What happens to conserved currents after spontaneos symmetry breaking?

1. Jul 17, 2012

alemsalem

should the current still be conserved? since it stills commutes with the Hamiltonian and symmetry is just hidden.

but I just read that the linear-σ model was invented to demonstrate how the axial current could be partially conserved?

Thanks!

2. Jul 18, 2012

tom.stoer

the axial current is not conserved due to the chiral anomaly; that's different from chiral symmetry breaking, b/c for spontaneous symmetry breaking the full charge operator still commutes with the Hamiltonian H, i.e. [H,Q] = 0, whereas for an anomaly the (renormalized) operator doesn't, i.e. [H,QA] ≠ 0!

http://en.wikipedia.org/wiki/Chiral_anomaly

3. Jul 18, 2012