Semi-fractality and localization on a chiral Cayley tree
How random weak links create a strange quantum halfway state
Physicists discovered that quantum particles hopping on a branching network with randomly weak connections can enter an unusual state that is neither fully spread out nor fully trapped. The particles occupy most of the network, yet concentrate their energy in a way normally seen only in completely localized systems—a phenomenon the researchers call semi-fractality. By varying the strength of the weak links, they found the system can shift between this semi-fractal regime and complete localization, revealing a new intermediate form of quantum confinement.
This work reveals new ways that disorder and symmetry shape quantum behavior, findings that could refine how physicists design materials with tailored electronic properties. Understanding these intermediate quantum states might help predict behavior in disordered materials used in real devices, from semiconductors to quantum sensors, where weak connections between components significantly affect performance.