The similarity renormalization group is used to transform the Dirac Hamiltonian with tensor coupling into a diagonal form. The upper(lower) diagonal element becomes a Schr¨odinger-like operator with the tensor component separated from the original Hamiltonian.Based on the operator, the tensor effect of the relativistic symmetries is explored with a focus on the single-particle energy contributed by the tensor coupling. The results show that the tensor coupling destroying(improving) the spin(pseudospin) symmetry is mainly attributed to the coupling of the spin-orbit and the tensor term, which plays an opposite role in the single-particle energy for the(pseudo-) spin-aligned and spin-unaligned states and has an important influence on the shell structure and its evolution.
利用反射不对称相对论平均场理论(reflection asymmetric relativistic mean field,简称RAS-RMF)对Xe、Ba和Ce同位素偶偶核形状演化进行研究.结果表明:RAS-RMF理论能很好地描述Xe、Ba和Ce同位素偶偶核的基态性质,计算出的结合能和四极形变与已有的实验数据一致,八极形变对基态性质有重要影响.获得的物质密度分布清晰地展现出Xe、Ba和Ce同位素偶偶核的形状演化规律,反射不对称自由度在其中起重要作用.
