3,221 research outputs found
Structural Invariance and the Energy Spectrum
We extend the application of the concept of structural invariance to bounded
time independent systems. This concept, previously introduced by two of us to
argue that the connection between random matrix theory and quantum systems with
a chaotic classical counterpart is in fact largely exact in the semiclassical
limit, is extended to the energy spectra of bounded time independent systems.
We proceed by showing that the results obtained previously for the
quasi-energies and eigenphases of the S-matrix can be extended to the
eigenphases of the quantum Poincare map which is unitary in the semiclassical
limit. We then show that its eigenphases in the chaotic case move rather
stiffly around the unit circle and thus their local statistical fluctuations
transfer to the energy spectrum via Bogomolny's prescription. We verify our
results by studying numerically the properties of the eigenphases of the
quantum Poincare map for billiards by using the boundary integral method.Comment: 10 pages, 5 figure
Determination of s(x) and \bar{s}(x) from a global QCD analysis
A new global QCD analysis of DIS data is presented. The \nu Fe and
\bar{\nu}Fe differential cross-section data are included to constrain the
strange component of the nucleon sea. As a result we found a hard strangeness
at high-x and some evidence for an asymmetry between xs(x) and x\bar{s}(x).Comment: 5 pages, 4 figure
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