Charge quantum interference device

The demonstration of coherent quantum phase slips (CQPS) in disordered superconductors has opened up a new route towards exploring the fundamental charge–phase duality in superconductors, with the promise of devices with new functionalities and a robust quantum current standard based on CQPS. Here we demonstrate a device that integrates several CQPS junctions: the charge quantum interference device. The charge quantum interference device becomes the dual of the well-known superconducting quantum interference device, and is a manifestation of the Aharonov–Casher effect in a continuous superconducting system devoid of dielectric barriers. The charge–phase duality in superconductors implies that the well-known SQUID has an analogue based on the interference of fluxons. Such a ‘charge quantum interference device’ (or CQUID) has now been experimentally demonstrated.