4,542 research outputs found

    Decay dynamics in the coupled-dipole model

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    Cooperative scattering in cold atoms has gained renewed interest, in particular in the context of single-photon superradiance, with the recent experimental observation of super-and subradiance in dilute atomic clouds. Numerical simulations to support experimental signatures of cooperative scattering are often limited by the number of dipoles which can be treated, well below the number of atoms in the experiments. In this paper, we provide systematic numerical studies aimed at matching the regime of dilute atomic clouds. We use a scalar coupled-dipole model in the low excitation limit and an exclusion volume to avoid density-related effects. Scaling laws for super-and subradiance are obtained and the limits of numerical studies are pointed out. We also illustrate the cooperative nature of light scattering by considering an incident laser field, where half of the beam has a π\pi phase shift. The enhanced subradiance obtained under such condition provides an additional signature of the role of coherence in the detected signal

    Photonic properties of one-dimensionally-ordered cold atomic vapors under conditions of electromagnetically induced transparency

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    We experimentally study the photonic properties of a cold-atom sample trapped in a one-dimensional optical lattice under the conditions of electromagnetically induced transparency. We show that such a medium has two photonic band gaps. One of them is in the transparency window and gives rise to a Bragg mirror, which is spectrally very narrow and dynamically tunable. We discuss the advantages and the limitations of this system. As an illustration of a possible application we demonstrate a two-port all-optical switch

    Selected Problems in Wrap-Around Financing: Suggested Approaches to Due-on-Sale Clauses and Purchaser\u27s Depreciable Basis

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    This article will address two unresolved issues surrounding the WA transaction which result from the inherent flexibility available for negotiating financing terms in the absence of an institutional lender. Part I discusses the circumstances warranting exclusion of the WA loan from the purchaser\u27s depreciable basis. Part II addresses whether, and when, a due-on-sale clause in the senior mortgage should negate the possibility of utilizing WA financing

    A Proposal for Evaluating Hybrid Section 1031/453 Transactions

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    Oil and Gas Taxation: A Study in Reform

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    Lessons Learned from Development of a Software Tool to Support Academic Advising

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    We detail some lessons learned while designing and testing a decision-theoretic advising support tool for undergraduates at a large state university. Between 2009 and 2011 we conducted two surveys of over 500 students in multiple majors and colleges. These surveys asked students detailed questions about their preferences concerning course selection, advising, and career paths. We present data from this study which may be helpful for faculty and staff who advise undergraduate students. We find that advising support software tools can augment the student-advisor relationship, particularly in terms of course planning, but cannot and should not replace in-person advising.Comment: 5 Figures, revised version including more figures and cross-referencin

    Try it on: Voice, concordancing and text-matching in doctoral writing

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    Appropriate use and acknowledgement of sources continues to be a central concern of academic integrity. A major challenge for research students in using sources is the development of a confident authorial voice that matches disciplinary expectations in language use, yet manages to do so without plagiarising through inappropriate text- matching or recycling of language. This is a daunting challenge for all research writers, particularly for English as an Additional Language (EAL) researchers who are still grappling with English grammar and syntax. In order to develop novice research writers' understanding of acceptable use of sources and mastery of disciplinary language, we have developed a process called "Try it on" that uses concordancing software alongside text-matching software (Turnitin). Here we present textual analyses of two cases using this process: in one, the student's percentage of matches decreased as he developed his authorial voice; in the second, the percentage of matches increased as the student's language choices came to reflect more closely the expected usage in the discipline, thus replicating the expected authorial voice for that particular audience. These cases demonstrate how "Try it on" can be used to help students write in an appropriate authorial voice while also avoiding plagiarism
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