FoldyWouthuysen Transformation. Exact Solution with Generalization to the TwoParticle Problem
Abstract
The Dirac Hamiltonian for a particle in a nonexplicitly timedependent field is converted to an even Dirac matrix by means of a single canonical transformation. When the interaction term is an odd Dirac matrix, the transformed Hamiltonian is expressed in a very simple form. An exact transformation is also found for twoparticle wave equations of Breit's type. The transformed Hamiltonian is then a uUseparating matrix, in Chraplyvy's sense. In the nonrelativistic limit expansions in powers of 1m or 1c are made. The approximate wave equations are in agreement with previous transformation results.
 Publication:

Physical Review
 Pub Date:
 August 1958
 DOI:
 10.1103/PhysRev.111.1011
 Bibcode:
 1958PhRv..111.1011E