22,945 research outputs found
Anomalous diffusion through coupling to a fractal environment: Microscopic derivation of the "whip-back" effect
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
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
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 . 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
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
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
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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