发表机构
University of Geneva; Constructor University; ETH Zurich（日内瓦大学; 康斯特鲁克特大学; 苏黎世联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究经典密码学中是否存在类似量子束缚纠缠的现象即界信息。通过证明给出两个比特和一个三进制位分布的例子，利用比较窃听者方式的差距。还表明束缚纠缠三量子比特态标准基测量非此例，其纯化态其他测量可产生界信息。
AI 中文摘要
束缚纠缠是量子理论中的一种极端不可逆性：某些态创建时需要耗费纠缠，但却无法从中提取出单态。25年前，吉辛和沃尔夫提出经典密码学是否也存在同样现象的问题。是否存在由两方和一个窃听者共享的关联，创建时耗费秘密比特但却无法提取？我们证明这种界信息存在并给出一个明确例子，即两个比特和一个三进制位的分布。证明利用了比较窃听者的两种方式之间的差距：一个在每次互信息比较中可能比另一个了解更多信息，但仍无法模拟对方的数据。我们进一步证明引发该猜想的分布，即束缚纠缠三量子比特态的标准基测量，本身并非例子：只要其创建耗费任何保密性，就能从中提取秘密密钥。相比之下，其纯化态的其他测量确实会产生界信息，即使对于其中的可分态也是如此。因此，这种类比是资源的类比，而非单个态及其测量结果的类比。
英文摘要
There exist bipartite quantum states that cost entanglement to create, yet from which no singlet can be distilled. This extreme irreversibility is known as bound entanglement. A quarter-century ago, Gisin and Wolf asked whether classical information theory admits the same phenomenon. Are there correlations, shared by two parties and an eavesdropper, that cost secret bits to create, yet from which none can be distilled? This question is part of a broader program exploring the relation between quantum and classical information theory. We answer it in the affirmative, providing a simple example, a distribution of two bits and a trit. Bound entanglement thus has a classical counterpart, bound information. An even more direct correspondence was originally conjectured, namely that measuring purifications of bound-entangled states yields distributions with bound information. The very states that motivated the conjecture, however, yield no bound information when measured in the standard basis, whereas suitable measurements of purifications of separable states do. The analogy between bound entanglement and bound information thus lies in the accounting of resources, not in a correspondence between individual quantum states and the classical probability distributions induced by measuring them.
Comments5 + 15 pages, 2 figures, 2 tables. v2: Revised presentation and expanded discussion. Added corollary establishing positive distillable key for the underlying two-qutrit states
