General Electrical Manipulations of Electron Spin
  Traditionally, the interactions related to the 3D spatial angular momentum have been studied completely, while the ones related to the generators of Lorentz boost are always ignored. In this paper we show that the generators of Lorentz boost have a nontrivial physical significance in quantum mechanics, and try to propose a most general theory about electrical manipulations of electron spin, where a new treatment and interpretation for the traditional Darwin term and spin-orbit coupling is given via the concept of electron's induced electric moment. Some electrostatic fields can even affect the spin quantum states of a resting electron, and parallel electric and magnetic fields can be simultaneously applied to fix on the spin orientation of electron. 
Z. Y. Wang, C. D. Xiong