21,375 research outputs found
Canonical-basis solution of the Hartree-Fock-Bogoliubov equation on three-dimensional Cartesian mesh
A method is presented to obtain the canonical-form solutions of the HFB
equation for atomic nuclei with zero-range interactions like the Skyrme force.
It is appropriate to describe pairing correlations in the continuum in
coordinate-space representations. An improved gradient method is used for
faster convergences under constraint of orthogonality between orbitals. To
prevent high-lying orbitals to shrink into a spatial point, a repulsive
momentum dependent force is introduced, which turns out to unveil the nature of
high-lying canonical-basis orbitals. The asymptotic properties at large radius
and the relation with quasiparticle states are discussed for the obtained
canonical basis.Comment: 23 pages including 17 figures, REVTeX4, revised version, scheduled to
appear in Phys. Rev. C, Vol.69, No.
Gamma-ray Polarimetry
An astrophysics application of a low noise Double-sided Silicon Strip
Detector (DSSD) is described. A Semiconductor Multiple-Compton Telescope (SMCT)
is being developed to explore the gamma-ray universe in the 0.1-20 MeV energy
band. Excellent energy resolution and polarization sensitivity are key features
of the SMCT. We have developed prototype modules for a low noise DSSD system,
which reached an energy resolution of 1.3 keV (FWHM) for 122 keV at 0 degree C.
Results of a gamma-ray imaging test are also presented.Comment: 6 pages, 9 figures. Contributed to International Workshop on Vertex
Detectors, Kailua-Kona, Hawaii USA, November 3-8, 200
Hartree-Fock+BCS approach to unstable nuclei with the Skyrme force
We reanalyze the results of our extensive Hartree-Fock + BCS calculation from
new points of view paying attention to the properties of unstable nuclei. The
calculation has been done with the Skyrme SIII force for the ground and shape
isomeric states of 1029 even-even nuclei ranging 2 <= Z <= 114. We also discuss
the advantages of the employed three-dimensional Cartesian-mesh representation,
especially on its remarkably high precision with apparently coarse meshes when
applied to atomic nuclei. In Appendices we give the coefficients of
finite-point numerical differentiation and integration formulae suitable for
Cartesian mesh representation and elucidate the features of each formula and
the differences from a method based on the Fourier transformation.Comment: 31 pages including 21 figures, Latex2
Analytical formula for numerical evaluations of the Wigner rotation matrices at high spins
The Wigner d function, which is the essential part of an irreducible
representation of SU(2) and SO(3) parameterized with Euler angles, has been
know to suffer from a serious numerical errors at high spins, if it is
calculated by means of the Wigner formula as a polynomial of cos and sin of
half of the second Euler angle. This paper shows a way to avoid this problem by
expressing the d functions as the Fourier series of the half angle. A precise
numerical table of the coefficients of the series is obtainable from a web
site.Comment: 5 pages, 5 figure
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