Signature and Angular Momentum in 3d-Cranked HFB states

In terms of the exaxt angular momentum projection, properties of the three dimensional cranked HFB (3d-CHFB) states are analyzed quantitatively in the context of the relation between the signature of an intrinsic symmetry and the parity of angular momentum, (-1)^I. We found that the tilted states have favorable features to describe states involved with high-K quantum number and/or odd total angular momentum. This implies that 3d-CHFB can describe properly the backbending phenomena like a "t-band and g-band" crossing, which is suggested in N=106 isotopes.Comment: 10 pages, 2 figure

Wobbling motion in the multi-bands crossing region

The backbending in the A=180 mass region is expected to be caused by multi-bands crossing between low-K (g- and s-bands) and high-K bands. % We analyze a mechanism of coupling of these bands in terms of a dynamical treatment for nuclear rotations, i.e., the wobbling motion. The wobbling states are produced through the generator coordinate method after angular momentum projection, in which the intrinsic states are constructed through the 2d-cranked HFB calculations.Comment: 9 pages, 3 PS figures: to appear in Phys.Lett.

Pairing correlation in nuclear matter from Skyrme force

The properties of pairing correlation in nuclear matter are investigated by using various versions of Skyrme forces. Truncation of states involving pairing correlation, necessary due to zero range nature of the Skyrme force, is discussed in detail. A plateau appears in pairing gap versus cutoff for each force. We propose to choose the cutoff parameter in the middle of the plateau so that the parameterization is independent of nuclides.Comment: Latex, Submitted to Phys. Lett. B, 8 pages, 1 table and 3 uuencoded postscript figures (modified) included, UT-Komaba 94-

Band Crossing studied by GCM with 3D-CHFB

We solved the constrained Hill-Wheeler Equation, and found several signatures of multi-band crossing in 182 Os.Comment: LaTeX 3 pages, 3 eps figures; Contribution to International Conference, Nuclear Structure at the extreme,Lewes, UK, (1998) Jun.17-1

Cranked Hartree-Fock-Bogoliubov Calculation for Rotating Bose-Einstein Condensates

A rotating bosonic many-body system in a harmonic trap is studied with the 3D-Cranked Hartree-Fock-Bogoliubov method at zero temperature, which has been applied to nuclear many-body systems at high spin. This method is a variational method extended from the Hartree-Fock theory, which can treat the pairing correlations in a self-consistent manner. An advantage of this method is that a finite-range interaction between constituent particles can be used in the calculation, unlike the original Gross-Pitaevskii approach. To demonstrate the validity of our method, we present a calculation for a toy model, that is, a rotating system of ten bosonic particles interacting through the repulsive quadrupole-quadrupole interaction in a harmonic trap. It is found that the yrast states, the lowest-energy states for the given total angular momentum, does not correspond to the Bose-Einstein condensate, except a few special cases. One of such cases is a vortex state, which appears when the total angular momentum $L$ is twice the particle number $N$ (i.e., $L=2N$).Comment: accepted to Phys. Rev.

Band Structures of 182^{182} Os Studied by GCM based on 3D-CHFB

Band structure properties of $^{182}$Os are investigated through a particle number and angular momentum constrained generator coordinate(GCM) calculation based on self-consistent three-dimensional cranking solutions. From the analysis of the wave function of the lowest GCM solution, we confirm that this nucleus shows a tilted rotational motion in its yrast states, at least with the present set of force parameters of the pairing-plus-quadrupole interaction Hamiltonian. A close examination of behavior of other GCM solutions reveals a sign of a possible occurrence of multi-band crossing in the nucleus. Furthermore, in the course of calculations, we have also found a new potential curve along the prime meridian on the globe of the $J=18\hbar$ sphere. Along this new solution the characters of proton and neutron gap parameters get interchanged. Namely, $\Delta_p$ almost vanishes while $\Delta_n$ grows to a finite value close to the one corresponding to the principal axis rotation(PAR). A state in the new solution curve at the PAR point turns out to have almost the same characteristic features of an yrare $s$-band state which gets located just above the $g$-band in our calculation. This fact suggests a new type of seesaw vibrational mode of the proton and the neutron pairing, occurring through a wobbling motion. The mode is considered to bridge the $g$-band states and the $s$-band states in the backbending region.Comment: LaTeX 19 pages; 14 ps figures; 1 table; submitted to Nucl.Phys.