11,398 research outputs found
Dark states of dressed Bose-Einstein condensates
We combine the ideas of dressed Bose-Einstein condensates, where an
intracavity optical field allows one to design coupled, multicomponent
condensates, and of dark states of quantum systems, to generate a full quantum
entanglement between two matter waves and two optical waves. While the matter
waves are macroscopically populated, the two optical modes share a single
photon. As such, this system offers a way to influence the behaviour of a
macroscopic quantum system via a microscopic ``knob''.Comment: 6 pages, no figur
Geophysical Methods: an Overview
Geophysics is expected to have a major role in lunar resource assessment when manned systems return to the Moon. Geophysical measurements made from a lunar rover will contribute to a number of key studies: estimating regolith thickness, detection of possible large-diameter lava tubes within maria basalts, detection of possible subsurface ice in polar regions, detection of conductive minerals that formed directly from a melt (orthomagmatic sulfides of Cu, Ni, Co), and mapping lunar geology beneath the regolith. The techniques that can be used are dictated both by objectives and by our abilities to adapt current technology to lunar conditions. Instrument size, weight, power requirements, and freedom from orientation errors are factors we have considered. Among the geophysical methods we believe to be appropriate for a lunar resource assessment are magnetics, including gradiometry, time-domain magnetic induction, ground-penetrating radar, seismic reflection, and gravimetry
The use of complementary and alternative medicine among california adults with and without cancer.
This article examines the extent and correlates of complementary and alternative medicine (CAM) use among a population-based sample of California adults that is highly diverse in terms of sociodemographic characteristics and health status. As a follow-up to a state-wide health survey of 55,428 people, 9187 respondents were interviewed by phone regarding their use of 11 different types of CAM providers, special diets, dietary supplements, mind-body interventions, self-prayer and support groups. The sample included all participants in the initial survey who reported a diagnosis of cancer, all the non-white respondents, as well as a random sample of all the white respondents. The relation of CAM use to the respondents' demographic characteristics and health status is assessed. CAM use among Californians is generally high, and the demographic factors associated with high rates of CAM use are the same in California as have been found in other studies. Those reporting a diagnosis of cancer and those who report other chronic health problems indicate a similar level of visits to CAM providers. However, those with cancer are less likely to report using special diets, and more likely to report using support groups and prayer. Health status, gender, ethnicity and education have an independent impact upon CAM use among those who are healthy as well as those who report suffering from chronic health problems, although the precise relation varies by the type of CAM used
Some boundary effects in quantum field theory
We have constructed a quantum field theory in a finite box, with periodic
boundary conditions, using the hypothesis that particles living in a finite box
are created and/or annihilated by the creation and/or annihilation operators,
respectively, of a quantum harmonic oscillator on a circle. An expression for
the effective coupling constant is obtained showing explicitly its dependence
on the dimension of the box.Comment: 12 pages, Late
The Shapes of Flux Domains in the Intermediate State of Type-I Superconductors
In the intermediate state of a thin type-I superconductor magnetic flux
penetrates in a disordered set of highly branched and fingered macroscopic
domains. To understand these shapes, we study in detail a recently proposed
"current-loop" (CL) model that models the intermediate state as a collection of
tense current ribbons flowing along the superconducting-normal interfaces and
subject to the constraint of global flux conservation. The validity of this
model is tested through a detailed reanalysis of Landau's original conformal
mapping treatment of the laminar state, in which the superconductor-normal
interfaces are flared within the slab, and of a closely-related straight-lamina
model. A simplified dynamical model is described that elucidates the nature of
possible shape instabilities of flux stripes and stripe arrays, and numerical
studies of the highly nonlinear regime of those instabilities demonstrate
patterns like those seen experimentally. Of particular interest is the buckling
instability commonly seen in the intermediate state. The free-boundary approach
further allows for a calculation of the elastic properties of the laminar
state, which closely resembles that of smectic liquid crystals. We suggest
several new experiments to explore of flux domain shape instabilities,
including an Eckhaus instability induced by changing the out-of-plane magnetic
field, and an analog of the Helfrich-Hurault instability of smectics induced by
an in-plane field.Comment: 23 pages, 22 bitmapped postscript figures, RevTex 3.0, submitted to
Phys. Rev. B. Higher resolution figures may be obtained by contacting the
author
Stability analysis of polarized domains
Polarized ferrofluids, lipid monolayers and magnetic bubbles form domains
with deformable boundaries. Stability analysis of these domains depends on a
family of nontrivial integrals. We present a closed form evaluation of these
integrals as a combination of Legendre functions. This result allows exact and
explicit formulae for stability thresholds and growth rates of individual
modes. We also evaluate asymptotic behavior in several interesting limits.Comment: 12 pages, 3 figures, Late
Pearling and Pinching: Propagation of Rayleigh Instabilities
A new category of front propagation problems is proposed in which a spreading
instability evolves through a singular configuration before saturating. We
examine the nature of this front for the viscous Rayleigh instability of a
column of one fluid immersed in another, using the marginal stability criterion
to estimate the front velocity, front width, and the selected wavelength in
terms of the surface tension and viscosity contrast. Experiments are suggested
on systems that may display this phenomenon, including droplets elongated in
extensional flows, capillary bridges, liquid crystal tethers, and viscoelastic
fluids. The related problem of propagation in Rayleigh-like systems that do not
fission is also considered.Comment: Revtex, 7 pages, 4 ps figs, PR
Dynamical CP Violation in Composite Higgs Models
The dynamical origin of the CP violation in electroweak theory is
investigated in composite Higgs models. The mechanism of the spontaneous CP
violation proposed in other context by Dashen is adopted to construct simple
models of the dynamical CP violation.
Within the models the size of the neutron electric dipole moment is estimated
and the constraint on the -parameter in K-meson decays is
discussed.Comment: 20 pages, 2 figures not included, uses LaTeX, HUPD-922
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