21,287 research outputs found
Lyapunov Spectra in SU(2) Lattice Gauge Theory
We develop a method for calculating the Lyapunov characteristic exponents of
lattice gauge theories. The complete Lyapunov spectrum of SU(2) gauge theory is
obtained and Kolmogorov-Sinai entropy is calculated. Rapid convergence with
lattice size is found.Comment: 7pp, DUKE-TH-93-5
Lattice Gluon Propagator in the Landau Gauge: A Study Using Anisotropic Lattices
Lattice gluon propagators are studied using tadpole and Symanzik improved
gauge action in Landau gauge. The study is performed using anisotropic lattices
with asymmetric volumes. The Landau gauge dressing function for the gluon
propagator measured on the lattice is fitted according to a leading power
behavior: with an exponent at small
momenta. The gluon propagators are also fitted using other models and the
results are compared. Our result is compatible with a finite gluon propagator
at zero momentum in Landau gauge.Comment: 14 pages, 4 figure
Atomistic pseudopotential calculations of the optical properties of InAs/InP self-assembled quantum dots
We present a comprehensive study of the optical properties of InAs/InP
self-assembled quantum dots (QDs) using an empirical pseudopotential method and
configuration interaction treatment of the many-particle effects. The results
are compared to those of InAs/GaAs QDs. The main results are: (i) The alignment
of emission lines of neutral exciton, charged exciton and biexciton in InAs/InP
QDs is quite different from that in InAs/GaAs QDs. (ii) The hidden correlation
in InAs/InP QDs is 0.7 - 0.9 meV, smaller than that in InAs/GaAs QDs. (iii) The
radiative lifetimes of neutral exciton, charged exciton and biexciton in
InAs/InP QDs are about twice longer than those in InAs/GaAs QDs. (v) The phase
diagrams of few electrons and holes in InAs/InP QDs differ greatly from those
in InAs/GaAs QDs. The filling orders of electrons and holes are shown to obey
the Hund's rule and Aufbau principle, and therefore the photoluminescence
spectra of highly charged excitons are very different from those of InAs/GaAs
QDs.Comment: 10 pages, 11 figure
Effective generation of Ising interaction and cluster states in coupled microcavities
We propose a scheme for realizing the Ising spin-spin interaction and atomic
cluster states utilizing trapped atoms in coupled microcavities. It is shown
that the atoms can interact with each other via the exchange of virtual photons
of the cavities. Through suitably tuning the parameters, an effective Ising
spin-spin interaction can be generated in this optical system, which is used to
produce the cluster states. This scheme does not need the preparation of
initial states of atoms and cavity modes, and is insensitive to cavity decay.Comment: 11pages, 2 figures, Revtex
Understanding the quality of out-of-class English learning
Out-of-class learning constitutes an important context for human development, and active engagement in out-of-class activities is associated with successful language development. However, not all out-of-class experiences are equally beneficial to learning, and it is of paramount importance to understand what quality out-of-class English language learning entails. This study surveyed 82 middle school EFL students on their out-of-class English language learning in order to identify the characteristics of the experiences that are associated with good learning outcomes. The study found that out-of-class learning composed of diversified constituents that met the varied needs in language learning and complemented in-class learning by striking a balance between focus on meaning and focus on form were positively associated with good English grades, English language learning efficacy, and enjoyment. It also found that parents and teachers were significant sources of influence on the quality of students' out-of-class learning.postprin
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