5,680 research outputs found
Discrete Symmetries of Off-Shell Electromagnetism
We discuss the discrete symmetries of the Stueckelberg-Schrodinger
relativistic quantum theory and its associated 5D local gauge theory, a
dynamical description of particle/antiparticle interactions, with monotonically
increasing Poincare-invariant parameter. In this framework, worldlines are
traced out through the parameterized evolution of spacetime events, advancing
or retreating with respect to the laboratory clock, with negative energy
trajectories appearing as antiparticles when the observer describes the
evolution using the laboratory clock. The associated gauge theory describes
local interactions between events (correlated by the invariant parameter)
mediated by five off-shell gauge fields. These gauge fields are shown to
transform tensorially under under space and time reflections, unlike the
standard Maxwell fields, and the interacting quantum theory therefore remains
manifestly Lorentz covariant. Charge conjugation symmetry in the quantum theory
is achieved by simultaneous reflection of the sense of evolution and the fifth
scalar field. Applying this procedure to the classical gauge theory leads to a
purely classical manifestation of charge conjugation, placing the CPT
symmetries on the same footing in the classical and quantum domains. In the
resulting picture, interactions do not distinguish between particle and
antiparticle trajectories -- charge conjugation merely describes the
interpretation of observed negative energy trajectories according to the
laboratory clock.Comment: 26 page
Phase analysis of the cosmic microwave background from an incomplete sky coverage
Phases of the spherical harmonic analysis of full-sky cosmic microwave
background (CMB) temperature data contain useful information complementary to
the ubiquitous angular power spectrum. In this letter we present a new method
of phase analysis on incomplete sky maps. It is based on Fourier phases of
equal-latitude pixel rings of the map, which are related to the mean angle of
the trigonometric moments from the full-sky phases. They have an advantage for
probing regions of interest without tapping polluted Galactic plane area, and
can localize non-Gaussian features and departure from statistical isotropy in
the CMB.Comment: 5 pages, 3 figures submitted to MNRAS Letters, replaced with minor
change
Property Surrendered by Surviving Spouse Flunks the Passing Requirement: The Tenth Circuit Denies the Marital Deduction in Schroeder v. United States
Telerobotic controller development
To meet NASA's space station's needs and growth, a modular and generic approach to robotic control which provides near-term implementation with low development cost and capability for growth into more autonomous systems was developed. The method uses a vision based robotic controller and compliant hand integrated with the Remote Manipulator System arm on the Orbiter. A description of the hardware and its system integration is presented
Task 6 storable propellant module environmental control technology Summary report
Thermal control concepts for space storable fluorine hydrazine propulsion modul
Methodology for urban rail and construction technology research and development planning
A series of transit system visits, organized by the American Public Transit Association (APTA), was conducted in which the system operators identified the most pressing development needs. These varied by property and were reformulated into a series of potential projects. To assist in the evaluation, a data base useful for estimating the present capital and operating costs of various transit system elements was generated from published data. An evaluation model was developed which considered the rate of deployment of the research and development project, potential benefits, development time and cost. An outline of an evaluation methodology that considered benefits other than capital and operating cost savings was also presented. During the course of the study, five candidate projects were selected for detailed investigation; (1) air comfort systems; (2) solid state auxiliary power conditioners; (3) door systems; (4) escalators; and (5) fare collection systems. Application of the evaluation model to these five examples showed the usefulness of modeling deployment rates and indicated a need to increase the scope of the model to quantitatively consider reliability impacts
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