On the Relativistic Quantum Force
  In the extension of the de-Broglie-Bohm causal quantum theory of motion to the relativistic particles, one faces with serious problems, like the problem of superluminal motion. This forces many authors to believe that there is not any satisfactory causal theory for particles of integer spin. In this paper, it is shown that the quantal behaviour is the result of direct-particle-interaction of the particle with all of its possibilities. The formulation is, then, extended to the relativistic particles of arbitrary spin. The presented theory has the following advantages. (1) It leads to a deeper understanding of the quantal behaviour. (2) It has no superluminal motion. (3) It is applicable to any spin. (4) It provides a framework for understanding the problem of creation and annihilation of particles. (5) It provides a framework for understanding the spin-statistics relationship. (6) It does not need the two fundamental assumptions of the de-Broglie-Bohm quantum theory of motion, i.e., the guiding-formula postulate and the statistical postulate. 
Ali Shojai and Mehdi Golshani