兰姆移位的一种半定量计算方法  

Lamb Shift Calculated by a Semiquantitative Method

作　　者：倪光炯[1] 王海滨[1] 严军[1] 李海龙 

机构地区：[1]复旦大学物理系,上海200433

出　　处：《高能物理与核物理》2000年第5期400-407,共8页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金资助!(19377102)

摘　　要：考虑一个自由电子以动量 p运动时因吸放虚光子而引起自能的辐射修正 ,用非协变形式的量子微扰论算出它有b2 p4的形式 .在此基础上加上真空极化修正和核有限半径引起的修正 ,算得氢原子 2S1/2 -2P1/2 态的兰姆移位为1 0 56.52 2MHz,比实验值 1 0 57.84 5MHz仅小 0 .1 3%。用Dirac方程作相对论性修正后 ,还计算了氢原子 4D5 /2 -4S1/2 态的能级差 ,所谓“超兰姆移位”和 1S态的“绝对”兰姆移位 .误差最大达 6.7% 。The radiative correction of self energy of an electron moving with momentum p and emitting absorbing the virtual photon is calculated by the noncovariant quantum perturbation theory to have the form being b 2p 4 . After adding modifications arising from the vacuum polarization and finite nucleus size,we find the Lamb shift (LS) of 2S 1/2 -2P 1/2 states in Hydrogen atom being 1056.522 MHz,smaller than the experimental value 1057.845 MHz by 0.13%. Taking the relativistic modification by Dirac equation into account,the energy differences of 4D 5/2 4 S 1/2 states, the so called Hyper LS and absolute LS of 1 S state in Hydrogen are also calculated with maximum discrepancy up to 6.7%. The reasons are analyzed.For dealing with the divergence,we propose a simple but effective regularization renormalization method,showing that we have to reconfirm the reduced mass first before bringing a finite and fixed modification to it via radiative corrections.

关 键 词：兰姆移位 量子电动力学 辐射修正 微扰论 

分 类 号：O413.2[理学—理论物理]