原子核手征对称性和摇摆运动的集体模型

Collective model of chiral and wobbling modes in nuclei

针对核物理近年来出现的手征对称性和摇摆运动等热点问题,介绍具有微观基础的集体哈密顿量理论的研究进展.首先,简要回顾手征对称性和摇摆运动的研究现状.接着,给出基于倾斜轴推转模型,构建微观集体哈密顿量理论的具体过程.随后,介绍新发展的集体哈密顿量理论对于手征对称性和摇摆运动的研究.具体包括:介绍手征双重带能量差随转动频率变化的微观机制的研究,给出了手征双重带能量差随转动频率逐渐减小,是双中心势势垒的逐渐增高抑制手征伙伴态之间量子隧穿的结论;介绍简单、纵向、横向3类摇摆运动的摇摆频率随转动频率演化的微观机制,得到了摇摆频率的演化趋势与集体势的软硬度相关的结论.

Recent progress of collective Hamiltonian for the chiral and wobbling modes in nuclei is reviewed. A brief introduction about the experimental and theoretical research statuses of the chirality and wobbling is given first. Procedures of con- structing collective Hamiltonian, based on the tilted axis cranking approach, are shown in details. The newly developed collective Hamiltonian is used to investigate the chiral and wobbling modes. For the chiral modes, we study the microscopic mechanism of the energy difference between the chiral doublets with respect to the rotational frequency. It is demonstrated that the gradually increased potential barrier suppresses the tunneling probabilities between the left- and right-handed states and thus causes the decreasing of the energy difference. For the wobbling modes, the variation trends of wobbling frequen- cies for simple, longitudinal, and transverse wobblers are studied and found to be related to the softness of the collective potential.