A Quantum Theoretical Formulation of Proper Time for Spin 1/2 Particles
  We find a quantum mechanical formulation of proper time for spin 1/2 particles within the framework of the Dirac theory. It is shown that an operator corresponds to the rate of the proper time and that the operator contains terms which oscillate with a very high frequency. We deduce, as an effect of these terms, the existence of an interference between the magnetic field and the rate of proper time. There is a possibility that the conclusion derived in this letter has some implications for astrophysics. 
Shoju Kudaka and Shuichi Matsumoto