4,172 research outputs found
Boundary breathers in the sinh-Gordon model
We present an investigation of the boundary breather states of the
sinh-Gordon model restricted to a half-line. The classical boundary breathers
are presented for a two parameter family of integrable boundary conditions.
Restricting to the case of boundary conditions which preserve the \phi -->
-\phi symmetry of the bulk theory, the energy spectrum of the boundary states
is computed in two ways: firstly, by using the bootstrap technique and
subsequently, by using a WKB approximation. Requiring that the two descriptions
of the spectrum agree with each other allows a determination of the
relationship between the boundary parameter, the bulk coupling constant, and
the parameter appearing in the reflection factor derived by Ghoshal to describe
the scattering of the sinh-Gordon particle from the boundary.Comment: 16 pages amslate
The sine-Gordon model with integrable defects revisited
Application of our algebraic approach to Liouville integrable defects is
proposed for the sine-Gordon model. Integrability of the model is ensured by
the underlying classical r-matrix algebra. The first local integrals of motion
are identified together with the corresponding Lax pairs. Continuity conditions
imposed on the time components of the entailed Lax pairs give rise to the
sewing conditions on the defect point consistent with Liouville integrability.Comment: 24 pages Latex. Minor modifications, added comment
Free Field Realization of Vertex Operators for Level Two Modules of
Free field relization of vertex operators for lvel two modules of
is shown through the free field relization of the modules
given by Idzumi in Ref.[4,5]. We constructed types I and II vertex operators
when the spin of the addociated evaluation modules is 1/2 and typ II's for the
spin 1.Comment: 15 pages, to appear in J.Phys.A:Math and Genera
Moyal Brackets in M-Theory
The infinite limit of Matrix Theory in 4 and 10 dimensions is described in
terms of Moyal Brackets. In those dimensions there exists a Bogomol'nyi bound
to the Euclideanized version of these equations, which guarantees that
solutions of the first order equations also solve the second order Matrix
Theory equations. A general construction of such solutions in terms of a
representation of the target space co-ordinates as non-local spinor bilinears,
which are generalisations of the standard Wigner functions on phase space, is
given.Comment: 10 pages, Latex, no figures. References altered, typos correcte
Boundary Reflection Matrix for Affine Toda Field Theory
We present one loop boundary reflection matrix for Toda field
theory defined on a half line with the Neumann boundary condition. This result
demonstrates a nontrivial cancellation of non-meromorphic terms which are
present when the model has a particle spectrum with more than one mass. Using
this result, we determine uniquely the exact boundary reflection matrix which
turns out to be \lq non-minimal' if we assume the strong-weak coupling \lq
duality'.Comment: 14 pages, Late
A q-analog of the ADHMN construction and axisymmetric multi-instantons
In the preceding paper (Phys. Lett. B463 (1999) 257), the authors presented a
q-analog of the ADHMN construction and obtained a family of anti-selfdual
configurations with a parameter q for classical SU(2) Yang-Mills theory in
four-dimensional Euclidean space. The family of solutions can be seen as a
q-analog of the single BPS monopole preserving (anti-)selfduality. Further
discussion is made on the relation to axisymmetric ansatz on anti-selfdual
equation given by Witten in the late seventies. It is found that the
q-exponential functions familiar in q-analysis appear as analytic functions
categorizing the anti-selfdual configurations yielded by axisymmetric ansatz.Comment: 11pages, Latex2e, to appear in Journal of Physics A: Mathematical and
General as a `Special Issue/Difference Equations
NOBLE - Flexible concept recognition for large-scale biomedical natural language processing
Background: Natural language processing (NLP) applications are increasingly important in biomedical data analysis, knowledge engineering, and decision support. Concept recognition is an important component task for NLP pipelines, and can be either general-purpose or domain-specific. We describe a novel, flexible, and general-purpose concept recognition component for NLP pipelines, and compare its speed and accuracy against five commonly used alternatives on both a biological and clinical corpus. NOBLE Coder implements a general algorithm for matching terms to concepts from an arbitrary vocabulary set. The system's matching options can be configured individually or in combination to yield specific system behavior for a variety of NLP tasks. The software is open source, freely available, and easily integrated into UIMA or GATE. We benchmarked speed and accuracy of the system against the CRAFT and ShARe corpora as reference standards and compared it to MMTx, MGrep, Concept Mapper, cTAKES Dictionary Lookup Annotator, and cTAKES Fast Dictionary Lookup Annotator. Results: We describe key advantages of the NOBLE Coder system and associated tools, including its greedy algorithm, configurable matching strategies, and multiple terminology input formats. These features provide unique functionality when compared with existing alternatives, including state-of-the-art systems. On two benchmarking tasks, NOBLE's performance exceeded commonly used alternatives, performing almost as well as the most advanced systems. Error analysis revealed differences in error profiles among systems. Conclusion: NOBLE Coder is comparable to other widely used concept recognition systems in terms of accuracy and speed. Advantages of NOBLE Coder include its interactive terminology builder tool, ease of configuration, and adaptability to various domains and tasks. NOBLE provides a term-to-concept matching system suitable for general concept recognition in biomedical NLP pipelines
Supersymmetric D-brane Bound States with B-field and Higher Dimensional Instantons on Noncommutative Geometry
We classify supersymmetric D0-Dp bound states with a non-zero B-field by
considering T-dualities of intersecting branes at angles. Especially, we find
that the D0-D8 system with the B-field preserves 1/16, 1/8 and 3/16 of
supercharges if the B-field satisfies the ``(anti-)self-dual'' condition in
dimension eight. The D0-branes in this system are described by eight
dimensional instantons on non-commutative R^8. We also discuss the extended
ADHM construction of the eight-dimensional instantons and its deformation by
the B-field. The modified ADHM equations admit a sort of the `fuzzy sphere'
(embeddings of SU(2)) solution.Comment: 20 pages, LaTeX file, typos corrected and references adde
Liouville integrable defects: the non-linear Schrodinger paradigm
A systematic approach to Liouville integrable defects is proposed, based on
an underlying Poisson algebraic structure. The non-linear Schrodinger model in
the presence of a single particle-like defect is investigated through this
algebraic approach. Local integrals of motions are constructed as well as the
time components of the corresponding Lax pairs. Continuity conditions imposed
upon the time components of the Lax pair to all orders give rise to sewing
conditions, which turn out to be compatible with the hierarchy of charges in
involution. Coincidence of our results with the continuum limit of the discrete
expressions obtained in earlier works further confirms our approach.Comment: 22 pages, Latex. Minor misprints correcte
Form factors of boundary fields for A(2)-affine Toda field theory
In this paper we carry out the boundary form factor program for the
A(2)-affine Toda field theory at the self-dual point. The latter is an
integrable model consisting of a pair of particles which are conjugated to each
other and possessing two bound states resulting from the scattering processes 1
+1 -> 2 and 2+2-> 1. We obtain solutions up to four particle form factors for
two families of fields which can be identified with spinless and spin-1 fields
of the bulk theory. Previously known as well as new bulk form factor solutions
are obtained as a particular limit of ours. Minimal solutions of the boundary
form factor equations for all A(n)-affine Toda field theories are given, which
will serve as starting point for a generalisation of our results to higher rank
algebras.Comment: 24 pages LaTeX, 1 figur
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