4,831 research outputs found
Anomalous magnetic properties near Mott transition in Kagom\'e lattice Hubbard model
We investigate the characteristics of the metallic phase near the Mott
transition in the Kagom\'e lattice Hubbard model using the cellular dynamical
mean field theory. By calculating the specific heat and spin correlation
functions, we demonstrate that the quasiparticles show anomalous properties in
the metallic phase close to the Mott transition. We find clear evidence for the
multi-band heavy quasiparticles in the specific heat, which gives rise to
unusual temperature dependence of the spin correlation functions.Comment: 2 pages, 3 figures, accepted for publication in J. Mag. Mag. Mater.
(Proceedings of the ICM, Kyoto, Japan, August 2006
Detection of an X-Ray Hot Region in the Virgo Cluster of Galaxies with ASCA
Based on mapping observations with ASCA, an unusual hot region with a spatial
extent of 1 square degree was discovered between M87 and M49 at a center
coordinate of R. A. = 12h 27m 36s and Dec. = (J2000). The X-ray
emission from the region has a 2-10 keV flux of ergs
s cm and a temperature of keV, which is
significantly higher than that in the surrounding medium of keV. The
internal thermal energy in the hot region is estimated to be ergs with a gas density of cm. A power-law
spectrum with a photon index is also allowed by the data. The hot
region suggests there is an energy input due to a shock which is probably
caused by the motion of the gas associated with M49, infalling toward the M87
cluster with a velocity km s.Comment: 12 pages, 3 figures, accepted to ApJ
Electric Field Modulation of Galvanomagnetic Properties of Mesoscopic Graphite
Electric field effect devices based on mesoscopic graphite are fabricated for
galvanomagnetic measurements. Strong modulation of magneto-resistance and Hall
resistance as a function of gate voltage is observed as sample thickness
approaches the screening length. Electric field dependent Landau level
formation is detected from Shubnikov de Haas oscillations in
magneto-resistance. The effective mass of electron and hole carriers has been
measured from the temperature dependant behavior of these oscillations.Comment: 4 pages, 4 figures included, submitted to Phys. Rev. Let
Comments on differential cross section of phi-meson photoproduction at threshold
We show that the differential cross section d_sigma/d_t of gamma p --> \phi p
reaction at the threshold is finite and its value is crucial to the mechanism
of the phi meson photoproduction and for the models of phi-N interaction.Comment: 8 pages, 2 figure
Mott Phase in Polarized Two-component Atomic Fermi Lattice Gas:A Playground for S=1/2 Heisenberg Model in Magnetic Field
We investigate effects of pseudo-spin population imbalance on Mott phases in
1D trapped two-component atomic Fermi gases loaded on optical lattices based on
the repulsive Hubbard model in harmonic traps. By using the density matrix
renormalization group method, we numerically calculate density profiles of each
component and clarify the pseudo-spin magnetism. Consequently, we find that all
the features from weakly imbalance to fully polarized cases are well described
by S=1/2 antiferromagnetic Heisenberg chain under magnetic field. These results
indicate that the Mott phases offer experimental stages for studying various
interacting spin systems
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Nucleotide specificity of the enzymatic and motile activities of dynein, kinesin, and heavy meromyosin.
The substrate specificities of dynein, kinesin, and myosin substrate turnover activity and cytoskeletal filament-driven translocation were examined using 15 ATP analogues. The dyneins were more selective in their substrate utilization than bovine brain kinesin or muscle heavy meromyosin, and even different types of dyneins, such as 14S and 22S dynein from Tetrahymena cilia and the beta-heavy chain-containing particle from the outer-arm dynein of sea urchin flagella, could be distinguished by their substrate specificities. Although bovine brain kinesin and muscle heavy meromyosin both exhibited broad substrate specificities, kinesin-induced microtubule translocation varied over a 50-fold range in speed among the various substrates, whereas heavy meromyosin-induced actin translocation varied only by fourfold. With both kinesin and heavy meromyosin, the relative velocities of filament translocation did not correlate well with the relative filament-activated substrate turnover rates. Furthermore, some ATP analogues that did not support the filament translocation exhibited filament-activated substrate turnover rates. Filament-activated substrate turnover and power production, therefore, appear to become uncoupled with certain substrates. In conclusion, the substrate specificities and coupling to motility are distinct for different types of molecular motor proteins. Such nucleotide "fingerprints" of enzymatic activities of motor proteins may prove useful as a tool for identifying what type of motor is involved in powering a motility-related event that can be reconstituted in vitro
Chandra observation of the central galaxies in A1060 cluster of galaxies
Chandra observation of the central region of the A1060 cluster of galaxies
resolved X-ray emission from two giant elliptical galaxies, NGC 3311 and NGC
3309. The emission from these galaxies consists of two components, namely the
hot interstellar medium (ISM) and the low-mass X-ray binaries (LMXBs). We found
the spatial extent of the ISM component was much smaller than that of stars for
both galaxies, while the ratios of X-ray to optical blue-band luminosities were
rather low but within the general scatter for elliptical galaxies. After
subtracting the LMXB component, the ISM is shown to be in pressure balance with
the intracluster medium of A1060 at the outer boundary of the ISM. These
results imply that the hot gas supplied from stellar mass loss is confined by
the external pressure of the intracluster medium, with the thermal conduction
likely to be suppressed. The cD galaxy NGC 3311 does not exhibit the extended
potential structure which is commonly seen in bright elliptical galaxies, and
we discuss the possible evolution history of the very isothermal cluster A1060.Comment: 12 pages, 7 figures, Latex2e(emulateapj5), accepted in Ap
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