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arXiv 1003.0716quant-ph
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测量后信息在状态判别中的应用

Using post-measurement information in state discrimination

Deepthi Gopal, Stephanie Wehner

摘要:

我们考虑一种特殊形式的状态歧视,在测量后,我们得到了额外的信息,可以帮助我们识别状态。这个任务在分析噪声存储模型中的量子密码协议中起着核心作用,其中状态的身份对应于某个位串,并且附加信息通常是作弊方最初未知的编码选择。我们首先提供简单的最优性条件的测量任何这样的问题,并显示上界和下界的成功概率。对于某一类问题,我们还提供了严格的界限如何有用的测量后的信息可以。特别是,我们表明,对于这个类找到最佳的测量后测量信息的状态歧视的任务,实际上减少到解决一个不同的问题,状态歧视没有这样的信息。然而,我们表明,相应的经典状态歧视问题与测量后的信息,这样的减少是不可能的,通过有关的成功概率违反贝尔不等式。这表明测量后的信息是区分经典世界和量子世界的另一个特征。

英文摘要:

We consider a special form of state discrimination in which after the measurement we are given additional information that may help us identify the state. This task plays a central role in the analysis of quantum cryptographic protocols in the noisy-storage model, where the identity of the state corresponds to a certain bit string, and the additional information is typically a choice of encoding that is initially unknown to the cheating party. We first provide simple optimality conditions for measurements for any such problem, and show upper and lower bounds on the success probability. For a certain class of problems, we furthermore provide tight bounds on how useful post-measurement information can be. In particular, we show that for this class finding the optimal measurement for the task of state discrimination with post-measurement information does in fact reduce to solving a different problem of state discrimination without such information. However, we show that for the corresponding classical state discrimination problems with post-measurement information such a reduction is impossible, by relating the success probability to the violation of Bell inequalities. This suggests the usefulness of post-measurement information as another feature that distinguishes the classical from a quantum world.

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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