A2 Toda theory in reduced WZNW framework and the representations of the W algebra

Using the reduced WZNW formulation we analyse the classical $W$ orbit content of the space of classical solutions of the $A_2$ Toda theory. We define the quantized Toda field as a periodic primary field of the $W$ algebra satisfying the quantized equations of motion. We show that this local operator can be constructed consistently only in a Hilbert space consisting of the representations corresponding to the minimal models of the $W$ algebra.Comment: 38 page

Finite size effects in boundary sine-Gordon theory

We examine the finite volume spectrum and boundary energy in boundary sine-Gordon theory, based on our recent results obtained by closing the boundary bootstrap. The spectrum and the reflection factors are checked against truncated conformal space, together with a (still unpublished) prediction by Al.B. Zamolodchikov for the boundary energy and the relation between the parameters of the scattering amplitudes and of the perturbed CFT Hamiltonian. In addition, a derivation of Zamolodchikov's formulae is given. We find an entirely consistent picture and strong evidence for the validity of the conjectured spectrum and scattering amplitudes, which together give a complete description of the boundary sine-Gordon theory on mass shell. (C) 2002 Elsevier Science B.V. All rights reserved

Boundary sine-Gordon model

We review our recent results on the on-shell description of sine-Gordon model with integrable boundary conditions. We determined the spectrum of boundary states together with their reflection factors by closing the boundary bootstrap and checked these results against WKB quantization and numerical finite volume spectra obtained from the truncated conformal space approach. The relation between a boundary resonance state and the semiclassical instability of a static classical solution is analyzed in detail.Comment: 15 pages, 7 eps figures, Talk presented at 'Workshop on Integrable Theories, Solitons and Duality', 1-6 July 2002, Sao Paulo, Brazi

SUSY sine-Gordon theory as a perturbed conformal field theory and finite size effects

We consider SUSY sine-Gordon theory in the framework of perturbed conformal field theory. Using an argument from Zamolodchikov, we obtain the vacuum structure and the kink adjacency diagram of the theory, which is cross-checked against the exact S-matrix prediction, first-order perturbed conformal field theory (PCFT), the NLIE method and truncated conformal space approach. We provide evidence for consistency between the usual Lagrangian description and PCFT on the one hand, and between PCFT, NLIE and a massgap formula conjectured by Baseilhac and Fateev, on the other. In addition, we extend the NLIE description to all the vacua of the theory. (C) 2003 Elsevier B.V. All rights reserved

Boundary form factors of the sinh-Gordon model with Dirichlet boundary conditions at the self-dual point

In this manuscript we present a detailed investigation of the form factors of boundary fields of the sinh-Gordon model with a particular type of Dirichlet boundary condition, corresponding to zero value of the sinh-Gordon field at the boundary, at the self-dual point. We follow for this the boundary form factor program recently proposed by Z. Bajnok, L. Palla and G. Takaks in hep-th/0603171, extending the analysis of the boundary sinh-Gordon model initiated there. The main result of the paper is a conjecture for the structure of all n-particle form factors of two particular boundary operators in terms of elementary symmetric polynomials in certain functions of the rapidity variables. In addition, form factors of boundary "descendant" fields have been constructedComment: 14 pages LaTex. Version to appear in J. Phys.