The Yrast Spectra of Weakly Interacting Bose-Einstein Condensates

The low energy quantal spectrum is considered as a function of the total angular momentum for a system of weakly interacting bosonic atoms held together by an external isotropic harmonic potential. It is found that besides the usual condensation into the lowest state of the oscillator, the system exhibits two additional kinds of condensate and associated thermodynamic phase transitions. These new phenomena are derived from the degrees of freedom of "partition space" which describes the multitude of different ways in which the angular momentum can be distributed among the atoms while remaining all the time in the lowest state of the oscillator

Low-energy M1 and E3 excitations in the proton-rich Kr-Zr region

Low-energy intrinsic $K^\pi$=1$^+$, $0^-$, $1^-$, $2^-$, and $3^-$ states in the even-even proton-rich Sr, Kr, and Zr nuclei are investigated using the quasiparticle random phase approximation. In the Z$\simeq$N nuclei the lowest-lying 1$^+$ states are found to carry unusually large $B(M1)$ strength. It is demonstrated that, unlike in the heavier nuclei, the octupole collectivity in the light zirconium region is small and, thus, is not directly correlated with the systematics of the lowest negative parity states.Comment: 15pages, REVTEX 3.0, JIHIR(ORNL) Document no.93-17, Postscript files for 14 figures are available on request from T.Nakatsusaka at [email protected]

Rotations of nuclei with reflection asymmetry correlations

We propose a collective Hamiltonian which incorporates interactions capable to generate rotations in nuclei with simultaneous presence of octupole and quadrupole deformations. It is demonstrated that the model formalism could be applied to reproduce the staggering effects observed in nuclear octupole bands. On this basis we propose that the interactions involved would provide a relevant handle in the study of collective phenomena in nuclei and other quantum mechanical systems with reflection asymmetry correlations.Comment: LaTeX, 9 pages plus 3 figures given in separate .ps files. To appear in the proceedings of the International Conference on Nuclear Structure and Related Topics (Dubna, Russia, 6-10/6/2000), ed. R. Jolos, V. Voronov, et a

Anomalous Crossing Frequency in Odd Proton Nuclei

A generic explanation for the recently observed anomalous crossing frequencies in odd proton rare earth nuclei is given. As an example, the proton ${1\over 2} [541]$ band in $^{175}$Ta is discussed in detail by using the angular momentum projection theory. It is shown that the quadrupole pairing interaction is decisive in delaying the crossing point and the changes in crossing frequency along the isotope chain are due to the different neutron shell fillings

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.

Pairing and continuum effects on low-frequency quadrupole vibrations in deformed Mg isotopes close to the neutron drip line

Low-frequency quadrupole vibrational modes in deformed $^{36,38,40}$Mg close to the neutron drip line are studied by means of the quasiparticle-random-phase approximation based on the coordinate-space Hartree-Fock-Bogoliubov formalism. Strongly collective $K^{\pi}=0^{+}$ and $2^{+}$ excitation modes carrying 10-20 Weisskopf units in the intrinsic isoscalar quadrupole transition strengths are obtained at about 3 MeV. There are two reasons for the enhancement of the transition strengths. First, the quasiparticle wave functions generating these modes possess spatially very extended structure. The asymptotic selection rules characterizing the $\beta$ and $\gamma$ vibrations in stable deformed nuclei are thus strongly violated. Second, the dynamic pairing effects act strongly to enhance the collectivity of these modes. It is suggested that the lowest $K^{\pi}=0^{+}$ collective mode is a particularly sensitive indicator of the nature of pairing correlations in deformed nuclei close to the neutron drip line.Comment: 23 pages including 11 figures and 8 tables. Submitted to NP

Superconformal Symmetry, The Supercurrent And Non-BPS Brane Dynamics

The Noether currents associated with the non-linearly realized super-Poincare' symmetries of the Green-Schwarz (Nambu-Goto-Akulov-Volkov) action for a non-BPS p=2 brane embedded in a N=1, D=4 target superspace are constructed. The R symmetry current, the supersymmetry currents, the energy-momentum tensor and the scalar central charge current are shown to be components of a world volume supercurrent. The centrally extended superconformal transformations are realized on the Nambu-Goldstone boson and fermion fields of the non-BPS brane. The superconformal currents form supersymmetry multiplets with the world volume conformal central charge current and special conformal current being the primary components of the supersymmetry multiplets containing all the currents. Correspondingly the superconformal symmetry breaking terms form supersymmetry multiplets the components of which are obtainable as supersymmetry transformations of the primary currents' symmetry breaking terms.Comment: 27 pages, LaTeX, Summary Tables Adde

Can adenine nucleotides predict primary nonfunction of the human liver homograft?

Sixty-eight primary liver grafts were analyzed to see whether adenine nucleotides (AN: ATP, ADP, and AMP) or purine catabolites (PC: adenosine, inosine, hypoxanthine, and xanthine) of tissue or effluent can predict primary graft nonfunction. AN, PC, and nicotinamide adenine dinucleotide, oxidized form (NAD+) of the tissue before (pretransplant) and after graft reperfusion (post-transplant) and of the effluent were analyzed. The graft outcome was classified into two groups (group A: successful, n = 64; group B: primary nonfunctioning, n = 4). No significant differences were observed in pretransplant measurements between groups A and B, whereas ATP, ADP, total AN, total AN + total PC (T) and NAD+, in post-transplant tissues, were significantly higher in group A. Xanthine in the effluent was significantly higher in group B than in group A. ATP, ADP, total AN, T, and NAD+ in post-transplant tissue were significantly associated with primary graft nonfunction by logistic regression analysis