On the uniqueness of the Dirac theory in curved and flat spacetime



In this work a number of examples are used to illustrate uniqueness of physical prediction of the Dirac theory in a curved and a flat spacetime. Dirac Hamiltonians in arbitrary, including time-dependent, gravitational fields uniquely determine physical characteristics of quantum-mechanical systems irrespective of the choice of the tetrad fields. Direct spin-rotation coupling that occurs with a certain choice of tetrads does not manifest itself in final physical characteristics of the systems and therefore does not represent a physically relevant effect.