722 research outputs found

    Multifunction MMIC For Miniaturized Solid State Switch Matrix

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    This paper describes a new multifunction MMIC expressly designed for a reconfiguration matrix equipment.This MMIC has been developed using a standard PHEMT process and includes two switches,a totally switchable-off amplifier and a temperature compensation circuit.The complete circuit has also been designed to interface a standard CMOS control level. Performed simulations and obtained results demonstrate the effectiveness of this approach in reaching compactness and reliability of satellite equipment

    NC pi0 Production in the MiniBooNE Antineutrino Data

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    The single largest background to future numubar to nuebar (numu to nue) oscillation searches is neutral current pi0 production. MiniBooNE, which began taking antineutrino data in January 2006, has the world's largest sample of pi0's produced by antineutrinos in the 1 GeV energy range. These neutral pions are primarily produced through the delta resonance but can also be created through "coherent production." The latter process is the coherent sum of glancing scatters of (anti)neutrinos off a neutron or proton, in which the nucleus is kept intact but a pi0 is created. Current analysis of NC pi0 production in the MiniBooNE antineutrino data will be discussed.Comment: 4 pages, including 5 figures. Proceedings of the 5th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt07), Batavia, Illinois, 30 May - 3 Jun 200

    Energy Relaxation in the Integer Quantum Hall Regime

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    We investigate the energy exchanges along an electronic quantum channel realized in the integer quantum Hall regime at filling factor νL=2\nu_L=2. One of the two edge channels is driven out-of-equilibrium and the resulting electronic energy distribution is measured in the outer channel, after several propagation lengths 0.8 μ0.8~\mum≤L≤30 μ\leq L\leq30~\mum. Whereas there are no discernable energy transfers toward thermalized states, we find efficient energy redistribution between the two channels without particle exchanges. At long distances L≥10 μL\geq10~\mum, the measured energy distribution is a hot Fermi function whose temperature is lower than expected for two interacting channels, which suggests the contribution of extra degrees of freedom. The observed short energy relaxation length challenges the usual description of quantum Hall excitations as quasiparticles localized in one edge channel.Comment: To be published in PRL, 10 pages including supplementary materia

    Microscale generation of entangled photons without momentum conservation

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    We report, for the first time, the generation of entangled photon pairs via type-0 spontaneous parametric down conversion in an ultra-thin wafer of lithium niobate in which momentum between the pump photon and daughter photons is not conserved. The characteristics of the emission are investigated using several techniques. We find that non-phase matched SPDC is a promising source of ultra-broadband two photon radiation that exhibits remarkably tight correlation widths in both the spatial and temporal domains.Comment: 9 pages, 8 figure

    The effects of Gilles de la Tourette syndrome and other chronic tic disorders on quality of life across the lifespan:a systematic review

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    Gilles de la Tourette syndrome (GTS) and other chronic tic disorders are neurodevelopmental conditions characterized by the presence of tics and associated behavioral problems. Whilst converging evidence indicates that these conditions can affect patients' quality of life (QoL), the extent of this impairment across the lifespan is not well understood. We conducted a systematic literature review of published QoL studies in GTS and other chronic tic disorders to comprehensively assess the effects of these conditions on QoL in different age groups. We found that QoL can be perceived differently by child and adult patients, especially with regard to the reciprocal contributions of tics and behavioral problems to the different domains of QoL. Specifically, QoL profiles in children often reflect the impact of co-morbid attention-deficit and hyperactivity symptoms, which tend to improve with age, whereas adults' perception of QoL seems to be more strongly affected by the presence of depression and anxiety. Management strategies should take into account differences in age-related QoL needs between children and adults with GTS or other chronic tic disorders

    Acoustic Phonon-Assisted Resonant Tunneling via Single Impurities

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    We perform the investigations of the resonant tunneling via impurities embedded in the AlAs barrier of a single GaAs/AlGaAs heterostructure. In the I(V)I(V) characteristics measured at 30mK, the contribution of individual donors is resolved and the fingerprints of phonon assistance in the tunneling process are seen. The latter is confirmed by detailed analysis of the tunneling rates and the modeling of the resonant tunneling contribution to the current. Moreover, fluctuations of the local structure of the DOS (LDOS) and Fermi edge singularities are observed.Comment: accepted in Phys. Rev.
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