6,780 research outputs found

    The non-local content of quantum operations

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    We show that quantum operations on multi-particle systems have a non-local content; this mirrors the non-local content of quantum states. We introduce a general framework for discussing the non-local content of quantum operations, and give a number of examples. Quantitative relations between quantum actions and the entanglement and classical communication resources needed to implement these actions are also described. We also show how entanglement can catalyse classical communication from a quantum action.Comment: 7 page

    Spruce Budworm and Other Lepidopterous Prey of Eumenid Wasps (Hymenoptera: Eumenidae) in Spruce-Fir Forests of Maine

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    Three species of eumenid wasps, Ancistrocerus adiabatus, Ancistrocerus antilope, and Euodynerus Ieucomelas, accepted and provisioned trap-nesting blocks with lepidopterous larvae, A pyralid. Nephopteryx sp., was the most commonly provisioned prey. A. adiabarus and E. leucomelas preyed on late instars of the spruce budworm, Choristoneura fumiferana: however. budworms accounted for only 6% of the provisioned prey. Estimates of budworm population densities before and after wasp predation, and subsample-s of provisioned prey indicated no significant reductions i = 0.065%) in budworm populations attributable to trap-nesting wasps

    Lorentz Invariance Violation and its Role in Quantum Gravity Phenomenology

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    The notion that gravitation might lead to a breakdown of standard space-time structure at small distances, and that this might affect the propagation of ordinary particles has led to a program to search for violations of Lorentz invariance as a probe of quantum gravity. Initially it was expected that observable macroscopic effects caused by microscopic violations of Lorentz invariance would necessarily be suppressed by at least one power of the small ratio between the Planck length and macroscopic lengths. Here we discuss the implications of the fact that this expectation is in contradiction with standard properties of radiative corrections in quantum field theories. In normal field theories, radiative corrections in the presence of microscopic Lorentz violation give macroscopic Lorentz violation that is suppressed only by the size of Standard Model couplings, in clear conflict with observation. In general, this conclusion can only be avoided by extreme fine tuning of the parameters of the theory.Comment: Draft chapter contributed to the book "Towards quantum gravity", being prepared by Daniele Oriti for Cambridge University Pres

    The Effect of Dry Needling to the Multifidus Muscle on Resting and Contracted Thickness of Transversus Abdominis in Subjects with Low Back Pain

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    Study Design: Randomized, double-blinded, controlled clinical trial. Objective: To measure the effects of dry needling to the lumbar multifidus (MF) muscle for any change in resting and contracted thickness of the transversus abdominis (TrA) muscle as well as symptoms and disability in individuals with low back pain (LBP). Background: Recent studies have demonstrated that individuals with LBP have diminished co-activation of the lumbar MF and TrA muscles, which when working appropriately in healthy individuals, contributes to spinal stability and function. A significant change in the resting and contracted thickness of TrA has been found with dry needling to the lumbar MF in healthy subjects, but this has yet to be studied in individuals with low back pain. Methods: Thirty adults with LBP were randomly assigned to receive dry needling intervention or a sham needling intervention to the lumbar MF. The participants received instruction on the deep corset contraction (DCC) for purposes of measuring TrA muscle relaxation and contracted thickness with real time ultrasound (US) imaging pre- and post-intervention. Along with the US measurements, the Oswestry Disability Index (ODI), the Global Rating of Change Scale (GROC) and the Numeric Pain Rating Scale (NPRS) were used to measure outcomes at baseline, immediately post-, 2-days post, and 7-days post intervention. (See pdf for full abstract

    Next-to-leading order QCD corrections to hadron+jet production in pp collisions at RHIC

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    We compute the next-to-leading order QCD corrections to the spin-independent and spin-dependent cross-sections for the production of a single-hadron accompanied by an opposite jet in hadronic collisions. This process is being studied experimentally at RHIC, providing a new tool to unveil the polarized gluon distribution Delta g. We perform a detailed analysis of the phenomenological impact of the observable at NLO accuracy and show that the preliminary data by the STAR collaboration confirms the idea of a small gluon polarization in the 0.05<x<0.3 range.Comment: 16 pages, 11 Figures included. Minor typos correcte

    Broadband sensitivity enhancement of detuned dual-recycled Michelson interferometers with EPR entanglement

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    We demonstrate the applicability of the EPR entanglement squeezing scheme for enhancing the shot-noise-limited sensitivity of a detuned dual-recycled Michelson interferometers. In particular, this scheme is applied to the GEO\,600 interferometer. The effect of losses throughout the interferometer, arm length asymmetries, and imperfect separation of the signal and idler beams are considered

    Global analysis of fragmentation functions for pions and kaons and their uncertainties

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    We present new sets of pion and kaon fragmentation functions obtained in NLO combined analyses of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and deep-inelastic lepton-proton scattering with either pions or kaons identified in the final state. At variance with all previous fits, the present analyses take into account data where hadrons of different electrical charge are identified, which allow to discriminate quark from anti-quark fragmentation functions without the need of non trivial flavor symmetry assumptions. The resulting sets are in good agreement with all data analyzed, which cover a much wider kinematical range than in previous fits. An extensive use of the Lagrange multiplier technique is made in order to assess the uncertainties in the extraction of the fragmentation functions and the synergy from the complementary data sets in our global analysis.Comment: 28 pages, 25 figure
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