Correcting qubit pulse distortions in superconducting qubits

Precise characterization of control pulses is essential to building reliable quantum computers. We use qubits as a probe to measure distortions of baseband pulses in both the high and low frequency domain, up to 500MHz. This allows us to identify and characterize several mechanisms for pulse distortion without using a prescribed model, and remove these distortions with high precision. We demonstrate improved gate fidelities using scalable techniques which we call IN-Situ Pulse Envelope Calibration Technique (INSPECT) at frequencies above the 2MHz regime and Echo Phase After Detune (EPAD) below 2MHz. In particular, our methods allow for the partial mitigation of low-frequency noise effects.