All-Resonance Controlled-Phase Gate on Two Nonlocal Nitrogen-Vacancy Center Ensembles Assisted by a Superconducting Quantum Circuit

The realization of universal quantum logical gates on nonlocal nitrogen-vacancy center ensembles (NVEs) is a basic task for universal quantum computing with NVEs. In contrast to previous works on the construction of gates, a one-step all-resonance scheme is proposed to construct a controlled-phase gate on two nonlocal NVEs that are coupled to different superconducting transmission line resonators connected by a superconducting transmon qubit. The gate can be easily realized using only one step. Moreover, the all-resonance operation allows the gate to be achieved within a short time. By considering the feasible parameters obtained in the experiments, this gate can be completed within 101 ns with a high fidelity of approximately 97.8%, which has reached the threshold of fault-tolerance quantum computing.