13,188 research outputs found

    Nonlinear quantum optical computing via measurement

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    We show how the measurement induced model of quantum computation proposed by Raussendorf and Briegel [Phys. Rev. Letts. 86, 5188 (2001)] can be adapted to a nonlinear optical interaction. This optical implementation requires a Kerr nonlinearity, a single photon source, a single photon detector and fast feed forward. Although nondeterministic optical quantum information proposals such as that suggested by KLM [Nature 409, 46 (2001)] do not require a Kerr nonlinearity they do require complex reconfigurable optical networks. The proposal in this paper has the benefit of a single static optical layout with fixed device parameters, where the algorithm is defined by the final measurement procedure.Comment: 14 pages, 4 figures, 4 table

    Fisher Hartwig determinants, conformal field theory and universality in generalised XX models

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    We discuss certain quadratic models of spinless fermions on a 1D lattice, and their corresponding spin chains. These were studied by Keating and Mezzadri in the context of their relation to the Haar measures of the classical compact groups. We show how these models correspond to translation invariant models on an infinite or semi-infinite chain, which in the simplest case reduce to the familiar XX model. We give physical context to mathematical results for the entanglement entropy, and calculate the spin-spin correlation functions using the Fisher-Hartwig conjecture. These calculations rigorously demonstrate universality in classes of these models. We show that these are in agreement with field theoretic and renormalization group arguments that we provide

    Quality-weld parameters for microwelding techniques and equipment

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    Limited-amplitude, controlled-decay process improves the reliability of microwelding. The system consists in building a capacitor-discharge welder for control of the shape of the weld pulse. Standard welders may be modified

    Enhancing choice? The role of technology in the career support market

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    This report explores the role that technology has played in the development of the career support market. This market is conceived broadly to include all possible resources that individuals might draw upon to support them in their career development. A key element is the role that is played by public-sector career services and by careers professionals; though these resources are supplemented by services paid for in a wide range of ways and delivered by a range of professionals and non-professionals.UKCE

    Careering through the Web: the potential of Web 2.0 and 3.0 technologies for career development and career support services

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    This paper examines the environment that the web provides for career exploration. Career practitioners have long seen value in engaging in technology and the opportunities offered by the internet, and this interest continues. However, this paper suggests that the online environment for career exploration is far broader than that provided by public-sector careers services. In addition to these services, there is a wide range of other players including private-sector career consultants, employers, recruitment companies and learning providers who are all contributing to a potentially rich career exploration environment.UKCE

    Quality weld parameters for microwelding techniques and equipment Final report

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    Amplitude controlled welding process for electronic circuit module

    Incoherence of Bose-Einstein condensates at supersonic speeds due to quantum noise

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    We calculate the effect of quantum noise in supersonic transport of Bose-Einstein condensates. When an obstacle obstructs the flow of atoms, quantum fluctuations cause atoms to be scattered incoherently into random directions. This suppresses the propagation of Cherenkov radiation, creating quantum turbulence and a crescent of incoherent atoms around the obstacle. We observe similar dynamics if the BEC is stirred by a laser beam: crescents of incoherent atoms are emitted from the laser's turning-points. Finally, we investigate supersonic flow through a disordered potential, and find that the quantum fluctuations generate an accumulation of incoherent atoms as the condensate enters the disorder.Comment: 6 pages, 5 figure
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