Achieving minimum-error discrimination of an arbitrary set of laser-light pulses
Achieving minimum-error discrimination of an arbitrary set of laser-light pulses
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DOI：
10.1103/physreva.87.052320
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发表时间：
2013-05-23
影响因子：
2.9
通讯作者：
Dutton, Zachary
中科院分区：
文献类型：
--
作者：
da Silva, Marcus P.;Guha, Saikat;Dutton, Zachary
激光被广泛用于通信和传感应用，因此相干态（理想激光器发出的光的量子态）的最佳鉴别具有巨大的实际意义。由于量子力学的基本限制，这种区分具有有限的最小错误概率。虽然用于两个相干态之间的最佳区分的具体光学电路是众所周知的，但推广到更大的相干态集合一直是具有挑战性的。在本文中，我们展示了如何使用资源有效的量子计算机来实现对任何相干态集的最佳区分。我们的构建利用了最近关于区分多拷贝量子假设的结果[Blume-Kohout，Croke和Zwolak，arXiv：1201.6625]。作为说明性的例子，我们分析了性能的歧视一个三元字母表，并显示如何的量子电路的接收器设计来区分一个二进制字母表可以重复使用在歧视多模假设。最后，我们表明，我们的结果可以用来实现量子限制的速率上的经典信息传输的有损光信道，这是已知的超过香农率的所有传统的光接收机。
Laser light is widely used for communication and sensing applications, so the optimal discrimination of coherent states-the quantum states of light emitted by an ideal laser-has immense practical importance. Due to fundamental limits imposed by quantum mechanics, such discrimination has a finite minimum probability of error. While concrete optical circuits for the optimal discrimination between two coherent states are well known, the generalization to larger sets of coherent states has been challenging. In this paper, we show how to achieve optimal discrimination of any set of coherent states using a resource-efficient quantum computer. Our construction leverages a recent result on discriminating multicopy quantum hypotheses [Blume-Kohout, Croke, and Zwolak, arXiv:1201.6625]. As illustrative examples, we analyze the performance of discriminating a ternary alphabet and show how the quantum circuit of a receiver designed to discriminate a binary alphabet can be reused in discriminating multimode hypotheses. Finally, we show that our result can be used to achieve the quantum limit on the rate of classical information transmission on a lossy optical channel, which is known to exceed the Shannon rate of all conventional optical receivers.