433 research outputs found
Form-factors of exponential fields in the sine-Gordon model
An integral representation for form-factors of exponential fields in the
sine-Gordon model is proposed.Comment: 8 pages, harvmac.tex, added the formula (25) for two soliton
form-factors at the reflectionless point
Particle-Field Duality and Form Factors from Vertex Operators
Using a duality between the space of particles and the space of fields, we
show how one can compute form factors directly in the space of fields. This
introduces the notion of vertex operators, and form factors are vacuum
expectation values of such vertex operators in the space of fields. The vertex
operators can be constructed explicitly in radial quantization. Furthermore,
these vertex operators can be exactly bosonized in momentum space. We develop
these ideas by studying the free-fermion point of the sine-Gordon theory, and
use this scheme to compute some form-factors of some non-free fields in the
sine-Gordon theory. This work further clarifies earlier work of one of the
authors, and extends it to include the periodic sector.Comment: 17 pages, 2 figures, CLNS 93/??
Form-factors of the sausage model obtained with bootstrap fusion from sine-Gordon theory
We continue the investigation of massive integrable models by means of the
bootstrap fusion procedure, started in our previous work on O(3) nonlinear
sigma model. Using the analogy with SU(2) Thirring model and the O(3) nonlinear
sigma model we prove a similar relation between sine-Gordon theory and a
one-parameter deformation of the O(3) sigma model, the sausage model. This
allows us to write down a free field representation for the
Zamolodchikov-Faddeev algebra of the sausage model and to construct an integral
representation for the generating functions of form-factors in this theory. We
also clear up the origin of the singularities in the bootstrap construction and
the reason for the problem with the kinematical poles.Comment: 16 pages, revtex; references added, some typos corrected. Accepted
for publication in Physical Review
Free field representation for the O(3) nonlinear sigma model and bootstrap fusion
The possibility of the application of the free field representation developed
by Lukyanov for massive integrable models is investigated in the context of the
O(3) sigma model. We use the bootstrap fusion procedure to construct a free
field representation for the O(3) Zamolodchikov- Faddeev algebra and to write
down a representation for the solutions of the form-factor equations which is
similar to the ones obtained previously for the sine-Gordon and SU(2) Thirring
models. We discuss also the possibility of developing further this
representation for the O(3) model and comment on the extension to other
integrable field theories.Comment: 14 pages, latex, revtex v3.0 macro package, no figures Accepted for
publication in Phys. Rev.
Exact Solution for 1D Spin-Polarized Fermions with Resonant Interactions
Using the asymptotic Bethe Ansatz, we obtain an exact solution of the
many-body problem for 1D spin-polarized fermions with resonant p-wave
interactions, taking into account the effects of both scattering volume and
effective range. Under typical experimental conditions, accounting for the
effective range, the properties of the system are significantly modified due to
the existence of "shape" resonances. The excitation spectrum of the considered
model has unexpected features, such as the inverted position of the particle-
and hole-like branches at small momenta, and roton-like minima. We find that
the frequency of the "breathing" mode in the harmonic trap provides an
unambiguous signature of the effective range.Comment: final version to be published in Phys. Rev. Let
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Flow-induced dynamic surface tension effects at nanoscale
The aim of this study is to investigate flow-induced dynamic surface tension effects, similar to the well-known Marangoni phenomena, but solely generated by the nanoscale topography of the substrates. The flow-induced surface tension effects are examined on the basis of a sharp interface theory. It is demonstrated how nanoscale objects placed at the boundary of the flow domain result in the generation of substantial surface forces acting on the bulk flow
Exact Results for Thermodynamics of the Classical Field Theories: Sine- and Sinh-Gordon Models
Using the recently obtained exact results for the expectation values of
operators in the sine- and sinh-Gordon models [A. B. Zamolodchikov and S.
Lukyanov, Nucl. Phys. B{\bf 493}, 571 (1997), V. Fateev, S. Lukyanov, A. B.
Zamolodchikov and Al. B. Zamolodchikov, Phys. Lett. B{\bf 406}, 83 (1997)] we
calculate the specific heat of the corresponding two dimensional Euclidean
(classical) models.
We show that the temperature dependence of the specific heat of the
sine-Gordon model, in the commensurate phase, has a maximum well below the
Kosterlitz-Thouless transition and that the sinh-Gordon model is
thermodynamically unstable in the strong coupling regime. We give also the
temperature dependence of the specific heat in the incommensurate phase of the
sine-Gordon model.Comment: 14 pages, including 6 figures; updated version; submitted to Phys.
Rev.
Quasi-one-dimensional anisotropic Heisenberg model in a transverse magnetic field
The phase diagram of weakly coupled chains in a transverse magnetic
field is studied using the mean-field approximation for the interchain coupling
and known exact results for an effective one-dimensional model. Results are
applied to the quasi-one-dimensional antiferromagnet and the
value of interchain interaction in this compound is estimated.Comment: 4 pages, 2 figure
Zero temperature geometric spin dephasing on a ring in presence of an Ohmic environment
We study zero temperature spin dynamics of a particle confined to a ring in
presence of spin orbit coupling and Ohmic electromagnetic fluctuations. We show
that the dynamics of the angular position are decoupled from the
spin dynamics and that the latter is mapped to certain correlations of a
spinless particle. We find that the spin correlations in the direction
(perpendicular to the ring) are finite at long times, i.e. do not dephase. The
parallel (in plane) components for spin \half do not dephase at weak
dissipation but they probably decay as a power law with time at strong
dissipation.Comment: 5 pages, submitted to EP
Isotopic distribution of fission fragments in collisions between 238U beam and 9Be and 12C targets at 24 MeV/u
Inverse kinematics coupled to a high-resolution spectrometer is used to
investigate the isotopic yields of fission fragments produced in reactions
between a 238U beam at 24 MeV/u and 9Be and 12C targets. Mass, atomic number
and isotopic distributions are reported for the two reactions. These
informations give access to the neutron excess and the isotopic distribution
widths, which together with the atomic-number and mass distributions are used
to investigate the fusion-fission dynamics.Comment: Submitted to PR
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