1,114 research outputs found
Exact conserved quantities on the cylinder II: off-critical case
With the aim of exploring a massive model corresponding to the perturbation
of the conformal model [hep-th/0211094] the nonlinear integral equation for a
quantum system consisting of left and right KdV equations coupled on the
cylinder is derived from an integrable lattice field theory. The eigenvalues of
the energy and of the transfer matrix (and of all the other local integrals of
motion) are expressed in terms of the corresponding solutions of the nonlinear
integral equation. The analytic and asymptotic behaviours of the transfer
matrix are studied and given.Comment: enlarged version before sending to jurnal, second part of
hep-th/021109
On one-point functions for sinh-Gordon model at finite temperature
Using fermionic basis we conjecture the exact formulae for the expectation
values of local fields in sinh-Gordon model. The conjecture is checked against
previously known results.Comment: 21 pages, some explanation on relation to the lattice model is adde
Semiclassical Particle Spectrum of Double Sine-Gordon Model
We present new theoretical results on the spectrum of the quantum field
theory of the Double Sine Gordon model. This non-integrable model displays
different varieties of kink excitations and bound states thereof. Their mass
can be obtained by using a semiclassical expression of the matrix elements of
the local fields. In certain regions of the coupling-constants space the
semiclassical method provides a picture which is complementary to the one of
the Form Factor Perturbation Theory, since the two techniques give information
about the mass of different types of excitations. In other regions the two
methods are comparable, since they describe the same kind of particles.
Furthermore, the semiclassical picture is particularly suited to describe the
phenomenon of false vacuum decay, and it also accounts in a natural way the
presence of resonance states and the occurrence of a phase transition.Comment: 32 pages, latex, 8 figure
The open XXZ and associated models at q root of unity
The generalized open XXZ model at root of unity is considered. We review
how associated models, such as the harmonic oscillator, and the lattice
sine-Gordon and Liouville models are obtained. Explicit expressions of the
local Hamiltonian of the spin XXZ spin chain coupled to dynamical
degrees of freedom at the one end of the chain are provided. Furthermore, the
boundary non-local charges are given for the lattice sine Gordon model and the
harmonic oscillator with open boundaries. We then identify the spectrum and
the corresponding Bethe states, of the XXZ and the q harmonic oscillator in the
cyclic representation with special non diagonal boundary conditions. Moreover,
the spectrum and Bethe states of the lattice versions of the sine-Gordon and
Liouville models with open diagonal boundaries is examined. The role of the
conserved quantities (boundary non-local charges) in the derivation of the
spectrum is also discussed.Comment: 31 pages, LATEX, minor typos correcte
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