1,282 research outputs found
Analysis and modelling of the temporal spread of African cassava mosaic virus and implications for disease control
Generalized duality between local vector theories in
The existence of an interpolating master action does not guarantee the same
spectrum for the interpolated dual theories. In the specific case of a
generalized self-dual (GSD) model defined as the addition of the Maxwell term
to the self-dual model in , previous master actions have furnished a
dual gauge theory which is either nonlocal or contains a ghost mode. Here we
show that by reducing the Maxwell term to first order by means of an auxiliary
field we are able to define a master action which interpolates between the GSD
model and a couple of non-interacting Maxwell-Chern-Simons theories of opposite
helicities. The presence of an auxiliary field explains the doubling of fields
in the dual gauge theory. A generalized duality transformation is defined and
both models can be interpreted as self-dual models. Furthermore, it is shown
how to obtain the gauge invariant correlators of the non-interacting MCS
theories from the correlators of the self-dual field in the GSD model and
vice-versa. The derivation of the non-interacting MCS theories from the GSD
model, as presented here, works in the opposite direction of the soldering
approach.Comment: 11 pages, no figures, to appear in J. of High Energy Phy
Asymptotic behaviour of the spectrum of a waveguide with distant perturbations
We consider the waveguide modelled by a -dimensional infinite tube. The
operator we study is the Dirichlet Laplacian perturbed by two distant
perturbations. The perturbations are described by arbitrary abstract operators
''localized'' in a certain sense, and the distance between their ''supports''
tends to infinity. We study the asymptotic behaviour of the discrete spectrum
of such system. The main results are a convergence theorem and the asymptotics
expansions for the eigenvalues. The asymptotic behaviour of the associated
eigenfunctions is described as well. We also provide some particular examples
of the distant perturbations. The examples are the potential, second order
differential operator, magnetic Schroedinger operator, curved and deformed
waveguide, delta interaction, and integral operator
A model for the atomic-scale structure of a dense, nonequilibrium fluid: the homogeneous cooling state of granular fluids
It is shown that the equilibrium Generalized Mean Spherical Model of fluid
structure may be extended to nonequilibrium states with equation of state
information used in equilibrium replaced by an exact condition on the two-body
distribution function. The model is applied to the homogeneous cooling state of
granular fluids and upon comparison to molecular dynamics simulations is found
to provide an accurate picture of the pair distribution function.Comment: 29 pages, 11 figures Revision corrects formatting of the figure
True Superconductivity in a 2D "Superconducting-Insulating" System
We present results on disordered amorphous films which are expected to
undergo a field-tuned Superconductor-Insulator Transition. Based on low-field
data and I-V characteristics, we find evidence of a low temperature
Metal-to-Superconductor transition. This transition is characterized by
hysteretic magnetoresistance and discontinuities in the I-V curves. The
metallic phase just above the transition is different from the "Fermi Metal"
before superconductivity sets in.Comment: 3 pages, 4 figure
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