Importance of multicranked configuration mixing for angular-momentum-projection calculations: Study of superdeformed rotational bands in Dy152 and Hg194

Abstract

Recently we have investigated an effective method of multicranked configuration-mixing for angular-momentum-projection calculation, where several cranked mean-field states are coupled after projection: The basic idea was originally proposed by Peierls and Thouless more than fifty years ago. With this method a good description of the rotational band has been achieved in a fully microscopic manner. In the present work, we apply the method to the high-spin superdeformed band, for which long rotational sequence is observed, and study how the good description is obtained for the rotational spectrum as well as the J (1) and J (2) moments of inertia as functions of angular momentum. The Gogny D1S force is employed as an effective interaction, and the yrast superdeformed bands in 152 Dy and 194 Hg are taken as typical examples in the A ≈ 150 and A ≈ 190 regions, respectively. The effect of pairing correlations is examined by the variation after particle-number projection approach to understand the different behaviors of J (2) moments of inertia observed in these two nuclei. The particle-number projection on top of the angular-momentum projection has been performed for the first time with the multicranked configuration-mixing.

Generator coordinate method with a conjugate momentum: Application to particle number projection

“…Wave functions similar to this have been considered in Refs. [28][29][30][31][32], in which the following ansatz was employed:…”

“…Recently, the idea based on the double projection method has been put forward by Borrajo et al [28,29] as well as by Shimada et al [30][31][32] for a calculation of rotational bands in deformed nuclei. These authors employed cranked-Hartree-Fock-Bogoliubov states with several deformations and rotational frequencies as basis states for the GCM calculations after performing the angular momentum projection.…”

“…This amounts to superposing many BCS states with different particle numbers after performing the particle number projection, as in Refs. [28][29][30][31][32] for rotational motions. This work can in fact be regarded as the first step in a long-range project of applications of the DGCM to nuclear collective motions.…”

Generator coordinate method with a conjugate momentum: application to the particle number projection

“…Recently, the idea based on the double projection method has been put forward by Borrajo et al [27,28] as well as by Shimada et al [29][30][31] for a calculation of rotational bands in deformed nuclei. These authors employed cranked-Hartree-Fock-Bogoliubov states with several deformations and rotational frequencies as basis states for the GCM calculations after performing the angular momentum projection.…”

“…This amounts to superposing many BCS states with different particle numbers after performing the particle number projection, as in Refs. [27][28][29][30][31] for rotational motions. This work can in fact be regarded as the first step in a long-range project of applications of the DGCM to nuclear collective motions.…”