18,268 research outputs found
Arkansas Cotton Variety Test 2016
The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas
AlGaAs top solar cell for mechanical attachment in a multi-junction tandem concentrator solar cell stack
The AstroPower self-supporting, transparent AlGaAs top solar cell can be stacked upon any well-developed bottom solar cell for improved system performance. This is an approach to improve the performance and scale of space photovoltaic power systems. Mechanically stacked tandem solar cell concentrator systems based on the AlGaAs top concentrator solar cell can provide near term efficiencies of 36 percent (AMO, 100x). Possible tandem stack efficiencies greater than 38 percent (100x, AMO) are feasible with a careful selection of materials. In a three solar cell stack, system efficiencies exceed 41 percent (100x, AMO). These device results demonstrate a practical solution for a state-of-the-art top solar cell for attachment to an existing, well-developed solar cell
Experimental Demonstration of Optimal Unambiguous State Discrimination
We present the first full demonstration of unambiguous state discrimination
between non-orthogonal quantum states. Using a novel free space interferometer
we have realised the optimum quantum measurement scheme for two non-orthogonal
states of light, known as the Ivanovic-Dieks-Peres (IDP) measurement. We have
for the first time gained access to all three possible outcomes of this
measurement. All aspects of this generalised measurement scheme, including its
superiority over a standard von Neumann measurement, have been demonstrated
within 1.5% of the IDP predictions
Gauge Theories with Cayley-Klein and Gauge Groups
Gauge theories with the orthogonal Cayley-Klein gauge groups and
are regarded. For nilpotent values of the contraction
parameters these groups are isomorphic to the non-semisimple Euclid,
Newton, Galilei groups and corresponding matter spaces are fiber spaces with
degenerate metrics. It is shown that the contracted gauge field theories
describe the same set of fields and particle mass as gauge
theories, if Lagrangians in the base and in the fibers all are taken into
account. Such theories based on non-semisimple contracted group provide more
simple field interactions as compared with the initial ones.Comment: 14 pages, 5 figure
The role of freestream turbulence scale in subsonic flow separation
The clarification of the role of freestream turbulence scale in determining the location of boundary layer separation is discussed. Modifications to the test facility were completed. Wind tunnel flow characteristics, including turbulence parameters, were determined with two turbulence generating grids, as well as no grid. These results are summarized. Initial results on the role of scale on turbulent boundary layer separation on the upper surface of an airfoil model are also discussed
Four-Fermi Effective Operators in Top-Quark Production and Decay
Effects of four-Fermi-type new interactions are studied in top-quark pair
production and their subsequent decays at future e^+e^- colliders.
Secondary-lepton-energy distributions are calculated for arbitrary longitudinal
beam polarizations. An optimal-observables procedure is applied for the
determination of new parameters.Comment: Polarized e^- plus unpolarized e^+ collisions were include
Inelastic scattering of light by a cold trapped atom: Effects of the quantum center-of-mass motion
The light scattered by a cold trapped ion, which is in the stationary state
of laser cooling, presents features due to the mechanical effects of
atom-photon interaction. These features appear as additional peaks (sidebands)
in the spectrum of resonance fluorescence. Among these sidebands the literature
has discussed the Stokes and anti-Stokes components, namely the sidebands of
the elastic peak. In this manuscript we show that the motion also gives rise to
sidebands of the inelastic peaks. These are not always visible, but, as we
show, can be measured in parameter regimes which are experimentally accessible.Comment: 10 pages, 4 figures, submitted to Phys. Rev.
Optimum detection for extracting maximum information from symmetric qubit sets
We demonstrate a class of optimum detection strategies for extracting the
maximum information from sets of equiprobable real symmetric qubit states of a
single photon. These optimum strategies have been predicted by Sasaki et al.
[Phys. Rev. A{\bf 59}, 3325 (1999)]. The peculiar aspect is that the detections
with at least three outputs suffice for optimum extraction of information
regardless of the number of signal elements. The cases of ternary (or trine),
quinary, and septenary polarization signals are studied where a standard von
Neumann detection (a projection onto a binary orthogonal basis) fails to access
the maximum information. Our experiments demonstrate that it is possible with
present technologies to attain about 96% of the theoretical limit.Comment: 10 pages, 11 figures, to be submitted to Phys. Rev. A Converted to
REVTeX4 format, and a few other minor modifications according to the comments
from PRA referre
Accessible information and optimal strategies for real symmetrical quantum sources
We study the problem of optimizing the Shannon mutual information for sources
of real quantum states i.e. sources for which there is a basis in which all the
states have only real components. We consider in detail the sources of equiprobable qubit states lying symmetrically around the great
circle of real states on the Bloch sphere and give a variety of explicit
optimal strategies. We also consider general real group-covariant sources for
which the group acts irreducibly on the subset of all real states and prove the
existence of a real group-covariant optimal strategy, extending a theorem of
Davies (E. B. Davies, IEEE. Inf. Theory {\bf IT-24}, 596 (1978)). Finally we
propose an optical scheme to implement our optimal strategies, enough simple to
be realized with present technology.Comment: RevTeX, 16 pages, 4 eps figures with psfig, submitted to Phys. Rev.
A, corrected output error of Fig. 1 in the previous versio
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