51,795 research outputs found

    Event-by-event simulation of the Hanbury Brown-Twiss experiment with coherent light

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    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

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    "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

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    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

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    It is shown that both the visibility V=1/2{\cal V} = 1/2 predicted for two-photon interference experiments with two independent sources\textcolor{black}{, like the Hanbury Brown-Twiss experiment,} and the visibility V=1{\cal V} = 1 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}{, V>1/2{\cal V} > 1/2,} 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

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    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

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    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 M∗=0.64−0.09+0.13M^* = 0.64^{+0.13}_{-0.09} GeV and Σv=0.29−0.10+0.06\Sigma_v = 0.29^{+0.06}_{-0.10} 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

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    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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