2,511 research outputs found
Spacecraft attitude determination by fanscan technique
To determine orientation, or attitude, of spacecraft in flight relative to data-receiving antenna on earth use fanbeam antenna which is offset in angle from spin axis of spacecraft and provides fan-like radiation pattern
Coherent Transport through an interacting double quantum dot: Beyond sequential tunneling
Various causes for negative differential conductance in transport through an
interacting double quantum dot are investigated. Particular focus is given to
the interplay between the renormalization of the energy levels due to the
coupling to the leads and the decoherence of the states. The calculations are
performed within a basis of many-particle eigenstates and we consider the
dynamics given by the von Neumann-equation taking into account also processes
beyond sequential tunneling. A systematic comparison between the levels of
approximation and also with different formalisms is performed. It is found that
the current is qualitatively well described by sequential processes as long as
the temperature is larger than the level broadening induced by the contacts.Comment: 11 pages, 5 figures included in tex
Generation of Squeezing in Higher Order Hermite-Gaussian Modes with an Optical Parametric Amplifier
We demonstrate quantum correlations in the transverse plane of continuous
wave light beams by producing -4.0 dB, -2.6 dB and -1.5 dB of squeezing in the
TEM00, TEM10 and TEM20 Hermite- Gauss modes with an optical parametric
amplifier, respectively. This has potential applications in quantum information
networking, enabling parallel quantum information processing. We describe the
setup for the generation of squeezing and analyze the effects of various
experimental issues such as mode overlap between pump and seed and nonlinear
losses.Comment: 7 pages, 4 figure
Splitting length distributions into peaks and the clean class concept
Fish, Growth rate, Mathematical models
Functional recovery is considered the most important target: a survey of dedicated professionals
Background: The aim of this study was to survey the relative importance of postoperative recovery targets and perioperative care items, as perceived by a large group of international dedicated professionals.
Methods: A questionnaire with eight postoperative recovery targets and 13 perioperative care items was mailed to participants of the first international Enhanced Recovery After Surgery (ERAS) congress and to authors of papers with a clear relevance to ERAS in abdominal surgery. The responders were divided into categories according to profession and region.
Results: The recovery targets ‘To be completely free of nausea’, ‘To be independently mobile’ and ‘To be able to eat and drink as soon as possible’ received the highest score irrespective of the responder's profession or region of origin. Equally, the care items ‘Optimizing fluid balance’, ‘Preoperative counselling’ and ‘Promoting early and scheduled mobilisation’ received the highest score across all groups.
Conclusions: Functional recovery, as in tolerance of food without nausea and regained mobility, was considered the most important target of recovery. There was a consistent uniformity in the way international dedicated professionals scored the relative importance of recovery targets and care items. The relative rating of the perioperative care items was not dependent on the strength of evidence supporting the items
Experimental Demonstration of Squeezed State Quantum Averaging
We propose and experimentally demonstrate a universal quantum averaging
process implementing the harmonic mean of quadrature variances. The harmonic
mean protocol can be used to efficiently stabilize a set of fragile squeezed
light sources with statistically fluctuating noise levels. The averaged
variances are prepared probabilistically by means of linear optical
interference and measurement induced conditioning. We verify that the
implemented harmonic mean outperforms the standard arithmetic mean strategy.
The effect of quantum averaging is experimentally tested both for uncorrelated
and partially correlated noise sources with sub-Poissonian shot noise or
super-Poissonian shot noise characteristics.Comment: 4 pages, 5 figure
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