1,045 research outputs found
Correlation functions in conformal Toda field theory I
Two-dimensional sl(n) quantum Toda field theory on a sphere is considered.
This theory provides an important example of conformal field theory with higher
spin symmetry. We derive the three-point correlation functions of the
exponential fields if one of the three fields has a special form. In this case
it is possible to write down and solve explicitly the differential equation for
the four-point correlation function if the fourth field is completely
degenerate. We give also expressions for the three-point correlation functions
in the cases, when they can be expressed in terms of known functions. The
semiclassical and minisuperspace approaches in the conformal Toda field theory
are studied and the results coming from these approaches are compared with the
proposed analytical expression for the three-point correlation function. We
show, that in the framework of semiclassical and minisuperspace approaches
general three-point correlation function can be reduced to the
finite-dimensional integral.Comment: 54 pages, JHEP styl
Lie and Noether symmetries of geodesic equations and collineations
The Lie symmetries of the geodesic equations in a Riemannian space are
computed in terms of the special projective group and its degenerates (affine
vectors, homothetic vector and Killing vectors) of the metric. The Noether
symmetries of the same equations are given in terms of the homothetic and the
Killing vectors of the metric. It is shown that the geodesic equations in a
Riemannian space admit three linear first integrals and two quadratic first
integrals. We apply the results in the case of Einstein spaces, the
Schwarzschild spacetime and the Friedman Robertson Walker spacetime. In each
case the Lie and the Noether symmetries are computed explicitly together with
the corresponding linear and quadratic first integrals.Comment: 19 page
Spatially and polarization resolved plasmon mediated transmission through continuous metal films
The experimental demonstration and characterization is made of the
plasmon-mediated resonant transmission through an embedded undulated continuous
thin metal film under normal incidence. 1D undulations are shown to enable a
spatially resolved polarisation filtering whereas 2D undulations lead to
spatially resolved, polarization independent transmission. Whereas the needed
submicron microstructure lends itself in principle to CD-like low-cost mass
replication by means of injection moulding and embossing, the present paper
demonstrates the expected transmission effects on experimental models based on
metal-coated photoresist gratings. The spectral and angular dependence in the
neighbourhood of resonance are investigated and the question of the excess
losses exhibited by surface plasmons is discusse
Variability in Zoobenthic Blue Carbon storage across a Southern Polar Gradient
The seabed of the Antarctic continental shelf hosts most of Antarctica's known species, including taxa considered indicative of vulnerable marine ecosystems (VMEs). Nonetheless, the potential impact of climatic and environmental change, including marine icescape transition, on Antarctic shelf zoobenthos, and their blue carbon-associated function, is still poorly characterised. To help narrow knowledge gaps, four continental shelf study areas, spanning a southern polar gradient, were investigated for zoobenthic (principally epi-faunal) carbon storage (a component of blue carbon), and potential environmental influences, employing a functional group approach. Zoobenthic carbon storage was highest at the two southernmost study areas (with a mean estimate of 41.6 versus 7.2 g C m−2) and, at each study area, increased with morphotaxa richness, overall faunal density, and VME indicator density. Functional group mean carbon content varied with study area, as did each group's percentage contribution to carbon storage and faunal density. Of the environmental variables explored, sea-ice cover and primary production, both likely to be strongly impacted by climate change, featured in variable subsets most highly correlating with assemblage and carbon storage (by functional groups) structures. The study findings can underpin biodiversity- and climate-considerate marine spatial planning and conservation measures in the Southern Ocean
Measurement of the inclusive branching fraction tau- ---> TAU-neutrino pi- pi0 + neutral meson(s)
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New Molecular Collisional Interaction Effect in Low-Energy Sputtering
Y. Yao, Z. Hargitai, M. Albert, R. G. Albridge, A. V. Barnes, J. M. Gilligan, B. Pratt Ferguson,
G. Lüpke, V. D. Gordon (currently with UT Austin), and N. H. Tolk are with the
Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 -- J. C. Tully is with the
Department of Physics and Department of Chemistry, Yale University, New Haven, Connecticut 06520 -- G. Betz and W. Husinsky are with the
Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Vienna, AustriaAn unexpected pronounced enhancement is observed in sputtering yields per atom for N2+
compared
to N+ from a polycrystalline gold target. This effect is seen when the kinetic energy per projectile
atom is below 500 eV and increases as projectile energy decreases to near-threshold energies.
Enhancements for O2+
over O+ begin at even lower kinetic energies below 100 eV per atom. This
new molecular interaction effect may be explained qualitatively by invoking a simple energy transfer
model which involves the vibrational frequency of the molecule and the collisional interaction time.
[S0031-9007(98)06668-X]Chemistr
Impurity state in the vortex core of d-wave superconductors: Anderson impurity model versus unitary impurity model
Using an extended Anderson/Kondo impurity model to describe the magnetic
moments around an impurity doped in high- d-wave cuprates and in
the framework of the slave-boson meanfield approach, we study numerically the
impurity state in the vortex core by exact diagonalization of the
well-established Bogoliubov-de Gennes equations. The low-energy impurity state
is found to be good agreement with scanning tunnelingmicroscopy observation.
After pinning a vortex on the impurity site, we compare the unitary impurity
model with the extended Anderson impurity model by examining the effect of the
magnetic field on the impurity state. We find that the impurity resonance in
the unitary impurity model is strongly suppressed by the vortex; while it is
insensitive to the field in the extended Anderson impurity model.Comment: 8 pages, 3 figure
Josephson Current in the Presence of a Precessing Spin
The Josephson current in the presence of a precessing spin between various
types of superconductors is studied. It is shown that the Josephson current
flowing between two spin-singlet pairing superconductors is not modulated by
the precession of the spin. When both superconductors have equal-spin-triplet
pairing state, the flowing Josephson current is modulated with twice of the
Larmor frequency by the precessing spin. It was also found that up to the
second tunneling matrix elements, no Josephson current can occur with only a
direct exchange interaction between the localized spin and the conduction
electrons, if the two superconductors have different spin-parity pairing
states.Comment: 5 pages, 1 figur
Study of the , , and in the radiative decays
In this paper we present an approach to study the radiative decay modes of
the into a photon and one of the tensor mesons ,
, as well as the scalar ones and .
Especially we compare predictions that emerge from a scheme where the states
appear dynamically in the solution of vector meson--vector meson scattering
amplitudes to those from a (admittedly naive) quark model. We provide evidence
that it might be possible to distinguish amongst the two scenarios, once
improved data are available.Comment: The large Nc argument improved; version published in EPJA
Excited B mesons from the lattice
We determine the energies of the excited states of a heavy-light meson
, with a static heavy quark and light quark with mass approximately
that of the strange quark from both quenched lattices and with dynamical
fermions. We are able to explore the energies of orbital excitations up to L=3,
the spin-orbit splitting up to L=2 and the first radial excitation. These mesons will be very narrow if their mass is less than 5775 MeV -- the
threshold. We investigate this in detail and present evidence that the
scalar meson (L=1) will be very narrow and that as many as 6
excited states will have energies close to the threshold and should also
be relatively narrow.Comment: 17 pages, 6 ps figure
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