35,917 research outputs found

    A Modified Version of the Waxman Algorithm

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    The iterative algorithm recently proposed by Waxman for solving eigenvalue problems, which relies on the method of moments, has been modified to improve its convergence considerably without sacrificing its benefits or elegance. The suggested modification is based on methods to calculate low-lying eigenpairs of large bounded hermitian operators or matrices

    Improving the Convergence of an Iterative Algorithm Proposed By Waxman

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    In the iterative algorithm recently proposed by Waxman for solving eigenvalue problems, we point out that the convergence rate may be improved. For many non-singular symmetric potentials which vanish asymptotically, a simple analytical relationship between the coupling constant of the potential and the ground state eigenvalue is obtained which can be used to make the algorithm more efficient

    Cities in fiction: Perambulations with John Berger

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    This paper explores selected novels by John Berger in which cities play a central role. These cities are places, partially real and partially imagined, where memory, hope, and despair intersect. My reading of the novels enables me to trace important themes in recent discourses on the nature of contemporary capitalism, including notions of resistance and universality. I also show how Berger?s work points to a writing that can break free from the curious capacity of capitalism to absorb and feed of its critique

    Landau level spectroscopy of ultrathin graphite layers

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    Far infrared transmission experiments are performed on ultrathin epitaxial graphite samples in a magnetic field. The observed cyclotron resonance-like and electron-positron-like transitions are in excellent agreement with the expectations of a single-particle model of Dirac fermions in graphene, with an effective velocity of c* = 1.03 x 10^6 m/s.Comment: 4 pages 4 figures Slight revisions following referees' comments. One figure modifie

    Covariant baryon charge radii and magnetic moments in a chiral constituent quark model

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    The charge radii and magnetic moments of all the light and strange baryons are investigated within the framework of a constituent quark model based on Goldstone-boson-exchange dynamics. Following the point-form approach to relativistic quantum mechanics, the calculations are performed in a manifestly covariant manner. Relativistic (boost) effects have a sizeable influence on the results. The direct predictions of the constituent quark model are found to fall remarkably close to the available experimental data.Comment: 6 pages, 4 table

    Conceptual design study of a Harrier V/STOL research aircraft

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    MCAIR recently completed a conceptual design study to define modification approaches to, and derive planning prices for the conversion of a two place Harrier to a V/STOL control, display and guidance research aircraft. Control concepts such as rate damping, attitude stabilization, velocity command, and cockpit controllers are to be demonstrated. Display formats will also be investigated, and landing, navigation and guidance systems flight tested. The rear cockpit is modified such that it can be quickly adapted to faithfully simulate the controls, displays and handling qualities of a Type A or Type B V/STOL. The safety pilot always has take command capability. The modifications studied fall into two categories: basic modifications and optional modifications. Technical descriptions of the basic modifications and of the optional modifications are presented. The modification plan and schedule as well as the test plan and schedule are presented. The failure mode and effects analysis, aircraft performance, aircraft weight, and aircraft support are discussed

    Isolated Prompt Photon Production in Hadronic Final States of e+e−e^+e^- Annihilation

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    We provide complete analytic expressions for the isolated prompt photon production cross section in e+e−e^+e^- annihilation reactions through one-loop order in quantum chromodynamics (QCD) perturbation theory. Functional dependences on the isolation cone size ÎŽ\delta and isolation energy parameter Ï”\epsilon are derived. The energy dependence as well as the full angular dependence of the cross section on Ξγ\theta_\gamma are displayed, where Ξγ\theta_\gamma specifies the direction of the photon with respect to the e+e−e^+e^- collision axis. We point out that conventional perturbative QCD factorization breaks down for isolated photon production in e+e−e^+e^- annihilation reactions in a specific region of phase space. We discuss the implications of this breakdown for the extraction of fragmentation functions from e+e−e^+e^- annihilation data and for computations of prompt photon production in hadron-hadron reactions.Comment: 54 pages RevTeX plus 19 postscript figures submitted together in one compressed fil

    The CP-violating pMSSM at the Intensity Frontier

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    In this Snowmass whitepaper, we describe the impact of ongoing and proposed intensity frontier experiments on the parameter space of the Minimally Supersymmetric Standard Model (MSSM). We extend a set of phenomenological MSSM (pMSSM) models to include non-zero CP-violating phases and study the sensitivity of various flavor observables in these scenarios Future electric dipole moment and rare meson decay experiments can have a strong impact on the viability of these models that is relatively independent of the detailed superpartner spectrum. In particular, we find that these experiments have the potential to probe models that are expected to escape searches at the high-luminosity LHC.Comment: 10 pages, 2 figures. Contributed to the Community Summer Study 2013, Minneapolis, MN July 29 - August 6, 201

    Discovering New Particles at Colliders

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    We summarize the activities of the New Particles Subgroup at the 1996 Snowmass Workshop. We present the expectations for discovery or exclusion of leptoquarks at hadron and lepton colliders in the pair production and single production modes. The indirect detection of a scalar lepton quark at polarized e+e−e^+e^- and ÎŒ+Ό−\mu^+\mu^- colliders is discussed. The discovery prospects for particles with two units of lepton number is discussed. We summarize the analysis of the single production of neutral heavy leptons at lepton colliders

    Resonant Excitation of Graphene K-Phonon and Intra-Landau-Level Excitons in Magneto-Optical Spectroscopy

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    Precise infrared magnetotransmission experiments have been performed in magnetic fields up to 32 T on a series of multilayer epitaxial graphene samples. We observe changes in the spectral features and broadening of the main cyclotron transition when the incoming photon energy is in resonance with the lowest Landau level separation and the energy of a K point optical phonon. We have developed a theory that explains and quantitatively reproduces the frequency and magnetic field dependence of the phenomenon as the absorption of a photon together with the simultaneous creation of an intervalley, intra-Landau-level exciton, and a K phonon.Comment: Main manuscript (5 pages); Supplementary Material (18 pages
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