269 research outputs found
Topological Phenomena in the Real Periodic Sine-Gordon Theory
The set of real finite-gap Sine-Gordon solutions corresponding to a fixed
spectral curve consists of several connected components. A simple explicit
description of these components obtained by the authors recently is used to
study the consequences of this property. In particular this description allows
to calculate the topological charge of solutions (the averaging of the
-derivative of the potential) and to show that the averaging of other
standard conservation laws is the same for all components.Comment: LaTeX, 18 pages, 3 figure
Elliptic solutions to difference non-linear equations and related many-body problems
We study algebro-geometric (finite-gap) and elliptic solutions of fully
discretized KP or 2D Toda equations. In bilinear form they are Hirota's
difference equation for -functions. Starting from a given algebraic
curve, we express the -function and the Baker-Akhiezer function in terms
of the Riemann theta function. We show that the elliptic solutions, when the
-function is an elliptic polynomial, form a subclass of the general
algebro-geometric solutions. We construct the algebraic curves of the elliptic
solutions. The evolution of zeros of the elliptic solutions is governed by the
discrete time generalization of the Ruijsenaars-Schneider many body system. The
zeros obey equations which have the form of nested Bethe-Ansatz equations,
known from integrable quantum field theories. We discuss the Lax representation
and the action-angle-type variables for the many body system. We also discuss
elliptic solutions to discrete analogues of KdV, sine-Gordon and 1D Toda
equations and describe the loci of the zeros.Comment: 22 pages, Latex with emlines2.st
Isomonodromic deformations and supersymmetric gauge theories
Seiberg-Witten solutions of four-dimensional supersymmetric gauge theories
possess rich but involved integrable structures. The goal of this paper is to
show that an isomonodromy problem provides a unified framework for
understanding those various features of integrability. The Seiberg-Witten
solution itself can be interpreted as a WKB limit of this isomonodromy problem.
The origin of underlying Whitham dynamics (adiabatic deformation of an
isospectral problem), too, can be similarly explained by a more refined
asymptotic method (multiscale analysis). The case of SU()
supersymmetric Yang-Mills theory without matter is considered in detail for
illustration. The isomonodromy problem in this case is closely related to the
third Painlev\'e equation and its multicomponent analogues. An implicit
relation to t\tbar fusion of topological sigma models is thereby expected.Comment: Several typos are corrected, and a few sentenses are altered. 19 pp +
a list of corrections (page 20), LaTe
Semiclassical Quantisation of Finite-Gap Strings
We perform a first principle semiclassical quantisation of the general
finite-gap solution to the equations of a string moving on R x S^3. The
derivation is only formal as we do not regularise divergent sums over stability
angles. Moreover, with regards to the AdS/CFT correspondence the result is
incomplete as the fluctuations orthogonal to this subspace in AdS_5 x S^5 are
not taken into account. Nevertheless, the calculation serves the purpose of
understanding how the moduli of the algebraic curve gets quantised
semiclassically, purely from the point of view of finite-gap integration and
with no input from the gauge theory side. Our result is expressed in a very
compact and simple formula which encodes the infinite sum over stability angles
in a succinct way and reproduces exactly what one expects from knowledge of the
dual gauge theory. Namely, at tree level the filling fractions of the algebraic
curve get quantised in large integer multiples of hbar = 1/lambda^{1/2}. At
1-loop order the filling fractions receive Maslov index corrections of hbar/2
and all the singular points of the spectral curve become filled with small
half-integer multiples of hbar. For the subsector in question this is in
agreement with the previously obtained results for the semiclassical energy
spectrum of the string using the method proposed in hep-th/0703191.
Along the way we derive the complete hierarchy of commuting flows for the
string in the R x S^3 subsector. Moreover, we also derive a very general and
simple formula for the stability angles around a generic finite-gap solution.
We also stress the issue of quantum operator orderings since this problem
already crops up at 1-loop in the form of the subprincipal symbol.Comment: 53 pages, 22 figures; some significant typos corrected, references
adde
- …