199,208 research outputs found
Spin effects in hard exclusive electroproduction of mesons
In this talk various spin effects in hard exclusive electroproduction of
mesons are briefly reviewed. The data are discussed in the light of recent
theoretical calculations within the frame work of the handbag approach.Comment: 11 pages, 12 figures, using Latex, talk presented at the conference
in honor of Prof. A. Efremov's 75th birthday held at Trento, July, 200
Integrable representations of the quantum affine special linear superalgebra
The simple integrable modules with finite dimensional weight spaces are
classified for the quantum affine special linear superalgebra
\U_q(\hat{\mathfrak{sl}}(M|N)) at generic . Any such module is shown to be
a highest weight or lowest weight module with respect to one of the two natural
triangular decompositions of the quantum affine superalgebra depending on
whether the level of the module is zero or not. Furthermore, integrable
\U_q(\hat{\mathfrak{sl}}(M|N))-modules at nonzero levels exist only if or
is .Comment: 31 page
The effect of bandwidth in scale-free network traffic
We model information traffic on scale-free networks by introducing the
bandwidth as the delivering ability of links. We focus on the effects of
bandwidth on the packet delivering ability of the traffic system to better
understand traffic dynamic in real network systems. Such ability can be
measured by a phase transition from free flow to congestion. Two cases of node
capacity C are considered, i.e., C=constant and C is proportional to the node's
degree. We figured out the decrease of the handling ability of the system
together with the movement of the optimal local routing coefficient ,
induced by the restriction of bandwidth. Interestingly, for low bandwidth, the
same optimal value of emerges for both cases of node capacity. We
investigate the number of packets of each node in the free flow state and
provide analytical explanations for the optimal value of . Average
packets traveling time is also studied. Our study may be useful for evaluating
the overall efficiency of networked traffic systems, and for allevating traffic
jam in such systems.Comment: 6 pages, 4 figure
Braiding non-Abelian quasiholes in fractional quantum Hall states
Quasiholes in certain fractional quantum Hall states are promising candidates
for the experimental realization of non-Abelian anyons. They are assumed to be
localized excitations, and to display non-Abelian statistics when sufficiently
separated, but these properties have not been explicitly demonstrated except
for the Moore-Read state. In this work, we apply the newly developed matrix
product state technique to examine these exotic excitations. For the Moore-Read
and the Read-Rezayi states, we estimate the quasihole radii, and
determine the correlation lengths associated with the exponential convergence
of the braiding statistics. We provide the first microscopic verification for
the Fibonacci nature of the Read-Rezayi quasiholes. We also
present evidence for the failure of plasma screening in the non-unitary
Gaffnian wave function.Comment: 9 pages, 9 figures; published versio
Matrix product state representation of non-Abelian quasiholes
We provide a detailed explanation of the formalism necessary to construct
matrix product states for non-Abelian quasiholes in fractional quantum Hall
model states. Our construction yields an efficient representation of the wave
functions with conformal-block normalization and monodromy, and complements the
matrix product state representation of fractional quantum Hall ground states.Comment: 14 pages, 2 figures; published versio
Notes on nonabelian (0,2) theories and dualities
In this paper we explore basic aspects of nonabelian (0,2) GLSM's in two
dimensions for unitary gauge groups, an arena that until recently has largely
been unexplored. We begin by discussing general aspects of (0,2) theories,
including checks of dynamical supersymmetry breaking, spectators and weak
coupling limits, and also build some toy models of (0,2) theories for bundles
on Grassmannians, which gives us an opportunity to relate physical anomalies
and trace conditions to mathematical properties. We apply these ideas to study
(0,2) theories on Pfaffians, applying recent perturbative constructions of
Pfaffians of Jockers et al. We discuss how existing dualities in (2,2)
nonabelian gauge theories have a simple mathematical understanding, and make
predictions for additional dualities in (2,2) and (0,2) gauge theories.
Finally, we outline how duality works in open strings in unitary gauge
theories, and also describe why, in general terms, we expect analogous
dualities in (0,2) theories to be comparatively rare.Comment: 93 pages, LaTeX; v2: typos fixe
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