18,022 research outputs found
Moderate deviations in Poisson approximation: a first attempt
Poisson approximation using Stein's method has been extensively studied in
the literature. The main focus has been on bounding the total variation
distance. This paper is a first attempt on moderate deviations in Poisson
approximation for right-tail probabilities of sums of dependent indicators. We
obtain results under certain general conditions for local dependence as well as
for size-bias coupling. These results are then applied to independent
indicators, 2-runs, and the matching problem.Comment: 21 page
Controllable Goos-H\"{a}nchen shifts and spin beam splitter for ballistic electrons in a parabolic quantum well under a uniform magnetic field
The quantum Goos-H\"{a}nchen shift for ballistic electrons is investigated in
a parabolic potential well under a uniform vertical magnetic field. It is found
that the Goos-H\"{a}nchen shift can be negative as well as positive, and
becomes zero at transmission resonances. The beam shift depends not only on the
incident energy and incidence angle, but also on the magnetic field and Landau
quantum number. Based on these phenomena, we propose an alternative way to
realize the spin beam splitter in the proposed spintronic device, which can
completely separate spin-up and spin-down electron beams by negative and
positive Goos-H\"{a}nchen shifts.Comment: 6 pages, 6 figure
meson production of high-energy nuclear collisions at NLO
The transverse momentum spectrum of meson in relativistic heavy-ion
collisions is studied at the next-to-leading-order (NLO) within the
perturbative QCD, where the jet quenching effect in the QGP is incorporated
with the effectively medium-modified fragmentation functions using the
higher-twist approach. We show that the theoretical simulations could give nice
descriptions of PHENIX data on meson in both and central collisions at the RHIC, and also provide numerical predictions of
spectra in central collisions with ~TeV at the
LHC. The ratios of in and in central
collisions at ~GeV are found to overlap in a wide region, which
matches well the measured ratio by PHENIX. We demonstrate that,
at the asymptotic region when the ratios of
in both and are almost determined only by
quark jets fragmentation and thus approach to the one in
scattering; in addition, the almost identical gluon (quark) contribution
fractions to and to result in a rather moderate variation of
distribution at intermediate and high region in
relative to that in ; while a slightly higher at small
in can be observed due to larger suppression of gluon
contribution fraction to as compared to the one to . The
theoretical prediction for at the LHC has also been presented.Comment: 7 pages, 8 figures, 2 typos corrected, revision for publicatio
On the error bound in a combinatorial central limit theorem
Let be an array of
independent random variables where . Let be a uniform random
permutation of , independent of , and let
. Suppose is standardized so that
. We prove that the Kolmogorov
distance between the distribution of and the standard normal distribution
is bounded by . Our approach is by
Stein's method of exchangeable pairs and the use of a concentration inequality.Comment: Published at http://dx.doi.org/10.3150/13-BEJ569 in the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
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