Local unambiguous discrimination of symmetric ternary states
Local unambiguous discrimination of symmetric ternary states
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DOI：
10.1103/physreva.99.022316
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发表时间：
2018-06
影响因子：
2.9
通讯作者：
K. Nakahira;Kentaro Kato;T. Usuda
中科院分区：
文献类型：
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作者：
K. Nakahira;Kentaro Kato;T. Usuda
我们调查明确的歧视与顺序测量，这是限制在本地测量和单向经典通信之间的给定量子态。如果给定的状态是二进制的，或者每个系统都是二维的，那么在某些情况下，顺序测量是否达到全局最优的无模糊测量是已知的。相比之下，对于两个以上的状态，每个状态的单个系统都是二维的，问题变得非常复杂。本文主要研究对称三元纯态，其中每个系统都是三维的，包括相移键控（PSK）光相干态和提升版本的“双三位一体”状态。我们提供了一个必要和充分条件的最佳顺序测量是全局最优的二分的情况下。给出了多体状态全局最优性的一个充分条件。人们可以很容易地判断这些条件是否适用于给定的状态。给出了一些例子，这表明，尽管局部测量和单向经典通信的限制，顺序测量可以在相当多的情况下是全局最优的。
We investigate unambiguous discrimination between given quantum states with a sequential measurement, which is restricted to local measurements and one-way classical communication. If the given states are binary or those each of whose individual systems is two-dimensional, then it is in some cases known whether a sequential measurement achieves a globally optimal unambiguous measurement. In contrast, for more than two states each of whose individual systems is more than two-dimensional, the problem becomes extremely complicated. This paper focuses on symmetric ternary pure states each of whose individual systems is three-dimensional, which include phase shift keyed (PSK) optical coherent states and a lifted version of "double trine" states. We provide a necessary and sufficient condition for an optimal sequential measurement to be globally optimal for the bipartite case. A sufficient condition of global optimality for multipartite states is also presented. One can easily judge whether these conditions hold for given states. Some examples are given, which demonstrate that, despite the restriction to local measurements and one-way classical communication, a sequential measurement can be globally optimal in quite a few cases.