1,665 research outputs found

    What makes good guidelines?

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    How would GW150914 look with future GW detector networks?

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    The first detected gravitational wave signal, GW150914, was produced by the coalescence of a stellar-mass binary black hole. Along with the subsequent detection of GW151226, GW170104 and the candidate event LVT151012, this gives us evidence for a population of black hole binaries with component masses in the tens of solar masses. As detector sensitivity improves, this type of source is expected to make a large contribution to the overall number of detections, but has received little attention compared to binary neutron star systems in studies of projected network performance. We simulate the observation of a system like GW150914 with different proposed network configurations, and study the precision of parameter estimates, particularly source location, orientation and masses. We find that the improvements to low frequency sensitivity that are expected with continued commissioning will improve the precision of chirp mass estimates by an order of magnitude, whereas the improvements in sky location and orientation are driven by the expanded network configuration. This demonstrates that both sensitivity and number of detectors will be important factors in the scientific potential of second generation detector networks.Comment: 18 pages, 5 figures, 2 table

    Distributed quantum information processing with minimal local resources

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    We present a protocol for growing graph states, the resource for one-way quantum computing, when the available entanglement mechanism is highly imperfect. The distillation protocol is frugal in its use of ancilla qubits, requiring only a single ancilla qubit when the noise is dominated by one Pauli error, and two for a general noise model. The protocol works with such scarce local resources by never post-selecting on the measurement outcomes of purification rounds. We find that such a strategy causes fidelity to follow a biased random walk, and that a target fidelity is likely to be reached more rapidly than for a comparable post-selecting protocol. An analysis is presented of how imperfect local operations limit the attainable fidelity. For example, a single Pauli error rate of 20% can be distilled down to 10\sim 10 times the imperfection in local operations.Comment: 4 pages of main paper with an additional 1 page appendix, 5 figures. Please contact me with any comment

    Occurrence of Two Species of Old World Bees, \u3ci\u3eAnthidium Manicatum\u3c/i\u3e and \u3ci\u3eA. Oblongatum\u3c/i\u3e (Apoidea: Megachilidae), in Northern Ohio and Southern Michigan

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    Anthidium manicatum and A. oblongatum are two European bees species that have recently established themselves in North America. Anthidium manicatum has previously been documented in New York and Ontario, Canada, and A. oblongatum has been documented in New York, New Jersey, Maryland, and eastern Pennsylvania. We surveyed a number of sites in Ohio, Michigan, and Indiana for these species in 2000 and 2001, and found both bee species to have extended their ranges into northern Ohio, and A. manicatum to have moved into southern Michigan. We present a key identifying the four Anthidium species now known from northeastern North America

    The Global Fight against the Stigma of Schizophrenia

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    Stigma attached to mental illness is the greatest obstacle to the improvement of the life of people with mental illness and their families. A global campaign hopes to remove this obstacle
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