Does Spontaneous Breakdown of Symmetry Imply Zero-Mass Particles?

Abstract

The implication of massless bosons from a proof by Goldstone, Salam, and Weinberg is shown to have a nonrelativistic analog that yields a massless boson excitation independent of model used. The operators and the invariance property relevant to the theory of superconductivity are used explicitly. It is concluded that there exists no general proof, independent of model and method of calculation, that establishes the existence of zero-mass particles in field theories with spontaneous breakdown of symmetry, but there are neventheless classes of field theories wherein-zero-mass panticles occur in consequence of the broken symmetry. (R.E.U.)