242 research outputs found

    One-step generation of high-quality squeezed and EPR states in cavity QED

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    We show how to generate bilinear (quadratic) Hamiltonians in cavity quantum electrodynamics (QED) through the interaction of a single driven three-level atom with two (one) cavity modes. With this scheme it is possible to generate one-mode mesoscopic squeezed superpositions, two-mode entanglements, and two-mode squeezed vacuum states (such the original EPR state), without the need for Ramsey zones and external parametric amplification. The degree of squeezing achieved is up to 99% with currently feasible experimental parameters and the errors due to dissipative mechanisms become practically negligible

    Quantum Chaos in the Yang-Mills-Higgs System at Finite Temperature

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    The quantum chaos in the finite-temperature Yang-Mills-Higgs system is studied. The energy spectrum of a spatially homogeneous SU(2) Yang-Mills-Higgs is calculated within thermofield dynamics. Level statistics of the spectra is studied by plotting nearest-level spacing distribution histograms. It is found that finite temperature effects lead to a strengthening of chaotic effects, i.e. spectrum which has Poissonian distribution at zero temperature has Gaussian distribution at finite-temperature.Comment: 6 pages, 5 figures, Revte

    A description of the ratio between electric and magnetic proton form factors by using space-like, time-like data and dispersion relations

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    We use the available information on the ratio between the electric and magnetic proton form factors coming from recently published space-like data and from the few available time-like data. We apply a dispersive procedure on these data to evaluate the behaviour of this ratio, as a complex function, for all values of q^2.Comment: 12 pages, 7 Encapsulated Postscript figures, uses epsfig, rotating, exscale, amsmath, cite, latexsym, graphics, color packages, added reference

    Spin and Isospin Effects in the NN -> NK Lambda Reaction Near Threshold

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    The spin and isospin structure of the amplitudes and observables for K+Lambda production in nucleon-nucleon collisions in the near-threshold region is analysed. It is shown that, with reasonable values for the relative strengths of the pi and rho terms in a meson-exchange model, one expects production on the neutron to be significantly stronger than that on the proton. Negative values of the spin-transfer coefficient D_NN are also predicted due to pi-rho interference.Comment: 5 pages, 3 figures, using the EPJA style file

    Why are Switzerland's Foreign Assets so Low? The Growing Financial Exposure of a Small Open Economy

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    Switzerland’s international investment position shows a puzzling feature since 1999: Large and persistent current account surpluses have failed to boost the value of Swiss foreign assets. In this paper, we link this pattern to the substantial increase in the leveraging of Switzerland’s international assets and liabilities over the last twenty years, which we document in detail. We estimate the impact of exchange rate and asset prices movements on Swiss net foreign assets, and show that they led to substantial valuations losses since 1999, accounting for between one-quarter and one-half of the gap between the net foreign assets and cumulated current account flows. We show how these adverse valuation effects have erased Switzerland’s advantage in terms of the yield on its net foreign asset position

    Magnetic Phase transitions in Plasmas and Transport Barriers

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    A model of magnetic phase transitions in plasmas is presented: plasma blobs with pressure excess or defect are dia- or para-magnets and move radially under the influence of the background plasma magnetisation. It is found that magnetic phase separation could be the underlying mechanism of L to H transitions and drive transport barrier formation. Magnetic phase separation and associated pedestal build up, as described here, can be explained by the well known interchange mechanism, now reinterpreted as a magnetisation interchange which remains relevant even when stable or saturated. A testable necessary criterion for the L to H transition is presented.Comment: 3 figures, 9 pages, equations created with MathType To be published in Nuclear Fusion, accepted August 201

    The Role of Macroprudential Policy for Financial Stability in East Asia’s Emerging Economies

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    This paper analyzes the role and scope of macroprudential policy in preventing financial instability in the context of East Asian economies. It analyzes the behavior of the housing market in a dynamic setting to identify some of the factors responsible for the volatility of housing markets and their susceptibility to boom-bust cycles, which it identifies as a key source of financial imbalances in these economies. It then discusses the causal nexus between price and financial stability and the roles and complementary nature of macroprudential and monetary policies in addressing aggregate risk in the financial system. The paper identifies currency and maturity mismatches, which contributed to the 1997 - 1998 Asian financial crisis, as ongoing concerns in these economies although the high levels of reserves in the region now act as a buffer

    A review of the off-label use of selamectin (Stronghold®/Revolution®) in dogs and cats

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    Since its introduction approximately seven years ago, selamectin (Stronghold®/Revolution®, Pfizer Inc.) has been used off-label to treat a number of ecto- and endoparasite conditions in dogs and cats. It has been used as a successful prophylactic against Dirofilaria repens and as a treatment for Aelurostrongylus abstrusus in cats. It has also been used to treat notoedric mange, infestation with the nasal mite Pneumonyssoides caninum, Cheyletiella spp. and Neotrombicula autumnalis infestations and larval Cordylobia anthropophaga infection. However, to date attempts to treat generalised canine demodicosis have not been successful. In all cases, treatment was apparently well tolerated by the host

    Measurement of D+- and D0 production in deep inelastic scattering using a lifetime tag at HERA

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    The production of D-+/-- and D-0-mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb(-1). The measurements cover the kinematic range 5 < Q(2) < 1000 GeV2, 0.02 < y < 0.7, 1.5 < p(T)(D) < 15 GeV and |eta(D)| < 1.6. Combinatorial background to the D-meson signals is reduced by using the ZEUS microvertex detector to reconstruct displaced secondary vertices. Production cross sections are compared with the predictions of next-to-leading-order QCD, which is found to describe the data well. Measurements are extrapolated to the full kinematic phase space in order to obtain the open-charm contribution, F-2(c (c) over bar), to the proton structure function, F-2
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