Single-spin-qubit geometric gate in a silicon quantum dot
Rong-Long Ma, Ao-Ran Li, Chu Wang, Zhenzhen Kong, Wei-Zhu Liao, Ming Ni, Sheng-Kai Zhu, Ning Chu, Chengxian Zhang, Di Liu, Gang Cao, Guilei Wang, Hai-Ou Li, Guo‐Ping Guo
Abstract
Preserving qubit coherence and maintaining high-fidelity qubit control under complex noise environment is an enduring challenge for scalable quantum computing. Here we demonstrate an addressable fault-tolerant single spin qubit with an average control fidelity of 99.12% via randomized benchmarking on a silicon quantum dot device with an integrated micromagnet. Its dephasing time ${T}_{2}^{\ensuremath{\ast}}$ is $1.025\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}\mathrm{s}$, and can be enlarged to $264\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}\mathrm{s}$ by using the Hahn-echo technique, reflecting strong low-frequency noise in our system. To break through the noise limitation, we introduce geometric quantum computing to obtain high control fidelity by exploiting its noise-resilient feature. However, the control fidelities of the geometric quantum gates are lower than 99%. According to our simulation, the noise-resilient feature of geometric quantum gates is masked by the heating effect. With further optimization to alleviate the heating effect, geometric quantum computing can be a potential approach to reproducibly achieving high-fidelity qubit control in a complex noise environment.