8,673 research outputs found
Chaotic itinerancy and power-law residence time distribution in stochastic dynamical system
To study a chaotic itinerant motion among varieties of ordered states, we
propose a stochastic model based on the mechanism of chaotic itinerancy. The
model consists of a random walk on a half-line, and a Markov chain with a
transition probability matrix. To investigate the stability of attractor ruins
in the model, we analyze the residence time distribution of orbits at attractor
ruins. We show that the residence time distribution averaged by all attractor
ruins is given by the superposition of (truncated) power-law distributions, if
a basin of attraction for each attractor ruin has zero measure. To make sure of
this result, we carry out a computer simulation for models showing chaotic
itinerancy. We also discuss the fact that chaotic itinerancy does not occur in
coupled Milnor attractor systems if the transition probability among attractor
ruins can be represented as a Markov chain.Comment: 6 pages, 10 figure
4p states and X-Ray Spectroscopy
The 4p states in transition metals and their compounds usually play minor
roles on their physical quantities. Recent development of resonant x-ray
scattering (RXS) at the K-edge of transition metals, however, casts light on
the 4p states, because the signals on orbital and magnetic superlattice spots
are brought about by the modulation in the 4p states. The 4p states are
extending in solids and thereby sensitive to electronic states at neighboring
sites. This characteristic determines the mechanism of RXS that the intensity
on the orbital superlattice spots are mainly generated by the lattice
distortion and those on magnetic superlattice spots by the coupling of the 4p
states with the orbital polarization in the 3d states at neighboring sites.
Taking up typical examples for orbital and magnetic RXS, we demonstrate these
mechanisms on the basis of the band structure calculation. Finally, we study
the MCD spectra at the K-edge, demonstrating that the same mechanism as the
magnetic RXS is working.Comment: 9 pages, 9 figures, submitted to Physica Scripta (comment
SUSY-QCD Corrections to Associated Production at the CERN Large Hadron Collider
We calculate the SUSY-QCD corrections to the inclusive total cross sections
of the associated production processes in the Minimal
Supersymmetric Standard Model(MSSM) at the CERN Large Hadron Collider(LHC). The
SUSY-QCD corrections can increase and decrease the total cross sections
depending on the choice of the SUSY parameters. When the SUSY-QCD
corrections increase the leading-order (LO) total cross sections significantly
for large tan (), which can exceed 10% and have the opposite
sign with respect to the QCD and the SUSY-EW corrections, and thus cancel with
them to some extent. Moreover, we also investigate the effects of the SUSY-QCD
on the differential distribution of cross sections in transverse momentum
and rapidity Y of W-boson, and the invariant mass .Comment: 24 pages, 10 figures; minor changes in references; two figures and
the corresponding disccusions added; a version to appear in PR
Transport magnetic currents driven by moving kink crystal in chiral helimagnets
We show that the bulk transport magnetic current is generated by the moving
magnetic kink crystal (chiral soliton lattice) formed in the chiral helimagnet
under the static magnetic field applied perpendicular to the helical axis. The
current is caused by the non-equilibrium transport momentum with the kink mass
being determined by the spin fluctuations around the kink crystal state. An
emergence of the transport magnetic currents is then a consequence of the
dynamical off-diagonal long range order along the helical axis. We derive an
explicit formula for the inertial mass of the kink crystal and the current in
the weak field limit.Comment: 5 pages, 3 figures, to appear in Phys. Rev.
Magnetic structure of free cobalt clusters studied with Stern-Gerlach deflection experiments
We have studied the magnetic properties of free cobalt clusters in two
semi-independent Stern-Gerlach deflection experiments at temperatures between
60 and 307 K. We find that clusters consisting of 13 to 200 cobalt atoms
exhibit behavior that is entirely consistent with superparamagnetism, though
complicated by finite-system fluctuations in cluster temperature. By fitting
the data to the Langevin function, we report magnetic moments per atom for each
cobalt cluster size and compare the results of our two measurements and all
those performed previously. In addition to a gradual decrease in moment per
atom with increasing size, there are oscillations that appear to be caused by
geometrical shell structure. We discuss our observations in light of the two
competing models for Langevin-like magnetization behavior in free clusters,
superparamagnetism and adiabatic magnetization, and conclude that the evidence
strongly supports the superparamagnetic model
Vertex Corrections on the Anomalous Hall Effect in Spin-polarized Two-dimensional Electron Gases with Rashba Spin-orbit Interaction
We study the effect of disorder on the intrinsic anomalous Hall (AH)
conductivity in a spin-polarized two-dimensional electron gas with a
Rashba-type spin-orbit interaction. We find that AH conductivity vanishes
unless the lifetime is spin-dependent, similar to the spin Hall (SH)
conductivity in the non-magnetic system. In addition, we find that the SH
conductivity does not vanish in the presence of magnetic scatterers. We show
that the SH conductivity can be controlled by changing the amount of the
magnetic impurities.Comment: Tex file only, no figure
Theoretical Analysis of Resonant Inelastic X-Ray Scattering Spectra in LaMnO3
We analyze the resonant inelastic x-ray scattering (RIXS) spectra at the K
edge of Mn in the antiferromagnetic insulating manganite LaMnO3. We make use of
the Keldysh-type Green-function formalism, in which the RIXS intensity is
described by a product of an incident-photon-dependent factor and a
density-density correlation function in the 3d states. We calculate the former
factor using the 4p density of states given by an ab initio band structure
calculation and the latter using a multi-orbital tight-binding model. The
ground state of the model Hamiltonian is evaluated within the Hartree-Fock
approximation. Correlation effects are treated within the random phase
approximation (RPA). We obtain the RIXS intensity in a wide range of
energy-loss 2-15 eV. The spectral shape is strongly modified by the RPA
correlation, showing good agreement with the experiments. The
incident-photon-energy dependence also agrees well with the experiments. The
present mechanism that the RIXS spectra arise from band-to-band transitions to
screen the core-hole potential is quite different from the orbiton picture
previously proposed, enabling a comprehensive understanding of the RIXS
spectra.Comment: 20 pages, 10 figures, To be published in PR
Suppression of the Persistent Spin Hall Current by Defect Scattering
We study the linear response spin Hall conductivity of a two-dimensional
electron gas (2DEG) in the presence of the Rashba spin orbit interaction in the
diffusive transport regime. When defect scattering is modeled by isotropic
short-range potential scatterers the spin Hall conductivity vanishes due to the
vertex correction. A non-vanishing spin Hall effect may be recovered for
dominantly forward defect scattering.Comment: Submitted to The Physical Review
Analisa Kadar H2s (Hidrogen Sulfida) dan Keluhan Kesehatan Saluran Pernapasan Serta Keluhan Iritasi Mata pada Masyarakat di Kawasan PT. Allegrindo Nusantara Desa Urung Panei Kecamatan Purba Kabupaten Simalungun Tahun 2013
Development of maintenance of increasing farm fields can affect the quality of the environment, one of which is the quality of the air can be decreased because of the pollution in the farm by impact. PT. Allegrindo Nusantara is one the largest farm in North Sumatra even in Southeast Asia which is located in the village of Urung Panei sub-district Purba district Simalungun. Hydrogen sulphide is a colorless gas, are very poisonous, combustible and having the characteristics of smell of rotten eggs. This research aims to know the levels of hydrogen sulfide and respiratory health complaints and complaints of irritation of the eye on people living in the area of hog farms PT. Allegrindo Nusantara. The type of research used are descriptive in nature. The population in this research is 90 people with respondents housewife with a sample is the total sampling. The results showed that levels of hydrogen sulfide in the hog farms PT. Allegrindo Nusantara 0,0002-0,016 ppm it not exceed the level indicated in the quality raw KepMenLH No. 50 in 1996. There are 36 people (40,0%) respondents who experienced respiratory tract health complaints during the last 3 months and 27 respondents (30,0%) people who suffered eye irritation complaints during the last 3 months. The conclusion is the importance of maintaining and improving the cleanliness of the farm to prevent the smell that can cause air pollution, monitoring of the air quality on an ongoing basis. In the community, it is important to use a mask and other protective as prevention efforts against respiratory tract health complaints and complaints of eye irritation
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