Measurement and advances in hybrid quantum system with P1 centers and superconducting qubits

A hybrid quantum system which contains spin ensembles, superconducting resonators and superconducting qubits, has been proposed as a way to realize quantum computer. In the first part of this poster, we coupled substitutional nitrogen centers (P1 centers) in diamond to a superconducting resonator with Zeeman effect. We observed a fast relaxation of spin population on the millisecond scale, which is much faster than the intrinsic spin longitudinal relaxation of P1 centers. By pump-probe experiments we attributed this process to a cross relaxation among different hyperfine splitted spin subensembles. In the second part, we demonstrate iSWAP gate and CR gate by using a 5-qubit quantum processor. The qubit anharmonicity is enhanced by using a parallel capacitor, meanwhile the qubit is still operated in transmon regime. Furthermore, we have proposed a new architecture of scalable superconducting qubits based on ring network structures. This design can efficiently avoid breakpoints of superconducting patterns and significantly improve the robustness of intra-connections of qubits. We will demonstrate a quantum processor based on this architecture, to implement a fault-tolerant operating scheme with fourteen transmon qubits, which support reliable logical qubits and universal gates.