Quantum measurements of atoms using cavity QED
Quantum measurements of atoms using cavity QED
复制标题
DOI：
10.1103/physreva.83.042339
复制
发表时间：
2011-04-29
影响因子：
2.9
通讯作者：
Everitt, Mark S.
中科院分区：
文献类型：
--
作者：
Dada, Adetunmise C.;Andersson, Erika;Everitt, Mark S.
广义量子测量是射影测量或冯·诺伊曼测量的重要扩展，因为它们可以用来描述任何可以在量子系统上实现的测量。描述了如何利用腔QED实现两种非标准量子测量。第一种测量最优且明确地区分了两个非正交量子态。第二个例子是演示超加性量子编码增益的测量。使用的实验工具是受拉姆齐脉冲和两原子塔维斯-卡明斯相互作用影响的单原子单一运算。我们展示了超加性量子编码增益如何受到原子场电离检测误差的影响，并且即使具有相当高的实验缺陷，仍然可以看到合理数量的超加性。到目前为止，这些类型的测量只在光子上实现。使用其他物理系统实现将是非常有趣的。这是出于基本原因，但也因为量子编码的增益通常随着码字长度的增加而增加，而且使用原子的实现比使用光子的实现更容易缩放。
Generalized quantum measurements are an important extension of projective or von Neumann measurements in that they can be used to describe any measurement that can be implemented on a quantum system. We describe how to realize two nonstandard quantum measurements using cavity QED. The first measurement optimally and unambiguously distinguishes between two nonorthogonal quantum states. The second example is a measurement that demonstrates superadditive quantum coding gain. The experimental tools used are single-atom unitary operations effected by Ramsey pulses and two-atom Tavis-Cummings interactions. We show how the superadditive quantum coding gain is affected by errors in the field-ionization detection of atoms and that even with rather high levels of experimental imperfections, a reasonable amount of superadditivity can still be seen. To date, these types of measurements have been realized only on photons. It would be of great interest to have realizations using other physical systems. This is for fundamental reasons but also since quantum coding gain in general increases with code word length, and a realization using atoms could be more easily scaled than existing realizations using photons.