超過量子容錯計算閾值的矽/矽鍺自旋量子位元控制

Abstract

矽自旋量子位元是實現可大規模量子計算的平台，大規模量子計算需要的量子糾錯碼要求量子位元操控保真度需超越 99% 的閾值。在此，我們展示了在矽元件中自旋量子位元的高保真度控制，我們展示了超越了此閾值並且接近 99.9% 的保真度目標。我們在純化後的矽/矽鍺自旋量子位元裝置中，實現了單量子位元閘 99.99% 的保真度，以及雙量子位元受控反閘(controlled-NOT gate) 99.5% 的保真度。此外，我們還證明了利用共用微波控制線同時控制多個自旋量子位元陣列的可行性，同時維持了約 99.9% 的單量子位元閘保真度。這些結果將在未來提升量子位元保真度時提供幫助，並且也突顯了自旋量子位元裝置在邁向實用量子計算方面的潛力。

Spin qubits in silicon are a leading platform for scalable quantum computation. To implement large-scale quantum computation, the ability to implement fault-tolerant surface code is needed, which requires qubit operation fidelities exceeding the 99% fault-tolerance threshold. Moreover, improving these operation fidelities further reduces the number of physical qubits required to encode a logical qubit with the same logical error rate, making it more practical to implement useful quantum computation. Here, we demonstrate high-fidelity control of spin qubits in isotopically purified silicon, surpassing the 99% threshold and approaching the practical fidelity target of 99.9%. We achieved 99.99% fidelity for single-qubit gates and 99.5% fidelity for two-qubit controlled-NOT gates in purified Si/SiGe spin qubit devices. Furthermore, we demonstrate the ability to control an array of spin qubits simultaneously with a shared control line while maintaining the ∼ 99.9% single-qubit gate fidelity. These results will help improve operation fidelities in future spin qubit devices and underscore the potential for spin qubit devices to be scaled up towards practical quantum computation.