32,670 research outputs found

    Knowledge Transfer Needs and Methods

    Get PDF
    INE/AUTC 12.3

    Enabling Data-Driven Transportation Safety Improvements in Rural Alaska

    Get PDF
    Safety improvements require funding. A clear need must be demonstrated to secure funding. For transportation safety, data, especially data about past crashes, is the usual method of demonstrating need. However, in rural locations, such data is often not available, or is not in a form amenable to use in funding applications. This research aids rural entities, often federally recognized tribes and small villages acquire data needed for funding applications. Two aspects of work product are the development of a traffic counting application for an iPad or similar device, and a review of the data requirements of the major transportation funding agencies. The traffic-counting app, UAF Traffic, demonstrated its ability to count traffic and turning movements for cars and trucks, as well as ATVs, snow machines, pedestrians, bicycles, and dog sleds. The review of the major agencies demonstrated that all the likely funders would accept qualitative data and Road Safety Audits. However, quantitative data, if it was available, was helpful

    Mixed State Entanglement and Quantum Error Correction

    Get PDF
    Entanglement purification protocols (EPP) and quantum error-correcting codes (QECC) provide two ways of protecting quantum states from interaction with the environment. In an EPP, perfectly entangled pure states are extracted, with some yield D, from a mixed state M shared by two parties; with a QECC, an arbi- trary quantum state ξ|\xi\rangle can be transmitted at some rate Q through a noisy channel χ\chi without degradation. We prove that an EPP involving one- way classical communication and acting on mixed state M^(χ)\hat{M}(\chi) (obtained by sharing halves of EPR pairs through a channel χ\chi) yields a QECC on χ\chi with rate Q=DQ=D, and vice versa. We compare the amount of entanglement E(M) required to prepare a mixed state M by local actions with the amounts D1(M)D_1(M) and D2(M)D_2(M) that can be locally distilled from it by EPPs using one- and two-way classical communication respectively, and give an exact expression for E(M)E(M) when MM is Bell-diagonal. While EPPs require classical communica- tion, QECCs do not, and we prove Q is not increased by adding one-way classical communication. However, both D and Q can be increased by adding two-way com- munication. We show that certain noisy quantum channels, for example a 50% depolarizing channel, can be used for reliable transmission of quantum states if two-way communication is available, but cannot be used if only one-way com- munication is available. We exhibit a family of codes based on universal hash- ing able toachieve an asymptotic QQ (or DD) of 1-S for simple noise models, where S is the error entropy. We also obtain a specific, simple 5-bit single- error-correcting quantum block code. We prove that {\em iff} a QECC results in high fidelity for the case of no error the QECC can be recast into a form where the encoder is the matrix inverse of the decoder.Comment: Resubmission with various corrections and expansions. See also http://vesta.physics.ucla.edu/~smolin/ for related papers and information. 82 pages latex including 19 postscript figures included using psfig macro

    Feynman-Stueckelberg electroweak interactions and isospin entanglement

    Full text link
    Entanglement in Quantum Field Theory is restricted to spacelike separations to the order of the Compton wavelength /mc\hbar/mc (e.g., S. J. Summers and R. Werner, {\it J. Math. Phys.}, {\bf 28}, 10,2440-2447, (1987)). Yet spin entanglement of electrons across macroscopic distances has been observed by Hensen { \it et al.} ({\it Nature}, {\bf 526}, doi:10.1038/nature/15759, (2015)). The parametrized relativistic quantum mechanics of Feynman and Stueckelberg admits spin singlets, across arbitrary separations, by providing a single covariant wave equation for tensor products of two Dirac spinors (A. F. Bennett, {\it Ann. Phys.} {\bf 345}, 1-16 (2014)). The formalism is extended here from quantum electrodynamics to the electroweak interaction. A relativistic Bell's inequality for Dirac spinors is extended here to weak isospin
    corecore