  In a recent paper [1], it has been proposed that relativistic wave-particle
duality can be embodied in a relation that shows that the four-velocity of a
particle is proportional to the Dirac four-current. In this note we bring out
some problems with that idea. In particular, we point out that, in line with
existing literature on Einstein-Cartan gravity with torsion, the spin-torsion
term should represent negative energy. Moreover, if what is proposed in Eq.
(20) of [1] is correct, then the spin torsion term would be zero in the rest
frame of the fermion. We suggest a possible resolution of that dilemma.
