21,200 research outputs found
Odd Parity and Line Nodes in Heavy Fermion Superconductors
Group theory arguments have demonstrated that a general odd parity order
parameter cannot have line nodes in the presence of spin-orbit coupling. In
this paper, it is shown that these arguments do not hold on the
zone face of a hexagonal close packed lattice. In particular, three of the six
odd parity representations vanish identically on this face. This has potential
relevance to the heavy fermion superconductor .Comment: 5 pages, revte
Photon Conserving Radiative Transfer around Point Sources in multi-dimensional Numerical Cosmology
Many questions in physical cosmology regarding the thermal and ionization
history of the intergalactic medium are now successfully studied with the help
of cosmological hydrodynamical simulations. Here we present a numerical method
that solves the radiative transfer around point sources within a three
dimensional cartesian grid. The method is energy conserving independently of
resolution: this ensures the correct propagation speeds of ionization fronts.
We describe the details of the algorithm, and compute as first numerical
application the ionized region surrounding a mini-quasar in a cosmological
density field at z=7.Comment: 5 pages, 4 figures, submitted to ApJ
Magnetic collimation of protostellar winds into bipolar outflows
Researchers describe self-consistent 2-D magnetohydrodynamic (MHD) simulations of the collimation of an isotropic protostellar wind into bipolar outflows by magnetic stresses in the ambient medium. A variety of ambient field strengths, wind luminosities, and density profiles were studied. Collimation occurs when the energy of the magnetic field swept up by the expanding bubble approaches the bubble thermal energy. Measured axial and radial expansion rates are in good agreement with the analytical predictions of Konigl (1982)
Hot Spots on the Fermi Surface of Bi2212: Stripes versus Superstructure
In a recent paper Saini et al. have reported evidence for a pseudogap around
(pi,0) at room temperature in the optimally doped superconductor Bi2212. This
result is in contradiction with previous ARPES measurements. Furthermore they
observed at certain points on the Fermi surface hot spots of high spectral
intensity which they relate to the existence of stripes in the CuO planes. They
also claim to have identified a new electronic band along Gamma-M1 whose one
dimensional character provides further evidence for stripes. We demonstrate in
this Comment that all the measured features can be simply understood by
correctly considering the superstructure (umklapp) and shadow bands which occur
in Bi2212.Comment: 1 page, revtex, 1 encapsulated postscript figure (color
Inverse Spin Hall Effect by Spin Injection
Motivated by a recent experiment[Nature {\bf 442}, 176 (2006)], we present a
quantitative microscopic theory to investigate the inverse spin-Hall effect
with spin injection into aluminum considering both intrinsic and extrinsic
spin-orbit couplings using the orthogonalized-plane-wave method. Our
theoretical results are in good agreement with the experimental data. It is
also clear that the magnitude of the anomalous Hall resistivity is mainly due
to contributions from extrinsic skew scattering, while its spatial variation is
determined by the intrinsic spin-orbit coupling.Comment: 5 pages, 3 figure
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