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Asymptotics of neutron Cooper pair in weakly bound nuclei
Asymptotic form of neutron Cooper pair penetrating to the exterior of nuclear
surface is investigated with the Bogoliubov theory for the superfluid Fermions.
Based on a two-particle Schr\"{o}dinger equation governing the Cooper pair wave
function and systematic studies for both weakly bound and stable nuclei, the
Cooper pair is shown to be spatially correlated even in the asymptotic large
distance limit, and the penetration length of the pair condensate is revealed
to be universally governed by the two-neutron separation energy and
the di-neutron mass
Pair correlation of giant halo nuclei in continuum Skyrme-Hartree-Fock-Bogoliubov theory
The giant halos predicted in neutron-rich Zr isotopes with are
investigated by using the self-consistent continuum Skyrme
Hartree-Fock-Bogoliubov approach, in which the asymptotic behavior of continuum
quasiparticle states is properly treated by the Green's function method. We
study in detail the neutron pair correlation involved in the giant halo by
analyzing the asymptotic exponential tail of the neutron pair condensate (pair
density) in addition to that of the neutron particle density. The neutron
quasiparticle spectra associated with these giant halo nuclei are examined. It
is found that the asymptotic exponential tail of the neutron pair condensate is
dominated by non-resonant continuum quasiparticle states corresponding to the
scattering states with low asymptotic kinetic energy. This is in contrast to
the asymptotic tail of the neutron density, whose main contributions arise from
the resonant quasiparticle states corresponding to the weakly-bound
single-particle orbits and resonance orbits in the Hartree-Fock potential
Water Content and Superconductivity in Na0.3CoO2*yH2O
We report here the correlation between the water content and
superconductivity in Na0.3CoO2*yH2O under the influences of elevated
temperature and cold compression. The x-ray diffraction of the sample annealed
at elevated temperatures indicates that intergrowths exist in the compound at
equilibrium when 0.6 < y < 1.4. Its low-temperature diamagnetization varies
linearly with y, but is insensitive to the intergrowth, indicative of quasi-2D
superconductivity. The Tc-onset, especially, shifts only slightly with y. Our
data from cold compressed samples, on the other hand, show that the water-loss
non-proportionally suppresses the diamagnetization, which is suggestive of weak
links.Comment: 10 pages, 10 figures; submitted to Physica C (August 13, 2003
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