2,453 research outputs found
Phase transitions and the internal noise structure of nonlinear Schr\"odi nger equation solitons
We predict phase-transitions in the quantum noise characteristics of systems
described by the quantum nonlinear Schr\"odinger equation, showing them to be
related to the solitonic field transition at half the fundamental soliton
amplitude. These phase-transitions are robust with respect to Raman noise and
scattering losses. We also describe the rich internal quantum noise structure
of the solitonic fields in the vicinity of the phase-transition. For optical
coherent quantum solitons, this leads to the prediction that eliminating the
peak side-band noise due to the electronic nonlinearity of silica fiber by
spectral filtering leads to the optimal photon-number noise reduction of a
fundamental soliton.Comment: 10 pages, 5 figure
The Mechanism Of Hydrotrope Action Of A Dicarboxylic Acid
The mechanism of the hydro trope action of a dicarboxylic acid Mono soap was investigated by determination of the change in order parameter of the amphiphile in a lamellar liquid crystal. The results showed addition of the hydro trope considerably to reduce the order while addition of a surfactant had no effect. © 1986
Quantum limits to center-of-mass measurements
We discuss the issue of measuring the mean position (center-of-mass) of a
group of bosonic or fermionic quantum particles, including particle number
fluctuations. We introduce a standard quantum limit for these measurements at
ultra-low temperatures, and discuss this limit in the context of both photons
and ultra-cold atoms. In the case of fermions, we present evidence that the
Pauli exclusion principle has a strongly beneficial effect, giving rise to a
1/N scaling in the position standard-deviation -- as opposed to a
scaling for bosons. The difference between the actual mean-position fluctuation
and this limit is evidence for quantum wave-packet spreading in the
center-of-mass. This macroscopic quantum effect cannot be readily observed for
non-interacting particles, due to classical pulse broadening. For this reason,
we also study the evolution of photonic and matter-wave solitons, where
classical dispersion is suppressed. In the photonic case, we show that the
intrinsic quantum diffusion of the mean position can contribute significantly
to uncertainties in soliton pulse arrival times. We also discuss ways in which
the relatively long lifetimes of attractive bosons in matter-wave solitons may
be used to demonstrate quantum interference between massive objects composed of
thousands of particles.Comment: 12 pages, 6 figures. Submitted to PRA. Revised to include more
references as well as a discussion of fermionic center-of-mas
Surfactants And The Stratum Corneum Lipids
A simplified mixture of model stratum corneum lipids was mixed with different surfactants to make a preliminary estimation of the influence of surfactants on the stratum corneum lipid structure. The results revealed differences between cationic and anionic surfactants and between anionic surfactants with different structures. © 1998
The Structure Of Lamellar Lyotropic Liquid Crystals From Lecithin And Alkanediols
Lamellar liquid crystals from lecithin and alkane diols were studied to determine the composition range of stability and geometrical dimensions using low-angle X-ray scattering. An estimation of the dislocation pattern was made from the optical pattern in polarized light. The ethylene glycol gave the widest range of stability for the lamellar structure, the range being reduced toward heptane diol, the longest member to give liquid crystals. The interlayer spacing was reduced with increasing chain length of the diol and the dislocation pattern remained identical. © 1981
A feasible "Kochen-Specker" experiment with single particles
We present a simple experimental scheme which can be used to demonstrate an
all-or-nothing type contradiction between non-contextual hidden variables and
quantum mechanics. The scheme, which is inspired by recent ideas by Cabello and
Garcia-Alcaine, shows that even for a single particle, path and spin
information cannot be predetermined in a non-contextual way.Comment: 4 pages, 3 figure
Soliton back-action evading measurement using spectral filtering
We report on a back-action evading (BAE) measurement of the photon number of
fiber optical solitons operating in the quantum regime. We employ a novel
detection scheme based on spectral filtering of colliding optical solitons. The
measurements of the BAE criteria demonstrate significant quantum state
preparation and transfer of the input signal to the signal and probe outputs
exiting the apparatus, displaying the quantum-nondemolition (QND) behavior of
the experiment.Comment: 5 pages, 5 figure
A Snapshot of How Entry-Level Occupational Therapy Programs Collect and Use Doctoral Capstone Outcomes
Entry-level occupational therapy doctorate (OTD) programs are required to gather program evaluation data regarding the doctoral capstone for accreditation purposes. This study aims to describe the processes used by a sample of OTD programs to gather doctoral capstone outcome data and to determine the type of data collected in order to understand the perspectives regarding doctoral capstone outcomes by doctoral capstone coordinators (DCCs) within the United States. The investigators used purposeful sampling to recruit DCCs at accredited entry-level OTD programs in the United States. The most common outcome data collected included information about the doctoral capstone experience from students, student performance outcomes, employment and scholarship outcomes from alumni and employers, and various outcomes from site/expert/faculty mentors. Results highlight the need to disseminate doctoral capstone outcomes as few participants in this study used the data they were collecting outside of their program. By sharing and reporting outcomes of the doctoral capstone, OTD programs, and the profession can collectively benefit. Development of common outcomes, collected across programs, can help to provide data large enough to draw meaningful conclusions regarding the value of the doctoral capstone in occupational therapy education and in strengthening the knowledge of the profession among the public
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