I just discovered the concept of phonons and the story of Brian Josephson (from reading "Sync" by Steven Strogatz). What the h....? So Phonon's are collective excitations of classical stuff made from QM ensembles, excitations made possible by the QM properties of the ensemble members? Are phonons not examples of non-local entanglement at classical scales? Can an ensemble of phonons have "collective excitations"? Does phonon evolution require collapse-like measurements, or preclude them, or i don't know, somehow absorb or erase them?