Interpretation of Coulomb breakup of 31Ne in terms of deformation

The recent experimental data on Coulomb breakup of the nucleus $^{31}$Ne are interpreted in terms of deformation. The measured large one-neutron removal cross-section indicates that the ground state of $^{31}$Ne is either s- or p-halo. The data can be most easily interpreted as the spin of the ground state being 3/2$^-$ coming from either the Nilsson level [330 1/2] or [321 3/2] depending on the neutron separation energy $S_n$. However, the possibility of 1/2$^{+}$ coming from [200 1/2] is not excluded. It is suggested that if the large ambiguity in the measured value of $S_n$ of $^{31}$Ne, 0.29$\pm1.64$ MeV, can be reduced by an order of magnitude, say to be $\pm$100 keV, one may get a clear picture of the spin-parity of the halo ground state.Comment: 8 pages, 4 figure

Dominance of Nuclear Processes in the Dissociation of 8B

We study the break-up of 8B in collisions with heavy-ions. The process is described in terms of inelastic excitations leading to states in the continuum. The effects of the nuclear and coulomb fields are included on the same footing in the microscopic construction of the transition matrix elements. The interplay between coulomb and nuclear excitation processes differs significantly from the situation encountered in reactions involving systems close to the stability line. In particular, nuclear excitation is found to remain predominant at energies well below the coulomb barrier,Comment: TEX file + 11 postscript figure

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

Phytohaemagglutinin on maternal and umbilical leukocytes

Almost all the umbilical lymphocytes showed more extensive blast cell formation than that of their mother's lymphocytes with PHA. Pathological conditions of mother in pregnancy and labor such as anemia, gestational toxicosis, difficult labor and asphyxia of babies, inhibited the normal response of both maternal and umbilical lymphocytes to PHA.</p

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.

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

"Beat" patterns for the odd-even staggering in octupole bands from a quadrupole-octupole Hamiltonian

We propose a collective Hamiltonian which incorporates the standard quadrupole terms, octupole terms classified according to the irreducible representations of the octahedron group, a quadrupole-octupole interaction, as well as a term for the bandhead energy linear in K (the projection of angular momentum on the body-fixed z-axis). The energy is subsequently minimized with respect to K for each given value of the angular momentum I, resulting in K values increasing with I within each band, even in the case in which K is restricted to a set of microscopically plausible values. We demonstrate that this Hamiltonian is able to reproduce a variety of ``beat'' patterns observed recently for the odd-even staggering in octupole bands of light actinides.Comment: LaTeX, 20 pages plus 12 figures given in separate .ps file

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

Nilsson diagrams for light neutron-rich nuclei with weakly-bound neutrons

Using Woods-Saxon potentials and the eigenphase formalism for one-particle resonances, one-particle bound and resonant levels for neutrons as a function of quadrupole deformation are presented, which are supposed to be useful for the interpretation of spectroscopic properties of some light neutron-rich nuclei with weakly-bound neutrons. Compared with Nilsson diagrams in text books which are constructed using modified oscillator potentials, we point out a systematic change of the shell structure in connection with both weakly-bound and resonant one-particle levels related to small orbital angular momenta $\ell$. Then, it is seen that weakly-bound neutrons in nuclei such as $^{15-19}$C and $^{33-37}$Mg may prefer to being deformed as a result of Jahn-Teller effect, due to the near degeneracy of the 1d$_{5/2}$-2s$_{1/2}$ levels and the 1f$_{7/2}$-2p$_{3/2}$ levels in the spherical potential, respectively. Furthermore, the absence of some one-particle resonant levels compared with the Nilsson diagrams in text books is illustrated.Comment: 12 pages, 5 figure

Quantum phase transition of dynamical resistance in a mesoscopic capacitor

We study theoretically dynamic response of a mesoscopic capacitor, which consists of a quantum dot connected to an electron reservoir via a point contact and capacitively coupled to a gate voltage. A quantum Hall edge state with a filling factor nu is realized in a strong magnetic field applied perpendicular to the two-dimensional electron gas. We discuss a noise-driven quantum phase transition of the transport property of the edge state by taking into account an ohmic bath connected to the gate voltage. Without the noise, the charge relaxation for nu>1/2 is universally quantized at R_q=h/(2e^2), while for nu<1/2, the system undergoes the Kosterlitz-Thouless transtion, which drastically changes the nature of the dynamical resistance. The phase transition is facilitated by the noisy gate voltage, and we see that it can occur even for an integer quantum Hall edge at nu=1. When the dissipation by the noise is sufficiently small, the quantized value of R_q is shifted by the bath impedance.Comment: 5 pages, 2 figures, proceeding of the 19th International Conference on the Application of High Magnetic Fields in Semiconductor Physics and Nanotechnology (HMF-19