37,465 research outputs found
Gauge techniques in time and frequency domain TLM
Typical features of the Transmission Line Matrix (TLM) algorithm in
connection with stub loading techniques and prone to be hidden in common
frequency domain formulations are elucidated within the propagator approach to
TLM. In particular, the latter reflects properly the perturbative character of
the TLM scheme and its relation to gauge field models. Internal 'gauge' degrees
of freedom are made explicit in the frequency domain by introducing the complex
nodal S-matrix as a function of operators that act on external or internal
fields or virtually couple the two. As a main benefit, many techniques and
results gained in the time domain thus generalize straight away. The recently
developed deflection method for algorithm synthesis, which is extended in this
paper, or the non-orthogonal node approximating Maxwell's equations, for
instance, become so at once available in the frequency domain. In view of
applications in computational plasma physics, the TLM model of a relativistic
charged particle current coupled to the Maxwell field is treated as a
prototype.Comment: 20 pages; Keywords: Gauge techniques, perturbative schemes, TLM
method, propagator approach, plasma physic
Constrained fitting of three-point functions
We determine matrix elements for semileptonic decay. The use of the
constrained fitting method and multiple smearings for both two- and three-point
correlators allows an improved calculation of the form factors.Comment: Talk given at Lattice2001(heavyquark), 3 pages, 4 figure
Civil Justice Systems in Europe and the United States
Professor Dr. Hein D. Kötz - dean of Bucerius Law School in Hamburg, Germany, and a leading scholar in comparative law - presents the inaugural Herbert L. Bernstein Memorial Lecture titled, Civil Justice Systems in Europe and the United States
Restriction of stable rank two vector bundles in arbitrary characteristic
Let be a smooth variety defined over an algebraically closed field of
arbitrary characteristic and \O_X(H) be a very ample line bundle on . We
show that for a semistable -bundle of rank two, there exists an integer
depending only on and such that the
restriction of to a general divisor in is again semistable. As
corollaries we obtain boundedness results, and weak versions of Bogomolov's
theorem and Kodaira's vanishing theorem for surfaces in arbitrary
characteristic.Comment: LaTeX document, 16 pages, no figure
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