Atomtronic superconducting quantum interference device in synthetic dimensions

Abstract: We propose atomtronic counterpart of superconducting quantum interference device (SQUID) in synthetic $2$-dimensional space. The system is composed of Bose-Einstein condensate (BEC) in two neighboring optical wells which is coupled to an external coherent light. Furthermore, availability of controllable atomtronic flux qubit in the synthetic dimensions is demonstrated with this system. Control parameter for the qubit is naturally provided by artificial magnetic flux originated from the coherent atom-light coupling. Comparing with traditional SQUID which requires at least $2$-dimensional circuits, the synthetic dimensional SQUID can be realized only in $1$-dimensional circuits. It should be a great advantage for the scalability and integration feature of quantum logic gates.