Anomalous Electron Velocity and Zitterbewegung

Dirac's Relativistic Wave Equation implies an electron velocity equal to the velocity of light of magnitude c, in apparent violation of Relativity. This theoretical result has been largely considered as a mathematical curiosity with little physical relevance. In this paper it is shown that a velocity c can be observed for an electron that is in a superposition of positive and negative energy states - called a zitterbewegung state. But this velocity c is attainable only by electron spin and electron charge, and not by electron mass. A zitterbewegung state is experimentally realizable when the electron is accelerated with sufficient energy so that its spatial wave function is confined within about a Compton wavelength h/mc. Such high energies are now available through the technology of plasma electron acceleration employed in plasma wakefield accelerators and laser-driven wakefield accelerators. Plasma acceleration conceived 30 years ago has been successfully accomplished within the past decade. Whereas spintronic analogues to zitterbewegung have been implemented, genuine electron zitterbewegung is only now realizable. It is therefore possible to observe electron spin and electron charge moving at the speed of light.