On the problem of Zitterbewegung of the Dirac electron
  Reformulation of Dirac equation in terms of real quadratic division algebra of quaternions is given. Similar equations with different mass term are identified as suitable for description of free propagating quark motion. The complete orthonormal set of the positive-energy plane wave solutions is presented. Therefore, Zitterbewegung phenomenon is absent in this formulation. The probability current is proportional to the momentum, as in standard Schrodinger wave mechanics. 
Daniel Sepunaru