14,621 research outputs found

    Fermionic Field Theory and Gauge Interactions on Random Lattices

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    Random-lattice fermions have been shown to be free of the doubling problem if there are no interactions or interactions of a non-gauge nature. However, gauge interactions impose stringent constraints as expressed by the Ward-Takahashi identities which could revive the free-field suppressed doubler modes in loop diagrams. After introducing a formulation for fermions on a new kind of random lattice, we compare random, naive and Wilson fermions in two dimensional Abelian background gauge theory. We show that the doublers are revived for random lattices in the continuum limit, while demonstrating that gauge invariance plays the critical role in this revival. Some implications of the persistent doubling phenomenon on random lattices are also discussed.Comment: 16 A4 pages, UM-P-93/0

    Simulations with Complex Measures

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    Towards a solution to the sign problem in the simulations of systems having indefinite or complex-valued measures, we propose a new approach which yields statistical errors smaller than the crude Monte Carlo using absolute values of the original measures. The 1D complex-coupling Ising model is employed as an illustration.Comment: 3 pages, postcript (95K), contribution to LAT93, UM-P-93/10

    APQ-102 imaging radar digital image quality study

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    A modified APQ-102 sidelooking radar collected synthetic aperture radar (SAR) data which was digitized and recorded on wideband magnetic tape. These tapes were then ground processed into computer compatible tapes (CCT's). The CCT's may then be processed into high resolution radar images by software on the CYBER computer

    Development of a ground signal processor for digital synthetic array radar data

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    A modified APQ-102 sidelooking array radar (SLAR) in a B-57 aircraft test bed is used, with other optical and infrared sensors, in remote sensing of Earth surface features for various users at NASA Johnson Space Center. The video from the radar is normally recorded on photographic film and subsequently processed photographically into high resolution radar images. Using a high speed sampling (digitizing) system, the two receiver channels of cross-and co-polarized video are recorded on wideband magnetic tape along with radar and platform parameters. These data are subsequently reformatted and processed into digital synthetic aperture radar images with the image data available on magnetic tape for subsequent analysis by investigators. The system design and results obtained are described

    EXTERNALITIES FROM ROAMING LIVESTOCK: EXPLAINING THE DEMISE OF THE OPEN RANGE

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    Fence-in laws in most states require ranchers to pay for fences to keep their livestock from trespassing onto othersÂ’' property. Some states, or jurisdictions within states, have a fence-out rule that requires ranchers'Â’ neighbors to pay for fences to keep livestock out. Both rules are Pareto optimal. Using a potential Pareto criterion, we show that a preference for fence-out in some areas may end as conditions change, such as increased nonranching land uses. Changed conditions may have legal consequences. Specific fence-out and fence cost-sharing provisions may be potentially Pareto inefficient and may be challenged for being unconstitutional under the due process clause.Livestock Production/Industries,

    Development of cadmium sulfide photovoltaic film cells Final report

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    Controlled carrier concentrations and improved cell conversion efficiencies in cadmium sulfide photovoltaic film cel

    Introduction: The Challenge of Risk Communication in a Democratic Society

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    The symposium editors review key issues concerning the relationship between risk communication and public participation
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