5,282 research outputs found

    Assessing the economic cost of unilateral oil conservation

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    Power resources ; Petroleum industry and trade

    Some implications of increased cooperation in world oil conservation

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    In this article, Stephen Brown and Hillard Huntington combine recent studies of world oil markets and the nascent literature on damage estimates from carbon dioxide (CO2) emissions to derive cost and benefit curves for the reduction of these emissions through cooperative programs of oil conservation. Their analysis shows that the desirability of extending cooperation in global energy conservation policies is essentially an empirical issue rather than a conceptual one. The current evidence suggests that over the next two decades, the Organization for Economic Cooperation and Development will have an incentive to reduce its oil consumption and the associated CO2 emissions by more than is optimal from a world perspective. During this period, extending cooperation to the oil-importing developing countries may push oil conservation too far.Petroleum industry and trade

    Coherent analysis of quantum optical sideband modes

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    We demonstrate a device that allows for the coherent analysis of a pair of optical frequency sidebands in an arbitrary basis. We show that our device is quantum noise limited and hence applications for this scheme may be found in discrete and continuous variable optical quantum information experiments.Comment: 3 pages, 3 figures, submitted to Optics Letter

    Are there spurious temperature trends in the United States Climate Division database

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    The United States (U.S.) Climate Division data set is commonly used in applied climatic studies in the United States. The divisional averages are calculated by including all available stations within a division at any given time. The averages are therefore vulnerable to shifts in average station location or elevation over time, which may introduce spurious trends within these data. This paper examines temperature trends within the 15 climate divisions of New England, comparing the NCDC\u27s U.S. Divisional Data to the U.S. Historical Climate Network (USHCN) data. Correlation and multiple regression revealed that shifts in latitude, longitude, and elevation have affected the quality of the NCDC divisional data with respect to the USHCN. As a result, there may be issues with regard to their use in decadal- to century-scale climate change studies

    Voltage-controlled wavelength conversion by terahertz electro-optic modulation in double quantum wells

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    An undoped double quantum well (DQW) was driven with a terahertz (THz) electric field of frequency \omega_{THz} polarized in the growth direction, while simultaneously illuminated with a near-infrared (NIR) laser at frequency \omega_{NIR}. The intensity of NIR upconverted sidebands \omega_{sideband}=\omega_{NIR} + \omega_{THz} was maximized when a dc voltage applied in the growth direction tuned the excitonic states into resonance with both the THz and NIR fields. There was no detectable upconversion far from resonance. The results demonstrate the possibility of using gated DQW devices for all-optical wavelength shifting between optical communication channels separated by up to a few THz.Comment: 3 pages, 6 figures. Figures 5 and 6 are JPEG files, figures/fig5.jpg and fig6.jp

    Multiplexed communication over a high-speed quantum channel

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    In quantum information systems it is of particular interest to consider the best way in which to use the non-classical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are amongst the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analogue bandwidth. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4 GHz comb of vacuum squeezing produced by a sub-threshold OPO, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel

    Demonstration of the spatial separation of the entangled quantum side-bands of an optical field

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    Quantum optics experiments on "bright" beams typically probe correlations between side-band modes. However the extra degree of freedom represented by this dual mode picture is generally ignored. We demonstrate the experimental operation of a device which can be used to separate the quantum side-bands of an optical field. We use this device to explicitly demonstrate the quantum entanglement between the side-bands of a squeezed beam
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