7,523 research outputs found
Quantization and simulation of Born-Infeld non-linear electrodynamics on a lattice
Born-Infeld non-linear electrodynamics arises naturally as a field theory
description of the dynamics of strings and branes. Most analyses of this theory
have been limited to studying it as a classical field theory. We quantize this
theory on a Euclidean 4-dimensional space-time lattice and determine its
properties using Monte-Carlo simulations. The electromagnetic field around a
static point charge is measured using Luscher-Weisz methods to overcome the
sign problem associated with the introduction of this charge. The D field
appears identical to that of Maxwell QED. However, the E field is enhanced by
quantum fluctuations, while still showing the short distance screening observed
in the classical theory. In addition, whereas for the classical theory, the
screening increases without bound as the non-linearity increases, the quantum
theory approaches a limiting conformal field theory.Comment: 24 pages, 10 figures. Latex with postscript figure
Report on the development of the Manned Orbital Research Laboratory /MORL/ system utilization potential. Task area IV - MORL SYSTEM improvement study, book 4
Communications and telemetry subsystem analyses for Manned Orbital Research Laboratory system improvement stud
Misleading signposts along the de Broglie-Bohm road to quantum mechanics
Eighty years after de Broglie's, and a little more than half a century after
Bohm's seminal papers, the de Broglie--Bohm theory (a.k.a. Bohmian mechanics),
which is presumably the simplest theory which explains the orthodox quantum
mechanics formalism, has reached an exemplary state of conceptual clarity and
mathematical integrity. No other theory of quantum mechanics comes even close.
Yet anyone curious enough to walk this road to quantum mechanics is soon being
confused by many misleading signposts that have been put up, and not just by
its detractors, but unfortunately enough also by some of its proponents.
This paper outlines a road map to help navigate ones way.Comment: Dedicated to Jeffrey Bub on occasion of his 65th birthday. Accepted
for publication in Foundations of Physics. A "slip of pen" in the
bibliography has been corrected -- thanks go to Oliver Passon for catching
it
Nonperturbative calculation of Born-Infeld effects on the Schroedinger spectrum of the hydrogen atom
We present the first nonperturbative numerical calculations of the
nonrelativistic hydrogen spectrum as predicted by first-quantized
electrodynamics with nonlinear Maxwell-Born-Infeld field equations. We also
show rigorous upper and lower bounds on the ground state.
When judged against empirical data our results significantly restrict the
range of viable values of the new electromagnetic constant which is introduced
by the Born-Infeld theory.
We assess Born's own proposal for the value of his constant.Comment: 4p., 2 figs, 1 table; submitted for publicatio
Biexcitons in two-dimensional systems with spatially separated electrons and holes
The binding energy and wavefunctions of two-dimensional indirect biexcitons
are studied analytically and numerically. It is proven that stable biexcitons
exist only when the distance between electron and hole layers is smaller than a
certain critical threshold. Numerical results for the biexciton binding
energies are obtained using the stochastic variational method and compared with
the analytical asymptotics. The threshold interlayer separation and its
uncertainty are estimated. The results are compared with those obtained by
other techniques, in particular, the diffusion Monte-Carlo method and the
Born-Oppenheimer approximation.Comment: 11 pages, 7 figure
Measurement of atomic diffraction phases induced by material gratings
Atom-surface interactions can significantly modify the intensity and phase of
atom de Broglie waves diffracted by a silicon nitride grating. This affects the
operation of a material grating as a coherent beam splitter. The phase shift
induced by diffraction is measured by comparing the relative phases of serveral
interfering paths in a Mach-Zehnder Na atom interferometer formed by three
material gratings. The values of the diffraction phases are consistent with a
simple model which includes a van der Waals atom-surface interaction between
the Na atoms and the silicon nitride grating bars.Comment: 4 pages, 5 figures, submitted to PR
Coupled dynamics of atoms and radiation pressure driven interferometers
We consider the motion of the end mirror of a cavity in whose standing wave
mode pattern atoms are trapped. The atoms and the light field strongly couple
to each other because the atoms form a distributed Bragg mirror with a
reflectivity that can be fairly high. We analyze how the dipole potential in
which the atoms move is modified due to this backaction of the atoms. We show
that the position of the atoms can become bistable. These results are of a more
general nature and can be applied to any situation where atoms are trapped in
an optical lattice inside a cavity and where the backaction of the atoms on the
light field cannot be neglected. We analyze the dynamics of the coupled system
in the adiabatic limit where the light field adjusts to the position of the
atoms and the light field instantaneously and where the atoms move much faster
than the mirror. We calculate the side band spectrum of the light transmitted
through the cavity and show that these spectra can be used to detect the
coupled motion of the atoms and the mirror.Comment: 11 pages; 13 figures; two added references and other minor
correction
Polarization and ellipticity of high-order harmonics from aligned molecules generated by linearly polarized intense laser pulses
We present theoretical calculations for polarization and ellipticity of
high-order harmonics from aligned N, CO, and O molecules generated
by linearly polarized lasers. Within the rescattering model, the two
polarization amplitudes of the harmonics are determined by the
photo-recombination amplitudes for photons emitted parallel and perpendicular
to the direction of the {\em same} returning electron wave packet. Our results
show clear species-dependent polarization states, in excellent agreement with
experiments. We further note that the measured polarization ellipse of the
harmonic furnishes the needed parameters for a "complete" experiment in
molecules.Comment: 4 pages, 4 figure
How to Reduce Plagiarism
Academic plagiarism is on the rise at colleges and universities. The advent of the World Wide Web (WWW) enables students to sort through thousands of published documents ready to cut and paste into their own papers. This teaching tip deals with how to reduce plagiarism in higher education
Rotating charged Black Holes in Einstein-Born-Infeld theories and their ADM mass
In this work, the solution of the Einstein equations for a slowly rotating
black hole with Born-Infeld charge is obtained. Geometrical properties and
horizons of this solution are analyzed. The conditions when the ADM mass (as in
the nonlinear static cases) and the ADM angular momentum of the system have
been modified by the non linear electromagnetic field of the black hole, are
considered.Comment: Final version and figures in journal. References and comments adde
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