Goldstone's theorem examines a generic continuous symmetry which is spontaneously broken; i.e., its currents … See more

• In fluids, the phonon is longitudinal and it is the Goldstone boson of the spontaneously broken Galilean symmetry. In solids, the situation is more complicated; the Goldstone bosons are the longitudinal and transverse … See more

The principle behind Goldstone's argument is that the ground state is not unique. Normally, by current conservation, the charge operator for any symmetry current is time-independent,
Acting with … See more

There is an arguable loophole in the theorem. If one reads the theorem carefully, it only states that there exist non-vacuum states with arbitrarily small energies. Take for example a chiral N = 1 super QCD model with a nonz… See more

A version of Goldstone's theorem also applies to nonrelativistic theories. It essentially states that, for each spontaneously broken symmetry, there corresponds some quasiparticle which is typically a … See more

Spontaneously broken global fermionic symmetries, which occur in some supersymmetric models, lead to Nambu–Goldstone fermions, or goldstinos. These have spin  1 / 2 , instead of 0, and carry all qu… See more