We consider a pilot-wave approach for the Dirac theory that was recently
proposed by Colin and Wiseman. In this approach, the particles perform a
zig-zag motion, due to stochastic jumps of their velocity. We respectively
discuss the one-particle theory, the many-particle theory and possible
extensions to quantum field theory. We also discuss the non-relativistic limit
of the one-particle theory. For a single particle, the motion is always
luminal, a feature that persists in the non-relativistic limit. For more than
one particle the motion is in general subluminal.Comment: 23 pages, no figures, LaTe