全光与电光量子极限反馈之比较
摘要
全光反馈可通过将源腔的输出经法拉第隔离器送入第二腔来实现，该第二腔通过非线性晶体与源腔耦合。若被驱动腔被强阻尼，则可绝热消去，并单独导出第一腔的主方程或量子朗之万方程。此推导针对任意状态的输入浴以及任意非线性耦合进行。若腔间耦合仅涉及被驱动腔的强度（或某一正交分量），则其对源腔的作用与利用直接（或零差）探测的电光反馈所得效果相同。若耦合涉及两个正交分量，此等价不再成立，且关于源振幅线性的耦合可在源腔中产生非经典态。使用外差探测的类似电光方案会引入额外噪声，阻碍非经典光的产生。与电光情形不同，全光反馈环路具有输出光束（从第二腔反射）。我们表明，即使源腔保持经典态，该输出也可能被压缩。
引用
@article{arxiv.quant-ph/0409050,
title = {All-optical versus electro-optical quantum-limited feedback},
author = {H. M. Wiseman and G. J. Milburn},
journal= {arXiv preprint arXiv:quant-ph/0409050},
year = {2009}
}
备注
21 pages. This is an old (1994) paper, but one which I thought was worth posting because in addition to what is described in abstract it has: (1) the first formulation (to my knowledge) of quantum trajectories for an arbitrary (i.e. squeezed, thermal etc.) broadband bath; (2) the prediction of a periodic modification to the detuning and damping of an oscillator for the simplest sort of all-optical feedback (i.e. a mirror) as seen in the recent experiment "Forces between a Single Atom and Its Distant Mirror Image", P. Bushev et al, Phys. Rev. Lett. 92, 223602 (2004)