  A new Bohmian quantum-relativistic model, in which from the Klein-Gordon
equation a generalization of the standard Zitterbewegung arises, is explored.
It is obtained by introducing a new independent time parameter, whose relative
motions are not directly observable but cause the quantum uncertainties of the
observables. Unlike Bohm's original theory, the quantum potential does not
affect the observable motion, as for a normal external potential, but it only
determines that one relative to the new time variable, of which the
Zitterbewegung of a free particle is an example. The model also involves a
relativistic revision of the uncertainty principle.
