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https://arxiv.org/pdf/cond-mat/0503400.pdf

Greiter argues that local electromagnetic gauge symmetry cannot change the state of a quantum system. On the other hand, in QED charge or particle conservation (if energy is too low to produce particle-antiparticle pairs) is the result of a global U(1) phase symmetry. This symmetry is broken and the states are not invariant under this symmetry. The latter symmetry is sometimes called a global gauge symmetry, which apparently gives rise to my confusion. So we have a "real" global symmetry, which transforms physically different states into each other, and a "local" gauge theory, which does not transform states. The confusion, Greiter is referring to, hence is probably due to Weinberg calling a global phase transformation also a gauge transformation, which is misleading, as the global transformation is a real symmetry operation?