What price the spin-statistics theorem?

Abstract

We examine a number of recent proofs of the spin-statistics theorem. All, of course, get the target result of Bose-Einstein statistics for identical integral spin particles and Fermi-Dirac statistics for identical half-integral spin particles. It is pointed out that these proofs, distinguished by their purported simple and intuitive kinematic character, require assumptions that are outside the realm of standard quantum mechanics. We construct a counterexample to these non-dynamical kinematic 'proofs' to emphasize the necessity of a dynamical proof as distinct from a kinematic proof. Sudarshan's simple non-relativistic dynamical proof is briefly described. Finally, we make clear the price paid for any kinematic 'proof'.