面内最优量子比特操作，控制保真度超过99%
In-plane optimal qubit operation with control fidelities exceeding 99 %
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中文总结 AI 辅助
本研究报道了平面锗量子点中的单空穴自旋量子比特，通过优化磁场方向降低自旋-电敏感性，在最优工作点实现99.82%的最大门保真度，并显著提升相干时间与操控性能。
中文摘要 AI 辅助
基于半导体量子点的空穴自旋量子比特因其全电操控特性，有望用于构建未来大规模量子计算机。然而，价带空穴的丰富物理机制导致量子比特性质具有各向异性。这为延长相干时间并实现高保真量子比特操控提供了机会。在此，我们报道了平面锗量子点中的单空穴自旋量子比特，并研究了其在面内磁场下对电荷噪声的各向异性敏感性。通过将纵向自旋-电敏感性（spin-electric susceptibility）与量子比特相干性和操控性能相关联，我们确定了一个最优工作点，在该点对电荷噪声的敏感性被最小化。我们发现，优化磁场方向可降低自旋-电敏感性，从而使Hahn-echo相干时间提升五倍，并将操控不保真度抑制近十倍。在最优工作点，门集断层扫描（gate set tomography）显示最大门保真度为99.82%。我们的发现增强了空穴自旋量子比特在可扩展量子信息处理中的应用前景。
英文摘要
Hole spin qubits based on semiconductor quantum dots are promising for building future large-scale quantum computers owing to their all-electrical manipulation. However, abundant physical mechanisms of valence band holes lead to anisotropic qubit properties. There is an opportunity to prolong the coherence time and achieve high-fidelity qubit manipulations. Here, we report a single-hole spin qubit in a planar germanium quantum dot and investigate its anisotropic susceptibility to charge noise under an in-plane magnetic field. By correlating the longitudinal spin-electric susceptibility with qubit coherence and control performance, we identify an optimal operating point where the sensitivity to charge noise is minimized. We find that optimizing the magnetic-field orientation reduces the spin-electric susceptibility, resulting in a five-fold enhancement of the Hahn-echo coherence time and a nearly tenfold suppression of control infidelity. At the optimal operating point, gate set tomography demonstrates the maximum gate fidelity of 99.82 %. Our finding enhances the prospects of hole spin qubits for scalable quantum information processing.
发表机构
- University of Science and Technology of China（中国科学技术大学）
- Beijing Superstring Academy of Memory Technology（北京超弦记忆技术研究院）
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