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arXiv 1004.0888quant-ph
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测量受限信道鉴别中的纠缠

Entanglement in channel discrimination with restricted measurements

William Matthews, Marco Piani, John Watrous

摘要:

研究了在量子信道鉴别的情况下,局域量子操作和经典通信(简称LOCC测量)可实现的测量功率。更确切地说,我们考虑的歧视程序,试图确定一个未知的渠道,统一选择从两个已知的替代品,采取以下形式:(i)在与辅助系统的可能纠缠状态中准备未知信道的输入,(ii)将未知信道应用于输入系统,以及(iii)在输出和辅助系统上执行LOCC测量,从而导致猜测给出了两个信道中的哪一个。在这样的过程中的测量的限制是LOCC测量是感兴趣的,因为它隔离了初始输入/辅助系统中的纠缠作为信道鉴别设置中的资源。我们证明,存在通道歧视的问题,这种限制程序可以在两个极端:他们可能是最佳的所有歧视程序的集合内(并同时优于所有的策略,使不使用纠缠),或者他们可能不会比未纠缠的策略(并同时次优的所有歧视程序的集合内)。

英文摘要:

We study the power of measurements implementable with local quantum operations and classical communication (or LOCC measurements for short) in the setting of quantum channel discrimination. More precisely, we consider discrimination procedures that attempt to identify an unknown channel, chosen uniformly from two known alternatives, that take the following form: (i) the input to the unknown channel is prepared in a possibly entangled state with an ancillary system, (ii) the unknown channel is applied to the input system, and (iii) an LOCC measurement is performed on the output and ancillary systems, resulting in a guess for which of the two channels was given. The restriction of the measurement in such a procedure to be an LOCC measurement is of interest because it isolates the entanglement in the initial input/ancillary systems as a resource in the setting of channel discrimination. We prove that there exist channel discrimination problems for which restricted procedures of this sort can be at either of the two extremes: they may be optimal within the set of all discrimination procedures (and simultaneously outperform all strategies that make no use of entanglement), or they may be no better than unentangled strategies (and simultaneously sub-optimal within the set of all discrimination procedures).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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