51,795 research outputs found
Event-by-event simulation of the Hanbury Brown-Twiss experiment with coherent light
We present a computer simulation model for the Hanbury Brown-Twiss experiment
that is entirely particle-based and reproduces the results of wave theory. The
model is solely based on experimental facts, satisfies Einstein's criterion of
local causality and does not require knowledge of the solution of a wave
equation. The simulation model is fully consistent with earlier work and
provides another demonstration that it is possible to give a particle-only
description of wave phenomena, rendering the concept of wave-particle duality
superfluous.Comment: Submitted to Commmun. Comput. Phy
Management of e-technology in China
"e" technology is bringing about many challenges for companies, in particular for their managers. This concerns a vast range of business processes in many sectors of the economy and in nearly every country of the world. In rapidly industrializing China, companies and other organizations are actively finding their way by adapting, developing and exploiting new e-technologies. The paper's focus is the identification of the management issues in implementing e-technology in China. The paper reports on research into difficulties of establishing and operating e-business in China. In particular, it discusses management related to e-technology sharing and application. A brief review of literature is followed by the analysis of three recent case studies: an international IT services alliance, a financial services provider and an international manufacturing joint venture. All case companies are applying e-technology in China, but the role of e-technology differs in the three cases: adding a service line to the existing business processes; developing a new business process; and increasing efficiency and effectiveness in business processes. The conclusions present the emerging management issues: cooperation is a key asset in networking; the choice of business models plays an important role; adequate management attention for details such as a training program is require
Edge States and Quantum Hall Effect in Graphene under a Modulated Magnetic Field
Graphene properties can be manipulated by a periodic potential. Based on the
tight-binding model, we study graphene under a one-dimensional (1D) modulated
magnetic field which contains both a uniform and a staggered component. New
chiral current-carrying edge states are generated at the interfaces where the
staggered component changes direction. These edge states lead to an unusual
integer quantum Hall effect (QHE) in graphene, which can be observed
experimentally by a standard four-terminal Hall measurement. When Zeeman spin
splitting is considered, a novel state is predicted where the electron edge
currents with opposite polarization propagate in the opposite directions at one
sample boundary, whereas propagate in the same directions at the other sample
boundary.Comment: 5 pages, 4 figure
Nonclassical effects in two-photon interference experiments: event-by-event simulations
It is shown that both the visibility predicted for
two-photon interference experiments with two independent
sources\textcolor{black}{, like the Hanbury Brown-Twiss experiment,} and the
visibility predicted for two-photon interference experiments
with a parametric down-conversion source\textcolor{black}{, like the
Ghosh-Mandel experiment,} can be explained \textcolor{black}{by a discrete
event simulation. This simulation approach reproduces the statistical
distributions of wave theory not by requiring the knowledge of the solution of
the wave equation of the whole system but by generating detection events
one-by-one according to an unknown distribution.} There is thus no need to
invoke quantum theory to explain the so-called nonclassical effects in the
interference of signal and idler photons in parametric down conversion. Hence,
a revision of the commonly accepted criterion of the nonclassical nature of
light\textcolor{black}{, ,} is called for.Comment: arXiv admin note: substantial text overlap with arXiv:1208.2368,
arXiv:1006.172
Data analysis of Einstein-Podolsky-Rosen-Bohm laboratory experiments
Data sets produced by three different Einstein-Podolsky-Rosen-Bohm (EPRB)
experiments are tested against the hypothesis that the statistics of this data
is described by quantum theory. Although these experiments generate data that
violate Bell inequalities for suitable choices of the time-coincidence window,
the analysis shows that it is highly unlikely that these data sets are
compatible with the quantum theoretical description of the EPRB experiment,
suggesting that the popular statements that EPRB experiments agree with quantum
theory lack a solid scientific basis and that more precise experiments are
called for.Comment: arXiv admin note: substantial text overlap with arXiv:1112.262
New QCD Sum Rules for Nucleons in Nuclear Matter
Two new QCD sum rules for nucleons in nuclear matter are obtained from a
mixed correlator of spin-1/2 and spin-3/2 interpolating fields. These new sum
rules, which are insensitive to the poorly known four-quark condensates,
provide additional information on the nucleon scalar self-energy. These new sum
rules are analyzed along with previous spin-1/2 interpolator-based sum rules
which are also insensitive to the poorly known four-quark condensates. The
analysis indicates consistency with the expectations of relativistic nuclear
phenomenology at nuclear matter saturation density. However, a weaker density
dependence near saturation is suggested. Using previous estimates of in-medium
condensate uncertainties, we find GeV and
GeV at nuclear matter saturation density.Comment: 10 page RevTeX Manuscript with embedded figures. Revised manuscript
accepted for publication. This and related papers may also be obtained from
http://www.phys.washington.edu/~derek/Publications.htm
The interaction of syllabification and voicing perception in american english
The current paper explores these two sorts of phonetic explanations of the relationship between syllabic position and the voicing contrast in American English. It has long been observed that the contrast between, for example, /p/ and /b/ is expressed differently, depending on the position of the stop with respect to the vowel. Preceding a vowel within a syllable, the contrast is largely one of aspiration. /p/ is aspirated, while /b/ is voiceless, or in some dialects voiced or even an implosive. Following a vowel within a syllable, both /p/ and /b/ both tend to lack voicing in the closure and the contrast is expressed largely by dynamic differences in the transition between the previous vowel and the stop. Here, vowel and closure duration are negatively correlated such that the /p/ has a shorter vowel and longer closure duration. This difference is often enhanced by the addition of glottalization to /p/. In addition to these differences, there are additional differences connected to higher-level organization involving stress and feet edges. To make the current discussion more tractable, we will restrict ourselves to the two conditions (CV and VC) laid out above
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