Achieving high-fidelity entangling operations between qubits is crucial for multi-qubit systems. This research studies errors in a silicon metal-oxide-semiconductor (MOS) quantum dot spin qubit processor, linking them to physical origins. Using this knowledge, the researchers demonstrate consistent, repeatable operation with >99% fidelity two-qubit gates. Analysis across multiple devices and extended periods captures variation and common error types, including slow nuclear and electrical noise, and contextual noise depending on the control sequence. The impact of qubit design, feedback systems, and robust gate design is investigated to inform future scalable, high-fidelity control strategies. The results highlight both the capabilities and challenges for scaling silicon spin-based qubits.

Tuomo Tanttu, Wee Han Lim, Jonathan Y. Huang, Nard Dumoulin Stuyck, Will Gilbert, Rocky Y. Su, MengKe Feng, Jesus D. Cifuentes, Amanda E. Seedhouse, Stefan K. Seritan, Corey I. Ostrove, Kenneth M. Rudinger, Ross C. C. Leon, Wister Huang, Christopher C. Escott, Kohei M. Itoh, Nikolay V. Abrosimov, Hans-Joachim Pohl, Michael L. W. Thewalt, Fay E. Hudson, Robin Blume-Kohout, Stephen D. Bartlett, Andrea Morello, Arne Laucht, Chih Hwan Yang, Andre Saraiva, Andrew S. Dzurak