76 research outputs found
Wave Mechanics and General Relativity: A Rapprochement
Using exact solutions, we show that it is in principle possible to regard
waves and particles as representations of the same underlying geometry, thereby
resolving the problem of wave-particle duality
The bang of a white hole in the early universe from a 6D vacuum state: Origin of astrophysical spectrum
Using a previously introduced model in which the expansion of the universe is
driven by a single scalar field subject to gravitational attraction induced by
a white hole during the expansion (from a 6D vacuum state), we study the origin
of squared inflaton fluctuations spectrum on astrophysical scales.Comment: Final version to be published in Eur. Phys. J.
Stochastic emergence of inflaton fluctuations in a SdS primordial universe with large-scale repulsive gravity from a 5D vacuum
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 SdS metric. Considering a 5D Ricci-flat SdS
static metric, we implement a planar coordinate transformation, in order to
obtain a 5D cosmological metric, from which the effective 4D SdS metric can be
induced on a 4D hypersurface. We found that at the end of inflation, the
squared fluctuations of the inflaton field are not exactly scale independent
and becomes sensitive with the mass of the BH.Comment: version accepted in European Physical Journal Plu
Wesson's IMT with a Weylian bulk
The foundations of Wesson's induced matter theory are analyzed. It is shown
that the 5D empty bulk must be regarded rather as a Weylian space than as a
Riemannian one.The framework of a Weyl-Dirac version of Wesson's theory is
elaborated and discussed. The bulk possesses in addition to the metric tensor a
Weylian connection vector as well Dirac's gauge function; there are no sources
(mass, current) in the bulk. On the 4D brane one obtains a geometrically based
unified theory of gravitation and electromagnetism with mass, currents and
equations induced by the 5D bulkComment: 29 page
Submanifolds in five-dimensional pseudo-Euclidean spaces and four-dimensional FRW universes
Equations for submanifolds, which correspond to embeddings of the
four-dimensional FRW universes in five-dimensional pseudo-Euclidean spaces, are
presented in convenient form in general case. Several specific examples are
considered.Comment: 7 pages, LaTeX, the mathematical part of this paper is based on the
withdrawn preprint arXiv:1012.0320 [gr-qc
An Embedding for General Relativity and its Implications for New Physics
We show that any solution of the 4D Einstein equations of general relativity
in vacuum with a cosmological constant may be embedded in a solution of the 5D
Ricci-flat equations with an effective 4D cosmological "constant" that is a
specific function of the extra coordinate. For unified theories of the forces
in higher dimensions, this has major physical implications
The Behavior of Kasner Cosmologies with Induced Matter
We extend the induced matter model, previously applied to a variety of
isotropic cases, to a generalization of Bianchi type-I anisotropic cosmologies.
The induced matter model is a 5D Kaluza-Klein approach in which assumptions of
compactness are relaxed for the fifth coordinate, leading to extra geometric
terms. One interpretation of these extra terms is to identify them as an
``induced matter'' contribution to the stress-energy tensor. In similar spirit,
we construct a five dimensional metric in which the spatial slices possess
Bianchi type-I geometry. We find a set of solutions for the five dimensional
Einstein equations, and determine the pressure and density of induced matter.
We comment on the long-term dynamics of the model, showing that the assumption
of positive density leads to the contraction over time of the fifth scale
factor.Comment: 14 page
Gravitational conformal invariance and coupling constants in Kaluza-Klein theory
We introduce a generalized gravitational conformal invariance in the context
of non-compactified 5D Kaluza-Klein theory. It is done by assuming the 4D
metric to be dependent on the extra non-compactified dimension. It is then
shown that the conformal invariance in 5D is broken by taking an absolute
cosmological scale over which the 4D metric is assumed to be dependent
weakly on the 5th dimension. This is equivalent to Deser's model for the
breakdown of the conformal invariance in 4D by taking a constant cosmological
mass term in the theory. We set the scalar field to its
background cosmological value leading to Einstein equation with the
gravitational constant and a small cosmological constant. A dual Einstein
equation is also introduced in which the matter is coupled to the higher
dimensional geometry by the coupling . Relevant interpretations of
the results are also discussed.Comment: 10 pages, LaTeX, some cghanges in the tex
Modern cosmologies from empty Kaluza-Klein solutions in 5D
We show that the empty five-dimensional solutions of
Davidson-Sonnenschtein-Vozmediano, {\em Phys. Rev.} {\bf D32} (1985)1330, in
the "old" Kaluza-Klein gravity, under appropriate interpretation can generate
an ample variety of cosmological models in 4D, which include the
higher-dimensional modifications to general relativity predicted by "modern"
versions of noncompactified 5D gravity as, e.g., induced-matter and braneworld
theories. This is the first time that these solutions are investigated in a
systematic way as embeddings for cosmological models in 4D. They provide a
different formulation, which is complementary to the approaches used in current
versions of 5D relativity.Comment: Accepted for publication in JHE
Inducing the cosmological constant from five-dimensional Weyl space
We investigate the possibility of inducing the cosmological constant from
extra dimensions by embedding our four-dimensional Riemannian space-time into a
five-dimensional Weyl integrable space. Following approach of the induced
matter theory we show that when we go down from five to four dimensions, the
Weyl field may contribute both to the induced energy-tensor as well as to the
cosmological constant, or more generally, it may generate a time-dependent
cosmological parameter. As an application, we construct a simple cosmological
model which has some interesting properties.Comment: 7 page
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