34,350 research outputs found

    Grover Algorithm with zero theoretical failure rate

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    In standard Grover's algorithm for quantum searching, the probability of finding the marked item is not exactly 1. In this Letter we present a modified version of Grover's algorithm that searches a marked state with full successful rate. The modification is done by replacing the phase inversion by two phase rotation through angle ϕ\phi. The rotation angle is given analytically to be ϕ=2arcsin(sinπ(4J+6)sinβ)\phi=2 \arcsin(\sin{\pi\over (4J+6)}\over \sin\beta), where sinβ=1N\sin\beta={1\over \sqrt{N}}, NN the number of items in the database, and JJ an integer equal to or greater than the integer part of (π2β)/(2β)({\pi\over 2}-\beta)/(2\beta). Upon measurement at (J+1)(J+1)-th iteration, the marked state is obtained with certainty.Comment: 5 pages. Accepted for publication in Physical Review

    A normalisation procedure for biaxial bias extension tests

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    Biaxial Bias Extension tests have been performed on a plain-weave carbon fibre engineering fabric. The test results have been normalised using both the upper and lower bound method proposed by Potluri et al. and also using a novel alternative normalisation method based on energy arguments. The normalised results from both methods are compared and discussed

    A search for X-ray polarization in cosmic X-ray sources

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    Fifteen strong X-ray sources were observed by the X-ray polarimeters on board the OSO-8 satellite from 1975 to 1978. The final results of this search for X-ray polarization in cosmic sources are presented in the form of upper limits for the ten sources which are discussed elsewhere. These limits in all cases are consistent with a thermal origin for the X-ray emission

    Count Me In: The dimensions of social inclusion through culture and sport

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    This study was set up to examine claims made for the ability of cultural projects to promote social inclusion (cultural projects are here taken to include those incorporating sport, the arts, media, heritage and outdoor adventure). This was to be achieved primarily by collecting evidence from a sample of 14 projects selected from some 200 that had volunteered their services. The report to the government’s Social Exclusion Unit (SEU) from the Policy Action Team (PAT10) (1999)2 noted the potential. In his foreword, Chris Smith (then Secretary of State for the Department for Culture Media and Sport (DCMS)) wrote: “… art and sport can not only make a valuable contribution to delivering key outcomes of lower long term unemployment, less crime, better health and better qualifications, but can also help to develop the individual pride, community spirit and capacity for responsibility that enable communities to run regeneration programmes themselves”. Similar statements have followed from other politicians, particularly in the recent Commons debate on sport and social exclusion (22/11/01), and again in the public health debate (13/12/01). However, the PAT 10 report also came to the same conclusion as previous commentators (e.g. Glyptis, 19893; Allison & Coalter, 19964; Long & Sanderson, 19985) that there is little ‘hard’ evidence of the social benefits that accrue

    Count Me In: The Dimensions of social inclusion through Culture, Media & Sport (Executive Summary)

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    This study was set up to examine claims made for the ability of cultural projects to promote social inclusion (cultural projects are here taken to include those incorporating sport, the arts, media, heritage and outdoor adventure). This was to be achieved primarily by collecting evidence from a sample of 14 projects selected from some 200 that had volunteered their services. The report to the government’s Social Exclusion Unit (SEU) from the Policy Action Team (PAT10) (1999) noted the potential. In his foreword, Chris Smith (then Secretary of State for the Department for Culture Media and Sport (DCMS)) wrote: “… art and sport can not only make a valuable contribution to delivering key outcomes of lower long term unemployment, less crime, better health and better qualifications, but can also help to develop the individual pride, community spirit and capacity for responsibility that enable communities to run regeneration programmes themselves”. Similar statements have followed from other politicians, particularly in the recent Commons debate on sport and social exclusion (22/11/01), and again in the public health debate (13/12/01). However, the PAT 10 report also came to the same conclusion as previous commentators (e.g. Glyptis, 19893; Allison & Coalter, 19964; Long & Sanderson, 1998) that there is little ‘hard’ evidence of the social benefits that accrue

    Dimerized and trimerized phases for spin-2 Bosons in a one-dimensional optical lattice

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    We study the phase diagram for spin-2 bosons loaded in a one-dimensional optical lattice. By using non-Abelian density matrix renormalization group (DMRG) method we identify three possible phases: ferromagnetic, dimerized, and trimerized phases. We sketch the phase boundaries based on DMRG. We illustrate two methods for identifying the phases. The first method is based on the spin-spin correlation function while in the second method one observes the excitation gap as a dimerization or a trimerization superlattice is imposed. The advantage of the second method is that it can also be easily implemented in experiments. By using the scattering lengths in the literature we estimate that 83^{83}Rb, 23^{23}Na, and 87^{87}Rb be ferromagnetic, dimerized, and trimerized respectively.Comment: 4 pages, 3 figures. Add acknowledgemen

    Far-flung Filaments of Ejecta in the Young Supernova Remnant G292.0+1.8

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    New optical images of the young SNR G292.0+1.8, obtained from the 0.9-m telescope at CTIO, show a more extensive network of filaments than had been known previously. Filaments emitting in [O III] are distributed throughout much of the 8 arcmin diameter shell seen in X-ray and radio images, including a few at the very outermost shell limits. We have also detected four small complexes of filaments that show [S II] emission along with [OIII]. In a single long-slit spectrum we find variations of almost an order of magnitude in the relative strengths of oxygen and sulfur lines, which must result from abundance variations. None of the filaments, with or without [S II], shows any evidence for hydrogen, so all appear to be fragments of pure SN ejecta. The [S II] filaments provide the first evidence for undiluted products of oxygen burning in the ejecta from the supernova that gave rise to G292.0+1.8. Some oxygen burning must have occurred, but the paucity of [S II]-emitting filaments suggests that either the oxygen burning was not extensive or that most of its products have yet to be excited. Most of the outer filaments exhibit radial, pencil-like morphologies that suggest an origin as Rayleigh-Taylor fingers of ejecta, perhaps formed during the explosion. Simulations of core-collapse supernovae predict such fingers, but these have never before been so clearly observed in a young SNR. The total flux from the SNR in [OIII] 5007 is 5.4 * 10**-12 ergs/cm**2/s. Using a distance of 6 kpc and an extinction correction corresponding to E(B-V) = 0.6 (lower than previous values but more consistent both with our data and radio and X-ray estimates of NH), this leads to a luminosity of 1.6 * 10**35 ergs/s in the 5007 Ang. line.Comment: 32 pages including 10 figures, and 3 tables, accepted for publication in AJ. Vol 132, July 2006. Higher resolution versions of the figures and a pdf of the manuscript can be found at http://www-int.stsci.edu/~long/papers/g292_optical

    Electrical characterization of the soft breakdown failure mode in MgO layers

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    The soft breakdown (SBD) failure mode in 20 nm thick MgO dielectric layers grown on Si substrates was investigated. We show that during a constant voltage stress, charge trapping and progressive breakdown coexist, and that the degradation dynamics is captured by a power-law time dependence. We also show that the SBD current-voltage (I-V) characteristics follow the power-law model I = aVb typical of this conduction mechanism but in a wider voltage window than the one reported in the past for SiO2. The relationship between the magnitude of the current and the normalized differential conductance was analyzed
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