S-Matrices of ϕ1,2\phi_{1,2} perturbed unitary minimal models: IRF-Formulation and Bootstrap-Program

We analyze the algebraic structure of $\phi_{1,2}$ perturbed minimal models relating them to graph-state models with an underlying Birman-Wenzl-Murakami algebra. Using this approach one can clarify some physical properties and reformulate the bootstrap equations. These are used to calculate the $S$-matrix elements of higher kinks, and to determine the breather spectrum of the $\phi_{1,2}$ perturbations of the unitary minimal models \M_{r,r+1}.Comment: 20 pp, SISSA 192/92/E

Local Operators in Massive Quantum Field Theories

Contribution to the proceedings of Schladming 1995. A review of the form factor approach and its utilisation to determine the space of local operators of integrable massive quantum theories is given. A few applications are discussed.Comment: 6 pages, late

On the Operator Content of the Sinh-Gordon Model

We classify the operator content of local hermitian scalar operators in the Sinh-Gordon model by means of independent solutions of the form-factor bootstrap equations. The corresponding linear space is organized into a tower-like structure of dimension $n$ for the form factors $F_{2n}$ and $F_{2n-1}$. Analyzing the cluster property of the form factors, a particular class of these solutions can be identified with the matrix elements of the operators $e^{k g\phi}$. We also present the complete expression of the form factors of the elementary field $\phi(x)$ and the trace of the energy-momentum tensor $\Theta(x)$.Comment: ISAS/EP/93/42, to appear in Phys. Lett.

On the S-matrix of the Sub-leading Magnetic Deformation of the Tricritical Ising Model in Two Dimensions

We compute the $S$-matrix of the Tricritical Ising Model perturbed by the subleading magnetic operator using Smirnov's RSOS reduction of the Izergin-Korepin model. The massive model contains kink excitations which interpolate between two degenerate asymmetric vacua. As a consequence of the different structure of the two vacua, the crossing symmetry is implemented in a non-trivial way. We use finite-size techniques to compare our results with the numerical data obtained by the Truncated Conformal Space Approach and find good agreement.Comment: 21 page

Counting the local fields in SG theory.

In terms of the form factor bootstrap we describe all the local fields in SG theory and check the agreement with the free fermion case. We discuss the interesting structure responsible for counting the local fields.Comment: 16 pages AMSTEX References to the papers by A. Koubek and G. Mussargo are added. In view of them the stasus of the problem with scalar S-matrices is reconsidered

Form Factors of the Elementary Field in the Bullough-Dodd Model

We derive the recursive equations for the form factors of the local hermitian operators in the Bullough-Dodd model. At the self-dual point of the theory, the form factors of the fundamental field of the Bullough-Dodd model are equal to those of the fundamental field of the Sinh-Gordon model at a specific value of the coupling constant.Comment: 14 pages, LATEX file, ISAS/EP/92/208;USP-IFQSC/TH/92-5

The space of local operators in perturbed conformal field theories,

The space of local operators in massive deformations of conformal field theories is analysed. For several model systems it is shown that one can define chiral sectors in the theory, such that the chiral field content is in a one-to-one correspondence with that of the underlying conformal field theory. The full space of operators consists of the descendent spaces of all scalar fields. If the theory contains asymptotic states which satisfy generalised statistics, the form factor equations admit in addition also solutions corresponding to the descendent spaces of the para-fermionic operators of the same spin as the asymptotic states. The derivation of these results uses $q$-sum expressions for the characters and $q$-difference equations used in proving Rogers-Ramanujan type identities.Comment: 38 pages, LaTeX, to appear in Nuclear Physics B

The Sub-leading Magnetic Deformation of the Tricritical Ising Model in 2D as RSOS Restriction of the Izergin-Korepin Model

We compute the $S$-matrix of the Tricritical Ising Model perturbed by the subleading magnetic operator using Smirnov's RSOS reduction of the Izergin-Korepin model. We discuss some features of the scattering theory we obtain, in particular a non trivial implementation of crossing-symmetry, interesting connections between the asymptotic behaviour of the amplitudes, the possibility of introducing generalized statistics, and the monodromy properties of the OPE of the unperturbed Conformal Field Theory.Comment: (13 pages

Complete Nondiagonal Reflection Matrices of RSOS/SOS and Hard Hexagon Models

In this paper we compute the most general nondiagonal reflection matrices of the RSOS/SOS models and hard hexagon model using the boundary Yang-Baxter equations. We find new one-parameter family of reflection matrices for the RSOS model in addition to the previous result without any parameter. We also find three classes of reflection matrices for the SOS model, which has one or two parameters. For the hard hexagon model which can be mapped to RSOS(5) model by folding four RSOS heights into two, the solutions can be obtained similarly with a main difference in the boundary unitarity conditions. Due to this, the reflection matrices can have two free parameters. We show that these extra terms can be identified with the `decorated' solutions. We also generalize the hard hexagon model by `folding' the RSOS heights of the general RSOS(p) model and show that they satisfy the integrability conditions such as the Yang- Baxter and boundary Yang-Baxter equations. These models can be solved using the results for the RSOS models.Comment: 18pages,Late

Finite Temperature Correlation Functions in Integrable QFT

Finite temperature correlation functions in integrable quantum field theories are formulated only in terms of the usual, temperature-independent form factors, and certain thermodynamic filling fractions which are determined from the thermodynamic Bethe ansatz. Explicit expressions are given for the one and two-point functions.Comment: 25 pages, 3 figures. In Latex. Uses Revte