Numerical evidence for monopoles in 3-dimensional Yang-Mills theory

Recently Anishetty, Majumdar and Sharatchandra have proposed a way of characterizing topologically non-trivial configurations for 2+1 dimensional Yang-Mills theory in a local and manifestly gauge invariant manner. In this paper paper we develop criteria to locate such objects in lattice gauge theory and find them in numerical simulations.Comment: 6 pages, 4 figures and 2 tables. Revtex. No changes in text. Problem with printing of figure fixed. To be published in PL-

Application of a coordinate space method for the evaluation of lattice Feynman diagrams in two dimensions

We apply a new coordinate space method for the evaluation of lattice Feynman diagrams suggested by L\"uscher and Weisz to field theories in two dimensions. Our work is to be presented for the theories with massless propagators. The main idea is to deal with the integrals in position space by making use of the recursion relation for the free propagator $G(x)$ which allows to compute the propagator recursively by its values around origin. It turns out that the method is very efficient and gives very precise results. We illustrate the technique by evaluating a number of two- and three-loop diagrams explicitly.Comment: 25 pages, Latex, 2 figures, revised by discussing some points in more detail and correcting a few typo

Topologically non-trivial configurations in 3-dimensional Yang-Mills theory

Recently Anishetty, Majumdar and Sharatchandra have proposed a way of characterizing topologically non-trivial configurations for 2+1-dimensional Yang-Mills theory in a local and manifestly gauge invariant manner. Here we develop criteria to locate such objects in lattice gauge theory and find them in numerical simulations.Comment: Poster presented at Lattice 2000 (Topology and Vacuum) 3 pages, 2 figure

Polyhedral realization of Crystal bases for Generalized Kac-Moody Algebras

In this paper, we give polyhedral realization of the crystal $B(\infty)$ of $U_q^-(\mathfrak g)$ for the generalized Kac-Moody algebras. As applications, we give explicit descriptions of crystals for the generalized Kac-Moody algebras of rank 2, 3 and {\it Monster Lie algebras}.Comment: 20 page

ESL students' computer-mediated communication practices: Context configuration

This paper examines how context is configured in ESL students’ language learning practices through computer-mediated communication (CMC). Specifically, I focus on how a group of ESL students jointly constructed the context of their CMC activities through interactional patterns and norms, and how configured affordances within the CMC environment mediated their learning experiences. After a brief review of relevant studies of CMC in the literature, I discuss ecological perspectives of language learning as a core construct of this study, to explain contextual fluidity in relation to learners’ agency in their learning. Next, I present an ethnographic study of how members of an ESL class constructed a community of social practices through synchronous CMC. The findings indicate that (a) the constructed interactional patterns and norms of the students’ CMC activities represented group dynamics among the participants, (b) the participants’ roles in joint construction of the activities reflected their language socialization experiences, and (c) the activities provided a way for spousal participants to assume academic identities, while becoming a social space for academic gatherings. This study highlights the fluidity of CMC language learning contexts; fluid contexts entail learners’ agency in dialogic engagements with the contextual elements of the learning environment as language socialization processes

New decoding scheme for LDPC codes based on simple product code structure

In this paper, a new decoding scheme for low-density parity-check (LDPC) codes using the concept of simple product code structure is proposed based on combining two independently received soft-decision data for the same codeword. LDPC codes act as horizontal codes of the product codes and simple algebraic codes are used as vertical codes to help decoding of the LDPC codes. The decoding capability of the proposed decoding scheme is defined and analyzed using the paritycheck matrices of vertical codes and especially the combined-decodability is derived for the case of single parity-check (SPC) and Hamming codes being used as vertical codes. It is also shown that the proposed decoding scheme achieves much better error-correcting capability in high signal to noise ratio (SNR) region with low additional decoding complexity, compared with a conventional decoding scheme.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl