Why classical physics fails to explain nuclear deformation in particle collisions

When heavy ions collide at near light-speed, their azimuthal flow patterns reveal the internal deformation of nuclei—but physicists have been using classical rigid-rotor models to interpret quantum objects. Comparing quantum and classical predictions across the nuclear chart shows quantum contributions account for nearly all deformation effects in light nuclei (10% in heavy ones), meaning current collision interpretations may miss crucial nuclear-structure signatures.