近日，澳大利亚新南威尔士大学的Andrew S. Dzurak&Tuomo Tanttu及其研究团队取得一项新进展。经过不懈努力，他们实现硅量子点中高保真双量子比特门的误差评估。相关研究成果已于2024年8月20日在国际知名学术期刊《自然—物理学》上发表。
本研究探讨了自旋量子比特处理器中的误差，并将其与物理起源联系起来。研究人员利用这一知识，在技术上重要的硅金属氧化物半导体量子点平台上，展示了保真度超过99%的双量子比特门的一致且可重复操作。通过对多台设备长期运行的物理误差和保真度进行分析，研究人员能够确保捕捉到各种变化和最常见的误差类型。
物理误差源包括单个量子比特上的慢速核噪声和电噪声，以及取决于所施加控制序列的上下文噪声。此外，研究人员还研究了量子比特设计、反馈系统和稳健门设计的影响，为未来可扩展、高保真度控制策略的设计提供依据。这项研究结果既突出了硅基自旋量子比特扩展为全尺寸量子处理器的潜力，也指出了面临的挑战。
据悉，在多量子比特系统中，始终如一地实现高保真度的量子比特纠缠操作对于系统性能至关重要。固态平台尤其容易受到由材料引起的量子比特间变异性所导致的误差的影响，这会导致性能不一致。
附：英文原文
Title: Assessment of the errors of high-fidelity two-qubit gates in silicon quantum dots
Author: Tanttu, Tuomo, Lim, Wee Han, Huang, Jonathan Y., Dumoulin Stuyck, Nard, Gilbert, Will, Su, Rocky Y., Feng, MengKe, Cifuentes, Jesus D., Seedhouse, Amanda E., Seritan, Stefan K., Ostrove, Corey I., Rudinger, Kenneth M., Leon, Ross C. C., Huang, Wister, Escott, Christopher C., Itoh, Kohei M., Abrosimov, Nikolay V., Pohl, Hans-Joachim, Thewalt, Michael L. W., Hudson, Fay E., Blume-Kohout, Robin, Bartlett, Stephen D., Morello, Andrea, Laucht, Arne, Yang, Chih Hwan, Saraiva, Andre, Dzurak, Andrew S.
Issue&Volume: 2024-08-20
Abstract: Achieving high-fidelity entangling operations between qubits consistently is essential for the performance of multi-qubit systems. Solid-state platforms are particularly exposed to errors arising from materials-induced variability between qubits, which leads to performance inconsistencies. Here we study the errors in a spin qubit processor, tying them to their physical origins. We use this knowledge to demonstrate consistent and repeatable operation with above 99% fidelity of two-qubit gates in the technologically important silicon metal-oxide-semiconductor quantum dot platform. Analysis of the physical errors and fidelities in multiple devices over extended periods allows us to ensure that we capture the variation and the most common error types. Physical error sources include the slow nuclear and electrical noise on single qubits and contextual noise that depends on the applied control sequence. Furthermore, we investigate the impact of qubit design, feedback systems and robust gate design to inform the design of future scalable, high-fidelity control strategies. Our results highlight both the capabilities and challenges for the scaling-up of silicon spin-based qubits into full-scale quantum processors.
DOI: 10.1038/s41567-024-02614-w
Source: https://www.nature.com/articles/s41567-024-02614-w