Control and mitigation of coherent errors with superconducting qubits

Improving gate performance is vital for scalable quantum computing. The universal quantum computing also requires the gate fidelity to reach a high level. For superconducting quantum processor, which operates in the microwave band, the single-qubit gates are usually realized with microwave driving. Coherent errors always happen during the one- and two-qubit operations. In this talk, we would like to analyze the coherent error effects to the single-qubit gate and propose an error mitigation scheme. There are three steps in our error mitigation method. First is the controlling of the detuning between qubits. Second, by applying the general decomposition procedure, arbitrary single-qubit gate can be decomposed as a sequence of X and virtual Z gates. Finally, by optimizing the parameters in virtual Z gates, the error constrained in the computational space can be corrected. Using our method, no additional compensation signals are needed, arbitrary single-qubit gate time will not be prolonged, and the circuit depth containing simultaneous single-qubit gates will also not increase.