Superconducting qubits with adjustable coupling, Part I: Architecture

Building a practical quantum computer requires a scalable architecture suitable for large numbers of qubits. A major challenge is to achieve on-demand qubit-qubit interaction, such that turning the coupling off allows isolated single-qubit operations and turning the coupling on allows multi-qubit operations. By combining the high coherence Xmon qubits with an adjustable inductance, we have developed a new qubit architecture called g-mon, which has a tunable qubit-qubit interaction from 10 MHz to -50 MHz. We achieved nanosecond control of the coupling from positive to negative through zero, allowing for a high on/off ratio exceeding 1000. With additional advantages such as high modularity and moderate-distance compatibility, the g-mon architecture provide a potential scalable approch for future quantum computers.