Entropic Uncertainty for Biased Measurements
Entropic Uncertainty for Biased Measurements
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DOI：
10.1109/qce57702.2023.00138
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
Walter O. Krawec
中科院分区：
文献类型：
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作者：
Walter O. Krawec
熵不确定性关系是强大的工具，尤其在量子密码学领域。它们通常会限制由于测量重叠，第三方对手对测量结果可能持有的不确定程度。然而，当两个测量基相互存在偏差时，标准的熵不确定性关系并不总能为熵提供最优下限。在此，我们针对特定量子态推导出一种新的熵不确定性关系，即便两个测量基不再相互无偏，该关系也能给出显著更高的下限。我们在两种不同的量子密码协议（包括测量设备存在故障/偏差的BB84协议）上评估了我们给出的下限，并表明，与先前使用标准熵不确定性关系的研究相比，在多种情形下，我们的新下限能产生显著更高的密钥生成率。
Entropic Uncertainty relations are powerful tools, especially in quantum cryptography. They typically bound the amount of uncertainty a third-party adversary may hold on a measurement outcome as a result of the measurement overlap. However, when the two measurement bases are biased towards one another, standard entropic uncertainty relations do not always provide optimal lower bounds on the entropy. Here, we derive a new entropic uncertainty relation, for certain quantum states, which can provide a significantly higher bound even if the two measurement bases are no longer mutually unbiased. We evaluate our bound on two different quantum cryptographic protocols, including BB84 with faulty/biased measurement devices, and show that our new bound can produce substantially higher key-rates under several scenarios when compared with prior work using standard entropic uncertainty relations.