Squeezing the angular momentum of an ensemble of complex multilevel atoms
Squeezing the angular momentum of an ensemble of complex multilevel atoms
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压缩复杂多能级原子系综的角动量
DOI：
10.1103/physreva.104.023710
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发表时间：
2021
影响因子：
2.9
通讯作者：
Jessen, P. S.
中科院分区：
文献类型：
--
作者：
Hemmer, D.;Montaño, E.;Baragiola, B. Q.;Norris, L. M.;Shojaee, E.;Deutsch, I. H.;Jessen, P. S.
集体原子自旋的压缩已经被证明可以提高原子钟和磁力计的灵敏度，使其水平大大低于标准量子极限。在大多数情况下，所需的原子-原子纠缠是通过与量子化探测场的色散相互作用或量子气体中的态相关碰撞产生的。这些实验通常使用复杂的多级原子，如Rb或Cs，相关的相互作用设计，使原子的行为像赝自旋粒子。我们证明了自旋压缩的可行性集体自旋组成的物理角动量ofCs原子，每个内部自旋-4超精细状态。通过色散量子非破坏（QND）测量的量子反作用产生至少5dB的峰值压缩，使用双色光学探针实现，在不牺牲测量强度的情况下最大限度地减少张量光位移。其他重要的发展包括成功应用复合脉冲技术，通过对最先进的磁屏蔽内的背景磁场进行宽带抑制，对集体自旋进行精确的动态控制。经典噪声的缺乏使我们能够将观察到的量子投影噪声和压缩与一个理论模型进行比较，该模型适当地解释了相关的原子物理和集体自旋的空间模式，找到了良好的定量一致性，从而验证了它在其他背景下的使用。我们的工作为量子反馈、确定性压缩和闭环磁力学实验奠定了基础。实时反馈的实现还可以为新类型的量子模拟创造机会，其中量子系统的演化以时间连续的QND测量的结果为条件。这样的方案有可能进入量子-经典边界附近的新机制，有机会研究混沌系统中与量子-经典对应相关的长期问题。
Squeezing of collective atomic spins has been shown to improve the sensitivity of atomic clocks and magnetometers to levels significantly below the standard quantum limit. In most cases the requisite atom-atom entanglement has been generated by dispersive interaction with a quantized probe field or by state-dependent collisions in a quantum gas. Such experiments typically use complex multilevel atoms like Rb or Cs, with the relevant interactions designed so that atoms behave like pseudospin-particles. We demonstrate the viability of spin squeezing for collective spins composed of the physical angular momenta ofCs atoms, each in an internal spin-4 hyperfine state. A peak metrological squeezing of at least 5dB is generated by quantum backaction from a dispersive quantum nondemolition (QND) measurement, implemented using a two-color optical probe that minimizes tensor light shifts without sacrificing measurement strength. Other significant developments include the successful application of composite pulse techniques for accurate dynamical control of the collective spin, enabled by broadband suppression of background magnetic fields inside a state-of-the-art magnetic shield. The absence of classical noise allows us to compare the observed quantum projection noise and squeezing to a theoretical model that properly accounts for both the relevant atomic physics and the spatial mode of the collective spin, finding good quantitative agreement and thereby validating its use in other contexts. Our work sets the stage for experiments on quantum feedback, deterministic squeezing, and closed-loop magnetometry. The implementation of real-time feedback may also create an opportunity for new types of quantum simulation, wherein the evolution of a quantum system is conditioned on the outcome of a time-continuous QND measurement. Such a scheme has the potential to access new regimes near the quantum-classical boundary, with opportunities to study long-standing issues related to quantum-classical correspondence in chaotic systems.
影响因子：
2.9
作者：
Jasperse, M.;Kewming, M. J.;Turner, L. D.
通讯作者：
Turner, L. D.
DOI：
--
发表时间：
2006
期刊：
--
影响因子：
--
作者：
Iroon Polytechniou-
通讯作者：
Iroon Polytechniou-
碱原子自旋系综中的内自旋控制、挤压和退相干
DOI：
--
发表时间：
2014
期刊：
影响因子：
--
作者：
Leigh M. Norris
通讯作者：
Leigh M. Norris