Spinorial approach to classical electrodynamics

Abstract:
It is well known that the so-called Lorentz Force can be regarded as a consequence of (infinitesimal) Lorentz transformations acting on the four-momentum of a charged massive point-particle in the presence of an external field. This can be spinorially re-formulated and the spinorial version of the equations describing the trajectory of the particle gives also the evolution of (classical) spin under the action of an external field. This equations in turn can be obtained from a spinorial lagrangian and the associated hamiltonian gives, in the case of a constant magnetic field, discrete values of the energy.