3,189 research outputs found

### On The 5D Extra-Force according to Basini-Capozziello-Leon Formalism and five important features: Kar-Sinha Gravitational Bending of Light, Chung-Freese Superluminal Behaviour, Maartens-Clarkson Black Strings, Experimental measures of Extra Dimensions on board International Space Station(ISS) and the existence of the Particle $Z$ due to a Higher Dimensional spacetime

We use the Conformal Metric as described in Kar-Sinha work on Gravitational
Bending of Light in a 5D Spacetime to recompute the equations of the 5D Force
in Basini-Capozziello-Leon Formalism and we arrive at a result that possesses
some advantages. The equations of the Extra Force as proposed by Leon are now
more elegant in Conformal Formalism and many algebraic terms can be simplified
or even suppressed. Also we recompute the Kar-Sinha Gravitational Bending of
Light affected by the presence of the Extra Dimension and analyze the
Superluminal Chung-Freese Features of this Formalism describing the advantages
of the Chung-Freese BraneWorld when compared to other Superluminal spacetime
metrics(eg:Warp Drive) and we describe why the Extra Dimension is invisible and
how the Extra Dimension could be made visible at least in theory.We also
examine the Maartens-Clarkson Black Holes in 5D(Black Strings) coupled to
massive Kaluza-Klein graviton modes predicted by Extra Dimensions theories and
we study experimental detection of Extra Dimensions on-board LIGO and LISA
Space Telescopes.We also propose the use of International Space Station(ISS) to
measure the additional terms(resulting from the presence of Extra Dimensions)
in the Kar-Sinha Gravitational Bending of Light in Outer Space to verify if we
really lives in a Higher Dimensional Spacetime.Also we demonstrate that
Particle $Z$ can only exists if the 5D spacetime exists.Comment: Withdrawn: author no longer wishes to post work on arXi

### Solar Radiation Pressure and Deviations from Keplerian Orbits

Newtonian gravity and general relativity give exactly the same expression for
the period of an object in circular orbit around a static central mass.
However, when the effects of the curvature of spacetime and solar radiation
pressure are considered simultaneously for a solar sail propelled satellite,
there is a deviation from Kepler's third law. It is shown that solar radiation
pressure affects the period of this satellite in two ways: by effectively
decreasing the solar mass, thereby increasing the period, and by enhancing the
effects of other phenomena, rendering some of them detectable. In particular,
we consider deviations from Keplerian orbits due to spacetime curvature, frame
dragging from the rotation of the sun, the oblateness of the sun, a possible
net electric charge of the sun, and a very small positive cosmological
constant.Comment: 4 pages, minor typo corrected, additional comment

### Quantum fluctuations for drag free geodesic motion

The drag free technique is used to force a proof mass to follow a geodesic
motion. The mass is protected from perturbations by a cage, and the motion of
the latter is actively controlled to follow the motion of the proof mass. We
present a theoretical analysis of the effects of quantum fluctuations for this
technique. We show that a perfect drag free operation is in principle possible
at the quantum level, in spite of the back action exerted on the mass by the
position sensor.Comment: 4 pages, 1 figure, RevTeX, minor change

### Trapping of strangelets in the geomagnetic field

Strangelets coming from the interstellar medium (ISM) are an interesting
target to experiments searching for evidence of this hypothetic state of
hadronic matter. We entertain the possibility of a {\it trapped} strangelet
population, quite analogous to ordinary nuclei and electron belts. For a
population of strangelets to be trapped by the geomagnetic field, these
incoming particles would have to fulfill certain conditions, namely having
magnetic rigidities above the geomagnetic cutoff and below a certain threshold
for adiabatic motion to hold. We show in this work that, for fully ionized
strangelets, there is a narrow window for stable trapping. An estimate of the
stationary population is presented and the dominant loss mechanisms discussed.
It is shown that the population would be substantially enhanced with respect to
the ISM flux (up to two orders of magnitude) due to quasi-stable trapping.Comment: 10 pp., 5 figure

### On the possibility of measuring relativistic gravitational effects with a LAGEOS-LAGEOS II-OPTIS-mission

In this paper we wish to preliminary investigate if it would be possible to
use the orbital data from the proposed OPTIS mission together with those from
the existing geodetic passive SLR LAGEOS and LAGEOS II satellites in order to
perform precise measurements of some general relativistic
gravitoelectromagnetic effects, with particular emphasis on the Lense-Thirring
effect.Comment: Abridged version. 16 pages, no figures, 1 table. First results from
the GGM01C Earth gravity model. GRACE data include

### Detectability of Strange Matter in Heavy Ion Experiments

We discuss the properties of two distinct forms of hypothetical strange
matter, small lumps of strange quark matter (strangelets) and of hyperon matter
(metastable exotic multihypernuclear objects: MEMOs), with special emphasis on
their relevance for present and future heavy ion experiments. The masses of
small strangelets up to A = 40 are calculated using the MIT bag model with
shell mode filling for various bag parameters. The strangelets are checked for
possible strong and weak hadronic decays, also taking into account multiple
hadron decays. It is found that strangelets which are stable against strong
decay are most likely highly negative charged, contrary to previous findings.
Strangelets can be stable against weak hadronic decay but their masses and
charges are still rather high. This has serious impact on the present high
sensitivity searches in heavy ion experiments at the AGS and CERN facilities.
On the other hand, highly charged MEMOs are predicted on the basis of an
extended relativistic mean-field model. Those objects could be detected in
future experiments searching for short-lived, rare composites. It is
demonstrated that future experiments can be sensitive to a much wider variety
of strangelets.Comment: 26 pages, 5 figures, uses RevTeX and epsf.st

### A Mission to Explore the Pioneer Anomaly

The Pioneer 10 and 11 spacecraft yielded the most precise navigation in deep
space to date. These spacecraft had exceptional acceleration sensitivity.
However, analysis of their radio-metric tracking data has consistently
indicated that at heliocentric distances of $\sim 20-70$ astronomical units,
the orbit determinations indicated the presence of a small, anomalous, Doppler
frequency drift. The drift is a blue-shift, uniformly changing with a rate of
$\sim(5.99 \pm 0.01)\times 10^{-9}$ Hz/s, which can be interpreted as a
constant sunward acceleration of each particular spacecraft of $a_P = (8.74 \pm
1.33)\times 10^{-10} {\rm m/s^2}$. This signal has become known as the Pioneer
anomaly. The inability to explain the anomalous behavior of the Pioneers with
conventional physics has contributed to growing discussion about its origin.
There is now an increasing number of proposals that attempt to explain the
anomaly outside conventional physics. This progress emphasizes the need for a
new experiment to explore the detected signal. Furthermore, the recent
extensive efforts led to the conclusion that only a dedicated experiment could
ultimately determine the nature of the found signal. We discuss the Pioneer
anomaly and present the next steps towards an understanding of its origin. We
specifically focus on the development of a mission to explore the Pioneer
Anomaly in a dedicated experiment conducted in deep space.Comment: 8 pages, 9 figures; invited talk given at the 2005 ESLAB Symposium
"Trends in Space Science and Cosmic Vision 2020", 19-21 April 2005, ESTEC,
Noordwijk, The Netherland

### Fundamental Physics with the Laser Astrometric Test Of Relativity

The Laser Astrometric Test Of Relativity (LATOR) is a joint European-U.S.
Michelson-Morley-type experiment designed to test the pure tensor metric nature
of gravitation - a fundamental postulate of Einstein's theory of general
relativity. By using a combination of independent time-series of highly
accurate gravitational deflection of light in the immediate proximity to the
Sun, along with measurements of the Shapiro time delay on interplanetary scales
(to a precision respectively better than 0.1 picoradians and 1 cm), LATOR will
significantly improve our knowledge of relativistic gravity. The primary
mission objective is to i) measure the key post-Newtonian Eddington parameter
\gamma with accuracy of a part in 10^9. (1-\gamma) is a direct measure for
presence of a new interaction in gravitational theory, and, in its search,
LATOR goes a factor 30,000 beyond the present best result, Cassini's 2003 test.
The mission will also provide: ii) first measurement of gravity's non-linear
effects on light to ~0.01% accuracy; including both the Eddington \beta
parameter and also the spatial metric's 2nd order potential contribution (never
measured before); iii) direct measurement of the solar quadrupole moment J2
(currently unavailable) to accuracy of a part in 200 of its expected size; iv)
direct measurement of the "frame-dragging" effect on light by the Sun's
gravitomagnetic field, to 1% accuracy. LATOR's primary measurement pushes to
unprecedented accuracy the search for cosmologically relevant scalar-tensor
theories of gravity by looking for a remnant scalar field in today's solar
system. We discuss the mission design of this proposed experiment.Comment: 8 pages, 9 figures; invited talk given at the 2005 ESLAB Symposium
"Trends in Space Science and Cosmic Vision 2020," 19-21 April 2005, ESTEC,
Noodrwijk, The Netherland

### Analytic approximations, perturbation methods, and their applications

The paper summarizes the parallel session B3 {\em Analytic approximations,
perturbation methods, and their applications} of the GR18 conference. The talks
in the session reported notably recent advances in black hole perturbations and
post-Newtonian approximations as applied to sources of gravitational waves.Comment: Summary of the B3 parallel session of the GR18 conferenc

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