63 research outputs found
The gravitational phase shift test of general relativity
The aim of this paper is to study the extra phase shift that general
relativity (GR) predicts for a radial light ray propagating in the vicinity of
a static spherical symmetric body. It appears that the gravitational phase
shift test yields a better sensitivity than the gravitational frequency shift
or the excess time delay of the photons. An experiment is proposed for this new
test of GR pertaining exclusively to the wave aspect of light.Comment: 4 pages, 1 figure. The abstract and experiments description are
lengthened ; typos and sign errors correcte
General relativity and quintessence explain the Pioneer anomaly
The anomalous time depending blueshift, the so-called "Pioneer anomaly", that
was detected in the radio-metric data from Pioneer 10/11, Ulysses and Galileo
spacecraft may not result from a real change of velocity. Rather, the Pioneer
anomaly may be understood within the framework of general relativity as a time
depending gravitational frequency shift accounting for the time dependence of
the density of the dark energy when the latter is identified with quintessence.
Thus, instead of being in conflict with Einstein equivalence principle, the
main Pioneer anomaly appears merely as a new validation of general relativity
in the weak field and low velocity limit.Comment: 14 pages, no figur
Temporal variation of Earth-based gravitational constant measurements
As one knows, strong discrepancies are found between the different precise
measurements of the gravitational constant carried out in Earth-based
laboratories. While the precision are increasing in different laboratories and
with various methods, these measurements are even more and more discordant. We
have shown since 2002 that an improved 5D Kaluza-Klein (KK) theory may provide
a satisfactory explanation to these discrepancies by referring to the
geomagnetic field as a possible cause. Here we take advantage of different
precise measurements performed at the same location but at different epoch to
address the temporal variation of the gravitational constant measurements.Comment: 15 pages, 9 figures, 9 table
A scalar field modelling of the rotational curves of spiral galaxies
In a previous work \cite{mbeleka}, we have modelled the rotation curves (RC)
of spiral galaxies by including in the equation of motion dynamical terms from
an external real self-interacting scalar field, , minimally coupled to
gravity and which respects the equivalence principle in the absence of
electromagnetic fields. This model appears to have three free parameters : the
turnover radius, , the maximum rotational velocity, , plus a strictly positive integer, . Here, the coupling of the
-field to other kinds of matter is emphasized at the expense of its
self-interaction. This reformulation presents the very advantageous possibility
that the same potential may be used now for all galaxies. New correlations are
established.Comment: 6 pages, poster presented at the symposium "The Dark Universe :
Matter, Energy, and Gravity", 2 - 5 April 2001, Space Telescope Science
Institute, Baltimore (USA, edited by M. Livio
A solution to the proton and deuteron size puzzle and the anomalous magnetic moment of the muon
We show that a proposal which involves an effective radius derived from an
effective potential that includes a linear extra-potential may solve both the
proton and deuteron size puzzle. Moreover, this solution preserves the e-{\mu}
universality and helps to solve the anomalous magnetic moment of the muon too.
Still, it is consistent with the rms magnetic radius of the proton and
deuteron, the rms charge radius of both the ordinary and muonic C12 as well as
the kaonic and pionic X-rays spectroscopy.Comment: 12 pages, 2 figure
Stream of dark matter as a possible cause of the opera clocks' synchronization signals delay
A stream of weakly interacting massive particles (WIMPs) gravitationally
scattered outwards within the Earth yields a delay, \delta t \simeq 60 ns, in
good agreement with the results of the OPERA experiment. Conversely, the OPERA
experiment may be seen as the unveiling of the first hint of a dark matter
particle probed with the photons of the GPS communication signals and using the
neutrino beam of the CNGS as a velocity standard. Our analysis yields the true
neutrino velocity, V_{\nu}, less than the speed of light in vacuum, one finds
(V_{\nu} - c)/c = - (1.8 \pm 0.4) x 10^{-9}. A new experimental test still
predicting \delta t \sim 60 ns instead of \delta t \sim 600 ns is suggested,
based on the use of the long baseline of the order 7 800 km between either the
Fermilab neutrino production site and the OPERA detector or the CERN neutrino
production site and the MINOS detector.Comment: 5 pages, no figur
Comment on "Constraining a possible dependence of Newton's constant on the Earth's magnetic field"
Recently A. Rathke has argued that the KK model explanation of the
discrepant measurements of Newton's constant is already ruled out due to
E\"otv\"os experiments by several orders of magnitude. The structure of the
action of the KK model is even qualified as inconsistent in the sense
that it would yield a negative energy of the electromagnetic field. Here, I
refute both claims and emphasize the possibility still open to reconcile the
experimental bounds on the test of the weak equivalence principle (WEP) with
scalar-tensor theories in general by some compensating mechanism.Comment: Latex2e, 10 pages, no figur
Special relativity is consistent with the opera measurements of the neutrino "velocity"
We show that special relativity (SR) may be consistent with the OPERA
measurements of the neutrino velocity provided the latter is corrected for the
second order term in V^2/c^2 implied by the velocity, V, of the alpha particles
from radioactive rocks of the experiment area, when properly accounted for in
the SR velocity addition law. An upper bound has been set on the velocity of
the OPERA neutrinos by using the deformed dispersion relation suggested by the
result of the experiment OPERA itself.Comment: 5 pages, no figur
Motion of a test body in the presence of an external scalar field which respects the weak equivalence principle
It is shown that the main contribution to the rotational curve of a spiral
galaxy may be due essentially to the interaction, in the general relativistic
spacetime, of the galactic matter with a very light long range scalar field
which respects the weak equivalence principle. The comparison of the
theoretical results with 23 spiral galaxy rotation curves shows a good
agreement between our proposal and observations.Comment: 13 pages, proceedings of the international conference "Conceptions of
space in physics", 29 September - 3 October 1997, Les Houches (France),
edited by Z. A. Golda, M. Heller and M. Lachieze-Re
Quantum Fluctuations Contribution to the Random Walk of a Single Molecule and New Estimate of the Planck Constant
It is shown, by considering the case of the harmonic oscillator, that quantum
fluctuations may be the most significant contribution to the random walk of a
single molecule. From this point, the controversy on the existence of a
standard quantum limit (SQL) is addressed and settled on the experimental
ground. Comparisons to the experimental data yet avalaible in the literature
provide a new estimate of the reduced Planck constant yielding \hbar = (1.1 \pm
0.2) ~ 10^{-34} J.s.Comment: 5 pages, 1 figur
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