Wang Chien-An, John Valentin, Tidjani Hanifa, Yu Cécile X, Ivlev Alexander S, Déprez Corentin, van Riggelen-Doelman Floor, Woods Benjamin D, Hendrickx Nico W, Lawrie William I L, Stehouwer Lucas E A, Oosterhout Stefan D, Sammak Amir, Friesen Mark, Scappucci Giordano, de Snoo Sander L, Rimbach-Russ Maximilian, Borsoi Francesco, Veldhorst Menno
QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands.
Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA.
Science. 2024 Jul 26;385(6707):447-452. doi: 10.1126/science.ado5915. Epub 2024 Jul 25.
Qubits that can be efficiently controlled are essential for the development of scalable quantum hardware. Although resonant control is used to execute high-fidelity quantum gates, the scalability is challenged by the integration of high-frequency oscillating signals, qubit cross-talk, and heating. Here, we show that by engineering the hopping of spins between quantum dots with a site-dependent spin quantization axis, quantum control can be established with discrete signals. We demonstrate hopping-based quantum logic and obtain single-qubit gate fidelities of 99.97%, coherent shuttling fidelities of 99.992% per hop, and a two-qubit gate fidelity of 99.3%, corresponding to error rates that have been predicted to allow for quantum error correction. We also show that hopping spins constitute a tuning method by statistically mapping the coherence of a 10-quantum dot system. Our results show that dense quantum dot arrays with sparse occupation could be developed for efficient and high-connectivity qubit registers.
可有效控制的量子比特对于可扩展量子硬件的发展至关重要。尽管共振控制用于执行高保真量子门，但高频振荡信号的集成、量子比特串扰和发热对其可扩展性构成了挑战。在此，我们表明，通过设计具有位点依赖自旋量子化轴的量子点之间的自旋跳跃，可以用离散信号建立量子控制。我们展示了基于跳跃的量子逻辑，获得了单比特门保真度为99.97%，每次跳跃的相干穿梭保真度为99.992%，以及双比特门保真度为99.3%，这对应于已预测可实现量子纠错的错误率。我们还表明，跳跃自旋通过统计映射10量子点系统的相干性构成了一种调谐方法。我们的结果表明，可以开发具有稀疏占据的密集量子点阵列，用于高效和高连接性的量子比特寄存器。
