基于粒子-空穴激发配对近似的核结构研究

在远离β稳定线原子核低激发态中来自多个主壳层的组态发挥重要作用，考虑多个主壳层的壳模型研究是当今原子核结构理论研究最活跃的前沿领域之一。然而对于中重和重核区原子核，严格壳模型计算因为组态空间太大而难以实现。本项目基于粒子-空穴激发的壳模型配对近似理论，对涉及到多个主壳层组态的核结构问题进行研究，主要内容包括：(1)计算轻核区反转岛原子核的低激发态，检验粒子-空穴激发配对近似的可靠性，研究声子激发模式和配对激发模式的竞争；(2)基于Brown-Rho标度的CD-Bonn势和包含手征三体力的N3LO势，构造密度依赖的壳模型有效相互作用，研究偶偶Sn同位素链的奇异电四极跃迁性质；(3)研究粒子-空穴激发组态对Pd-102核素和邻近同位素低激发态的贡献，着重研究潮汐波集体运动的微观机制；(4)发展双重耦合的粒子-空穴激发配对近似理论，研究有限数目酉极限冷中子系统的普适性质和配对关联。

In low-lying states of atomic nuclei far from the β stability line, configurations arising from multiple major shells play an important role, and the shell-model calculation of multiple major shells is one of the most important frontiers in theoretical studies of nuclear structure. However, the configuration space of such calculation is too gigantic to handle for nuclei in medium-heavy and heavy mass regions. In this project we shall study several issues associated with configurations of multiple major shells, in the framework of the nucleon-pair approximation with particle-hole excitations. Our studies include four aspects: (1) we shall calculate low-lying states of the inversion-island nuclei, and study the validity of the nucleon-pair approximation with particle-hole excitations and the competition between phonon-type excitations and nucleon-pair excitations across closed shells; (2) we shall construct density-dependent shell-model effective interactions based on the CD-Bonn potential with Brown-Rho scaling and the N3LO potential with chiral three-nucleon forces, and study the exotic property of electric quadrupole transitions in the even-even Sn isotopic chain; (3) we shall study the contributions of particle-hole excitation configurations in low-lying states of Pd-102 and its neighboring isotopes, with focus on the microscopic mechanism of the tidal-wave collective motion; (4) we shall develop the two-folded-coupling pair approximation with particle-hole excitations, and study the universal property and pairing correlation in finite-number cold neutron systems in the unitary limit.