Exact vortex solutions of the complex sine-Gordon theory on the plane

We construct explicit multivortex solutions for the first and second complex sine-Gordon equations. The constructed solutions are expressible in terms of the modified Bessel and rational functions, respectively. The vorticity-raising and lowering Backlund transformations are interpreted as the Schlesinger transformations of the fifth Painleve equation.Comment: 10 pages, 1 figur

Duality in Complex sine-Gordon Theory

New aspects of the complex sine-Gordon theory are addressed through the reformulation of the theory in terms of the gauged Wess-Zumino-Witten action. A dual transformation between the theory for the coupling constant \b > 0 and the theory for \b < 0 is given which agrees with the Krammers-Wannier duality in the context of perturbed conformal field theory. The B\"{a}cklund transform and the nonlinear superposition rule for the complex sine-Gordon theory are presented and from which, exact solutions, solitons and breathers with U(1) charge, are derived. We clarify topological and nontopological nature of neutral and charged solitons respectively, and discuss about the duality between the vector and the axial U(1) charges.Comment: 10 pages, LaTe

Dyonic Giant Magnons

We study the classical spectrum of string theory on AdS_5 X S^5 in the Hofman-Maldacena limit. We find a family of classical solutions corresponding to Giant Magnons with two independent angular momenta on S^5. These solutions are related via Pohlmeyer's reduction procedure to the charged solitons of the Complex sine-Gordon equation. The corresponding string states are dual to BPS boundstates of many magnons in the spin-chain description of planar N=4 SUSY Yang-Mills. The exact dispersion relation for these states is obtained from a purely classical calculation in string theory.Comment: LaTeX file, 16 pages. One figure. Corrected reference

Noncoaxial multivortices in the complex sine-Gordon theory on the plane

We construct explicit multivortex solutions for the complex sine-Gordon equation (the Lund-Regge model) in two Euclidean dimensions. Unlike the previously found (coaxial) multivortices, the new solutions comprise $n$ single vortices placed at arbitrary positions (but confined within a finite part of the plane.) All multivortices, including the single vortex, have an infinite number of parameters. We also show that, in contrast to the coaxial complex sine-Gordon multivortices, the axially-symmetric solutions of the Ginzburg-Landau model (the stationary Gross-Pitaevskii equation) {\it do not} belong to a broader family of noncoaxial multivortex configurations.Comment: 40 pages, 7 figures in colou

Локальные и сплайновые аппроксимации в цифровой обработке геомагнитных наблюдений

Methods of local and spline approximations for digital processing of geomagnetic observations are proposed for consideration. Algorithms for calculating piecewise-linear, sinusoidal and pol-ynomial local approximation models have been developed. An algorithm for calculating the spline approximation model is developed. The generated mathematical apparatus is focused on solving problems of parameter estimation, filtering and spectral analysis for geomagnetic observations.Предлагаются к рассмотрению методы локальных и сплайновых аппроксимаций для цифровой обработки геомагнитных наблюдений. Разработаны алгоритмы вычислений кусочно- линейных, синусоидальных и полиномиальных локальных аппроксимационных моделей. Разработан алгоритм вычисления сплайновой аппроксимационной модели. Сформированный математический аппарат ориентирован на решения задач оценивания параметров, фильтрации и спектрального анализа для геомагнитных наблюдений

Massive Integrable Soliton Theories

Massive integrable field theories in $1+1$ dimensions are defined at the Lagrangian level, whose classical equations of motion are related to the ``non-abelian'' Toda field equations. They can be thought of as generalizations of the sine-Gordon and complex sine-Gordon theories. The fields of the theories take values in a non-abelian Lie group and it is argued that the coupling constant is quantized, unlike the situation in the sine-Gordon theory, which is a special case since its field takes values in an abelian group. It is further shown that these theories correspond to perturbations of certain coset conformal field theories. The solitons in the theories will, in general, carry non-abelian charges.Comment: 18 pages, no figures, plain tex with macro include

Quantum scattering of charged solitons in the complex sine-Gordon model

The scattering of charged solitons in the complex sine-Gordon field theory is investigated. An exact factorizable S-matrix for the theory is proposed when the renormalized coupling constant takes the values $\lambda^{2}_{R}=4\pi/k$ for any integer $k>1$: the minimal S-matrix associated with the Lie algebra $a_{k-1}$. It is shown that the proposed S-matrix reproduces the leading semiclassical behaviour of all amplitudes in the theory and is the minimal S-matrix which is consistent with the semiclassical spectrum of the model. The results are completely consistent with the description of the complex sine-Gordon theory as the SU$(2)/{\rm U}(1)$ coset model at level $k$ perturbed by its first thermal operator.Comment: SWAT-4

Magnons, their Solitonic Avatars and the Pohlmeyer Reduction

We study the solitons of the symmetric space sine-Gordon theories that arise once the Pohlmeyer reduction has been imposed on a sigma model with the symmetric space as target. Under this map the solitons arise as giant magnons that are relevant to string theory in the context of the AdS/CFT correspondence. In particular, we consider the cases S^n, CP^n and SU(n) in some detail. We clarify the construction of the charges carried by the solitons and also address the possible Lagrangian formulations of the symmetric space sine-Gordon theories. We show that the dressing, or Backlund, transformation naturally produces solitons directly in both the sigma model and the symmetric space sine-Gordon equations without the need to explicitly map from one to the other. In particular, we obtain a new magnon solution in CP^3. We show that the dressing method does not produce the more general "dyonic" solutions which involve non-trivial motion of the collective coordinates carried by the solitons.Comment: 52 page

The complex Sine-Gordon equation as a symmetry flow of the AKNS Hierarchy

It is shown how the complex sine-Gordon equation arises as a symmetry flow of the AKNS hierarchy. The AKNS hierarchy is extended by the ``negative'' symmetry flows forming the Borel loop algebra. The complex sine-Gordon and the vector Nonlinear Schrodinger equations appear as lowest negative and second positive flows within the extended hierarchy. This is fully analogous to the well-known connection between the sine-Gordon and mKdV equations within the extended mKdV hierarchy. A general formalism for a Toda-like symmetry occupying the ``negative'' sector of sl(N) constrained KP hierarchy and giving rise to the negative Borel sl(N) loop algebra is indicated.Comment: 8 pages, LaTeX, typos corrected, references update