4,472 research outputs found

    Part of the D - dimensional Spiked harmonic oscillator spectra

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    The pseudoperturbative shifted - l expansion technique PSLET [5,20] is generalized for states with arbitrary number of nodal zeros. Interdimensional degeneracies, emerging from the isomorphism between angular momentum and dimensionality of the central force Schrodinger equation, are used to construct part of the D - dimensional spiked harmonic oscillator bound - states. PSLET results are found to compare excellenly with those from direct numerical integration and generalized variational methods [1,2].Comment: Latex file, 20 pages, to appear in J. Phys. A: Math. & Ge

    Vector meson spectral function and dilepton rate in an effective mean field model

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    We have studied the vector meson spectral function (VMSF) in a hot and dense medium within an effective QCD model namely the Nambu-Jona-Lasinio (NJL) and its Polyakov Loop extended version (PNJL) with and without the effect of isoscalar vector interaction (IVI). The effect of the IVI has been taken into account using the ring approximation. We obtained the dilepton production rate (DPR) using the VMSF and observed that at moderate temperature it is enhanced in the PNJL model as compared to the NJL and Born rate due to the suppression of color degrees of freedom.Comment: 5 pages, 7 figures, conference proceedings of the XXI DAE-BRNS HEP Symposium, IIT Guwahati, December 2014; to appear in 'Springer Proceedings in Physics Series

    Bound - states for truncated Coulomb potentials

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    The pseudoperturbative shifted - ll expansion technique PSLET is generalized for states with arbitrary number of nodal zeros. Bound- states energy eigenvalues for two truncated coulombic potentials are calculated using PSLET. In contrast with shifted large-N expansion technique, PSLET results compare excellently with those from direct numerical integration.Comment: TEX file, 22 pages. To appear in J. Phys. A: Math. & Ge

    Medium magnetizations for longitudinal high-density digital recordings

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    ©2003 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.This paper reports on the influences of magnetic media remanent magnetizations on the output levels in digital magnetic tape and disk recording. While at low densities a high magnetization is required for a high output, a lower magnetization is required at high densities. However, for particular applications, an output near to the maximum can be obtained from a wide range of remanent magnetization values, which suggests possible uses for media with diverse properties

    Equilibrium Distribution of Heavy Quarks in Fokker-Planck Dynamics

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    We obtain within Fokker-Planck dynamics an explicit generalization of Einstein's relation between drag, diffusion and equilibrium distribution for a spatially homogeneous system, considering both the transverse and longitudinal diffusion for dimension n>1. We then provide a complete characterization of when the equilibrium distribution becomes a Boltzmann/J"uttner distribution, and when it satisfies the more general Tsallis distribution. We apply this analysis to recent calculations of drag and diffusion of a charm quark in a thermal plasma, and show that only a Tsallis distribution describes the equilibrium distribution well. We also provide a practical recipe applicable to highly relativistic plasmas, for determining both diffusion coefficients so that a specific equilibrium distribution will arise for a given drag coefficient.Comment: 4 pages including 2 figure

    Gyromagnetic ratio of rapidly rotating compact stars in general relativity

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    We numerically calculate equilibrium configurations of uniformly rotating and charged neutron stars, in the case of insulating material and neglecting the electromagnetic forces acting on the equilibrium of the fluid. This allows us to study the behaviour of the gyromagnetic ratio for those objects, when varying rotation rate and equation of state for the matter. Under the assumption of low charge and incompressible fluid, we find that the gyromagnetic ratio is directly proportional to the compaction parameter M/R of the star, and very little dependent on its angular velocity. Nevertheless, it seems impossible to have g=2 for these models with low charge-to-mass ratio, where matter consists of a perfect fluid and where the collapse limit is never reached.Comment: 11 pages, 6 figures, accepted for publication in Classical and Quantum Gravit

    Rethinking the QCD collisional energy loss

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    It is shown that to leading order the collisional energy loss of an energetic parton in the hot quark gluon plasma reads dE/dxα(mD2)T2dE/dx \sim \alpha(m_D^2)T^2, where the scale of the coupling is determined by the (parametrically soft) Debye screening mass. Compared to previous expressions derived by Bjorken and other authors, dEB/dxα2T2ln(ET/mD2)dE^B/dx \sim \alpha^2 T^2 \ln(ET/m_D^2), the rectified result takes into account the running of the coupling, as dictated by quantum corrections beyond tree level. As one significant consequence, due to asymptotic freedom, the QCD collisional energy loss becomes independent of the jet energy in the limit ETE \gg T. It is advocated that this resummation improved perturbative result might be useful to (re-)estimate the collisional energy loss for temperatures relevant in heavy ion phenomenology.Comment: contribution to "Hot Quarks 2006", Villasimius, Italy, 15-20 May 200

    Memory effects in radiative jet energy loss

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    In heavy-ion collisions the created quark-gluon plasma forms a quickly evolving background, leading to a time dependent radiative behavior of high momentum partons traversing the medium. We use the Schwinger Keldysh formalism to describe the jet evolution as a non-equilibrium process including the Landau-Pomeranschuk-Migdal effect. Concentrating on photon emission, a comparison of our results to a quasistatic calculation shows good agreement, leading to the conclusion that the radiative behavior follows the changes in the medium almost instantaneously

    Work-related injuries sustained by emergency medical technicians and paramedics in Turkey

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    BACKGROUND: Evaluated in the present study were locations, descriptions, and results of work-related injuries (WRIs) sustained by emergency medical technicians (EMTs) and paramedics in Turkey’s most crowded city, İstanbul. METHODS: After the present study had been accepted by the urban health authority, a questionnaire was emailed to the healthcare personnel of İstanbul’s 195 ambulance stations. RESULTS: Included in the present study were the responses of 901 members of staff (660 EMTs and 241 paramedics), with a mean age of 29.5±6.1 (min: 18; max: 61). The majority of participants (94.9%) had encountered verbal abuse from the public, and 39.8% had encountered physical violence from patients’ relatives. Levels of satisfaction with work in emergency medical services (EMS) was also evaluated, and 510 participants (57.6%) were unhappy. Regarding gender, female employees were more likely to be verbally attacked (p=0.01), while males were more likely to be physically attacked (p=0.001). It was reported that motor vehicle accidents (MVAs) were the most common cause of WRIs (81.4%), followed by needle-stick injuries (52.2%), ocular exposure to blood and other fluids (30.9%), and sharp injuries (22.5%). Only 10.5% (n=95) of WRIs were reported to authorities; 488 (54.2%) of participants just attended to the practice to prevent possible WRIs. CONCLUSION: For paramedics and EMTs, risk of WRI is obviously high. Strategies to decrease and prevent verbal and physical violence should be developed. © 2016 TJTES

    Evidence for spin-triplet superconducting correlations in metal-oxide heterostructures with non-collinear magnetization

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    Heterostructures composed of ferromagnetic La0.7Sr0.3MnO3, ferromagnetic SrRuO3, and superconducting YBa2Cu3Ox were studied experimentally. Structures of composition Au/La0.7Sr0.3MnO3/SrRuO3/YBa2Cu3Ox were prepared by pulsed laser deposition, and their high quality was confirmed by X-ray diffraction and reflectometry. A non-collinear magnetic state of the heterostructures was revealed by means of SQUID magnetometry and polarized neutron reflectometry. We have further observed superconducting currents in mesa-structures fabricated by deposition of a second superconducting Nb layer on top of the heterostructure, followed by patterning with photolithography and ion-beam etching. Josephson effects observed in these mesa-structures can be explained by the penetration of a triplet component of the superconducting order parameter into the magnetic layers.Comment: 10 pages, 6 figure
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