289 research outputs found
Truncated Hilbert space approach to the 2d theory
We apply the massive analogue of the truncated conformal space approach to
study the two dimensional theory in finite volume. We focus on the
broken phase and determine the finite size spectrum of the model numerically.
We interpret the results in terms of the Bethe-Yang spectrum, from which we
extract the infinite volume masses and scattering matrices for various
couplings. We compare these results against semiclassical analysis and
perturbation theory. We also analyze the critical point of the model and
confirm that it is in the Ising universality class.Comment: pdflatex, 35 pages with 29 pdf figures. Binary program is also
attached, run on linux as: phi4 config.dat, v2: typos corrected, comparison
to other works and references added, vacuum splitting analysis corrected,
comparison to sine-Gordon TCSA added, v3: improved numerics, analysis on
excited kink added, critical point investigate
Symplectic leaves of W-algebras from the reduced Kac-Moody point of view
The symplectic leaves of W-algebras are the intersections of the symplectic
leaves of the Kac-Moody algebras and the hypersurface of the second class
constraints, which define the W-algebra. This viewpoint enables us to classify
the symplectic leaves and also to give a representative for each of them. The
case of the (W_{2}) (Virasoro) algebra is investigated in detail, where the
positivity of the energy functional is also analyzed.Comment: Latex, 6 pages, Talk presented by Z. Bajnok at the Second
International Conference on Geometry, Integrability and Quantization, Varna,
200
Explicit boundary form factors: the scaling Lee-Yang model
We provide explicit expressions for boundary form factors in the boundary
scaling Lee-Yang model for operators with the mildest ultraviolet behavior for
all integrable boundary conditions. The form factors of the boundary stress
tensor take a determinant form, while the form factors of the boundary primary
field contain additional explicit polynomials.Comment: 18 pages, References adde
A2 Toda theory in reduced WZNW framework and the representations of the W algebra
Using the reduced WZNW formulation we analyse the classical orbit content
of the space of classical solutions of the Toda theory. We define the
quantized Toda field as a periodic primary field of the 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 algebra.Comment: 38 page
Toda theory in the reduced WZNW framework
We consider the Toda theory in the reduced WZNW framework. Analysing the classical representation space of the symmetry algebra (which is the corresponding algebra) we determine its classical highest weight representations. We quantise the model promoting only the relevant quantities to operators. Using the quantised equation of motion we determine the selection rules for the field that corresponds to one of the Toda fields and give restrictions for its amplitude functions and for the structure of the Hilbert space of the model
Boundary reduction formula
An asymptotic theory is developed for general non-integrable boundary quantum
field theory in 1+1 dimensions based on the Langrangean description. Reflection
matrices are defined to connect asymptotic states and are shown to be related
to the Green functions via the boundary reduction formula derived. The
definition of the -matrix for integrable theories due to Ghoshal and
Zamolodchikov and the one used in the perturbative approaches are shown to be
related.Comment: 12 pages, Latex2e file with 5 eps figures, two Appendices about the
boundary Feynman rules and the structure of the two point functions are adde
C2 TODA THEORY IN THE REDUCED WZNW FRAMEWORK
We consider the Toda theory in the reduced WZNW framework. Analysing
the classical representation space of the symmetry algebra (which is the
corresponding algebra) we determine its classical highest weight
representations. We quantise the model promoting only the relevant quantities
to operators. Using the quantised equation of motion we determine the selection
rules for the field that corresponds to one of the Toda fields and give
restrictions for its amplitude functions and for the structure of the Hilbert
space of the model.Comment: 26 pages, TeX, ITP Budapest 501, minor modification
Solving topological defects via fusion
Integrable defects in two-dimensional integrable models are purely
transmitting thus topological. By fusing them to integrable boundaries new
integrable boundary conditions can be generated, and, from the comparison of
the two solved boundary theories, explicit solutions of defect models can be
extracted. This idea is used to determine the transmission factors and defect
energies of topological defects in sinh-Gordon and Lee-Yang models. The
transmission factors are checked in Lagrangian perturbation theory in the
sinh-Gordon case, while the defect energies are checked against defect
thermodynamic Bethe ansatz equations derived to describe the ground-state
energy of diagonal defect systems on a cylinder. Defect bootstrap equations are
also analyzed and are closed by determining the spectrum of defect bound-states
in the Lee-Yang model.Comment: LaTeX, 24 pages, 34 eps figure
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