7,936 research outputs found

    Constraint on teleportation over multipartite pure states

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    We first define a quantity exhibiting the usefulness of bipartite quantum states for teleportation, called the quantum teleportation capability, and then investigate its restricted shareability in multi-party quantum systems. In this work, we verify that the quantum teleportation capability has a monogamous property in its shareability for arbitrary three-qutrit pure states by employing the monogamy inequality in terms of the negativity.Comment: 4 pages, 1 figur

    Long-term starin monitoring data of jacket-type offshore structure for tidal current power generation under severe tidal current environments

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    Structural strain responses of the jacket-type Uldolmok tidal current power plant structure under severe\ud tidal environments were analyzed using long-term measurement data from construction to normal operation. From the\ud measured data during construction, it was found that there were significant changes in strain responses at the steps of\ud jacket lifting, weight-block loading, pile ejection and insertion. Strains due to permanent and tidal current loads were\ud analyzed during removal work on one among six jacket legs, and it was found that the strains due to permanent load\ud were much significantly changed after removal of on jacket leg. From the measurement data during normal operation, it\ud was observed that strain responses were obviously fluctuated with M2 and M4 tidal periods and also with relatively\ud short period of about 11 min due to the peculiar tidal characteristics in the Uldolmok strait

    Optical properties of pyrochlore oxide Pb2Ru2O7δPb_{2}Ru_{2}O_{7-{\delta}}

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    We present optical conductivity spectra for Pb2Ru2O7δPb_{2}Ru_{2}O_{7-{\delta}} single crystal at different temperatures. Among reported pyrochlore ruthenates, this compound exhibits metallic behavior in a wide temperature range and has the least resistivity. At low frequencies, the optical spectra show typical Drude responses, but with a knee feature around 1000 \cm. Above 20000 \cm, a broad absorption feature is observed. Our analysis suggests that the low frequency responses can be understood from two Drude components arising from the partially filled Ru t2gt_{2g} bands with different plasma frequencies and scattering rates. The high frequency broad absorption may be contributed by two interband transitions: from occupied Ru t2gt_{2g} states to empty ege_{g} bands and from the fully filled O 2p bands to unoccupied Ru t2gt_{2g} states.Comment: 4 pages, 6 figure

    Is Vacuum Decay Significant in Ekpyrotic and Cyclic Models?

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    It has recently been argued that bubble nucleation in ekpyrotic and cyclic cosmological scenarios can lead to unacceptable inhomogeneities unless certain constraints are satisfied. In this paper we show that this is not the case. We find that bubble nucleation is completely negligible in realistic models.Comment: 3 pages, 1 figure, minor revision

    Generation of ultrashort electrical pulses in semiconductor waveguides

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    We report a novel device capable of generating ultrashort electrical pulses on a coplanar waveguide (CPW) by means of optical rectification. The device consists of a completely passive GaAs-based optical waveguide, which is velocity matched to a CPW line. Optical pulses are injected into the device and electrical pulses are collected at the output. Experimental results obtained in the laboratory show the potential of this device for high speed optical-to-electrical conversion

    Petrography and Geochemistry of Metals in Almahata Sitta Ureilites

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    Ureilites are ultramafic achondrites, predominantly composed of olivine and pyroxenes with accessory carbon, metal and sulfide. The majority of ureilites are believed to represent the mantle of the ureilite parent body (UPB) [1]. Although ureilites have lost much of their original metal [2], the metal that remains retains a record of the formative processes. Almahata Sitta is predominantly composed of unbrecciated ureilites with a wide range of silicate compositions [3,4]. As a fall it presents a rare opportunity to examine fresh ureilite metal in-situ, and analyzing their highly siderophile element (HSE) ratios gives clues to their formation. Bulk siderophile element analyses of Almahata Sitta fall within the range observed in other ureilites [5]. We have examined the metals in seven ureilitic samples of Almahata Sitta (AS) and one associated chondrite fragment (AS#25)

    Are Muslims the New Catholics? Europe’s Headscarf Laws in Comparative Historical Perspective

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    In this paper a biologically-inspired model for partly occluded patterns is proposed. The model is based on the hypothesis that in human visual system occluding patterns play a key role in recognition as well as in reconstructing internal representation for a pattern’s occluding parts. The proposed model is realized with a bidirectional hierarchical neural network. In this network top-down cues, generated by direct connections from the lower to higher levels of hierarchy, interact with the bottom-up information, generated from the un-occluded parts, to recognize occluded patterns. Moreover, positional cues of the occluded as well as occluding patterns, that are computed separately but in the same network, modulate the top-down and bottom-up processing to reconstruct the occluded patterns. Simulation results support the presented hypothesis as well as effectiveness of the model in providing a solution to recognition of occluded patterns. The behavior of the model is in accordance to the known human behavior on the occluded patterns

    Application of response surface methodology to laser-induced breakdown spectroscopy : influences of hardware configuration

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    Response Surface Methodology (RSM) was employed to optimise LIBS analysis of single crystal silicon at atmospheric pressure and under vacuum conditions (pressure ~10-6mbar). Multivariate analysis software (StatGraphics 5.1) was used to design and analyse several multi-level, full factorial RSM experiments. A Quality Factor (QF) was conceived as the response parameter for the experiments, representing the quality of the LIBS spectrum captured for a given hardware configuration. The QF enabled the hardware configuration to be adjusted so that a best compromise between resolution, signal intensity and signal noise could be achieved. The effect on the QF of simultaneously adjusting spectrometer gain, gate delay, gate width, lens position and spectrometer slit width was investigated, and the conditions yielding the best QF determined

    Non-Fermi liquid behavior and scaling of low frequency suppression in optical conductivity spectra of CaRuO3_3

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    Optical conductivity spectra σ1(ω)\sigma_1(\omega) of paramagnetic CaRuO3_3 are investigated at various temperatures. At T=10 K, it shows a non-Fermi liquid behavior of σ1(ω)1/ω12\sigma_1(\omega)\sim 1/{\omega}^{\frac 12}, similar to the case of a ferromagnet SrRuO3_3. As the temperature (TT) is increased, on the other hand, σ1(ω)\sigma_1(\omega) in the low frequency region is progressively suppressed, deviating from the 1/{\omega}^{\frac 12%}-dependence. Interestingly, the suppression of σ1(ω)\sigma_1(\omega) is found to scale with ω/T\omega /T at all temperatures. The origin of the % \omega /T scaling behavior coupled with the non-Fermi liquid behavior is discussed.Comment: 4 pages, 3 figure
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