Namkung Min, Kwon Younghun
School of Applied Mathematics, National Research University Higher School of Economics, 101000 Moscow, Russia.
Department of Applied Physics, Hanyang University, Ansan, Kyunggi-Do 425-791, Korea.
Entropy (Basel). 2020 Dec 16;22(12):1422. doi: 10.3390/e22121422.
Unambiguous quantum state discrimination is a strategy where the conclusive result can always be trusted. This strategy is very important, since it can be used for various quantum information protocols, including quantum key distribution. However, in the view of quantumness, it is not clear what is going on in performing unambiguous quantum state discrimination. To answer the question, we investigate coherence distribution when unambiguous discrimination is performed by generalized measurement. Specially, we study coherence distribution in three cases, which consist of unambiguous quantum state discrimination, sequential quantum state discrimination, and assisted optimal discrimination, which are considered to be a family of unambiguous quantum state discrimination. In this investigation, we show that the structure of generalized measurements performing various types of unambiguous quantum state discrimination can be understood in terms of coherence distribution. Our result is not limited to the discrimination of two pure quantum states, but it is extended to the discrimination of two mixed states.
无歧义量子态判别是一种其结论性结果总能被信赖的策略。该策略非常重要，因为它可用于各种量子信息协议，包括量子密钥分发。然而，从量子性的角度来看，在执行无歧义量子态判别时究竟发生了什么尚不清楚。为回答这个问题，我们研究通过广义测量进行无歧义判别时的相干分布。具体而言，我们研究三种情况下的相干分布，这三种情况包括无歧义量子态判别、顺序量子态判别和辅助最优判别，它们被视为一族无歧义量子态判别。在这项研究中，我们表明执行各种类型无歧义量子态判别的广义测量的结构可以根据相干分布来理解。我们的结果不仅限于两个纯量子态的判别，还扩展到了两个混合态的判别。
