3,135 research outputs found
Eigenvalue correlations in QCD with a chemical potential
We discuss a new Random Matrix Model for QCD with a chemical potential that
is based on the symmetries of the Dirac operator and can be solved exactly for
all eigenvalue correlations for any number of flavors. In the microscopic limit
of small energy levels the results should be an accurate description of QCD.
This new model can also be scaled so that all physical observables remain at
their values until a first order chiral restoration transition is
reached. This gives a more realistic model for the QCD phase diagram than
previous RMM. We also mention how the model might aid in determining the phase
diagram of QCD from future numerical simulations.Comment: 3 pages, 3 figures, Lattice2004(non-zero
Contextual normalization applied to aircraft gas turbine engine diagnosis
Diagnosing faults in aircraft gas turbine engines is a complex problem. It involves several tasks,
including rapid and accurate interpretation of patterns in engine sensor data. We have investigated
contextual normalization for the development of a software tool to help engine repair technicians
with interpretation of sensor data. Contextual normalization is a new strategy for employing
machine learning. It handles variation in data that is due to contextual factors, rather than the
health of the engine. It does this by normalizing the data in a context-sensitive manner. This
learning strategy was developed and tested using 242 observations of an aircraft gas turbine
engine in a test cell, where each observation consists of roughly 12,000 numbers, gathered over a
12 second interval. There were eight classes of observations: seven deliberately implanted classes
of faults and a healthy class. We compared two approaches to implementing our learning strategy:
linear regression and instance-based learning. We have three main results. (1) For the given
problem, instance-based learning works better than linear regression. (2) For this problem,
contextual normalization works better than other common forms of normalization. (3) The
algorithms described here can be the basis for a useful software tool for assisting technicians with
the interpretation of sensor data
Universal correlations in spectra of the lattice QCD Dirac operator
Recently, Kalkreuter obtained complete Dirac spectra for lattice
gauge theory both for staggered fermions and for Wilson fermions. The lattice
size was as large as . We performed a statistical analysis of these data
and found that the eigenvalue correlations can be described by the Gaussian
Symplectic Ensemble for staggered fermions and by the Gaussian Orthogonal
Ensemble for Wilson fermions. In both cases long range spectral fluctuations
are strongly suppressed: the variance of a sequence of levels containing
eigenvalues on average is given by
( is equal to 4 and 1, respectively) instead of for a
random sequence of levels. Our findings are in agreement with the anti-unitary
symmetry of the lattice Dirac operator for with staggered fermions
which differs from Wilson fermions (with the continuum anti-unitary symmetry).
For , we predict that the eigenvalue correlations are given by the
Gaussian Unitary Ensemble.Comment: Talk present at LATTICE96(chirality in QCD), 3 pages, Late
Quantum chaos in QCD at finite temperature
We study complete eigenvalue spectra of the staggered Dirac matrix in
quenched QCD on a lattice. In particular, we investigate the
nearest-neighbor spacing distribution for various values of both
in the confinement and deconfinement phase. In both phases except far into the
deconfinement region, the data agree with the Wigner surmise of random matrix
theory which is indicative of quantum chaos. No signs of a transition to
Poisson regularity are found, and the reasons for this result are discussed.Comment: 3 pages, 6 figures (included), poster presented by R. Pullirsch at
"Lattice 97", to appear in the proceeding
QCD critical point and event-by-event fluctuations in heavy ion collisions
A summary of work done in collaboration with K. Rajagopal and E. Shuryak. We
show how heavy ion collision experiments, in particular, event-by-event
fluctuation measurements, can lead to the discovery of the critical point on
the phase diagram of QCD.Comment: 4 pages. Summary of work done in collaboration with K. Rajagopal and
E. Shuryak (hep-ph/9903292). To be published in the proceedings of Quark
Matter 99, Torino, Italy, May 10-14, 199
Lower Bounds for Discrepancy
We find the best asymptotic lower bounds for the coefficient of the leading
term of the norm of the two-dimensional (axis-parallel) discrepancy that
can be obtained by K.Roth's orthogonal function method among a large class of
test functions. We use methods of combinatorics, probability, complex and
harmonic analysis.Comment: a slightly different version of the article is accepted to
"Mathematika
EMIGRATIONAL INCLINATION - STAYING OR LEAVING – FREE MIGRATION POSSIBILITIES AND TENDENCIES IN B. A. Z. COUNTY
In this recent study we would like to show how migration affects in Borsod-Abaúj-Zemplén County, which components it has, what differences are there between gross and net emigrational inclination, what measures have been done by the ones who are determined to leave Hungary in expectations of a foreign job. A 375-element-sample was taken and had been appraised in order to measure the net emigration, the emigrational network and so the emigrational shell.migration, motivational factors, emigrational network, Labor and Human Capital,
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