552 research outputs found
Integrability, Non-integrability and confinement
We discuss the main features of quantum integrable models taking the classes
of universality of the Ising model and the repulsive Lieb-Liniger model as
paradigmatic examples. We address the breaking of integrability by means of two
approaches, the Form Factor Perturbation Theory and semiclassical methods. Each
of them has its own advantage. Using the first approach, one can relate the
confinement phenomena of topological excitations to the semi-locality of the
operator which breaks integrability. Using the second approach, one can control
the bound states which arise in each phase of the theory and predict that their
number cannot be more than two.Comment: Invited talk at StatPhys24, Cairns (Australia) 2010. 27 pages, 16
figure
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 for the form factors and
. Analyzing the cluster property of the form factors, a particular
class of these solutions can be identified with the matrix elements of the
operators . We also present the complete expression of the form
factors of the elementary field and the trace of the energy-momentum
tensor .Comment: ISAS/EP/93/42, to appear in Phys. Lett.
Stress-Energy Tensor and Ultraviolet Behaviour in Massive Integrable Quantum Field Theories
The short distance behaviour of massive integrable quantum field theories is
analyzed in terms of the form factor approach. We show that the on-shell
dynamics is compatible with different definitions of the stress-energy tensor
of the theory. In terms of form factors, this is equivalent to
having a possible non-zero matrix element of the trace of on
one-particle state. Each choice of induces a different scaling behaviour
of the massive theory in the ultraviolet limit.Comment: 32 pages LATEX file (Three figures not included in the text)
ISAS/EP/93/6
Universal Ratios and Correlation Functions
We review some recent results concerning the quantitative analysis of the
universality classes of two-dimensional statistical models near their critical
point. We also discuss the exact calculation of the two--point correlation
functions of disorder operators in a free theory of complex bosonic and
fermionic field, correlators ruled by a Painleve differential equation.Comment: 10 pages, JHEP Proceedings of the Workshop on Integrable Theories,
Solitons and Duality, IFT-Unesp, Sao Paulo, Brasi
Effective potentials and kink spectra in non-integrable perturbed conformal field theories
We analyze the evolution of the effective potential and the particle spectrum
of two-parameter families of non-integrable quantum field theories. These
theories are defined by deformations of conformal minimal models M_m by using
the operators Phi_{1,3}, Phi_{1,2} and Phi_{2,1}. This study extends to all
minimal models the analysis previously done for the classes of universality of
the Ising, the Tricritical Ising and the RSOS models. We establish the symmetry
and the duality properties of the various models also identifying the limiting
theories that emerge when m goes to infinity.Comment: 30 pages, pdflatex,17 figures
1D Lieb-Liniger Bose Gas as Non-Relativistic Limit of the Sinh-Gordon Model
The repulsive Lieb-Liniger model can be obtained as the non-relativistic
limit of the Sinh-Gordon model: all physical quantities of the latter model
(S-matrix, Lagrangian and operators) can be put in correspondence with those of
the former. We use this mapping, together with the Thermodynamical Bethe Ansatz
equations and the exact form factors of the Sinh-Gordon model, to set up a
compact and general formalism for computing the expectation values of the
Lieb-Liniger model both at zero and finite temperature. The computation of
one-point correlators is thoroughly detailed and, when possible, compared with
known results in the literature.Comment: published version, 27 pages, 10 figure
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