标题： 旋转核平均场描述中破缺的D2对称性的恢复 显示英文标题

标题： Restoration of the Broken D2-Symmetry in the Mean Field Description of Rotating Nuclei

摘要： 在转动带中观察到的 signature 效应是由于固有的 D2 对称性。当核自旋的倾斜（非主轴）取向变得稳定时，平均场 cranking 近似自然会打破这种对称性。双峰势能曲面上两个与对称相关的极小值之间的可能隧穿现象表现为转动带的典型分支。我们通过在选定的一组倾斜和非倾斜 cranking准粒子态内对核哈密顿量进行对角化来描述这个所有核子都参与的多体过程。这种微观方法能够恢复被打破的 D2 对称性，并重现与对称相关的 HFB 态之间的量子涨落，这些涨落表现为带能量的分裂以及平行的带内 M1 跃迁的交错。 显示英文摘要

摘要： Signature effects observed in rotational bands are a consequence of an inherent D2-symmetry. This symmetry is naturally broken by the mean field cranking approximation when a tilted (non-principal) axis orientation of the nuclear spin becomes stable. The possible tunneling forth and back between the two symmetry-related minima in the double-humped potential-energy surface appears as a typical bifurcation of the rotational band. We describe this many-body process in which all nucleons participate by diagonalizing the nuclear Hamiltonian within a selected set of tilted and non-tilted cranking quasiparticle states. This microscopic approach is able to restore the broken D2 symmetry and reproduce the quantum fluctuations between symmetry- related HFB states which emerge as splitting of the band energies and in parallel staggering in intraband M1 transitions.