On the Dirac equation with PT-symmetric potentials in the presence of   position-dependent mass
  The relativistic problem of fermions subject to a PT-symmetric potential in the presence of position-dependent mass is reinvestigated. The influence of the PT-symmetric potential in the continuity equation and in the orthonormalization condition are analyzed. In addition, a misconception diffused in the literature on the interaction of neutral fermions is clarified. 
Luis B. Castro
quant-ph hep-th math-ph math.MP