Two component theory and electron magnetic moment
The two-component formulation of quantum electrodynamics is studied. The relation with the usual Dirac formulation is exhibited, and the Feynman rules for the two-component form of the theory are presented in terms of familiar objects. The transformation from the Dirac theory to the two-component theory is quite amusing, involving Faddeev-Popov ghost loops of a fermion type with bose statistics. The introduction of an anomalous magnetic moment in the two-component formalism is simple; it is not equivalent to a Pauli term in the Dirac formulation. Such an anomalous magnetic moment appears not to destroy the renormalizability of the theory but violates unitarity.