789 research outputs found
Rational Map of CP^2 with No Invariant Foliation
Conference Poster presented at: Midwest Dynamical Systems Conference, Champaign/Urbana, IL November 1-3, 2013
Rational Maps of CP^2 with No Invariant Foliation
We present simple examples of rational maps of the complex projective plane with equal first and second dynamical degrees and no invariant foliation
Photon-number-resolution with sub-30-ps timing using multi-element superconducting nanowire single photon detectors
A photon-number-resolving detector based on a four-element superconducting
nanowire single photon detector is demonstrated to have sub-30-ps resolution in
measuring the arrival time of individual photons. This detector can be used to
characterize the photon statistics of non-pulsed light sources and to mitigate
dead-time effects in high-speed photon counting applications. Furthermore, a
25% system detection efficiency at 1550 nm was demonstrated, making the
detector useful for both low-flux source characterization and high-speed
photon-counting and quantum communication applications. The design, fabrication
and testing of this detector are described, and a comparison between the
measured and theoretical performance is presented.Comment: 13 pages, 5 figure
Exact soliton solutions of coupled nonlinear Schr\"odinger equations: Shape changing collisions, logic gates and partially coherent solitons
The novel dynamical features underlying soliton interactions in coupled
nonlinear Schr{\"o}dinger equations, which model multimode wave propagation
under varied physical situations in nonlinear optics, are studied. In this
paper, by explicitly constructing multisoliton solutions (upto four-soliton
solutions) for two coupled and arbitrary -coupled nonlinear Schr{\"o}dinger
equations using the Hirota bilinearization method, we bring out clearly the
various features underlying the fascinating shape changing (intensity
redistribution) collisions of solitons, including changes in amplitudes, phases
and relative separation distances, and the very many possibilities of energy
redistributions among the modes of solitons. However in this multisoliton
collision process the pair-wise collision nature is shown to be preserved in
spite of the changes in the amplitudes and phases of the solitons. Detailed
asymptotic analysis also shows that when solitons undergo multiple collisions,
there exists the exciting possibility of shape restoration of atleast one
soliton during interactions of more than two solitons represented by three and
higher order soliton solutions. From application point of view, we have shown
from the asymptotic expressions how the amplitude (intensity) redistribution
can be written as a generalized linear fractional transformation for the
-component case. Also we indicate how the multisolitons can be reinterpreted
as various logic gates for suitable choices of the soliton parameters, leading
to possible multistate logic. In addition, we point out that the various
recently studied partially coherent solitons are just special cases of the
bright soliton solutions exhibiting shape changing collisions, thereby
explaining their variable profile and shape variation in collision process.Comment: 50 Pages, 13 .jpg figures. To appear in PR
Resonance Effects in the Nonadiabatic Nonlinear Quantum Dimer
The quantum nonlinear dimer consisting of an electron shuttling between the
two sites and in weak interaction with vibrations, is studied numerically under
the application of a DC electric field. A field-induced resonance phenomenon
between the vibrations and the electronic oscillations is found to influence
the electronic transport greatly. For initially delocalization of the electron,
the resonance has the effect of a dramatic increase in the transport. Nonlinear
frequency mixing is identified as the main mechanism that influences transport.
A characterization of the frequency spectrum is also presented.Comment: 7 pages, 6 figure
Simple method for excitation of a Bose-Einstein condensate
An appropriate, time-dependent modification of the trapping potential may be
sufficient to create effectively collective excitations in a cold atom
Bose-Einstein condensate. The proposed method is complementary to earlier
suggestions and should allow the creation of both dark solitons and vortices.Comment: 8 pages, 7 figures, version accepted for publication in Phys. Rev.
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Application of PILATUS II Detector Modules for High Resolution X-Ray Imaging Crystal Spectrometers on the Alcator C-Mod Tokamak
A new type of X-ray imaging crystal spectrometer for Doppler measurements of the radial profiles of the ion temperature and plasma rotation velocity in tokamak plasmas is presently being developed in a collaboration between various laboratories. The spectrometer will consist of a spherically bent crystal and a two-dimensional position sensitive detector; and it will record temporally and spatially resolved X-ray line spectra from highly-charged ions. The detector must satisfy challenging requirements with respect to count rate and spatial resolution. The paper presents the results from a recent test of a PILATUS II detector module on Alcator C-Mod, which demonstrate that the PILATUS II detector modules will satisfy these requirements
Supersymmetric Relations Among Electromagnetic Dipole Operators
Supersymmetric contributions to all leptonic electromagnetic dipole operators
have essentially identical diagramatic structure. With approximate slepton
universality this allows the muon anomalous magnetic moment to be related to
the electron electric dipole moment in terms of supersymmetric phases, and to
radiative flavor changing lepton decays in terms of small violations of slepton
universality. If the current discrepancy between the measured and Standard
Model values of the muon anomalous magnetic moment is due to supersymmetry, the
current bound on the electron electric dipole moment then implies that the
phase of the electric dipole operator is less than . Likewise
the current bound on decay implies that the fractional
selectron-smuon mixing in the left-left mass squared matrix, \delta m_{\smuon
\selectron}^2 / m_{\slepton}^2, is less than . These relations and
constraints are fairly insensitive to details of the superpartner spectrum for
moderate to large .Comment: Latex, 38 pages, 2 figure
PREDICTING THE SUMMER TEMPERATURE OF SMALL STREAMS IN SOUTHWESTERN WISCONSIN 1
One of the biggest challenges in managing cold water streams in the Midwest is understanding how stream temperature is controlled by the complex interactions among meteorologic processes, channel geometry, and ground water inflow. Inflow of cold ground water, shade provided by riparian vegetation, and channel width are the most important factors controlling summer stream temperatures. A simple screening model was used to quantitatively evaluate the importance of these factors and guide management decisions. The model uses an analytical solution to the heat transport equation to predict steady-state temperature throughout a stream reach. The model matches field data from four streams in southwestern Wisconsin quite well (typically within 1°C) and helps explain the observed warming and cooling trends along each stream reach. The distribution of ground water inflow throughout a stream reach has an important influence on stream temperature, and springs are especially effective at providing thermal refuge for fish. Although simple, this model provides insight into the importance of ground water and the impact different management strategies, such as planting trees to increase shade, may have on summer stream temperature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74032/1/j.1752-1688.2005.tb03714.x.pd
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