The velocity and angular momentum of a free Dirac electron
arXiv:physics/9804024
Abstract
It is shown that, in Dirac theory, there is a spatial velocity of a free electron which commutes with the Hamiltonian, so it is a conserved quantity of the motion. Furthermore, there is a spatial orbital angular momentum which also commutes with the Hamiltonian and is a constant of the motion.
5 pages,latex