33,489 research outputs found

    Magnetic Properties of Pd_(0.996)Mn_(0.004) Films for High Resolution Thermometry

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    We have previously reported on the temperature and magnetic field dependence of the magnetic susceptibility of thin Pd_(1−x)Mn_x alloy films. Extensive new measurements on sputtered films show that a commercial quality sputtering process produces a film with the same dependence of Curie temperature on x as previously reported for bulk samples of the same material. These measurements and parameters from the Renormalization Group theory for a Heisenberg ferromagnet, yield an estimate for T_c of 1.16 ± 0.01 K when x − 0.004, consistent with previously reported bulk result

    Randomized benchmarking of atomic qubits in an optical lattice

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    We perform randomized benchmarking on neutral atomic quantum bits (qubits) confined in an optical lattice. Single qubit gates are implemented using microwaves, resulting in a measured error per randomized computational gate of 1.4(1) x 10^-4 that is dominated by the system T2 relaxation time. The results demonstrate the robustness of the system, and its viability for more advanced quantum information protocols.Comment: 11 pages, 4 figure

    Survey of EPA facilities for solar thermal energy applications

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    A study was done to assess the feasibility of applying solar thermal energy systems to EPA facilities. A survey was conducted to determine those EPA facilities where solar energy could best be used. These systems were optimized for each specific application and the system/facility combinations were ranked on the basis of greatest cost effectiveness

    Boundary-detection algorithm for locating edges in digital imagery

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    The author has identified the following significant results. Initial development of a computer program which implements a boundary detection algorithm to detect edges in digital images is described. An evaluation of the boundary detection algorithm was conducted to locate boundaries of lakes from LANDSAT-1 imagery. The accuracy of the boundary detection algorithm was determined by comparing the area within boundaries of lakes located using digitized LANDSAT imagery with the area of the same lakes planimetered from imagery collected from an aircraft platform

    Bringing the toys to life: Animacy, reference, and anthropomorphism in Toy Story

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    In the children’s film Toy Story, toys spring to life when their human owners are away, creating an alternative world of transferred animacy relations signalled by visual and linguistic cues. The storylines and characters explore the nature of animacy and relationships between conspecifics and ‘others’. Our analysis focuses on the use of referring expressions as they reflect the animacy of their referents, as it develops and changes during the course of the narrative. We relate these findings to well-established scales of animacy which link our perception of the world to the categories imposed by language. We find that, as predicted by models of animacy proposed by Dahl (2008) and Yamamoto (1999), among others, shifts in reference – specifically from common noun to proper noun to pronoun, and from collective to individuated referents – reflect characters’ shifting conceptualisation of, and empathy with, each other. We argue that referring expressions are used at key points in the film script to subtly mediate accessible cues to animacy like eyes, speech and motion, and to guide viewers’ empathies and allegiances, extending our understanding of animacy beyond ordinary anthropocentrism

    Self-Consistent Screening Approximation for Flexible Membranes: Application to Graphene

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    Crystalline membranes at finite temperatures have an anomalous behavior of the bending rigidity that makes them more rigid in the long wavelength limit. This issue is particularly relevant for applications of graphene in nano- and micro-electromechanical systems. We calculate numerically the height-height correlation function G(q)G(q) of crystalline two-dimensional membranes, determining the renormalized bending rigidity, in the range of wavevectors qq from 10710^{-7} \AA1^{-1} till 10 \AA1^{-1} in the self-consistent screening approximation (SCSA). For parameters appropriate to graphene, the calculated correlation function agrees reasonably with the results of atomistic Monte Carlo simulations for this material within the range of qq from 10210^{-2} \AA1^{-1} till 1 \AA1^{-1}. In the limit q0q\rightarrow 0 our data for the exponent η\eta of the renormalized bending rigidity κR(q)qη\kappa_R(q)\propto q^{-\eta} is compatible with the previously known analytical results for the SCSA η0.82\eta\simeq 0.82. However, this limit appears to be reached only for q<105q<10^{-5} \AA1^{-1} whereas at intermediate qq the behavior of G(q)G(q) cannot be described by a single exponent.Comment: 5 pages, 4 figure

    Differential Light Shift Cancellation in a Magnetic-Field-Insensitive Transition of 87^{87}Rb

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    We demonstrate near-complete cancellation of the differential light shift of a two-photon magnetic-field-insensitive microwave hyperfine (clock) transition in 87^{87}Rb atoms trapped in an optical lattice. Up to 95(2)95(2)% of the differential light shift is canceled while maintaining magnetic-field insensitivity. This technique should have applications in quantum information and frequency metrology.Comment: 5 pages, 4 figure

    Decoherence of one-dimensional flying qubits due to their cross-talk and imperfections

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    We study decoherence of propagating spin-1/2 excitations in generic (non-integrable and/or disordered) spin chains. We find the relevant decoherence times to be shorter in both the near-critical and diffusive regimes (if any), which fact might have important implications for the recently proposed spin chain-based implementations of quantum information processing.Comment: Latex, 5 pages, no figure
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