PSEUDOCLASSICAL FOLDY-WOUTHUYSEN TRANSFORMATION AND CANONICAL QUANTIZATION OF (D=2N)-DIMENSIONAL RELATIVISTIC PARTICLE WITH SPIN IN AN EXTERNAL ELECTROMAGNETIC-FIELD

The canonical quantization of a (D=2n)-dimensional Dirac particle with spin in an arbitrary external electromagnetic field is performed in a gauge that makes it possible to describe simultaneously particles and antiparticles (both massive and massless) already at the classical le vel. A pseudoclassical Foldy-Wouthuysen transformation is used to find the canonical (Newton-Wigner) coordinates. The connection between thi s quantization scheme and Blount's picture describing the behavior of a Dirac particle in an external electromagnetic field is discussed.