Implementation of the SMART protocol for global qubit control in silicon

• URL: http://arxiv.org/abs/2108.00836v3
• Date: Thu, 9 Sep 2021 08:35:52 GMT
• Title: Implementation of the SMART protocol for global qubit control in silicon
• Authors: Ingvild Hansen, Amanda E. Seedhouse, Kok Wai Chan, Fay Hudson, Kohei M. Itoh, Arne Laucht, Andre Saraiva, Chih Hwan Yang and Andrew S. Dzurak
• Abstract summary: We implement a new protocol to control a single spin microwave in a silicon quantum dot. Universal control of a single qubit is demonstrated using Stark modulated shift control via the local gate. This work shows that future scalable spin qubit arrays could be operated using global microwave control and local gate addressability.
• Score: 0.623014942746354
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Quantum computing based on spins in the solid state allows for densely-packed arrays of quantum bits. While high-fidelity operation of single qubits has been demonstrated with individual control pulses, the operation of large-scale quantum processors requires a shift in paradigm towards global control solutions. Here we report the experimental implementation of a new type of qubit protocol - the SMART (Sinusoidally Modulated, Always Rotating and Tailored) protocol. As with a dressed qubit, we resonantly drive a two-level system with a continuous microwave field, but here we add a tailored modulation to the dressing field to achieve increased robustness to detuning noise and microwave amplitude fluctuations. We implement this new protocol to control a single spin confined in a silicon quantum dot and confirm the optimal modulation conditions predicted from theory. Universal control of a single qubit is demonstrated using modulated Stark shift control via the local gate electrodes. We measure an extended coherence time of $2$ ms and an average Clifford gate fidelity $>99$ $\%$ despite the relatively long qubit gate times ($>15$ $\unicode[serif]{x03BC}$s, $20$ times longer than a conventional square pulse gate), constituting a significant improvement over a conventional spin qubit and a dressed qubit. This work shows that future scalable spin qubit arrays could be operated using global microwave control and local gate addressability, while maintaining robustness to relevant experimental inhomogeneities.

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