23,196 research outputs found

    Loss-tolerant operations in parity-code linear optics quantum computing

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    A heavy focus for optical quantum computing is the introduction of error-correction, and the minimisation of resource requirements. We detail a complete encoding and manipulation scheme designed for linear optics quantum computing, incorporating scalable operations and loss-tolerant architecture.Comment: 8 pages, 6 figure

    Trident: A three-pronged galaxy survey. I. Lyman alpha emitting galaxies at z~2 in GOODS North

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    Context. Lyman alpha emitting galaxies (LAEs) are used to probe the distant universe and are therefore important for galaxy evolution studies and for providing clues to the nature of the epoch of reionization, but the exact circumstances under which Lyman alpha escapes a galaxy are still not fully understood. Aims. The Trident project is designed to simultaneously examine Lyman alpha, H-alpha and Lyman Continuum emission from galaxies at redshift z~2, thus linking together these three aspects of ionising radiation in galaxies. In this paper, we outline the strategy of this project and examine the properties of LAEs in the GOODS North field. Methods. We performed a narrowband LAE survey in GOODS North using existing and two custom made filters at the Nordic Optical Telescope with MOSCA. We use complementary broad band archival data in the field to make a careful candidate selection and perform optical to near-IR SED fitting. We also estimate far-infrared luminosities by matching our candidates to detections in Spitzer/MIPS 24{\mu}m and Herschel/PACS catalogs. Results. We find a total of 25 LAE candidates, probing mainly the bright end of the LAE luminosity function with L_Ly {\alpha} ~ 1-15e42 erg/s. They display a range of masses of ~0.5-50e9 M_solar, and average ages from a few tens of Myr to 1 Gyr when assuming a constant star formation history. The majority of our candidates also show signs of recent elevated star formation. Three candidates have counterparts in the GOODS-Herschel far-IR catalogue, with luminosities consistent with ultra-luminous infrared galaxies (ULIRGs). Conclusions. The wide range of parameters derived from our SED fitting, as well as part of our sample being detected as ULIRGs, seems to indicate that at these Lyman alpha luminosities, LAEs do not necessarily have to be young dwarfs, and that a lack of dust is not required for Lyman alpha to escape.Comment: 16 pages, 12 figures. Accepted version for publication in A&

    Efficient Parity Encoded Optical Quantum Computing

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    We present a linear optics quantum computation scheme with a greatly reduced cost in resources compared to KLM. The scheme makes use of elements from cluster state computation and achieves comparable resource usage to those schemes while retaining the circuit based approach of KLM

    Loss Tolerant Optical Qubits

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    We present a linear optics quantum computation scheme that employs a new encoding approach that incrementally adds qubits and is tolerant to photon loss errors. The scheme employs a circuit model but uses techniques from cluster state computation and achieves comparable resource usage. To illustrate our techniques we describe a quantum memory which is fault tolerant to photon loss

    Energy efficient engine high-pressure turbine single crystal vane and blade fabrication technology report

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    The objective of the High-Pressure Turbine Fabrication Program was to demonstrate the application and feasibility of Pratt & Whitney Aircraft-developed two-piece, single crystal casting and bonding technology on the turbine blade and vane configurations required for the high-pressure turbine in the Energy Efficient Engine. During the first phase of the program, casting feasibility was demonstrated. Several blade and vane halves were made for the bonding trials, plus solid blades and vanes were successfully cast for materials evaluation tests. Specimens exhibited the required microstructure and chemical composition. Bonding feasibility was demonstrated in the second phase of the effort. Bonding yields of 75 percent for the vane and 30 percent for the blade were achieved, and methods for improving these yield percentages were identified. A bond process was established for PWA 1480 single crystal material which incorporated a transient liquid phase interlayer. Bond properties were substantiated and sensitivities determined. Tooling die materials were identified, and an advanced differential thermal expansion tooling concept was incorporated into the bond process

    Programmed schedule holds for improving launch vehicle holds

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    Baseline definition and system optimization are used for the analysis of programmed holds developed through prelaunch system analysis. Identification of design specifications for ground support equipment and maintenance concepts, and design specifications are used to describe the functional utilization of the overall flow process

    Consumer responses to corporate social irresponsibility: The role of moral emotions, evaluations, and social cognitions

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    We investigate the mediating roles of moral emotions and attitudes between perceptions of corporate irresponsible actions, on the one hand, and consumer responses, on the other hand, and further examine their contingencies based on consumer social cognitions. Our findings show that, for corporate transgressions, multiple social cognitions (moral identity, relational and collective self‐concepts, and affective empathy) moderate the elicitation of negative moral emotions (contempt and anger) and overall evaluations (attitudes), which, in turn, lead to negative responses toward the company (negative word of mouth, complaint behaviors, and boycotting). Our study adds to extant research on corporate social irresponsibility by examining three generic reactions people have toward corporate social irresponsibility and demonstrating important boundary conditions. In addition, hypotheses are tested on a sample of adult consumers. Implications for communication by firms are considered.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149212/1/mar21197.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149212/2/mar21197_am.pd

    EXPERIMENTAL METHODS IN CONSUMER PREFERENCE STUDIES

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    Controlled experimental auctions can be used to elicit preferences for food products. We describe results from two series of experiments in which subjects revealed their willingness-to-pay for safer food. In one series, the risk reduction technology was not specified; in the other, it was identified as food irradiation. The results provide some evidence on the acceptability of food irradiation as a risk reduction technology.Consumer/Household Economics,

    MUSE-inspired view of the quasar Q2059-360, its Lyman alpha blob, and its neighborhood

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    The radio-quiet quasar Q2059-360 at redshift z=3.08z=3.08 is known to be close to a small Lyman α\alpha blob (LAB) and to be absorbed by a proximate damped Lyα\alpha (PDLA) system. Here, we present the Multi Unit Spectroscopic Explorer (MUSE) integral field spectroscopy follow-up of this quasi-stellar object (QSO). Our primary goal is to characterize this LAB in detail by mapping it both spatially and spectrally using the Lyα\alpha line, and by looking for high-ionization lines to constrain the emission mechanism. Combining the high sensitivity of the MUSE integral field spectrograph mounted on the Yepun telescope at ESO-VLT with the natural coronagraph provided by the PDLA, we map the LAB down to the QSO position, after robust subtraction of QSO light in the spectral domain. In addition to confirming earlier results for the small bright component of the LAB, we unveil a faint filamentary emission protruding to the south over about 80 pkpc (physical kpc); this results in a total size of about 120 pkpc. We derive the velocity field of the LAB (assuming no transfer effects) and map the Lyα\alpha line width. Upper limits are set to the flux of the N V λ12381242\lambda 1238-1242, C IV λ15481551\lambda 1548-1551, He II λ1640\lambda 1640, and C III] λ15481551\lambda 1548-1551 lines. We have discovered two probable Lyα\alpha emitters at the same redshift as the LAB and at projected distances of 265 kpc and 207 kpc from the QSO; their Lyα\alpha luminosities might well be enhanced by the QSO radiation. We also find an emission line galaxy at z=0.33z=0.33 near the line of sight to the QSO. This LAB shares the same general characteristics as the 17 others surrounding radio-quiet QSOs presented previously. However, there are indications that it may be centered on the PDLA galaxy rather than on the QSO.Comment: Accepted for publication in Astronomy & Astrophysics; 16 pages, 19 figure

    Quasi-Periodic Pulsations during the Impulsive and Decay phases of an X-class Flare

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    Quasi-periodic pulsations (QPP) are often observed in X-ray emission from solar flares. To date, it is unclear what their physical origins are. Here, we present a multi-instrument investigation of the nature of QPP during the impulsive and decay phases of the X1.0 flare of 28 October 2013. We focus on the character of the fine structure pulsations evident in the soft X-ray time derivatives and compare this variability with structure across multiple wavelengths including hard X-ray and microwave emission. We find that during the impulsive phase of the flare, high correlations between pulsations in the thermal and non-thermal emissions are seen. A characteristic timescale of ~20s is observed in all channels and a second timescale of ~55s is observed in the non-thermal emissions. Soft X-ray pulsations are seen to persist into the decay phase of this flare, up to 20 minutes after the non-thermal emission has ceased. We find that these decay phase thermal pulsations have very small amplitude and show an increase in characteristic timescale from ~40s up to ~70s. We interpret the bursty nature of the co-existing multi-wavelength QPP during the impulsive phase in terms of episodic particle acceleration and plasma heating. The persistent thermal decay phase QPP are most likely connected with compressive MHD processes in the post-flare loops such as the fast sausage mode or the vertical kink mode.Comment: 7 pages, 4 figures, 1 tabl
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