适用于配对近似计算的集体对凝聚组态变分方法  

Variational Approach for Pair Determination in Nucleon Pair Approximation

作　　者：覃珍珍 雷杨 QIN Zhenzhen;LEI Yang(School of Science,Southwest University of Science and Technology,Mianyang 621010,Sichuan,China;School of National Defense Science and Technology,Southwest University of Science and Technology,Mianyang 621010,Sichuan,China)

机构地区：[1]西南科技大学理学院,四川绵阳621010 [2]西南科技大学国防科技学院,四川绵阳621010

出　　处：《原子核物理评论》2020年第3期516-522,共7页Nuclear Physics Review

基　　金：四川省科技创新人才项目(2019JDRC0017);西南科技大学博士基金项目(18zx7147);西南科技大学教育改革项目(19xn0044);西南科技大学高教研究专项(19GJZX19)。

摘　　要：集体对凝聚组态(collective-pair condensate)的能量变分可用于判断在原子核低激发态中哪些集体对是重要的,并且可以同时给出这些重要集体对的具体结构。这在一定程度上缓解了此前原子核配对近似(Nucleon Pair Approximation,NPA)计算一直深受困扰的集体对不确定性问题。针对过渡区原子核^(132)Ba的试探性计算体现了这种方法的优越性。它可以给出^(132)Ba的三轴形变参数,它也定量地说明了这一原子核I=10基带回弯效应的主导集体对种类。更为重要的是,中子负宇称对凝聚状态的变分计算解释了为什么负宇称集体对这种回弯效应可以呈现出巨大影响。We propose a pair-condensation variation approach to evaluate the importance of collective pairs and determine their structure in low-lying states.Based on such a variation,the Nucleon Pair Approximation(NPA)could avoid the collective-pair uncertainty,which the previous NPA calculations have suffered a lot.With the trial calculation for transitional ^(132) Ba,we exemplify the ability of our variation approach.In detail,the variation can be adopted to calculate the quadrupole deformation parameters with non-axisymmetric deformation degree of freedom.It conclusively helps the NPA to decide which collective pair is essential for obtaining a lower yrast level scheme and reproducing the I=10 backbending.With the optimized condensation of neutron negative-parity pairs,we explain why the neutron negative-parity pairs have a large impact on the backbending behavior.

关 键 词：原子核配对近似 集体对凝聚变分 三轴形变 集体对重要性的定量表征 

分 类 号：O571.53[理学—粒子物理与原子核物理]