退相干受限氮空位色心系综中的门合成
Gate Synthesis in Dephasing-Limited Nitrogen-Vacancy Ensembles
- Institut quantique, Université de Sherbrooke（舍布鲁克大学量子研究所）
- Département de physique, Université de Sherbrooke（舍布鲁克大学物理系）
- Keysight Technologies Canada（是德科技加拿大）
- Département de génie électrique et de génie informatique, Université de Sherbrooke（舍布鲁克大学电气与计算机工程系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
针对系综NV色心退相干限制下的门控制，提出ZXZXZ分解与复合脉冲方法，抑制误差累积超70%，实现鲁棒单比特控制。
AI中文摘要：
系综氮空位（NV）色心广泛应用于量子传感和磁力测量，其性能取决于微波脉冲序列的精确实现。在这些系统中，非均匀展宽和短相干时间限制了可靠的多脉冲控制，而硬件缺陷和非共振激发会扭曲所实现的旋转，使得任意门的直接校准变得繁琐。为解决这一问题，我们实现了一种采用ZXZXZ门分解的控制框架，该分解使用固定角度、相位参数化的脉冲，通过单个校准的$\pi/2$基元（$X_{\pi/2}$）以及虚拟Z操作实现通用单量子比特控制。我们比较了标准脉冲与为高功率操作设计的复合脉冲，该高功率操作处于拉比频率与超精细分裂相当的 regime，导致超精细能级间的非均匀演化。使用预定的$\pi/2$脉冲序列组合，我们观察到标准脉冲在重复应用下迅速偏离理想行为，而复合脉冲在较长序列中抑制了这种误差累积超过70%，尽管其持续时间更长。相比之下，随机基准测试对两种实现给出了相似的衰减因子，突显了其对相干控制误差的有限敏感性。这些结果为短相干系综系统中的鲁棒控制提供了一条实用途径，并强调了脉冲级表征的重要性。
英文摘要：
Ensemble nitrogen-vacancy (NV) centers are widely used for quantum sensing and magnetometry, where performance depends on the accurate implementation of microwave pulse sequences. In these systems, inhomogeneous broadening and short coherence times limit reliable multi-pulse control, while hardware imperfections and off-resonant excitation distort implemented rotations, making direct calibration of arbitrary gates tedious. To address this, we implement a control framework with a ZXZXZ gate decomposition which uses fixed-angle, phase-parameterized pulses, enabling universal single-qubit control from a single calibrated $ π/2$ primitive ($X_{π/2}$) along with virtual Z operations. We compare a standard pulse with a composite pulse designed for high-power operation in a regime where the Rabi frequency is comparable to the hyperfine splitting, leading to non-uniform evolution across hyperfine levels. Using pre-determined combinations of $π/2$ pulse sequences, we observe that standard pulses rapidly deviate from ideal behavior under repeated application, while the composite pulse suppresses this error accumulation by more than 70$\%$ for longer sequences despite its longer duration. In contrast, randomized benchmarking yields similar decay factors for both implementations, highlighting its limited sensitivity to coherent control errors. These results establish a practical route to robust control in short-coherence ensemble systems and emphasize the importance of pulse-level characterization.
