Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268

Thu., January 15, 2004, at 3:00 p.m.

"Pairing correlations in fastly rotating nuclei"

Philippe Quentin, Centre d'Etudes Nucleaires de Bordeaux Gradignan
6008 Conference Room

By way of comparison with state of the art Routhian Hartree-Fock Bogoliubov calculations, the dynamical effect of pairing correlations in fastly rotating nuclei is shown to be equivalent to simple counter rotating intrinsic vortical currents as encountered in classical fluid mechanics in the Chandrasekhar S-type ellipsoids. Specifically it is shown that calculations within two approaches : Routhian Hartree-Fock Bogoliubov and Routhian Hartree-Fock (no pairing !) with a constraint on an operator "measuring" these intrinsic currents (the so-called Kelvin circulation operator) yield very similar results. Secondly, through calculations using a very simple model ansatz again compared with the Routhian Hartree-Fock Bogoliubov approach, the usual Mottelson-Valatin Coriolis antipairing effect is quantitatively validated. Finally using a recently proposed fully microscopic treatment of pairing correlations expilicitly conserving the particle number while using current parametrisations of the effective nucleon-nucleon interactions, one produces more realistic descriptions than the usual quasiparticle approach in the regions of spuriously alleged normal to superfluid transitions at very high spins. For all these points, numerical examples are provided for various nuclear and deformation ranges (SD states in the A~150 or 190 nuclei, ND in rare-earth or very heavy nuclei).