About spin precession in electromagnetic wave
arXiv:hep-ph/9903336
Abstract
It is shown that two ways of the description of the 1/2-spin precession in a circularly polarized electromagnetic wave: on the basis of the Bargmann-Michel-Telegdi equation and on the basis of the Dirac equation with Pauli term give the same result in the second order on the wave's field for arbitrary wave length.
7 pages