13,104 research outputs found
On signal-noise decomposition of timeseries using the continuous wavelet transform: Application to sunspot index
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
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 and the
chiral splitting probability 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 spin and a new ref. are adde
Triplet luminescent dinuclear-gold(I) complex-based light-emitting diodes with low turn-on voltage
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
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 as the next lightest supersymmetric particle. In this
paper we study the possibility of detecting 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 . 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
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 KFeSe from First Principles Calculations
Electronic structure and magnetic properties for iron-selenide KFeSe
are studied by first-principles calculations. The ground state is stripe-like
antiferromagnetic with calculated 2.26 magnetic moment on Fe atoms; and
the , coupling strengths are calculated to be 0.038 eV and 0.029 eV.
The states around are dominated by the Fe-3d orbitals which hybridize
noticeably to the Se-4p orbitals. While the band structure of KFeSe is
similar to a heavily electron-doped BaFeAs or FeSe system, the Fermi
surface of KFeSe is much closer to \fs11 system since the electron
sheets around is symmetric with respect to - exchange. These
features, as well as the absence of Fermi surface nesting, suggest that the
parental KFeSe 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
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
- …