The discussion revolves around the question of why an atom can possess nonzero total angular momentum in its ground state, despite having no net electric dipole moment. Participants explore concepts related to symmetry breaking, classical analogies, and the nature of quantum mechanical states.
Participants express differing views on the implications of angular momentum in quantum mechanics, with no consensus reached on whether the behavior observed in atoms is special or a continuation of classical principles. The discussion remains unresolved regarding the nature of ground state angular momentum.
Participants reference classical analogies and quantum mechanical principles, but the discussion does not clarify the assumptions underlying these comparisons or the specific conditions under which the statements apply.
mfb said:A classical, charged, rotating ring has no dipole moment, but nonzero angular momentum.
Why do you expect that this is something special to get the same in quantum mechanics? There are orbitals with angular momentum, and if there are is a single electron in one of those orbitals you get a nonzero total angular momentum.