Gate sequencing approach to reduce calibration and equipment overhead in qubit control

The set of any single pi/2 polar angle rotation on the Bloch sphere together with arbitrary azimuthal rotations (Z gates) allow universal gating on any two computational states. With qubit state sensitive readout, a simple 1D scan of transverse pulse amplitude can identify a candidate pi/2 polar angle gate. With just a single polar angle gate in the universal gate set, non-idealities in the polar angle as a function of pulse amplitude are ignorable. Z gates straightforwardly compensate for any azimuthal rotations accrued during such a pulse. Using this sequencing approach we demonstrate 0.9996(2) single qubit Clifford fidelities on a superconducting transmon qubit without the need for additional compensation for interactions with the second excited state, which reduces calibration overhead. In addition, this high fidelity gate sequencing uses only a single arbitrary waveform generator channel rather than the two that are typically required. Taken together, these attributes yield a simple, efficient, and robust new technique for single-qubit control.