Feedback control of coherent spin states using weak nondestructive measurements
Feedback control of coherent spin states using weak nondestructive measurements
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使用弱无损测量对相干自旋态进行反馈控制
DOI：
10.1103/physreva.89.063619
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发表时间：
2014
影响因子：
2.9
通讯作者：
P. Bouyer
中科院分区：
文献类型：
--
作者：
T. Vanderbruggen;R. Kohlhaas;A. Bertoldi;E. Cantin;A. Landragin;P. Bouyer
我们考虑集体随机旋转下的赝自旋系综的退相干，并从理论和实验两方面研究如何结合实时反馈校正的无损测量可以保护状态免受这种退相干过程。我们从理论上描述了反馈效率与不同的参数-相干性，熵，保真度-并表明，达到最大效率在弱测量制度，当投影的状态引起的测量是可以忽略不计的。本文详细介绍了发表在[Phys. Rev. Lett. [textbf{110}，210503（2013）]，其中反馈方案稳定了被捕获的超冷原子的相干自旋态，并且用色散光学检测进行非破坏性探测。此外，我们还研究了原子数和旋转角等参数对方法性能的影响。我们分析了限制反馈效率的各种退相干源，并提出了如何减轻其影响。结果表明，该方法的原子干涉仪的实时相干控制的潜力。
We consider the decoherence of a pseudo-spin ensemble under collective random rotations, and study, both theoretically and experimentally, how a nondestructive measurement combined with real-time feedback correction can protect the state against such a decoherence process. We theoretically characterize the feedback efficiency with different parameters --- coherence, entropy, fidelity --- and show that a maximum efficiency is reached in the weak measurement regime, when the projection of the state induced by the measurement is negligible. This article presents in detail the experimental results published in [Phys. Rev. Lett. \textbf{110}, 210503 (2013)], where the feedback scheme stabilizes coherent spin states of trapped ultra-cold atoms, and nondestructively probed with a dispersive optical detection. In addition, we study the influence of several parameters, such as atom number and rotation angle, on the performance of the method. We analyze the various decoherence sources limiting the feedback efficiency and propose how to mitigate their effect. The results demonstrate the potential of the method for the real-time coherent control of atom interferometers.