21,941 research outputs found
Classical and Quantum Nonultralocal Systems on the Lattice
We classify nonultralocal Poisson brackets for 1-dimensional lattice systems
and describe the corresponding regularizations of the Poisson bracket relations
for the monodromy matrix . A nonultralocal quantum algebras on the lattices for
these systems are constructed.For some class of such algebras an
ultralocalization procedure is proposed.The technique of the modified
Bethe-Anzatz for these algebras is developed.This technique is applied to the
nonlinear sigma model problem.Comment: 33 pp. Latex. The file is resubmitted since it was spoiled during
transmissio
Renormalization programme for effective theories
We summarize our latest developments in perturbative treating the effective
theories of strong interactions. We discuss the principles of constructing the
mathematically correct expressions for the S-matrix elements at a given loop
order and briefly review the renormalization procedure. This talk shall provide
the philosophical basement as well as serve as an introduction for the material
presented at this conference by A. Vereshagin and K. Semenov-Tian-Shansky.Comment: 6 pages, talk given at HSQCD 2004, Russia, May 2004, to be published
in Proceeding
Drinfeld-Sokolov reduction for difference operators and deformations of W-algebras. II. General Semisimple Case
The paper is the sequel to q-alg/9704011. We extend the Drinfeld-Sokolov
reduction procedure to q-difference operators associated with arbitrary
semisimple Lie algebras. This leads to a new elliptic deformation of the Lie
bialgebra structure on the associated loop algebra. The related classical
r-matrix is explicitly described in terms of the Coxeter transformation. We
also present a cross-section theorem for q-gauge transformations which
generalizes a theorem due to R.Steinberg.Comment: 19 pp., AMS-LaTeX. The paper replaces a temporarily withdrawn text;
the first part (written by E. Frenkel, N. Reshetikhin, and M. A.
Semenov-Tian-Shansky) is available as q-alg/970401
Bootstrap and the Parameters of Pion-Nucleon Resonances
In this talk we demonstrate the results of application of the perturbative
effective theory formalism developed in recent papers to the calculation of
elastic scattering amplitude. Restrictions on the contributing
resonance parameters are obtained and the low energy coefficients are
calculated.Comment: 6 pages, talk given at the X. International Conference On Hadron
Spectroscopy (HADRON'03), August 31 - September 6, 2003, Aschaffenburg,
Germany; to appear in Proceeding
Dual parametrization of GPDs versus the double distribution Ansatz
We establish a link between the dual parametrization of GPDs and a popular
parametrization based on the double distribution Ansatz, which is in prevalent
use in phenomenological applications. We compute several first forward-like
functions that express the double distribution Ansatz for GPDs in the framework
of the dual parametrization and show that these forward-like functions make the
dominant contribution into the GPD quintessence function. We also argue that
the forward-like functions with contribute to the
leading singular small- behavior of the imaginary part of DVCS
amplitude. This makes the small- behavior of \im A^{DVCS} independent
of the asymptotic behavior of PDFs. Assuming analyticity of Mellin moments of
GPDs in the Mellin space we are able to fix the value of the -form factor in
terms of the GPD quintessence function and the forward-like function
.Comment: 18 pages, 5 figures. A version that appeared in Eur. Phys. J. A. Some
of the statements were refined and misprints in the formulas were correcte
Localizable Effective Theories, Bootstrap and the Parameters of Hadron Resonances
We discuss the basic principles of constructing a meaningful perturbative
scheme for effective theory. The main goal of this talk is to explain the
approach and to present recent results obtained with the help of the method of
Cauchy forms in several complex variables.Comment: 6 pages, Talk given at the X. International Conference On Hadron
spectroscopy (HADRON'03), August 31 - September 6, 2003, Aschaffenburg,
Germany; to appear in Proceeding
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