3,357 research outputs found
Coherent analysis of quantum optical sideband modes
We demonstrate a device that allows for the coherent analysis of a pair of
optical frequency sidebands in an arbitrary basis. We show that our device is
quantum noise limited and hence applications for this scheme may be found in
discrete and continuous variable optical quantum information experiments.Comment: 3 pages, 3 figures, submitted to Optics Letter
Teleportation of Nonclassical Wave Packets of light
We report on the experimental quantum teleportation of strongly nonclassical
wave packets of light. To perform this full quantum operation while preserving
and retrieving the fragile non-classicality of the input state, we have
developed a broadband, zero-dispersion teleportation apparatus that works in
conjunction with time-resolved state preparation equipment. Our approach brings
within experimental reach a whole new set of hybrid protocols involving
discrete- and continuous-variable techniques in quantum information processing
for optical sciences
An integrated study of earth resources in the State of California based on ERTS-1 and supporting aircraft data
There are no author-identified significant results in this report
Use of ERTS-1 data in identification, classification, and mapping of salt-affected soils in California
There are no author-identified significant results in this report
Impact of culture towards disaster risk reduction
Number of natural disasters has risen sharply worldwide making the risk of disasters a global concern. These disasters have created significant losses and damages to humans, economy and society. Despite the losses and damages created by disasters, some individuals and communities do not attached much significance to natural disasters. Risk perception towards a disaster not only depends on the danger it could create but also the behaviour of the communities and individuals that is governed by their culture. Within this context, this study examines the relationship between culture and disaster risk reduction (DRR). A comprehensive literature review is used for the study to evaluate culture, its components and to analyse a series of case studies related to disaster risk.
It was evident from the study that in some situations, culture has become a factor for the survival of the communities from disasters where as in some situations culture has acted as a barrier for effective DRR activities. The study suggests community based DRR activities as a mechanism to integrate with culture to effectively manage disaster risk
Demonstration of the spatial separation of the entangled quantum side-bands of an optical field
Quantum optics experiments on "bright" beams typically probe correlations
between side-band modes. However the extra degree of freedom represented by
this dual mode picture is generally ignored. We demonstrate the experimental
operation of a device which can be used to separate the quantum side-bands of
an optical field. We use this device to explicitly demonstrate the quantum
entanglement between the side-bands of a squeezed beam
Observation of magnetic field generation via the Weibel instability in interpenetrating plasma flows
Collisionless shocks can be produced as a result of strong magnetic fields in
a plasma flow, and therefore are common in many astrophysical systems. The
Weibel instability is one candidate mechanism for the generation of
sufficiently strong fields to create a collisionless shock. Despite their
crucial role in astrophysical systems, observation of the magnetic fields
produced by Weibel instabilities in experiments has been challenging. Using a
proton probe to directly image electromagnetic fields, we present evidence of
Weibel-generated magnetic fields that grow in opposing, initially unmagnetized
plasma flows from laser-driven laboratory experiments. Three-dimensional
particle-in-cell simulations reveal that the instability efficiently extracts
energy from the plasma flows, and that the self-generated magnetic energy
reaches a few percent of the total energy in the system. This result
demonstrates an experimental platform suitable for the investigation of a wide
range of astrophysical phenomena, including collisionless shock formation in
supernova remnants, large-scale magnetic field amplification, and the radiation
signature from gamma-ray bursts
Social cohesion as a real-life phenomenon: assessing the explanatory power of the universalist and particularist perspectives
Theory for the electromigration wind force in dilute alloys
A multiple scattering formulation for the electromigration wind force on
atoms in dilute alloys is developed. The theory describes electromigration via
a vacancy mechanism. The method is used to calculate the wind valence for
electromigration in various host metals having a close-packed lattice
structure, namely aluminum, the noble metals copper, silver and gold and the
transition metals. The self-electromigration results for aluminum and the
noble metals compare well with experimental data. For the metals small
wind valences are found, which make these metals attractive candidates for the
experimental study of the direct valence.Comment: 18 pages LaTeX, epsfig, 8 figures. to appear in Phys. Rev. B 56 of
15/11/199
Development of an Interpretive Simulation Tool for the Proton Radiography Technique
Proton radiography is a useful diagnostic of high energy density (HED)
plasmas under active theoretical and experimental development. In this paper we
describe a new simulation tool that interacts realistic laser-driven point-like
proton sources with three dimensional electromagnetic fields of arbitrary
strength and structure and synthesizes the associated high resolution proton
radiograph. The present tool's numerical approach captures all relevant physics
effects, including effects related to the formation of caustics.
Electromagnetic fields can be imported from PIC or hydrodynamic codes in a
streamlined fashion, and a library of electromagnetic field `primitives' is
also provided. This latter capability allows users to add a primitive, modify
the field strength, rotate a primitive, and so on, while quickly generating a
high resolution radiograph at each step. In this way, our tool enables the user
to deconstruct features in a radiograph and interpret them in connection to
specific underlying electromagnetic field elements. We show an example
application of the tool in connection to experimental observations of the
Weibel instability in counterstreaming plasmas, using particles
generated from a realistic laser-driven point-like proton source, imaging
fields which cover volumes of mm. Insights derived from this
application show that the tool can support understanding of HED plasmas.Comment: Figures and tables related to the Appendix are included in the
published journal articl
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