75,664 research outputs found

    Accelerating Staggered Fermion Dynamics with the Rational Hybrid Monte Carlo (RHMC) Algorithm

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    Improved staggered fermion formulations are a popular choice for lattice QCD calculations. Historically, the algorithm used for such calculations has been the inexact R algorithm, which has systematic errors that only vanish as the square of the integration step-size. We describe how the exact Rational Hybrid Monte Carlo (RHMC) algorithm may be used in this context, and show that for parameters corresponding to current state-of-the-art computations it leads to a factor of approximately seven decrease in cost as well as having no step-size errors.Comment: 4 pages, 2 figures, 1 tabl

    Exact 2+1 flavour RHMC simulations

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    We consider the Rational Hybrid Monte Carlo algorithm for performing exact 2+1 flavour fermion simulations. The specific cases of ASQTAD and domain wall fermions are considered. We find that in both cases the naive performance is similar to conventional hybrid algorithms.Comment: 3 pages, no figure

    Algorithm Shootout: R versus RHMC

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    We present initial results comparing the RHMC and R algorithms on large lattices with small quark masses using chiral fermions. We also present results concerning staggered fermions near the deconfinement/chiral phase transition. We find that the RHMC algorithm not only eliminates the step-size error of the R algorithm, but is also considerably more efficient. We discuss several possibilities for further improvement to the RHMC algorithm.Comment: Proceedings from Lattice 2005 (Dublin

    Diamond-Like Carbon film from Liquid Gas on Metallic Substrates

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    Liquid gas was used to produce DLC films on Cu, Al and steel substrates by DC plasma technique. The absorption in IR reflectance indicates, grown films are DLC. By deconvolution of room temperature UV-visible spectra of the films grown at 50 mtorr and 200{}^\circC, in addition to the spectra lines reported for CL, PL, PLC and ESR, some new spectra lines were obtained. We also, have seen exciton absorption line at room temperature.Comment: 6 pages, Postscript, 2 figure

    Are Young People's Educational Outcomes Linked to their Sense of Control?

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    This paper analyzes the link between young people's sense (locus) of control over their lives and their investments in education. We find that young people with a more internal locus of control have a higher probability of finishing secondary school and, conditional on completion, meeting the requirements to obtain a university entrance rank. Moreover, those with an internal locus of control who obtain a university entrance rank achieve somewhat higher rankings than do their peers who have a more external locus of control. Not surprisingly, there is a negative relationship between growing up in disadvantage and educational outcomes. However, this effect does not appear to operate indirectly by increasing the likelihood of having a more external locus of control. In particular, we find no significant relationship between family welfare history and young people's locus of control.locus of control, parental socio-economic background, education