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The description of two-particle transfer in superfluid systems
Gambacurta D., Lacroix D.
Physical Review C 86 (2012) 064320 - http://hal.in2p3.fr/in2p3-00748182
Physique/Matière Condensée/Supraconductivité
Physique/Physique Nucléaire Expérimentale
Physique/Physique Nucléaire Théorique
The description of two-particle transfer in superfluid systems
D. Gambacurta1, D. Lacroix1
1 :  GANIL - Grand Accélérateur National d'Ions Lourds
Bvd Henri Becquerel - BP 55027 - 14076 CAEN CEDEX 5
Exact results of pair transfer probabilities for the Richardson model with equidistant or random level spacing are presented. The results are then compared either to particle-particle random phase approximation (ppRPA) in the normal phase or quasi-particle random phase approximation (QRPA) in the superfluid phase. We show that both ppRPA and QRPA are globally well reproducing the exact case although some differences are seen in the superfluid case. In particular the QRPA overestimates the pair transfer probabilities to excited states in the vicinity of the normal-superfluid phase transition, which might explain the difficult in detecting collective pairing phenomena as for example the Giant Pairing Vibration. The shortcoming of QRPA can be traced back to the breaking of particle number that is used to incorporate pairing. A method, based on direct diagonalization of the Hamiltonian in the space of two quasi-particle projected onto good particle number is shown to improve the description of pair transfer probabilities in superfluid systems.

Articles dans des revues avec comité de lecture
Physical Review C (Phys. Rev. C)
Publisher American Physical Society
ISSN 0556-2813 (eISSN : 1089-490X)

GANIL 21012-129 T
9 pages, 7 figures
Pairing – transfer – nuclear models
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