1,062 research outputs found
Five dimensional relativity and two times
It is possible that null paths in 5D appear as the timelike paths of massive
particles in 4D, where there is an oscillation in the fifth dimension around
the hypersurface we call spacetime. A particle in 5D may be regarded as
multiply imaged in 4D, and the 4D weak equivalence principle may be regarded as
a symmetry of the 5D metric.Comment: 15 pages, in press in Phys. Lett.
Inflation from the bang of a white hole induced from a 6D vacuum state
Using ideas of STM theory, but starting from a 6D vacuum state, we propose an
inflationary model where the universe emerges from the blast of a white hole.
Under this approach, the expansion is affected by a geometrical deformation
induced by the gravitational attraction of the hole, which should be
responsible for the k_{R}-non invariant spectrum of galaxies (and likewise of
the matter density) today observed.Comment: 9 pages, 1 figure Accepted for publication in Physics Letters
Inflationary cosmology from STM theory of gravity
I study the power-law and de Sitter expansions for the universe during
inflation from the STM theory of gravity. In a de Sitter expansion the
additional dimension is related to the cosmological constant. I find from
experimental data that the mass of the inflaton field is . In
power-law expansion, the fifth coordinate appears to be a dimensionless
constant. The interesting here is that the -value depends on the initial
conditions. I find the 5D line element for this inflationary expansion, which
is a function of the classical component of the inflaton.Comment: final versio
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.Comment: 6 pages; to appear in Physics Letters
Quantum origin of pre-big bang collapse from Induced Matter theory of gravity
We revisit a collapsing pre-big-bang model of the universe to study with
detail the non-perturbative quantum dynamics of the dispersal scalar field
whose dynamics becomes from the dynamical foliation of test massless scalar
field on a 5D Riemann-flat metric, such that the extra space-like
coordinate is noncompact. The important result here obtained is that the
evolution of the system, which is described thorough the equation of state has
the unique origin in the quantum contributions of the effective 4D scalar
field.Comment: final version to be published in Physics Letters B. arXiv admin note:
substantial text overlap with arXiv:1107.210
Time-Dependent Solution for a Star Immersed in a Background Radiation
We study a time-dependent and spherically-symmetric solution with a star-like
source. We show that this solution can be interpreted as an exterior solution
of a contracting star which has a decreasing temperature and is immersed in a
homogenous and isotropic background radiation. Distribution of the temperature
in the fields and close-to Schwarzschild approximation of the solution are
studied. By identifying the radiation with the cosmic background one, we find
that the close-to-Schwarzschild approximate solution is valid in a wide range
in our solar system. Possible experimental tests of the solution are discussed
briefly.Comment: Latex, 7 pages, no figures, to appear in J. Math. Phys.(2002
Cosmological expansion governed by a scalar field from a 5D vacuum
We consider a single field governed expansion of the universe from a five
dimensional (5D) vacuum state. Under an appropiate change of variables the
universe can be viewed in a effective manner as expanding in 4D with an
effective equation of state which describes different epochs of its evolution.
In the example here worked the universe fistly describes an inflationary phase,
followed by a decelerated expansion. Thereafter, the universe is accelerated
and describes a quintessential expansion to finally, in the future, be vacuum
dominated.Comment: version accepted in Phys. Lett.
Gravitational waves during inflation in presence of a decaying cosmological parameter from a 5D vacuum theory of gravity
We study gravitational waves generated during the inflationary epoch in
presence of a decaying cosmological parameter on a 5D geometrical background
which is Riemann flat. Two examples are considered, one with a constant
cosmological parameter and the second with a decreasing one.Comment: accepted in Phys. Lett.
Scalar Metric fluctuations in space time matter inflation
Using the Ponce de Leon background metric, which describes a 5D universe in
an apparent vacuum: , we study the effective 4D evolution of
both, the inflaton and gauge-invariant scalar metric fluctuations, in the
recently introduced model of space time matter inflation.Comment: (improved version) Accepted in Physics Letters
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.
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