Quantum process tomography with coherent states
Quantum process tomography with coherent states
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DOI：
10.1088/1367-2630/13/1/013006
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发表时间：
2010-09
影响因子：
3.3
通讯作者：
S. Rahimi-Keshari;A. Scherer;A. Mann;A. Rezakhani;A. Lvovsky;B. Sanders
中科院分区：
文献类型：
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作者：
S. Rahimi-Keshari;A. Scherer;A. Mann;A. Rezakhani;A. Lvovsky;B. Sanders
我们发展了一种基于仅用相干态探测未知量子过程来表征量子光学过程的增强技术。我们的方法极大地改进了原始建议(Lobino等人2008 Science 322 563)，该建议使用过滤后的Glauber-suarshan分解来确定该过程对任意状态的影响。我们引入了一般量子过程对相干态输入的作用和它对任意量子态的作用之间的一种新的关系。这种关系消除了调用状态的Glauber-Sudarshan表示的需要；因此，它极大地简化了过程识别的任务，并消除了潜在的错误来源。这种新的关系也使得该方法能够直接扩展到多模式和非轨迹保持过程。我们用几个例子来说明我们的形式，在这些例子中，我们推导了在Fock基下的几个基本量子光学过程的解析表示。特别是，我们引入了光子数截止作为一个合理的物理资源限制，并在实际应用中解决了资源与精度之间的权衡。结果表明，过程估计的精度与光子数截止值的平方根成反比。
We have developed an enhanced technique for characterizing quantum optical processes based on probing unknown quantum processes only with coherent states. Our method substantially improves the original proposal (Lobino et al 2008 Science 322 563), which uses a filtered Glauber–Sudarshan decomposition to determine the effect of the process on an arbitrary state. We introduce a new relation between the action of a general quantum process on coherent state inputs and its action on an arbitrary quantum state. This relation eliminates the need to invoke the Glauber–Sudarshan representation for states; hence, it dramatically simplifies the task of process identification and removes a potential source of error. The new relation also enables straightforward extensions of the method to multi-mode and non-trace-preserving processes. We illustrate our formalism with several examples, in which we derive analytic representations of several fundamental quantum optical processes in the Fock basis. In particular, we introduce photon-number cutoff as a reasonable physical resource limitation and address resource versus accuracy trade-off in practical applications. We show that the accuracy of process estimation scales inversely with the square root of photon-number cutoff.