Spin dynamics in nonuniform electromagnetic wave fields

Abstract

Based on solution of Dirac equation, the dynamics of a quantum particle with a half-integer spin (fermion) in the field of an arbitrary inhomogeneous electromagnetic wave has been analysed revealing some features of bound motion defined by so-called optical lattice (channeling). It is shown that, in the first order of expansion in longitudinal energy, the effective interaction potential of a fermion coincides with that of a scalar particle, while the spin features of interaction in this field appear only in the next expansion term. Semiclassical approximation in a spin dynamics for an arbitrary particle in an inhomogeneous optical lattice field indicates that at channeling conditions the polarisation vector affirms a smooth precession, the rate of which is defined by the difference between the magnetic moment of the particle and its anomalous part.

Keywords

• Optical lattice
• Spin rotation
• Laser channeling