热原子核中的对关联  

Pairing correlations in hot nuclei

作　　者：刘朗[1] 

机构地区：[1]江南大学理学院,无锡214122

出　　处：《中国科学：物理学、力学、天文学》2016年第1期106-113,共8页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：中央高校基本科研业务费专项资金(编号:JUSRP1035);国家自然科学基金资助项目(批准号:11305077)

摘　　要：本文介绍了协变密度泛函理论研究热原子核对关联的工作.该工作在协变密度泛函理论框架下,引入严格保持粒子数守恒的类壳模型方法来处理对关联.基于正则系综理论分析了^(162)Dy原子核的热力学性质,计算了该原子核的比热容,得到了随温度变化的"S"型曲线,发现对关联对此"S"型曲线至关重要.在保持粒子数守恒的条件下,对能隙随温度平滑变化,表明原子核从超流态转变到正常态.该工作还分析了不同辛弱数对热原子核的影响,发现温度在1 Me V以内,热原子核的性质主要由辛弱数为0,2和4的态所决定.The phase transition of pairing correlations is one of the interesting phenomena of hot nuclei and is always connected with broken symmetry. In this work, the pairing correlations in hot nuclei 162Dy are investigated in terms of the thermodynamical properties by covariant density functional theory. The thermodynamical quantities are evaluated by the canonical ensemble theory and the paring correlations are treated by a shell-model-like approach, in which the particle number is conserved exactly. An S-shaped heat capacity curve as a function of temperature has been obtained, which indicates a pairing transition from the superfluid to the normal state. The properties of hot nuclei are studied in terms of defined seniority component. It is found that the one-pair-broken （s= 2） states play crucial roles in the appearance of the S shape of the heat capacity curve. Meanwhile, we could predict that higher seniority sates may lead to higher term S shape of heat capacity at high temperature. Moreover, compared with the calculation results of finite temperature BCS, the pairing gap varies smoothly with the temperature due to the effect of the particle-number conservation, which indicates a gradual transition from the superfluid to the normal state.

关 键 词：热原子核 对关联 粒子数守恒 162Dy 

分 类 号：O571[理学—粒子物理与原子核物理]