Quantum process discrimination with restricted strategies
Quantum process discrimination with restricted strategies
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DOI：
10.1103/physreva.104.062609
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发表时间：
2021-04
影响因子：
2.9
通讯作者：
K. Nakahira
中科院分区：
文献类型：
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作者：
K. Nakahira
量子过程（包括量子态、通道和超通道）的鉴别是量子信息理论中的一个基本课题。当鉴别策略被限制在量子力学允许的所有策略的给定子集时，分析可以实现的最佳性能通常是有趣的。本文给出了一个一般形式的任务，寻找最大的成功概率判别量子过程作为凸优化问题的拉格朗日对偶问题显示零对偶间隙。所提出的公式可以适用于任何限制策略。我们还得到了一个最优的限制策略是最优的所有策略的集合内的必要条件和充分条件。我们提供了一个简单的例子，在这个例子中，由我们的公式给出的对偶问题比原来的问题更容易解决。我们还表明，每个限制过程歧视问题的最佳性能可以写在一定的鲁棒性措施。这一发现有可能提供更深入的了解各种限制策略的歧视性能。
The discrimination of quantum processes, including quantum states, channels, and superchannels, is a fundamental topic in quantum information theory. It is often of interest to analyze the optimal performance that can be achieved when discrimination strategies are restricted to a given subset of all strategies allowed by quantum mechanics. In this paper, we present a general formulation of the task of finding the maximum success probability for discriminating quantum processes as a convex optimization problem whose Lagrange dual problem exhibits zero duality gap. The proposed formulation can be applied to any restricted strategy. We also derive necessary and sufficient conditions for an optimal restricted strategy to be optimal within the set of all strategies. We provide a simple example in which the dual problem given by our formulation can be much easier to solve than the original problem. We also show that the optimal performance of each restricted process discrimination problem can be written in terms of a certain robustness measure. This finding has the potential to provide a deeper insight into the discrimination performance of various restricted strategies.