6,202 research outputs found
On the Relativistic Formulation of Matter
A critical analysis of the relativistic formulation of matter reveals some
surprising inconsistencies and paradoxes. Corrections are discovered which lead
to the long-sought-after equality of the gravitational and inertial masses,
which are otherwise different in general relativity.
Realizing the potentially great impact of the discovered corrections, an
overview of the situation is provided resulting from the newly discovered
crisis, amid the evidences defending the theory.Comment: In press with Astrophys. Space Sci. (The final publication can be
seen at springerlink.com
THERMODYNAMIC PROPERTIES TO 6000 DEG K FOR 210 SUBSTANCES INVOLVING THE FIRST 18 ELEMENTS
Thermodynamic properties to 6000-deg kelvin for substances involving first 18 elements in their natural stat
Noncommutative Einstein-Maxwell pp-waves
The field equations coupling a Seiberg-Witten electromagnetic field to
noncommutative gravity, as described by a formal power series in the
noncommutativity parameters , is investigated. A large
family of solutions, up to order one in , describing
Einstein-Maxwell null pp-waves is obtained. The order-one contributions can be
viewed as providing noncommutative corrections to pp-waves. In our solutions,
noncommutativity enters the spacetime metric through a conformal factor and is
responsible for dilating/contracting the separation between points in the same
null surface. The noncommutative corrections to the electromagnetic waves,
while preserving the wave null character, include constant polarization, higher
harmonic generation and inhomogeneous susceptibility. As compared to pure
noncommutative gravity, the novelty is that nonzero corrections to the metric
already occur at order one in .Comment: 19 revtex pages. One refrence suppressed, two references added. Minor
wording changes in the abstract, introduction and conclusio
Shuttle on-orbit contamination and environmental effects
Ensuring the compatibility of the space shuttle system with payloads and payload measurements is discussed. An extensive set of quantitative requirements and goals was developed and implemented by the space shuttle program management. The performance of the Shuttle system as measured by these requirements and goals was assessed partly through the use of the induced environment contamination monitor on Shuttle flights 2, 3, and 4. Contamination levels are low and generally within the requirements and goals established. Additional data from near-term payloads and already planned contamination measurements will complete the environment definition and allow for the development of contamination avoidance procedures as necessary for any payload
Killing vectors and anisotropy
We consider an action that can generate fluids with three unequal stresses
for metrics with a spacelike Killing vector. The parameters in the action are
directly related to the stress anisotropies. The field equations following from
the action are applied to an anisotropic cosmological expansion and an
extension of the Gott-Hiscock cosmic string
Scalar Fields Nonminimally Coupled to pp Waves
Here, we report pp waves configurations of three-dimensional gravity for
which a scalar field nonminimally coupled to them acts as a source. In absence
of self-interaction the solutions are gravitational plane waves with a profile
fixed in terms of the scalar wave. In the self-interacting case, only power-law
potentials parameterized by the nonminimal coupling constant are allowed by the
field equations. In contrast with the free case the self-interacting scalar
field does not behave like a wave since it depends only on the wave-front
coordinate. We address the same problem when gravitation is governed by
topologically massive gravity and the source is a free scalar field. From the
pp waves derived in this case, we obtain at the zero topological mass limit,
new pp wave solutions of conformal gravity for any arbitrary value of the
nonminimal coupling parameter. Finally, we extend these solutions to the
self-interacting case of conformal gravity.Comment: 14 pages, RevTeX. Minor changes. To appear in Phys. Rev.
Relativistic stellar oscillations treated as an initial value problem
The linearized Einstein equations for a static, spherically symmetric fluid ball and its empty surroundings are considered. It is shown that, given initial data obeying the constraints, there exists a unique solution, which describes the motion of the perturbed fluid and the gravitational waves propagating inside and outside the fluid ball. The physical junction conditions for the boundary of the ball suffice to determine the evolution inside and outside of the ball in terms of initial values. The equation of state is assumed smooth and such that the density and the speed of sound remain positive for vanishing pressure
Prediction of unsteady aerodynamic loadings caused by leading edge and trailing edge control surface motions in subsonic compressible flow: Analysis and results
A theoretical analysis and computer program was developed for the prediction of unsteady lifting surface loadings caused by motions of leading edge and trailing edge control surfaces having sealed gaps. The final form of the downwash integral equation was formulated by isolating the singularities from the nonsingular terms and using a preferred solution process to remove and evaluate the downwash discontinuities in a systematic manner. Comparisons of theoretical and experimental pressure data are made for several control surface configurations. The comparisons indicate that reasonably accurate theoretical pressure distributions and generalized forces may be obtained for a wide variety of control surface configurations. Spanwise symmetry or antisymmetry of motion, and up to six control surfaces on each half span can be accommodated
Fermat Potentials for Non-Perturbative Gravitational Lensing
The images of many distant galaxies are displaced, distorted and often
multiplied by the presence of foreground massive galaxies near the line of
sight; the foreground galaxies act as gravitational lenses. Commonly, the lens
equation, which relates the placement and distortion of the images to the real
source position in the thin-lens scenario, is obtained by extremizing the time
of arrival among all the null paths from the source to the observer (Fermat's
principle). We show that the construction of envelopes of certain families of
null surfaces consitutes an alternative variational principle or version of
Fermat's principle that leads naturally to a lens equation in a generic
spacetime with any given metric. We illustrate the construction by deriving the
lens equation for static asymptotically flat thin lens spacetimes. As an
application of the approach, we find the bending angle for moving thin lenses
in terms of the bending angle for the same deflector at rest. Finally we apply
this construction to cosmological spacetimes (FRW) by using the fact they are
all conformally related to Minkowski space.Comment: accepted for publication in Phys. Rev.
Spin Hall effect of Photons in a Static Gravitational Field
Starting from a Hamiltonian description of the photon within the set of
Bargmann-Wigner equations we derive new semiclassical equations of motion for
the photon propagating in static gravitational field. These equations which are
obtained in the representation diagonalizing the Hamiltonian at the order
, present the first order corrections to the geometrical optics. The
photon Hamiltonian shows a new kind of helicity-magnetotorsion coupling.
However, even for a torsionless space-time, photons do not follow the usual
null geodesic as a consequence of an anomalous velocity term. This term is
responsible for the gravitational birefringence phenomenon: photons with
distinct helicity follow different geodesics in a static gravitational field.Comment: 6 page
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