Berry phase and backbending

Backbending is a typical phenomenon in the rotational spectra of superfluid nuclei. It is caused by the rotational alignment of a pair of nucleons and depends on topological properties of the Hartree-Fock-Bogoliubov spectrum in the rotating frame characterized by diabolic points and Berry phases.Comment: 15 pages, 6 figures, chapter in "Fifty Years of Nuclear BCS", eds. R.A. Broglia and V.Zelevinsk

Overlap of quasiparticle random-phase approximation states for nuclear matrix elements of the neutrino-less double beta decay

Quasiparticle random-phase approximation (QRPA) is applied to two nuclei, and overlap of the QRPA excited states based on the different nuclei is calculated. The aim is to calculate the overlap of intermediate nuclear states of the double-beta decay. We use the like-particle QRPA after the closure approximation is applied to the nuclear matrix elements. The overlap is calculated rigorously by making use of the explicit equation of the QRPA ground state. The formulation of the overlap is shown, and a test calculation is performed. The effectiveness of the truncations used is shown.Comment: 3 minor corrections and 1 minor chang

Relativistic mean-field description of the dynamics of giant resonances

The relativistic mean-field theory provides a framework in which the nuclear many-body problem is described as a self-consistent system of nucleons and mesons. In the mean-field approximation, the self-consistent time evolution of the nuclear system describes the dynamics of collective motion: nuclear compressibility from monopole resonances, regular and chaotic dynamics of isoscalar and isovector collective vibrations.Comment: LaTeX, 10 pages, 5 figures, Invited Talk, Topical Conference on Giant resonances, Varenna, May 1998, to be published in Nucl. Phys.

Properties of superdeformed fission isomers in the cranked relativistic Hartree-Bogoliubov theory

The rotational and deformation properties of superdeformed fission isomers in the $A\sim 240$ mass region have been investigated within the framework of the cranked relativistic Hartree-Bogoliubov theory. The dependence of the results of the calculations on the parametrization of the RMF Lagrangian has been studied. The rotational properties are best described by the NL1 force.Comment: 5 pages, uses epsf.sty and hip-artc.sty, 1 PostScript figure, contribution to the Proceedings of the International Symposium on Exotic Nuclear Structures, May 15-20, 2000, Debrecen, Hungar

Revisiting the displacement operator for quantum systems with position-dependent mass

Recently R. N. Costa Filho et al. (PRA 84, 050102(R) (2011)) have introduced a position dependent infinitesimal translation operator which corresponds to a position dependent linear momentum and consequently to a position dependent effective mass quantum particle. Although there is no doubt in novelty of the idea and the formalism, we believe that some aspects of the quantum mechanics could be complemented in their original work. Here in this letter first we address those points and then an alternative will be introduced. Finally we apply the formalism for a quantum particle under a null potential confined in a square well and the results will be compared with those in the paper mentioned above.Comment: 4 pages, 3 figures. Final version to appear in Phys. Rev.

Superdeformations in Relativistic and Non-Relativistic Mean Field Theories

The applications of the extensions of relativistic mean field (RMF) theory to the rotating frame, such as cranked relativistic mean field (CRMF) theory and cranked relativistic Hartree-Bogoliubov (CRHB) theory, for the description of superdeformed bands in the $A\sim 60$, 140-150 and 190 mass regions are overviewed and compared briefly with the results obtained in non-relativistic mean field theories.Comment: 18 pages including 5 figures in PostScript, requires epsf.sty, invited talk presented at the International Conference on Achievements and Perspectives in Nuclear Structure, Crete, Greece, July 11-17, 1999, will be published in Physica Script