22,945 research outputs found

    Anomalous diffusion through coupling to a fractal environment: Microscopic derivation of the "whip-back" effect

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    Two models for quantum Brownian motion - the Oscillator Bath (OB) model and the Random-Band-Matrix (RBM) model - are compared and a relation between the spectral density function I(w) and the variance (Vab)^2 is established. The extension to a fractal environment is then considered and the microscopic origin of anomalous diffusion is discussed. In particular, it is shown that the asymptotic behavior of the normalized velocity auto-correlation function (VACF) is entirely determined by the band form factor. This allows for a microscopic derivation of the "whip-back" effect.Comment: 4 pages, 1 figur

    Operational Integrator-Patent

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    Solid state operational integrato

    Operational integrator

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    System operates in the nonreturn-to-zero mode, maintaining the increased bit density capability of this mode but with much higher noise immunity than conventional schemes offer. This integrator performs a mathematical integrating function on inputs from 100 Hz through 100 MHz

    Effective chiral theory of kaon-nucleon scattering

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    We apply the relativistic chiral SU(3) Lagrangian density to kaon-nucleon scattering imposing constraints from the pion-nucleon s- and p-wave threshold parameters at chiral order Q2Q^2. The s and u channel decouplet baryon exchange is included explicitly and is found to play a crucial role in understanding the empirical s- and p-wave nuclear kaon dynamics quantitatively.Comment: 12 pages, 5 figures, invited talk "International Workshop XXVII on Gross Properties of Nuclei and Nuclear Excitations", Hirschegg, Austria, January, 200

    Chiral SU(3) Symmetry and Strangeness

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    In this talk we review recent progress on the systematic evaluation of the kaon and antikaon spectral functions in dense nuclear matter based on a chiral SU(3) description of the low-energy pion-, kaon- and antikaon-nucleon scattering data.Comment: 9 pages, 4 figures, invited talk given by M.F.M.L. at the SQM2001 conferenc

    Covariant meson-baryon scattering with chiral and large N_c constraints

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    We give a review of recent progress on the application of the relativistic chiral SU(3) Lagrangian to meson-baryon scattering. It is shown that a combined chiral and 1/N_c expansion of the Bethe-Salpeter interaction kernel leads to a good description of the kaon-nucleon, antikaon-nucleon and pion-nucleon scattering data typically up to laboratory momenta of p_lab about 500 MeV. We solve the covariant coupled channel Bethe-Salpeter equation with the interaction kernel truncated to chiral order Q^3 where we include only those terms which are leading in the large N_c limit of QCD.Comment: 27 pages, 5 figures, Invited talk given by M.F.M.L. at the IARD 2000 meetin

    Charmed meson resonances from chiral coupled-channel dynamics

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    Charmed meson resonances with quantum numbers J^P=0^+ and J^P=1^+ are generated in terms of chiral coupled-channel dynamics. At leading order in the chiral expansion a parameter-free prediction is obtained for the scattering of Goldstone bosons off charmed pseudo-scalar and vector mesons. The recently announced narrow open charm states observed by the BABAR and CLEO collaborations are reproduced. We suggest the existence of states that form an anti-triplet and a sextet representation of the SU(3) group. In particular, so far unobserved narrow isospin-singlet states with negative strangeness are predicted.Comment: Presented at Hadron 03: 10th International Conference on Hadron Spectroscopy, Aschaffenburg, Germany, 31 Aug - 6 Sep 200
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