Department of Physics, Princeton University, Princeton, NJ 08544, USA.
Department of Physics, University of Konstanz, D-78457 Konstanz, Germany.
Science. 2018 Jan 26;359(6374):439-442. doi: 10.1126/science.aao5965. Epub 2017 Dec 7.
Single-qubit rotations and two-qubit CNOT operations are crucial ingredients for universal quantum computing. Although high-fidelity single-qubit operations have been achieved using the electron spin degree of freedom, realizing a robust CNOT gate has been challenging because of rapid nuclear spin dephasing and charge noise. We demonstrate an efficient resonantly driven CNOT gate for electron spins in silicon. Our platform achieves single-qubit rotations with fidelities greater than 99%, as verified by randomized benchmarking. Gate control of the exchange coupling allows a quantum CNOT gate to be implemented with resonant driving in ~200 nanoseconds. We used the CNOT gate to generate a Bell state with 78% fidelity (corrected for errors in state preparation and measurement). Our quantum dot device architecture enables multi-qubit algorithms in silicon.
单量子比特旋转和双量子比特 CNOT 操作是通用量子计算的关键组成部分。尽管使用电子自旋自由度已经实现了高保真度的单量子比特操作，但由于核自旋退相和电荷噪声的快速发展，实现稳健的 CNOT 门一直具有挑战性。我们展示了一种用于硅中电子自旋的高效共振驱动 CNOT 门。我们的平台通过随机基准测试验证了单量子比特旋转的保真度大于 99%。通过交换耦合的门控控制，在 ~200 纳秒内可以使用共振驱动来实现量子 CNOT 门。我们使用 CNOT 门以 78%的保真度（针对状态制备和测量中的错误进行了修正）生成了贝尔态。我们的量子点器件架构使硅中的多量子比特算法成为可能。
