186 research outputs found
Hidden Symmetries of Stochastic Models
In the matrix product states approach to species diffusion processes the
stationary probability distribution is expressed as a matrix product state with
respect to a quadratic algebra determined by the dynamics of the process. The
quadratic algebra defines a noncommutative space with a quantum group
action as its symmetry. Boundary processes amount to the appearance of
parameter dependent linear terms in the algebraic relations and lead to a
reduction of the symmetry. We argue that the boundary operators of
the asymmetric simple exclusion process generate a tridiagonal algebra whose
irriducible representations are expressed in terms of the Askey-Wilson
polynomials. The Askey-Wilson algebra arises as a symmetry of the boundary
problem and allows to solve the model exactly.Comment: This is a contribution to the Proc. of the O'Raifeartaigh Symposium
on Non-Perturbative and Symmetry Methods in Field Theory (June 2006,
Budapest, Hungary), published in SIGMA (Symmetry, Integrability and Geometry:
Methods and Applications) at http://www.emis.de/journals/SIGMA
On a "New" Deformation of GL(2)
We refute a recent claim in the literature of a "new" quantum deformation of
GL(2).Comment: 4 pages, LATE
Superembedding methods for 4d N=1 SCFTs
We extend SO(4,2) covariant lightcone embedding methods of four-dimensional
CFTs to N=1 superconformal field theory (SCFT). Manifest superconformal
SU(2,2|1) invariance is achieved by realizing 4D superconformal space as a
surface embedded in the projective superspace spanned by certain complex chiral
supermatrices. Because SU(2,2|1) acts linearly on the ambient space, the
constraints on correlators implied by superconformal Ward identities are
automatically solved in this formalism. Applications include new, compact
expressions for correlation functions containing one anti-chiral superfield and
arbitrary chiral superfield insertions, and manifestly invariant expressions
for the superconformal cross-ratios that parametrize the four-point function of
two chiral and two anti-chiral fields. Superconformal expressions for the
leading singularities in the OPE of chiral and anti-chiral operators are also
given. Because of covariance, our expressions are valid in any superconformally
flat background, e.g., AdS_4 or R times S^3.Comment: 33 pages, clarification of constraints, version to appear in PR
Using Problems to Introduce some Tools and Technologies for Implementation of Graphics and Animation in C#
This paper is devoted to the learning of event programming by using Visual C# in specialized training in Informatics in high schools. Some basic tools and technologies for the implementation of graphics and animation in C# are discussed. Two example problems are proposed
Cataloguing the Slavonic Manuscript Collection of the Plovdiv Public Library – Problems and MARC 21* Solutions
MARC 21 (‘Machine-Readable Cataloguing’) is a US library standard established worldwide and recently translated also in Bulgarian (those parts used most by librarians in their everyday work). The Bulgarian translations are freely available on the NALIS website (http://www.nalis.bg/) under the Library Standards Section, where also an Online Multilingual Dictionary of MARC 21 Terms can be found. All these works are approved by the US Library of Congress and published on its MARC 21 website under Translations (http://www.loc.gov/marc/translations.html#bulgarian).The paper presents a standardised scheme for describing the whole Slavonic Manuscript Collection kept at the Plovdiv Public Library. This scheme will be used for generating a structured pool of palaeographic and codicological data with a view to integrating the respective digital objects (digitised copies of the respective manuscripts and metadata, i.e. the descriptions, to them) into a digital content management platform. The experience gained in creating the catalogue of the Plovdiv Library’s Slavonic Manuscripts may be useful when discussing a unified methodology and a scheme for a machine-readable cataloguing of the Bulgarian manuscript collections in general. Besides, the principles of adapting the proposed standard to MARC 21 Bibliographic are enlisted. The template prepared, will be applied in ALEPH 500 and further developed in a related forthcoming activity
A realization of the quantum Lorentz group
A realization of a deformed Lorentz algebra is considered and its irreducible
representations are found; in the limit , these are precisely the
irreducible representations of the classical Lorentz group.Comment: This a short version of the Phys.Lett.B publicatio
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