兰姆移位的一种半定量计算方法

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b₂p⁴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2S_1/2–2P_1/2态的兰姆移位为1056.522MHz,比实验值1057.845MHz仅小0.13%. 用Dirac方程作相对论性修正后,还计算了氢原子4D_5/2–4S_1/2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%,并分析了原因.

Lamb Shift Calculated by a Semiquantitative Method

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.