We report the achievement of single-qubit gates with sub-part-per-million error rates, in a trapped-ion $^{ 43}$Ca$^{ +}$ hyperfine clock qubit. We explore the speed/fidelity trade-off for gate times $4.4\leq t_{ g}\leq35~\mu$s, and benchmark a minimum error per Clifford gate of $1.5(4) \times 10^{ -7}$. Calibration errors are suppressed to $< 10^{ -8}$, leaving qubit decoherence ($T_{ 2}\approx 70$ s), leakage, and measurement as the dominant error contributions. The ion is held above a microfabricated surface-electrode trap which incorporates a chip-integrated microwave resonator for electronic qubit control; the trap is operated at room temperature without magnetic shielding.
Categories: quant-ph