High-fidelity single spin-qubit control with an Intel-developed AWG

Quantum computing promises to tackle exciting and computationally difficult problems. Intel is leveraging 50 years of experience in semiconductor manufacturing to develop silicon-based spin qubit devices. Whereas the electrons, whose spin states are used as qubit states, are all identical, their surroundings are not. Hence, precise calibration of the signals controlling the qubits is required. Moreover, spin qubits require multiple voltage control lines per qubit, plus potentially shared microwave control lines. To orchestrate these increasingly complex setups, we use an in-house developed control and calibration software. It allows us to produce hardware agnostic pulse sequences that are interpreted by the control electronics. In particular, we demonstrate that an in-house developed arbitrary waveform generator (AWG), which relies on direct digital synthesis to translate instructions into precisely timesd pulses (arbitrary waveforms), is a useful tool for coherent qubit control. Leveraging the AWG’s high instruction bandwidth (upload speed), coupled with a large memory, we achieve single-qubit randomized benchmarking fidelities approaching 99.9% in a natural Silicon sample.