17,878 research outputs found

    Electronic structure of an electron on the gyroid surface, a helical labyrinth

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    Previously reported formulation for electrons on curved periodic surfaces is used to analyze the band structure of an electron bound on the gyroid surface (the only triply-periodic minimal surface that has screw axes). We find that an effect of the helical structure appears as the bands multiply sticking together on the Brillouin zone boundaries. We elaborate how the band sticking is lifted when the helical and inversion symmetries of the structure are degraded. We find from this that the symmetries give rise to prominent peaks in the density of states.Comment: RevTeX, 4 pages, 6 figure

    Tau polarization effects in the CNGS tau-neutrino appearance experiments

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    We studied tau polarization effects on the decay distributions of tau produced in the CNGS tau-neutrino appearance experiments. We show that energy and angular distributions for the decay products in the laboratory frame are significantly affected by the tau polarization. Rather strong azimuthal asymmetry about the tau momentum axis is predicted, which may have observable consequences in experiments even with small statistics.Comment: 5 pages, 6 eps figures, espcrc2.sty; Proceedings of the 4th International Workshop on Neutrino-Nucleus Interactions in the Few GeV Region (NuInt05), September 26-29, 2005, Okayama, Japa

    New Dissipation Relaxation Phenomenon in Oscillating Solid He-4

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    We describe the first observations on the time-dependent dissipation when the drive level of a torsional oscillator containing solid He-4 is abruptly changed. The relaxation of dissipation in solid He-4 shows rich dynamical behavior including exponential and logarithmic time-dependent decays, hysteresis, and memory effects.Comment: 4 pages, 4 figure

    Passing through the `chiral limit' in quenched QCD with Wilson fermions

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    We investigate the limit of vanishing quark mass in quenched lattice QCD with unimproved Wilson fermions at β=6.0\beta=6.0. Exploiting the correlations of propagators at different time slices we extract pion masses extremely close to the `chiral limit', despite the presence of `exceptional configurations'. With this at hand, the existence of quenched chiral logarithms can be demonstrated, provided, finite size effects are small. With reference to the phase diagram proposed by Aoki also the range κ>κc\kappa > \kappa_c is investigated. The width of a potential parity-flavor violating phase can, if at all, hardly be resolved.Comment: LATTICE98(spectrum

    Perturbative study for domain-wall fermions in 4+1 dimensions

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    We investigate a U(1) chiral gauge model in 4+1 dimensions formulated on the lattice via the domain-wall method. We calculate an effective action for smooth background gauge fields at a fermion one loop level. From this calculation we discuss properties of the resulting 4 dimensional theory, such as gauge invariance of 2 point functions, gauge anomalies and an anomaly in the fermion number current.Comment: 39 pages incl. 9 figures, REVTeX+epsf, uuencoded Z-compressed .tar fil

    Multifractality of the quantum Hall wave functions in higher Landau levels

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    To probe the universality class of the quantum Hall system at the metal-insulator critical point, the multifractality of the wave function ψ\psi is studied for higher Landau levels, N=1,2N=1,2, for various range (σ)(\sigma ) of random potential. We have found that, while the multifractal spectrum f(α)f(\alpha) (and consequently the fractal dimension) does vary with NN, the parabolic form for f(α)f(\alpha) indicative of a log-normal distribution of ψ\psi persists in higher Landau levels. If we relate the multifractality with the scaling of localization via the conformal theory, an asymptotic recovery of the single-parameter scaling with increasing σ\sigma is seen, in agreement with Huckestein's irrelevant scaling field argument.Comment: 10 pages, revtex, 5 figures available on request from [email protected]

    The Guidebook, the Friend, and the Room: Visitor Experience in a Historic House

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    In this paper, we describe an electronic guidebook prototype and report on a study of its use in a historic house. Supported by mechanisms in the guidebook, visitors constructed experiences that had a high degree of interaction with three entities: the guidebook, their companions, and the house and its contents. For example, we found that most visitors played audio descriptions played through speakers (rather than using headphones or reading textual descriptions) to facilitate communication with their companions
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