18,566 research outputs found
Darwin-Lagrangian Analysis for the Interaction of a Point Charge and a Magnet: Considerations Related to the Controversy Regarding the Aharonov-Bohm and Aharonov-Casher Phase Shifts
The classical electromagnetic interaction of a point charge and a magnet is
discussed by first calculating the interaction of point charge with a simple
model magnetic moment and then suggesting a multiparticle limit. The Darwin
Lagrangian is used to analyze the electromagnetic behavior of the model
magnetic moment (composed of two oppositely charged particles of different mass
in an initially circular orbit) interacting with a passing point charge. The
changing mangetic moment is found to put a force back on a passing charge; this
force is of order 1/c^2 and depends upon the magnitude of the magnetic moment.
It is suggested that in the limit of a multiparticle magnetic toroid, the
electric fields of the passing charge are screened out of the body of the
magnet while the magnetic fields penetrate into the magnet. This is consistent
with our understanding of the penetration of electromagnetic velocity fields
into ohmic conductors. Conservation laws are discussed. The work corresponds to
a classical electromagnetic analysis of the interaction which is basic to
understanding the controversy over the Aharonov-Bohm and Aharonov-Casher phase
shifts and represents a refutation of the suggestions of Aharonov, Pearle, and
Vaidman.Comment: 33 page
Derivation of the Blackbody Radiation Spectrum from a Natural Maximum-Entropy Principle Involving Casimir Energies and Zero-Point Radiation
By numerical calculation, the Planck spectrum with zero-point radiation is
shown to satisfy a natural maximum-entropy principle whereas alternative
choices of spectra do not. Specifically, if we consider a set of
conducting-walled boxes, each with a partition placed at a different location
in the box, so that across the collection of boxes the partitions are uniformly
spaced across the volume, then the Planck spectrum correspond to that spectrum
of random radiation (having constant energy kT per normal mode at low
frequencies and zero-point energy (1/2)hw per normal mode at high frequencies)
which gives maximum uniformity across the collection of boxes for the radiation
energy per box. The analysis involves Casimir energies and zero-point radiation
which do not usually appear in thermodynamic analyses. For simplicity, the
analysis is presented for waves in one space dimension.Comment: 11 page
The Paradoxical Forces for the Classical Electromagnetic Lag Associated with the Aharonov-Bohm Phase Shift
The classical electromagnetic lag assocated with the Aharonov-Bohm phase
shift is obtained by using a Darwin-Lagrangian analysis similar to that given
by Coleman and Van Vleck to identify the puzzling forces of the Shockley-James
paradox. The classical forces cause changes in particle velocities and so
produce a relative lag leading to the same phase shift as predicted by Aharonov
and Bohm and observed in experiments. An experiment is proposed to test for
this lag aspect implied by the classical analysis but not present in the
currently-accepted quantum topological description of the phase shift.Comment: 8 pages, 3 figure
Elements of Design for Containers and Solutions in the LinBox Library
We describe in this paper new design techniques used in the \cpp exact linear
algebra library \linbox, intended to make the library safer and easier to use,
while keeping it generic and efficient. First, we review the new simplified
structure for containers, based on our \emph{founding scope allocation} model.
We explain design choices and their impact on coding: unification of our matrix
classes, clearer model for matrices and submatrices, \etc Then we present a
variation of the \emph{strategy} design pattern that is comprised of a
controller--plugin system: the controller (solution) chooses among plug-ins
(algorithms) that always call back the controllers for subtasks. We give
examples using the solution \mul. Finally we present a benchmark architecture
that serves two purposes: Providing the user with easier ways to produce
graphs; Creating a framework for automatically tuning the library and
supporting regression testing.Comment: 8 pages, 4th International Congress on Mathematical Software, Seoul :
Korea, Republic Of (2014
Adaptive optics program update at TMT
The TMT first light AO facility consists of the Narrow Field Infra-Red AO System (NFIRAOS), the associated Laser Guide Star Facility (LGSF) and the AO Executive Software (AOESW). Design, fabrication and prototyping activities of the TMT first light AO systems and their components have significantly ramped up in Canada, China, France, and in the US. NFIRAOS is an order 60 x 60 laser guide star (LGS) multi-conjugate AO (MCAO) system, which provides uniform, diffraction-limited performance in the J, H, and K bands over 34 x 34 arc sec fields with 50 per cent sky coverage at the galactic pole, as required to support the TMT science cases. NFIRAOS includes two deformable mirrors, six laser guide star wavefront sensors, one high order Pyramid WFS for natural guide star AO, and up to three low-order, IR, natural guide star on-instrument wavefront sensors (OIWFS) and four on-detector guide windows (ODGW) within each client instrument. The first light LGSF system includes six sodium lasers to generate the NFIRAOS laser guide stars.
In this paper, we will provide an update on the progress in designing, prototyping, fabricating and modeling the TMT first light AO systems and their AO components over the last two years. TMT is continuing with detailed AO modeling to support the design and development of the first light AO systems and components. Major modeling topics studied during the last two years include further studies in the area of pyramid wavefront sensing, high precision astrometry, PSF reconstruction for LGS MCAO, LGSF wavefront error budget and sophisticated low order mode temporal filtering
The Zero-Point Field and Inertia
A brief overview is presented of the basis of the electromagnetic zero-point
field in quantum physics and its representation in stochastic electrodynamics.
Two approaches have led to the proposal that the inertia of matter may be
explained as an electromagnetic reaction force. The first is based on the
modeling of quarks and electrons as Planck oscillators and the method of
Einstein and Hopf to treat the interaction of the zero-point field with such
oscillators. The second approach is based on analysis of the Poynting vector of
the zero-point field in accelerated reference frames. It is possible to derive
both Newton's equation of motion, F=ma, and its relativistic co-variant form
from Maxwell's equations as applied to the zero-point field of the quantum
vacuum. This appears to account, at least in part, for the inertia of matter.Comment: 8 pages, no fig
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