Conformal Affine Toda Fields from a Gauged WZNW

The general conformal affine Toda (CAT) fields are derived as the result of imposing the constraint explicitly on the gauged WZNW action. The reduction procedure naturally indicates the integrability of the resulting system. The action, equations of motion, canonical Poisson brackets for this system are derived from WZNW model. The energy momentum tensor is derived also and is shown to be traceless after being improved.     

Integrable Systems and Two-Dimensional Gravity from Conformally Reduced WZNW Model

Imposing constraints with an integer ordering on WZNW model a large series of conformal invariant integrable systems will result. In this letter, a general approach for imposing the first and the second class constraints based on an arbitrary grading scheme of the Lie algebras of the WZNW groups is presented. The first order constraints correspond to integrable systems containing super Toda and conformal affine Toda systems as examples and are related to two-dimensional induced gravity, whilst the second order constraints correspond to supersymmetric-like integrable systems containing super Toda and conformal affine super Toda systems (for super WZNW groups) and are conjectured to be related to twodimensional induced supergravity.     

W-algebras for generalized Toda theories

The generalized Toda theories obtained in a previous paper by the conformal reduction of WZNW theories possess a new class ofW-algebras, namely the algebras of gauge-invariant polynomials of the reduced theories. An algorithm for the construction of base-elements for theW-algebras of all such generalized Toda theories is found, and theW-algebras for the maximalSL(N,R) generalized Toda theories are constructed explicitly, the primary field basis being identified.     

Affine Super Toda Theories as Reduced WZNW Model

The afllne euper Toda theoriea are obtained by imposing second order constraints on the eupergroup-valued WZNW model. The reduction is Hamiltonian so that one can get various properth of affine euper Toda eystem from that of WZNW model.     

ClassicalA n -W-geometry

By analyzing theextrinsic geometry of two dimensional surfaces chirally embedded inC P ⁿ (theC P ⁿ W-surface [1]), we give exact treatments in various aspects of the classical W-geometry in the conformal gauge: First, the basis of tangent and normal vectors are defined at regular points of the surface, such that their infinitesimal displacements are given by connections which coincide with the vector potentials of the (conformal)A _n -Toda Lax pair. Since the latter is known to be intrinsically related with the W symmetries, this gives the geometrical meaning of theA _n W-Algebra. Second, W-surfaces are put in one-to-one correspondence with solutions of the conformally-reduced WZNW model, which is such that the Toda fields give the Cartan part in the Gauss decomposition of its solutions. Third, the additional variables of the Toda hierarchy are used as coordinates ofC P ⁿ . This allows us to show that W-transformations may be extended as particular diffeomorphisms of this target-space. Higher-dimensional generalizations of the WZNW equations are derived and related with the Zakharov-Shabat equations of the Toda hierarchy. Fourth, singular points are studied from a global viewpoint, using our earlier observation [1] that W-surfaces may be regarded as instantons. The global indices of the W-geometry, which are written in terms of the Toda fields, are shown to be the instanton numbers for associated mappings of W-surfaces into the Grassmannians. The relation with the singularities of W-surface is derived by combining the Toda equations with the Gauss-Bonnet theorem.     

Loop Group-Valued CS and WZNW models,integrable systems,and self-dual Yang-Mills theory

Affine CS and WZNW theories with values in infinite-dimensional (loop) groups are proposed. It appears that the affine CS theory naturally introduces a spectral parameter into a CS theory. The Sinh-Gordon, KdV, and nonlinear Schrödinger equations are obtained, via Hamiltonian reductions, from the affine WZNW. It is shown that the self-dual Yang-Mills (SDYM) equation is related to the equation of motion of the affine WZNW and, thus, symmetry algebra underlying the SDYM can be identified with the affine two-loop Kac-Moody algebra of the affine WZNW.K. C. Wong Research Award Winner, address after 28 October 1992: Department of Mathematics, University of Queensland, Brisbane, Queensland 4072, Australia.     

Conformally Reduced WZNW Theory,New Extended Chiral Algebras and Their Associated Toda Type Integrable Systems (Ⅰ) General Framework

We propose and analyse a large class of conformal reductions Cons [g(H,d)] of WZNW theory based on the integral gradations of the underlying Lie algebra g.The W-bases of the associated W-algebras W[g(H,d)] are constru ted under the generalized Drinfeld-Sokolov gauge which we call O'Raifeartaigh gauge of the constrained Kac-Moody currents,and the equations of motion of the extended Toda type integrable systems corresponding to these Walgebras are derived also.     

Heterotic Toda fields

A non-left-right symmetric conformal integrable Toda field theory is constructed. It is found that the conformal algebra for this model is the product of a left chiral W_r+1 algebra and a right chiral W_r+1² algebra. The general classical solution is constructed out of the chiral vectors satisfying the so-called classical exchange algebra. In addition, we derived an explicit Wronskian type solution in relation to the constrained WZNW theory. We also showed that the A_∞ limit of this model is precisely the (B₂, C₁) flow of the standard Toda lattice hierarchy.     

Affine Yang-Mills theory and affine self-dual Chern-Simons Solitons

A four-dimensional affine Yang-Mills theory, i.e. Yang—Mills gauge theory with values in an affine Kac-Moody algebra, is constructed which can give rise to a spontaneous breakdown of the affine symmetry. The affine self-dual Yang-Mills equation (which is a special kind of affine YM theory) in four dimensions is dimensionally reduced to the affine self-dual Chem-Simons equation in two dimensions. The latter is shown to have soliton solutions which satisfy the conformal affine Toda equations.K. C. Wong Research Award Winner; address after 28 October 1992: Department of Mathematics, University of Queensland, Brisbane, Queensland 4072, Australia.     

Towards a field theory of the plateau transitions in the integer quantum Hall effect

We suggest a procedure for calculating correlation functions of the local densities of states (DOS) at the plateau transitions in the integer quantum Hall effect (IQHE). We argue that their correlation functions are appropriately described in terms of the SL( )/SU(2) WZNW model (at the usual Ka –Moody point and with the level 6≤k≤8 ). In this model we have identified the operators corresponding to the local DOS, and derived the partial differential equation determining their correlation functions. The OPEs for powers of the local DOS obtained from this equation are in agreement with available results.     

Quantum group symmetries and non-local currents in 2D QFT

We construct and study the implications of some new non-local conserved currents that exist is a wide variety of massive integrable quantum field theories in 2 dimensions, including the sine-Gordon theory and its generalization to affine Toda theory. These non-local currents provide a non-perturbative formulation of the theories. The symmetry algebras correspond to the quantum affine Kac-Moody algebras. TheS-matrices are completely characterized by these symmetries. FormalS-matrices for the imaginary-coupling affine Toda theories are thereby derived. The application of theseS-matrices to perturbed coset conformal field theory is studied. Non-local charges generating the finite dimensional Quantum Group in the Liouville theory are briefly presented. The formalism based on non-local charges we describe provides an algernative to the quantum inverse scattering method for solving integrable quantum field theories in 2d.     

Constrained current algebras and g/u(1) conformal field theories

Operator quantization of the WZNW theory invariant with respect to an affine Lie algebra with a constrained subalgebra is performed using Dirac's procedure. Upon quantization the initial energy-momentum tensor is replaced by the g/u(1)^d coset construction. The WZNW theory with a constrained current is equivalent to the su(2)/u(1) conformal field theory.     

Reflection amplitudes of boundary Toda theories and thermodynamic Bethe ansatz

We study the ultraviolet asymptotics in A_n affine Toda theories with integrable boundary actions. The reflection amplitudes of non-affine Toda theories in the presence of conformal boundary actions have been obtained from the quantum mechanical reflections of the wave functional in the Weyl chamber and used for the quantization conditions and ground-state energies. We compare these results with the thermodynamic Bethe ansatz derived from both the bulk and (conjectured) boundary scattering amplitudes. The two independent approaches match very well and provide the non-perturbative checks of the boundary scattering amplitudes for Neumann and (+) boundary conditions.     

The Complete Solution of the Classical SL(2,ℝ/U(1) Gauged WZNW Field Theory

We prove that any gauged WZNW model has a Lax pair representation, and give explicitly the general solution of the classical equations of motion of the SL(2,ℝ/U(1) theory. We calculate the symplectic structure of this solution by solving a differential equation of the Gelfand–Dikii type with initial state conditions at infinity, and transform the canonical physical fields non-locally onto canonical free fields. The results will, finally, be collected in a local B?cklund transformation. These calculations prepare the theory for an exact canonical quantization. Received: 9 June 1998 / Accepted: 7 March 1999     

一个经典完全可积的非共形约束的SL(2,R)Wess-Zumino-Novikov-Witten模型(Ⅰ)

通过在ＳＬ（２，Ｒ）Ｗｅｓｓ－Ｚｕｍｉｎｏ－Ｎｏｖｉｋｏｖ－Ｗｉｔｔｅｎ（缩写为ＷＺＮＷ）模型中加入破坏共形对称性的约束，获得了一个新的经典完全可积的二维场论体系，它把著名的ｓｉｎｈ－Ｇｏｒｄｏｎ方程作为其特例。这个广义ｓｉｎｈ－Ｇｏｒｄｏｎ体系的特点是完全可积性和可超定域化，并且描写这些特点的ｒ矩阵是杨－Ｂａｘｔｅｒ方程（经典的）的一个解，它反对称，依赖于两个谱参数，但通过Ｌｏｏｐ代数的自同构变换和谱参数的重新定义后，此ｒ矩阵仍是依赖于一个谱参数的三角型ｒ矩阵。 关键词：     

Moduli Space of IIB Superstring and SUYM in AdS5 × S5

This paper consists of two parts. In part I, we interpret the hidden symmetry of the moduli space of IIB superstring on AdS₅×S⁵ in terms of the chiral embedding in AdS₅, which turns out to be the CP³ conformal affine Toda model. We review how the position μ of poles in the Riemann-Hilbert formulation of dressing transformation and the value of loop parameter μ in the vertex operator of affine algebra determine the moduli space of the soliton solutions, which describes the moduli space of the Green-Schwarz superstring. We show also how this affine SU(4) symmetry affinizes the conformal symmetry in the twistor space, and how a soliton string corresponds to a Robinson congruence with twist and dilation spin coefficients μ of twistor. In part II, by extending the dressing symmetric action of IIB string in AdS₅×S⁵ to the D₃ brane, we find a gauged WZW action of Higgs Yang-Mills field including the 2-cocycle of axially anomaly. The left and right twistor structures of left and right α-planes glue into an ambitwistor. The symmetry group of Nahm equations is centrally extended to an affine group, thus we explain why the spectral curve is given by affine Toda.     

On the Connections of W Algebras from Different Reductions of WZNW Theory

The possible isomorphic relations between W algebras from various conformal reductions of WZNW model are investigated and the criterion for the isomorphism of W algebras is given.In the special case of sl₃ WZNW theory,we show explicitly the isomorphism between W[(111)₂] and W[(12)₁] and discuss the constraint-gauge condition transmutation between the O'Raifeartaigh gauges and the transmutation of conformal weights under the isomorphism transformation.