快慢激光相位噪声对Mølmer-Sørensen离子阱门保真度的影响
Influence of fast and slow laser phase noise on the fidelity of the Mølmer-Sørensen trapped-ion gate
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中文总结 AI 辅助
本文理论分析MS离子阱门中快慢激光相位噪声对保真度的影响，推导噪声哈密顿量与平均门误差解析式，并验证于数值模拟。
中文摘要 AI 辅助
高保真度的双量子比特纠缠门对于在量子处理器上实现有用的量子算法至关重要。Mølmer-Sørensen（MS）门因其对离子温度的鲁棒性以及已展示的创纪录保真度，已成为离子阱量子计算中的常见选择。然而，驱动激光场的频谱不纯会影响门性能，其中相位噪声通过在不同时间尺度上运行的机制影响量子比特动力学。在本工作中，我们对MS门中的激光相位噪声进行了全面的理论分析，识别出两个对门保真度影响最大的频谱范围：频率接近运动模式谱的“快”噪声，以及频率在逆门时间量级上的“慢”噪声。我们推导了两种常见激光束几何构型的噪声哈密顿量，并获得了以激光噪声功率谱密度和门参数表示的平均门误差的解析表达式。对于缓慢变化的噪声谱，我们提供了简化的误差估计。此外，我们还将我们的发现与先前发表的数值模拟进行了验证。
英文摘要
High-fidelity two-qubit entangling gates are essential for the realization of useful quantum algorithms on quantum processors. The Mølmer-Sørensen (MS) gate has become a common choice for trapped-ion quantum computing due to its resilience to ion temperature and its demonstrated record fidelities. However, the spectral impurity of the driving laser field impacts gate performance, with phase noise influencing the qubit dynamics through mechanisms operating on different timescales. In this work, we present a comprehensive theoretical analysis of laser phase noise in the MS gate, identifying two spectral ranges which influence the gate fidelity the most: "fast" noise at frequencies near the motional mode spectrum, and "slow" noise at frequencies on the order of the inverse gate time. We derive the noise Hamiltonians for two common laser beam geometries and obtain analytical expressions for the average gate error in terms of the laser noise power spectral density and gate parameters. For slowly varying noise spectra, we provide simplified error estimates. In addition, we validate our findings against previously published numerical simulations.
