Fisher information and entanglement of non-Gaussian spin states
Fisher information and entanglement of non-Gaussian spin states
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DOI：
10.1126/science.1250147
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发表时间：
2014-07-25
期刊：
影响因子：
56.9
通讯作者：
Oberthaler, Markus K.
中科院分区：
文献类型：
--
作者：
Strobel, Helmut;Muessel, Wolfgang;Oberthaler, Markus K.
纠缠是提高测量灵敏度的关键量子资源。然而，在介观原子系统中纠缠的产生仅限于高斯统计描述的压缩态。在这里，我们报告的非高斯多体纠缠态的创建和表征。我们开发了一个通用的方法来提取Fisher信息，这表明，一个经典的不稳定系统的量子动力学创建的量子态，没有自旋压缩，但仍然纠缠。提取的Fisher信息量化计量有用的纠缠，我们证实了贝叶斯相位估计与子散粒噪声灵敏度。这些方法可扩展到大粒子数，并直接适用于其他量子系统。
Entanglement is the key quantum resource for improving measurement sensitivity beyond classical limits. However, the production of entanglement in mesoscopic atomic systems has been limited to squeezed states, described by Gaussian statistics. Here, we report on the creation and characterization of non-Gaussian many-body entangled states. We develop a general method to extract the Fisher information, which reveals that the quantum dynamics of a classically unstable system creates quantum states that are not spin squeezed but nevertheless entangled. The extracted Fisher information quantifies metrologically useful entanglement, which we confirm by Bayesian phase estimation with sub-shot-noise sensitivity. These methods are scalable to large particle numbers and applicable directly to other quantum systems.