Enhancing Gate Fidelity via Crosstalk Mitigation and Pulse Predistortion

The fidelity of gate operations in multiqubit arrays is degraded by spurious crosstalk and pulse distortion due to the frequency-dependent transfer function of the qubit wiring. Crosstalk can lead to undesired bias shifts and spurious rotations in spectator qubits, while the distortion of baseband signals from coupling to nearby normal metals and magnetic materials can lead to spurious z-rotations. Here, we describe approaches to mitigating and correcting both crosstalk and distortion of microwave and baseband qubit control signals. We demonstrate the effectiveness of the methods by performing simultaneous two-qubit randomized benchmarking with and without appropriate mitigation.