Some Generalizations of the Foldy-Wouthuysen Transformation

Abstract

A canonical transformation similar to that given by Foldy and Wouthuysen is obtained for the spin zero and one theories. For free particles positive and negative charge states are separately described by one or three component wave functions. It is found that the resulting forms for operators and the non-relativistic limits are quite similar to that for spin ½. The resulting similarity is found to carry over to still higher spins. Particles moving in magnetic fields are described most simply using the transformed representation.