33,236 research outputs found
Data Modeling with Large Random Matrices in a Cognitive Radio Network Testbed: Initial Experimental Demonstrations with 70 Nodes
This short paper reports some initial experimental demonstrations of the
theoretical framework: the massive amount of data in the large-scale cognitive
radio network can be naturally modeled as (large) random matrices. In
particular, using experimental data we will demonstrate that the empirical
spectral distribution of the large sample covariance matrix---a Hermitian
random matrix---agree with its theoretical distribution (Marchenko-Pastur law).
On the other hand, the eigenvalues of the large data matrix ---a non-Hermitian
random matrix---are experimentally found to follow the single ring law, a
theoretical result that has been discovered relatively recently. To our best
knowledge, our paper is the first such attempt, in the context of large-scale
wireless network, to compare theoretical predictions with experimental
findings.Comment: 4 pages, 11 figure
QCD and Rescattering in Nuclear Targets
We review the extension of the factorization formalism of perturbative QCD to
soft rescattering associated with hard processes in nuclei.Comment: Latex 16 pages, including 18 figures, to appear in the Proceedings of
Hard Probe Collaboratio
Reply to "Comment on 'Semiquantum-key distribution using less than four quantum states' "
Recently Boyer and Mor pointed out the first conclusion of Lemma 1 in our
original paper is not correct, and therefore, the proof of Theorem 5 based on
Lemma 1 is wrong. Furthermore, they gave a direct proof for Theorem 5 and
affirmed the conclusions in our original paper. In this reply, we admit the
first conclusion of Lemma 1 is not correct, but we need to point out the second
conclusion of Lemma 1 is correct. Accordingly, all the proofs for Lemma 2,
Lemma 3, and Theorems 3--6 are only based on the the second conclusion of Lemma
1 and therefore are correct.Comment: 1 pag
Fragmentation, NRQCD and Factorization in Heavy Quarkonium Production
We discuss factorization in heavy quarkonium production in high energy
collisions using NRQCD. Infrared divergences at NNLO are not matched by
conventional NRQCD matrix elements. However, we show that gauge invariance and
factorization require that conventional NRQCD production matrix elements be
modified to include Wilson lines or non-abelian gauge links. With this
modification NRQCD factorization for heavy quarkonium production is restored at
NNLO.Comment: 3pages Latex, 3eps figures, Talk given by G. C. Nayak at PANIC05
Santa Fe, NM, USA, October 24-28, 200
NRQCD Factorization and Velocity-dependence of NNLO Poles in Heavy Quarkonium Production
We study the transition of a heavy quark pair from octet to singlet color
configurations at next-to-next-to-leading order (NNLO) in heavy quarkonium
production. We show that the infrared singularities in this process are
consistent with NRQCD factorization to all orders in the heavy quark relative
velocity v. This factorization requires the gauge-completed matrix elements
that we introduced previously to prove NNLO factorization to order v ^2.Comment: 23pages latex, 2 figure
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