Aharonov–Casher effect and the coherent flux tunneling in the hybrid charge quantum interference device

By exploiting the Aharonov–Casher effect, we demonstrate a significant suppression of magnetic flux tunneling in a hybrid charge quantum interference device. The main part of this device is two Josephson junctions with a small superconducting island between them. To minimize phase fluctuations across Josephson junctions, this structure is embedded in a compact superinductive NbN loop. The interference between the flux tunneling paths is determined by the island-induced charge, which is controlled by an external voltage. The charge sensitive operation of the device is subjected to poisoning by the quasiparticles generated in the NbN film.