4,540 research outputs found
Half quantum vortex in superfluid He-A phase in parallel plate geometry
The half quantum vortex(HQV) in condensate has been studied, since it was
predicted by Salomaa and Volovik in superfluid He-A phase. However, an
experimental evidence for its existence has not been reported so far. Motivated
by a recent experimental report by Yamashita et al\cite{yamashita}, we study
the HQVs in superfluid He confined between two parallel plates with a gap D
10 m in the presence of a magnetic field H 26 mT
perpendicular to the parallel plates. We find that the bound HQVs are more
stable than the singular vortices and free pairs of HQVs, when the rotation
perpendicular to the parallel plates is below the critical speed, 2 rad/s. The bound pair of HQVs accompanies the tilting of -vector out of the plane, which leads to an additional absorption in NMR
spectra. Our study appears to describe the temperature and rotation dependence
of the observed satellite NMR signal, which supports the existence of the HQVs
in He.Comment: 5 pages, 5 figure
The small mixing angle and the lepton asymmetry
We present the correlation of low energy CP phases, both Dirac and Majorana,
and the lepton asymmetry for the baryon asymmetry in the universe, with a
certain class of Yukawa matrices that consist of two right-handed neutrinos and
include one texture zero in themselves. For cases in which the amount of the
lepton asymmetry turns out to be proportional to , we
consider the relation between two types of CP phases and the relation of
versus the Jarlskog invariant or the amplitude of neutrinoless double beta
decay as varies.Comment: 17 pages, 14 figures, information for figures added, version
published in PR
Possible f-wave superconductivity in SrRuO?
Until recently it has been believed that the superconductivity in
SrRuO is described by p-wave pairing. However, both the recent specific
heat and the magnetic penetration depth measurements on the purest single
crystals of SrRuO appear to be explained more consistently in terms of
f-wave superconductivity. In order to further this hypothesis, we study
theoretically the thermodynamics and thermal conductivity of f-wave
superconductors in a planar magnetic field. We find the simple expressions for
these quantities when and , which should be
readily accessible experimentally.Comment: 6 pages, 2 figure
LWR fuel performance analysis : fuel cracking and relocation
"Final report for research project sponsored by Northeast Utilities Service Company, Yankee Atomic Electric Co. under the MIT Energy Laboratory Electric Utility Program.
Gap Symmetry an Thermal Conductivity in Nodal Superconductors
There are now many nodal superconductors in heavy fermion (HF) systems,
charge conjugated organic metals, high Tc cuprates and ruthenates. On the other
hand only few of them have a well established gap function. We present here a
study of the angular dependent thermal conductivity in the vortex state of some
of the nodal superconductors. We hope it will help to identify the nodal
directions in the gap function of UPd_2Al_3, UNi_2Al_3, UBe_13 and URu_2Si_2.Comment: 4 pages, 5 figure
Gap Anisotropy and de Haas-van Alphen Effect in Type-II Superconductors
We present a theoretical study on the de Haas-van Alphen (dHvA) oscillation
in the vortex state of type-II superconductors, with a special focus on the
connection between the gap anisotropy and the oscillation damping. Numerical
calculations for three different gap structures clearly indicate that the
average gap along extremal orbits is relevant for the magnitude of the extra
damping, thereby providing a support for experimental efforts to probe gap
anisotropy through the dHvA signal. We also derive an analytic formula for the
extra damping which gives a good fit to the numerical results.Comment: 5 pages, 1 figure, changes in Introductio
Abnormal systolic blood pressure response during exercise is related to subendocardial hypoperfusion detected by exercise 201Tl myocardial scintigraphy in patient with hypertrophic cardiomyopathy
Balcells, EugèniaPla general, d'alguns dels elements que formen la taula periòdica. Cadascun dels 112 elements és representat pel seu espectre de color. Es van produir diverses còpies de l'obra, aquesta està a la Biblioteca de la Facultat de Química
Sound propagation in density wave conductors and the effect of long-range Coulomb interaction
We study theoretically the sound propagation in charge- and spin-density
waves in the hydrodynamic regime. First, making use of the method of comoving
frame, we construct the stress tensor appropriate for quasi-one dimensional
systems within tight-binding approximation. Taking into account the screening
effect of the long-range Coulomb interaction, we find that the increase of the
sound velocity below the critical temperature is about two orders of magnitude
less for longitudinal sound than for transverse one. It is shown that only the
transverse sound wave with displacement vector parallel to the chain direction
couples to the phason of the density wave, therefore we expect significant
electromechanical effect only in this case.Comment: revtex, 14 pages (in preprint form), submitted to PR
Half-quantum vortex and d-soliton in SrRuO
Assuming that the superconductivity in SrRuO is described by a planar
p-wave order parameter, we consider possible topological defects in
SrRuO. In particular, it is shown that both of the -soliton
and half-quantum vortex can be created in the presence of the magnetic field
parallel to the - plane. We discuss how one can detect the -soliton and half-quantum vortex experimentally.Comment: 8 pages, 3 figure
Unconventional spin density wave in Bechgaard salt (TMTSF)2NO3
Among many Bechgaard salts, TMTSF2NO3 exhibits very anomalous low temperature
properties. Unlike conventional spin density wave (SDW), TMTSF2NO3 undergoes
the SDW transition at \T_SDW\approx 9.5 K and the low temperature
quasiparticle excitations are gapless. Also, it is known that TMTSF2NO3 does
not exhibit superconductivity even under pressure, while FISDW is found in
TMTSF2NO3 only for P=8.5 kbar and B>20 T. Here we shall show that both the
angle dependent magnetoresistance data and the nonlinear Hall resistance of
TMTSF2NO3 at ambient pressure are interpreted satisfactory in terms of
unconventional spin density wave (USDW). Based on these facts, we propose a new
phase diagram for Bechgaards salts.Comment: 4 pages, 4 figs, RevTe
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