1,014 research outputs found
Bosonization and Duality in Arbitrary Dimensions: New Results
A generic massive Thirring Model in three space-time dimensions exhibits a
correspondence with a topologically massive bosonized gauge action associated
to a self-duality constraint, and we write down a general expression for this
relationship.
We also generalize this structure to dimensions, by adopting the
so-called doublet approach, recently introduced. In particular, a non-
conventional formulation of the bosonization technique in higher dimensions (in
the spirit of ), is proposed and, as an application, we show how fermionic
(Thirring-like) representations for bosonic topologically massive models in
four dimensions may be built up.Comment: Revised version, to appear in Phys. Rev.
A grid-enabled problem solving environment for parallel computational engineering design
This paper describes the development and application of a piece of engineering software that provides a problem solving environment (PSE) capable of launching, and interfacing with, computational jobs executing on remote resources on a computational grid. In particular it is demonstrated how a complex, serial, engineering optimisation code may be efficiently parallelised, grid-enabled and embedded within a PSE.
The environment is highly flexible, allowing remote users from different sites to collaborate, and permitting computational tasks to be executed in parallel across multiple grid resources, each of which may be a parallel architecture. A full working prototype has been built and successfully applied to a computationally demanding engineering optimisation problem. This particular problem stems from elastohydrodynamic lubrication and involves optimising the computational model for a lubricant based on the match between simulation results and experimentally observed data
Propagators for p-forms in AdS_{2p+1} and correlation functions in the AdS_7/(2,0) CFT correspondence
In AdS_{2p+1} we construct propagators for p-forms whose lagrangians contain
terms of the form A / d A. In particular we explore the case of forms
satisfying ``self duality in odd dimensions'', and the case of forms with a
topological mass term. We point out that the ``complete'' set of maximally
symmetric bitensors previously used in all the other propagator papers is
incomplete - there exists another bitensor which can and does appear in the
formulas for the propagators in this particular case. Nevertheless, its
presence does not affect the other propagators computed so far.
On the AdS side of the correspondence we compute the 2 and 3 point functions
involving the self-dual tensor of the maximal 7d gauged supergravity (sugra),
S_{\mu\nu\rho}. Since the 7 dimensional antisymmetric self-dual tensor obeys
first order field equations (S + * d S=0), to get a nonvanishing 2 point
function we add a certain boundary term (to satisfy the variational principle
on a manifold with boundary) to the 7d action. The 3 point functions we compute
are of the type SSB and SBB, describing vertex interactions with the gauge
fields B_{\mu}.Comment: 21 pages, Latex file, one reference adde
The large-scale energetic ion layer in the high latitude Jovian magnetosphere as revealed by Ulysses/HI-SCALE cross-field intensity-gradient measurements
Ulysses investigated the high latitude Jovian magnetosphere for a second time
after Pioneer 11 mission and gave us the opportunity to search the structure
and the dynamics of this giant magnetosphere above the magnetodisc.
Kivelson(1976) and Kennel & Coroniti(1979) reported that Pioneer 11 observed
energetic particle intensities at high latitudes at the same level with those
measured in the plasma sheet and inferred that they were not consistent with
the magnetodisc model. Ulysses observations supported the idea about a
large-scale layer of energetic ions and electrons in the outer high latitude
Jovian magnetosphere (Cowley et al.1996; Anagnostopoulos et al. 2001). This
study perform a number of further tests for the existence of the large scale
layer of energetic ions in the outer high latitude Jovian magnetosphere by
studying appropriate cross-B field anisotropies in order to monitor the ion
northward/southward intensity gradients. In particular, we examined
Ulysses/HI-SCALE observations of energetic ions with large gyro-radius
(0.5-1.6MeV protons and >2.5MeV heavy(Z>5) ions) in order to compare instant
intensity changes with remote sensing intensity gradients. Our analysis
confirms the existence of an energetic particle layer in the north hemisphere,
during the inbound trajectory of Ulysses traveling at moderate latitudes, and
in the south high-latitude duskside magnetosphere, during the outbound segment
of the spacecraft trajectory. Our Ulysses/HI-SCALE data analysis also provides
evidence for the detection of an energetic proton magnetopause boundary layer
during the outbound trajectory of the spacecraft. During Ulysses flyby of
Jupiter the almost permanent appearance of alternative northward and southward
intensity gradients suggests that the high latitude layer appeared to be a
third major area of energetic particles, which coexisted with the radiation
belts and the magnetodisc.Comment: 37 pages, 11 figures, 1 tabl
Comparison of structural transformations and superconductivity in compressed Sulfur and Selenium
Density-functional calculations are presented for high-pressure structural
phases of S and Se. The structural phase diagrams, phonon spectra,
electron-phonon coupling, and superconducting properties of the isovalent
elements are compared. We find that with increasing pressure, Se adopts a
sequence of ever more closely packed structures (beta-Po, bcc, fcc), while S
favors more open structures (beta-Po, simple cubic, bcc). These differences are
shown to be attributable to differences in the S and Se core states. All the
compressed phases of S and Se considered are calculated to have weak to
moderate electron-phonon coupling strengths consistent with superconducting
transition temperatures in the range of 1 to 20 K. Our results compare well
with experimental data on the beta-Po --> bcc transition pressure in Se and on
the superconducting transition temperature in beta-Po S. Further experiments
are suggested to search for the other structural phases predicted at higher
pressures and to test theoretical results on the electron-phonon interaction
and superconducting properties
- âŠ