On stress-energy tensors

Abstract

We show how to introduce the “Noether Operator” of a (possibly constrained) variational principle even when the Lagrangian contains spinor fields (and their derivatives to any finite order). After relating that operator to the so-called “canonical” and “symmetric” stress-energy tensors, we construct explicitly the divergence by which these differ. A brief appendix illustrates the method of dealing with spinors by calculating Tμv for the Dirac equation.