891 research outputs found

    Overview of progress in neutrino scattering measurements

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    Recent progress in neutrino scattering experiments with few GeV neutrino beams is reviewed, focusing on new experimental input since the beginning of the NuInt workshop series in 2001. Progress in neutrino quasi-elastic scattering, resonance production, coherent pion production, scattering in the transition region between the resonance and deep inelastic regimes, and nuclear effects in neutrino-nucleus scattering, is discussed.Comment: To appear in the proceedings of 5th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt07), Batavia, Illinois, 30 May - 3 Jun 2007. Submitted to AIP Conf.Pro

    Vertex Intrinsic Fitness: How to Produce Arbitrary Scale-Free Networks

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    We study a recent model of random networks based on the presence of an intrinsic character of the vertices called fitness. The vertices fitnesses are drawn from a given probability distribution density. The edges between pair of vertices are drawn according to a linking probability function depending on the fitnesses of the two vertices involved. We study here different choices for the probability distribution densities and the linking functions. We find that, irrespective of the particular choices, the generation of scale-free networks is straightforward. We then derive the general conditions under which scale-free behavior appears. This model could then represent a possible explanation for the ubiquity and robustness of such structures.Comment: 4 pages, 3 figures, RevTe

    Can a 3+2 Oscillation Model Explain the NuTeV Electroweak Results?

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    The weak mixing angle result from NuTeV falls three standard deviations above the value determined by global electroweak fits. It has been suggested that one possible explanation for this result could be the oscillation of electron neutrinos in the NuTeV beam to sterile neutrinos. This article examines several cases of masses and mixings for 3+2 neutrino oscillation models which fit the current oscillation data at 99% CL. We conclude that electron to sterile neutrino oscillations can account for only up to a third of a standard deviation between the NuTeV determination of the weak mixing angle and the standard model.Comment: 3 pages, 2 figures, submitted to Brief Report

    A variable delay integrated receiver for differential phase-shift keying optical transmission systems

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    An integrated variable delay receiver for DPSK optical transmission systems is presented. The device is realized in silicon-on-insulator technology and can be used to detect DPSK signals at any bit-rates between 10 and 15 Gbit/s

    Sense and sensitivity of double beta decay experiments

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    The search for neutrinoless double beta decay is a very active field in which the number of proposals for next-generation experiments has proliferated. In this paper we attempt to address both the sense and the sensitivity of such proposals. Sensitivity comes first, by means of proposing a simple and unambiguous statistical recipe to derive the sensitivity to a putative Majorana neutrino mass, m_bb. In order to make sense of how the different experimental approaches compare, we apply this recipe to a selection of proposals, comparing the resulting sensitivities. We also propose a "physics-motivated range" (PMR) of the nuclear matrix elements as a unifying criterium between the different nuclear models. The expected performance of the proposals is parametrized in terms of only four numbers: energy resolution, background rate (per unit time, isotope mass and energy), detection efficiency, and bb isotope mass. For each proposal, both a reference and an optimistic scenario for the experimental performance are studied. In the reference scenario we find that all the proposals will be able to partially explore the degenerate spectrum, without fully covering it, although four of them (KamLAND-Zen, CUORE, NEXT and EXO) will approach the 50 meV boundary. In the optimistic scenario, we find that CUORE and the xenon-based proposals (KamLAND-Zen, EXO and NEXT) will explore a significant fraction of the inverse hierarchy, with NEXT covering it almost fully. For the long term future, we argue that Xe-based experiments may provide the best case for a 1-ton scale experiment, given the potentially very low backgrounds achievable and the expected scalability to large isotope masses.Comment: 30 pages, 12 figures, 6 table

    Realization of quantum walks with negligible decoherence in waveguide lattices

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    Quantum random walks are the quantum counterpart of classical random walks, and were recently studied in the context of quantum computation. Physical implementations of quantum walks have only been made in very small scale systems severely limited by decoherence. Here we show that the propagation of photons in waveguide lattices, which have been studied extensively in recent years, are essentially an implementation of quantum walks. Since waveguide lattices are easily constructed at large scales and display negligible decoherence, they can serve as an ideal and versatile experimental playground for the study of quantum walks and quantum algorithms. We experimentally observe quantum walks in large systems (similar to 100 sites) and confirm quantum walks effects which were studied theoretically, including ballistic propagation, disorder, and boundary related effects

    The Orbital Angular Momentum of Light for Ultra-High Capacity Data Centers

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    The potential of orbital angular momentum (OAM) of light in data center scenarios is presented. OAMs can be exploited for short reach ultra-high bit rate fiber links and as additional multiplexing domain in transparent ultra-high capacity optical switches. Recent advances on OAM integrated photonic technology are also reported. Finally demonstration of OAM-based fiber links (aggregate throughput 17.9 Tb/s) and two layers OAM-WDM-based optical switches are presented exploiting OAM integrated components and demonstrating the achievable benefits in terms of size, weight and power consumption (SWaP) compared to different technologies

    Nonlinear properties of AlGaAs waveguides in continuous wave operation regime

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    Aluminum Gallium Arsenide (AlGaAs) is an attractive platform for the development of integrated optical circuits for all-optical signal processing thanks to its large nonlinear coefficients in the 1.55-ÎŒm telecommunication spectral region. In this paper we discuss the results of the nonlinear continuous-wave optical characterization of AlGaAs waveguides at a wavelength of 1.55 ÎŒm. We also report the highest value ever reported in the literature for the real part of the nonlinear coefficient in this material (Re(Îł) ≈521 W<sup>−1</sup>m<sup>−1</sup>)

    Barreau : invisible Ă  la Haye

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    High precision integrated photonic thermometry enabled by a transfer printed diamond resonator on GaN waveguide chip

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    We demonstrate a dual-material integrated photonic thermometer, fabricated by high accuracy micro-transfer printing. A freestanding diamond micro-disk resonator is printed in close proximity to a gallium nitride on a sapphire racetrack resonator, and respective loaded Q factors of 9.1 × 104 and 2.9 × 104 are measured. We show that by using two independent wide-bandgap materials, tracking the thermally induced shifts in multiple resonances, and using optimized curve fitting tools the measurement error can be reduced to 9.2 mK. Finally, for the GaN, in a continuous acquisition measurement we record an improvement in minimum Allan variance, occurring at an averaging time four times greater than a comparative silicon device, indicating better performance over longer time scales
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