13,104 research outputs found

    On signal-noise decomposition of timeseries using the continuous wavelet transform: Application to sunspot index

    Get PDF
    We show that the continuous wavelet transform can provide a unique decomposition of a timeseries in to 'signal-like' and 'noise-like' components: From the overall wavelet spectrum two mutually independent skeleton spectra can be extracted, allowing the separate detection and monitoring in even non-stationary timeseries of the evolution of (a) both stable but also transient, evolving periodicities, such as the output of low dimensional dynamical systems and (b) scale-invariant structures, such as discontinuities, self-similar structures or noise. An indicative application to the monthly-averaged sunspot index reveals, apart from the well-known 11-year periodicity, 3 of its harmonics, the 2-year periodicity (quasi-biennial oscillation, QBO) and several more (some of which detected previously in various solar, earth-solar connection and climate indices), here proposed being just harmonics of the QBO, in all supporting the double-cycle solar magnetic dynamo model (Benevolenskaya, 1998, 2000). The scale maximal spectrum reveals the presence of 1/f fluctuations with timescales up to 1 year in the sunspot number, indicating that the solar magnetic configurations involved in the transient solar activity phenomena with those characteristic timescales are in a self-organized-critical state (SOC), as previously proposed for the solar flare occurence (Lu and Hamilton, 1991).Comment: 22 pages, 2 figure

    Quark Orbital Angular Momentum in the Baryon

    Full text link
    Analytical and numerical results, for the orbital and spin content carried by different quark flavors in the baryons, are given in the chiral quark model with symmetry breaking. The reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular momentum for each quark flavor in the proton as a function of the partition factor κ\kappa and the chiral splitting probability aa is shown. The cancellation between the spin and orbital contributions in the spin sum rule and in the baryon magnetic moments is discussed.Comment: 26 pages, 3 figures, revised version with minor eq. no and ref. no. corrections. Discussion on the Λ\Lambda spin and a new ref. are adde

    Triplet luminescent dinuclear-gold(I) complex-based light-emitting diodes with low turn-on voltage

    Get PDF
    The electroluminescence (EL) from a dinuclear-gold(I)-chlorate compound containing bridging phosphine ligands [Au 2(dppm)Cl 2] as emitting layer is reported. Devices with a structure Al/Au 2(dppm)Cl 2/indium-tin-oxide demonstrated a uniform emission under the driving voltage below 1 V. The EL emission was from triplet excited state and the emission color of the device was found to depend on the deposition rate of Au 2(dppm)Cl 2, which can be explained as the different aggregation forms of the stacking compound in the deposition process. © 1999 American Institute of Physics.published_or_final_versio

    Phenomenology of quintessino dark matter -- Production of NLSP particles

    Full text link
    In the model of quintessino as dark matter particle, the dark matter and dark energy are unified in one superfield, where the dynamics of the Quintessence drives the Universe acceleration and its superpartner, quintessino, makes up the dark matter of the Universe. This scenario predicts the existence of long lived Ï„~\tilde{\tau} as the next lightest supersymmetric particle. In this paper we study the possibility of detecting Ï„~\tilde{\tau} produced by the high energy cosmic neutrinos interacting with the earth matter. By a detailed calculation we find that the event rate is one to several hundred per year at a detector with effective area of 1km21 km^2. The study in this paper can be also applied for models of gravitino or axino dark matter particles.Comment: 16 pages, 5 figures, a new section about NLSP stau is added, references adde

    Poynting vector, energy density and energy velocity in anomalous dispersion medium

    Get PDF
    The Poynting vector, energy density and energy velocity of light pulses propagating in anomalous dispersion medium (used in WKD-like experiments) are calculated. Results show that a negative energy density in the medium propagates along opposite of incident direction with such a velocity similar to the negative group velocity while the direction of the Poynting vector is positive. In other words, one might say that a positive energy density in the medium would propagate along the positive direction with a speed having approximately the absolute valueof the group velocity. We further point out that neither energy velocity nor group velocity is a good concept to describe the propagation process of light pulse inside the medium in WKD experiment owing to the strong accumulation and dissipation effects.Comment: 6 page

    Electronic Structure of KFe2_2Se2_2 from First Principles Calculations

    Full text link
    Electronic structure and magnetic properties for iron-selenide KFe2_2Se2_2 are studied by first-principles calculations. The ground state is stripe-like antiferromagnetic with calculated 2.26 μB\mu_B magnetic moment on Fe atoms; and the J1J_1, J2J_2 coupling strengths are calculated to be 0.038 eV and 0.029 eV. The states around EFE_F are dominated by the Fe-3d orbitals which hybridize noticeably to the Se-4p orbitals. While the band structure of KFe2_2Se2_2 is similar to a heavily electron-doped BaFe2_2As2_2 or FeSe system, the Fermi surface of KFe2_2Se2_2 is much closer to \fs11 system since the electron sheets around MM is symmetric with respect to xx-yy exchange. These features, as well as the absence of Fermi surface nesting, suggest that the parental KFe2_2Se2_2 could be regarded as an electron over-doped 11 system with possible local moment magnetism.Comment: accepted by Chinese Physics Letter, to appear as Chinese Physics Letter, Vol 28, page 057402 (2011

    Multiparty simultaneous quantum identity authentication based on entanglement swapping

    Get PDF
    We present a multiparty simultaneous quantum identity authentication protocol based on entanglement swapping. In our protocol, the multi-user can be authenticated by a trusted third party simultaneously
    • …
    corecore