GENERALIZED TOTAL ANGULAR-MOMENTUM OPERATOR FOR THE DIRAC-EQUATION IN CURVED SPACE-TIME

It is found that an operator of the form i5[f-(16)f;] commutes with the Dirac operator whenever f is an antisymmetric tensor satisfying the Penrose-Floyd equation f(;)=0. Such a tensor exists notably in the Kerr solutions and in the flat-space limit wherein the operator can be interpreted as the square root of the ordinary total squared angular momentum Casimir operator of the rotation group. © 1979 The American Physical Society.