3,491 research outputs found
Dynamical Realization of Macroscopic Superposition States of Cold Bosons in a Tilted Double Well
We present exact expressions for the quantum sloshing of Bose-Einstein
condensates in a tilted two-well potential. Tunneling is suppressed by a small
potential difference between wells, or tilt. However, tunneling resonances
occur for critical values of the tilt when the barrier is high. At resonance,
tunneling times on the order of 10-100 ms are possible. Furthermore, such
tilted resonances lead to a dynamical scheme for creating few-body NOON-like
macroscopic superposition states which are protected by the many body
wavefunction against potential fluctuations.Comment: 6 pages, 5 figures, final version, only minor changes from previous
arXiv versio
The Deep SWIRE Field III. WIYN Spectroscopy
We present the results of spectroscopy using HYDRA on the WIYN 3.5m telescope
of objects in the deep SWIRE radio field. The goal of the project was to
determine spectroscopic redshifts for as many of the brighter objects in the
field as possible, especially those detected in the radio and at 24 microns.
These redshifts are primarily being used in studies of galaxy evolution and the
connection of that evolution to AGN and star-formation. Redshifts measured for
365 individual objects are reported. The redshifts range from 0.03 to 2.5,
mostly with z < 0.9. The sources were selected to be within the WIYN HYDRA
field of approximately 30' in radius from the center of the SWIRE deep field,
10h46m00s, 59d 01'00" (J2000). Optical sources for spectroscopic observation
were selected from a r-band image of the field. A priority list of
spectroscopic targets was established in the following order: 20cm detections,
24 micron detections, galaxies with r < 20 and the balance made up of fainter
galaxies in the field. We provide a table listing the galaxy positions,
measured redshift and error, and note any emission lines that were visible in
the spectrum. In practice almost all the galaxies with r < 19 were observed
including all of the radio sources and most of the 24 microns sources with r <
20 and a sample of radio sources which had fainter optical counterparts on the
r-band image.Comment: 6 pages, 3 tables, 2 figures, full electronic tables at
http://www.aoc.nrao.edu/~fowen/papers/SWIRE/WIYNpaper3/, accepted ApJ Suppl
Serie
A contemporary analysis of the growth, effects, and adjustments to automation
The objective of this thesis is to compile and analyze information on automation, beginning with its background and origin and continuing through various contemporary issues, directly or indirectly related to its development; namely, the need for automation in advancing our present-day society, socially and economically; the present-day uses and future expectations; factors standing in the way or automatic development; effects, both good and bad, attributed to automation by management, labor, and business; beliefs of management, labor and business as to the methods of adjusting these effects for the benefit of all mankind; and the question concerning automation\u27s being the primary cause of unemployment reported in many communities today
The Mass Assembly of Fossil Groups of Galaxies in the Millennium Simulation
The evolution of present-day fossil galaxy groups is studied in the
Millennium Simulation. Using the corresponding Millennium gas simulation and
semi-analytic galaxy catalogues, we select fossil groups at redshift zero
according to the conventional observational criteria, and trace the haloes
corresponding to these groups backwards in time, extracting the associated dark
matter, gas and galaxy properties. The space density of the fossils from this
study is remarkably close to the observed estimates and various possibilities
for the remaining discrepancy are discussed. The fraction of X-ray bright
systems which are fossils appears to be in reasonable agreement with
observation, and the simulations predict that fossil systems will be found in
significant numbers (3-4% of the population) even in quite rich clusters. We
find that fossils assemble a higher fraction of their mass at high redshift,
compared to non-fossil groups, with the ratio of the currently assembled halo
mass to final mass, at any epoch, being about 10 to 20% higher for fossils.
This supports the paradigm whereby fossils represent undisturbed, early-forming
systems in which large galaxies have merged to form a single dominant
elliptical.Comment: 11 pages, 8 figures, submitted to MNRA
Iatrogenic acute angle closure glaucoma masked by general anaesthesia and intensive care.
Acute angle closure glaucoma is a medical emergency which can result in blindness. As it is very painful patients are usually referred rapidly to an ophthalmologist. If it occurs following general anaesthesia however, the diagnosis may not be considered and symptoms such as pain and vomiting wrongly attributed. Delayed diagnosis puts the patient at risk both from the ocular complications of acute angle closure glaucoma, and also from inappropriate investigation and intervention. We report an illustrative case where bilateral acute angle closure glaucoma followed a general anaesthetic. The correct diagnosis was delayed for 11 days
Mesonic Form Factors
We have started a program to compute the electromagnetic form factors of
mesons. We discuss the techniques used to compute the pion form factor and
present preliminary results computed with domain wall valence fermions on MILC
asqtad lattices, as well as Wilson fermions on quenched lattices. These methods
can easily be extended to rho-to-gamma-pi transition form factors.Comment: 7 pages, 6 figures, Workshop on Lattice Hadron Physics 2003 (LHP2003
Nucleon electroweak form factors: Analysis of their spectral functions
We investigate the imaginary parts of the nucleon electromagnetic and axial
form factors close to threshold in the framework of heavy baryon chiral
perturbation theory. For the isovector electromagnetic form factors, we recover
the well known strong enhancement near threshold. For the isoscalar ones, we
show that there is no visible enhancement due to the three--pion continuum.
This justifies the use of vector meson poles only in dispersion--theoretical
calculations. We also calculate the imaginary part of the nucleon isovector
axial form factor and show that it is small in the threshold region.Comment: 14 pp, ReVTeX or LaTeX, uses epsf, 7 figure
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