Comparative study of requantization of time-dependent mean-field for pairing dynamics

摘要

To describe quantal collective phenomena, it is useful to requantize thetime-dependent mean-field dynamics. We study the time-dependentHartree-Fock-Bogoliubov (TDHFB) theory for the two-level pairing Hamiltonian,and compare results of different quantization methods. The one constructingmicroscopic wave functions, using the TDHFB trajectories fulfilling theEinstein-Brillouin-Keller quantization condition, turns out to be the mostaccurate. The method is based on the stationary-phase approximation to the pathintegral. We also examine the performance of the collective model which assumesthat the pairing gap parameter is the collective coordinate. The applicabilityof the collective model is limited for the nuclear pairing with a small numberof single-particle levels, because the pairing gap parameter represents only ahalf of the pairing collective space.