Title: Lorentz covariant and gauge invariant description of orbital and spin angular momentum and the non-symmetric energy momentum tensor,
Abstract: Starting from covariant expressions, a gauge independent separation of
orbital and spin angular momentum for electrodynamics is presented. This
results from the non-symmetric canonical energy momentum tensor of the
electromagnetic field. The origin of the difficulty is discussed and a
covariant gauge invariant spin vector is derived. The paradox concerning the
spin angular momentum of a plane wave finds a natural solution.