its (quadratic) potential hill along all the evolution of the universe and a mass of the order of the Hubble parameter. In the model here developed the only free parameter is the Hubble parameter, which could be reconstructed in future from Super Nova Acceleration Probe (SNAP) data.

Extra force and extra mass from non-compact Kaluza-Klein theory in a cosmological model

Using the Hamilton-Jacobi formalism, we study extra force and extra mass in a recently introduced non-compact Kaluza-Klein cosmological model. We examine the inertial 4D mass m0 of the inflaton field on a 4D FRW bulk in two examples. We find that m0 has a geometrical origin and antigravitational effects on a non-inertial 4D bulk should be a consequence of the motion of the fifth coordinate with respect to the 4D bulk.

Induced current and redefinition of electric and magnetic fields from non-compact Kaluza–Klein theory: An experimental signature of the fifth dimension

The field equations for gravitation and electromagnetism with sources in four dimensions can be interpreted as arising from the vacuum Einstein equations in five dimensions. Gauge invariance of the electromagnetic potentials leads to a “generalized” electromagnetic field tensor. We use the action principle to derive the equations of motion for free electromagnetic fields in flat spacetime, and isolate an effective electromagnetic current with a source that is purely higher-dimensional in origin. This current provides, at least in principle, a means of detecting extra dimensions experimentally.

De Sitter inflationary expansion from a noncompact KK theory: a nonperturbative quantum (scalar) field formalism

We develop a nonperturbative quantum scalar field formalism from a noncompact Kaluza–Klein (KK) theory using the induced-matter theory of gravity during inflation. We study the particular case of a de Sitter expansion for the universe.

The evolution of the universe from non-compact Kaluza-Klein theory

We develope a 5D mechanism inspired in the Campbell's theorem, to explain the (neutral scalar field governed) evolution of the universe from a initially inflationary expansion that has a change of phase towards a decelerated expansion and thereinafter evolves towards the present day observed celerated (quintessential) expansion.

Origin of FRW cosmology in slow-roll inflationfrom non-compact Kaluza-Klein theory

Using a recently introduced formalism we discuss slow-roll inflaton from Kaluza-Klein theory without the cylinder condition. In particular, some examples corresponding to polynomic and hyperbolic $\phi$-potentials are studied. We find that the evolution of the fifth coordinate should be determinant for both, the evolution of the early inflationary universe and the quantum fluctuations.

Noncompact Kaluza–Klein theory and inflationary cosmology: a complete formalism

A formalization of the recently introduced formalism for inflation is developed from a noncompact Kaluza–Klein theory. In particular, the case for a single scalar field inflationary model is studied. We obtain that the scalar potential, which assume different representations in different frames, has a geometrical origin.

Single field inflationary models with non-compact Kaluza–Klein theory

We discuss a semiclassical treatment to inflationary models from Kaluza–Klein theory without the cylinder condition. We conclude that the evolution of the early universe could be described by a geodesic trajectory of a cosmological 5D metric here proposed, so that the effective 4D FRW background metric should be a hypersurface on a constant fifth dimension.

Transport properties of an electron gas in a magnetic field. II. The oscillatory transport coefficients: Lowell Dworin, Columbia University, New York, New York

In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza–Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that 〈δρ〉/ρb depends on the coupling of Φ with δφ and the spectral index of its spectrum is 0.9483<n1<1.