81,524 research outputs found

    Pulsar Velocity with Three-Neutrino Oscillations in Non-adiabatic Processes

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    We have studied the position dependence of neutrino energy on the Kusenko-Segr\`{e} mechanism as an explanation of the proper motion of pulsars. The mechanism is also examined in three-generation mixing of neutrinos and in a non-adiabatic case. The position dependence of neutrino energy requires the higher value of magnetic field such as B3×1015B\sim 3\times 10^{15} Gauss in order to explain the observed proper motion of pulsars. It is shown that possible non-adiabatic processes decrease the neutrino momentum asymmetry, whereas an excess of electron neutrino flux over other flavor neutrino fluxes increases the neutrino momentum asymmetry. It is also shown that a general treatment with all three neutrinos does not modify the result of the two generation treatment if the standard neutrino mass hierarchy is assumed.Comment: 8 pages, REVTEX, no figure

    Impurity scattering and Friedel oscillations in mono-layer black phosphorus

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    We study the effect of impurity scattering effect in black phosphorurene (BP) in this work. For single impurity, we calculate impurity induced local density of states (LDOS) in momentum space numerically based on tight-binding Hamiltonian. In real space, we calculate LDOS and Friedel oscillation analytically. LDOS shows strong anisotropy in BP. Many impurities in BP are investigated using TT-matrix approximation when the density is low. Midgap states appear in band gap with peaks in DOS. The peaks of midgap states are dependent on impurity potential. For finite positive potential, the impurity tends to bind negative charge carriers and vise versa. The infinite impurity potential problem is related to chiral symmetry in BP

    Tensor coupling effects on spin symmetry in anti-Lambda spectrum of hypernuclei

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    The effects of ΛˉΛˉω\bar\Lambda\bar\Lambda\omega-tensor coupling on the spin symmetry of Λˉ\bar{\Lambda} spectra in Λˉ\bar{\Lambda}-nucleus systems have been studied with the relativistic mean-field theory. Taking 12^{12}C+Λˉ\bar{\Lambda} as an example, it is found that the tensor coupling enlarges the spin-orbit splittings of Λˉ\bar\Lambda by an order of magnitude although its effects on the wave functions of Λˉ\bar{\Lambda} are negligible. Similar conclusions has been observed in Λˉ\bar{\Lambda}-nucleus of different mass regions, including 16^{16}O+Λˉ\bar{\Lambda}, 40^{40}Ca+Λˉ\bar{\Lambda} and 208^{208}Pb+Λˉ\bar{\Lambda}. It indicates that the spin symmetry in anti-lambda-nucleus systems is still good irrespective of the tensor coupling.Comment: 12 pages, 3 figures

    Shockley-Ramo theorem and long-range photocurrent response in gapless materials

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    Scanning photocurrent maps of gapless materials, such as graphene, often exhibit complex patterns of hot spots positioned far from current-collecting contacts. We develop a general framework that helps to explain the unusual features of the observed patterns, such as the directional effect and the global character of photoresponse. We show that such a response is captured by a simple Shockley-Ramo-type approach. We examine specific examples and show that the photoresponse patterns can serve as a powerful tool to extract information about symmetry breaking, inhomogeneity, chirality, and other local characteristics of the system.Comment: 7 pgs, 3 fg

    Scalable Mining of Common Routes in Mobile Communication Network Traffic Data

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    A probabilistic method for inferring common routes from mobile communication network traffic data is presented. Besides providing mobility information, valuable in a multitude of application areas, the method has the dual purpose of enabling efficient coarse-graining as well as anonymisation by mapping individual sequences onto common routes. The approach is to represent spatial trajectories by Cell ID sequences that are grouped into routes using locality-sensitive hashing and graph clustering. The method is demonstrated to be scalable, and to accurately group sequences using an evaluation set of GPS tagged data
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