3,152 research outputs found
Classical integrability of chiral and classical curves
In this letter, classical chiral is studied in the lightcone gauge
. The once integrated equation of motion for the current is shown to
be of the Lax form, which demonstrates an infinite number of conserved
quantities. Specializing to gauge group SU(2), we show that solutions to the
classical equations of motion can be identified with a very large class of
curves. We demonstrate this correspondence explicitly for two solutions. The
classical fermionic fields associated with these currents are then obtained.Comment: Final version to appear in Mod. Phys. Lett. A. A reference and two
footnotes added. 6 pages revte
A grid-based infrastructure for distributed retrieval
In large-scale distributed retrieval, challenges of latency, heterogeneity, and dynamicity emphasise the importance of infrastructural support in reducing the development costs of state-of-the-art solutions. We present a service-based infrastructure for distributed retrieval which blends middleware facilities and a design framework to âliftâ the resource sharing approach and the computational services of a European Grid platform into the domain of e-Science applications. In this paper, we give an overview of the DILIGENT Search Framework and illustrate its exploitation in the ïŹeld of Earth Science
Exact C=1 Boundary Conformal Field Theories
We present a solution of the problem of a free massless scalar field on the
half line interacting through a periodic potential on the boundary. For a
critical value of the period, this system is a conformal field theory with a
non-trivial and explicitly calculable S-matrix for scattering from the
boundary. Unlike all other exactly solvable conformal field theories, it is
non-rational ({\it i.e.} has infinitely many primary fields). It describes the
critical behavior of a number of condensed matter systems, including
dissipative quantum mechanics and of barriers in ``quantum wires''.Comment: harvmac, 10 pages, PUPT-1432/IASSNS-HEP-93/7
Dilaton, moduli and string/five-brane duality as seen from four dimensions
A naive dimensional reduction of the supergravity theory that
naturally arises in five-brane models is used to determine the r\^ole of two
fields which are basic ingredients of string models: the dilaton and, among the
moduli, the breathing mode. It is shown that, under the duality transformation
that relates five-branes and strings, these two fields exchange the r\^oles of
10-dimensional dilaton and radius of the compact manifold. A description of
this phenomenon in terms of the linear multiplets of the 4-dimensional
supergravity is also presented.Comment: 14 pages, Latex, NSF-ITP-93-6
Semileptonic and rare B meson decays into a light pseudoscalar meson
In the framework of a QCD relativistic potential model we evaluate the form
factors describing the exclusive decays B => \pi l nu and B => K l+ l-. The
present calculation extends a previous analysis of B meson decays into light
vector mesons. We find results in agreement with the data, when available, and
with the theoretical constraints imposed by the Callan-Treiman relation and the
infinite heavy quark mass limit.Comment: 11 pages LaTeX + 2 figure
Magnetic Monopoles in String Theory
Magnetic monopole solutions to heterotic string theory are discussed in
toroidal compactifications to four spacetime dimensions. Particular emphasis is
placed on the relation to previously studied fivebrane solutions in ten
dimensions and on the possibility of constructing exact monopole solutions
related to symmetric fivebranes.Comment: 24 pages (Corrected title
Nematic cells with defect-patterned alignment layers
Using Monte Carlo simulations of the Lebwohl--Lasher model we study the
director ordering in a nematic cell where the top and bottom surfaces are
patterned with a lattice of point topological defects of lattice
spacing . We find that the nematic order depends crucially on the ratio of
the height of the cell to . When the system is very
well--ordered and the frustration induced by the lattice of defects is relieved
by a network of half--integer defect lines which emerge from the point defects
and hug the top and bottom surfaces of the cell. When the
system is disordered and the half--integer defect lines thread through the cell
joining point defects on the top and bottom surfaces. We present a simple
physical argument in terms of the length of the defect lines to explain these
results. To facilitate eventual comparison with experimental systems we also
simulate optical textures and study the switching behavior in the presence of
an electric field
Information Loss and Anomalous Scattering
The approach of 't Hooft to the puzzles of black hole evaporation can be
applied to a simpler system with analogous features. The system is
dimensional electrodynamics in a linear dilaton background. Analogues of black
holes, Hawking radiation and evaporation exist in this system. In perturbation
theory there appears to be an information paradox but this gets resolved in the
full quantum theory and there exists an exact -matrix, which is fully
unitary and information conserving. 't Hooft's method gives the leading terms
in a systematic approximation to the exact result.Comment: 18 pages, 3 figures (postscript files available soon on request),
(earlier version got corrupted by mail system
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