Goldstone boson: Difference between revisions

(Goldstone's Argument fails for gauge theories)
Letting A become large leads to a contradiction.
This argument fails completely for a gauge theory since the space of states for a gauge theory now has a [[positive semidefinite]] [[norm]] instead of a positive definite one, and it's not possible to construct an orthogonal state using the previous construction.
== Nonrelativistic theories ==