52,631 research outputs found
On indecomposable modules over the Virasoro algebra
It is proved that an indecomposable Harish-Chandra module over the Virasoro
algebra must be (i) a uniformly bounded module, or (ii) a module in Category
, or (iii) a module in Category , or (iv) a module which
contains the trivial module as one of its composition factors.Comment: 5 pages, Latex, to appear in Science in China
Magnetic properties of a spin-3 Chromium condensate
We study the ground state properties of a spin-3 Cr condensate subject to an
external magnetic field by numerically solving the Gross-Piteavskii equations.
We show that the widely adopted single-mode approximation is invalid under a
finite magnetic field. In particular, a phase separation like behavior may be
induced by the magnetic field. We also point out the possible origin of the
phase separation phenomenon.Comment: 6 pages, 5 figure
On length spectrum metrics and weak metrics on Teichmüller spaces of surfaces with boundary
We define and study metrics and weak metrics on the Teichmüller space of a surface of topologically finite type with boundary. These metrics and weak metrics are associated to the hyperbolic length spectrum of simple closed curves and of properly embedded arcs in the surface. We give a comparison between the defined metrics on regions of Teichmüller space which we call -relative -thick parts} for and
Transverse Quark Distribution in Mesons - QCD Sum Rule Approach -
QCD sum rules are used to compute the first few moments of the mesonic quark
momentum. Transverse, longitudinal and mixed transverse-longitudinal components
are examined. The transverse size of the pion is shown to be dictated by the
gluon condensate, even though the mass and the longitudinal distribution are
dominated by the quark condensate. The implications of our results for color
transparency physics and finite temperature QCD are discussed.Comment: 8 pages, Latex, Univ. of Washington preprint DOE/ER/40427-24-N9
B-Physics Observables and Electroweak Precision Data in the CMSSM, mGMSB and mAMSB
We explore electroweak precision observables (EWPO) and -physics
observables (BPO) in the CMSSM, the mGMSB and the mAMSB. We perform a chi^2
analysis based on the combination of current EWPO and BPO data. For the first
time this allows the comparison of the mGMSB and mAMSB in terms of EWPO and BPO
with the CMSSM. We find that relatively low mass scales in all three scenarios
are favored. However, the current data from EWPO and BPO can hardly exclude any
parameters at the level of Delta chi^2 = 9. Remarkably the mAMSB scenario,
despite having one free GUT scale parameter less than the other two scenarios,
has a somewhat lower total minimum chi^2. We present predictions for the
lightest Higgs boson mass, based on the chi^2 analysis of current data, where
relatively good compatibility with the bounds from Higgs searches at LEP is
found. We also present the predictions for other Higgs sector parameters and
SUSY mass scales, allowing to compare the reach of the LHC and the ILC in the
three scenarios. We furthermore explore the future sensitivities of the EWPO
and BPO for the current best-fit results and for a hypothetical point with
somewhat higher mass scales that results in a similar Higgs and SUSY spectrum
in the three scenarios. We find that the future improvement of the accuracy of
the EWPO and BPO will lead to a significant gain in the indirect parameter
determination. The improvement is similar in the CMSSM, mGMSB and mAMSB and
will yield constraints to the parameter space even for heavy Higgs and SUSY
mass scales.Comment: 53 pages, 27 figures, discussion extended. Version to appear in JHE
Macroscopic Quantum Tunneling Effect of Z2 Topological Order
In this paper, macroscopic quantum tunneling (MQT) effect of Z2 topological
order in the Wen-Plaquette model is studied. This kind of MQT is characterized
by quantum tunneling processes of different virtual quasi-particles moving
around a torus. By a high-order degenerate perturbation approach, the effective
pseudo-spin models of the degenerate ground states are obtained. From these
models, we get the energy splitting of the ground states, of which the results
are consistent with those from exact diagonalization methodComment: 25 pages, 14 figures, 4 table
Distributed -Coloring in Sublogarithmic Rounds
We give a new randomized distributed algorithm for -coloring in
the LOCAL model, running in
rounds in a graph of maximum degree~. This implies that the
-coloring problem is easier than the maximal independent set
problem and the maximal matching problem, due to their lower bounds of by Kuhn, Moscibroda, and Wattenhofer [PODC'04].
Our algorithm also extends to list-coloring where the palette of each node
contains colors. We extend the set of distributed symmetry-breaking
techniques by performing a decomposition of graphs into dense and sparse parts
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