论文标题
单个值得信赖的值是必要的，足以实现极端无信号相关性的量子
Single trusted qubit is necessary and sufficient for quantum realisation of extremal no-signaling correlations
论文作者
论文摘要
可以从Quantum toragtum no-Signal的理论的角度来考虑量子统计，其中没有一个或仅一定数量的量子系统被信任。在这些情况下，状态的作用分别由所谓的无信号框或无信号组合发挥。到目前为止，已经显示出在单个测量运行的通常的铃铛非本地性场景中，量子统计信息永远无法在无标志框中重现极端的非本地点。我们在这里提供了一般的禁止规则，即使允许任意顺序测量，后者也是真实的。另一方面，我们证明了一个积极的结果表明，已经一个受信任的量子量已经足以使量子理论在相应的无信号组合集中产生一个自我测试的极端点。该结果为对对手的一般信号对手提供了加密协议的安全证明的可能性。
Quantum statistics can be considered from the perspective of postquantum no-signaling theories in which either none or only a certain number of quantum systems are trusted. In these scenarios, the role of states is played by the so-called no-signaling boxes or no-signaling assemblages respectively. It has been shown so far that in the usual Bell non-locality scenario with a single measurement run, quantum statistics can never reproduce an extremal non-local point within the set of no-signaling boxes. We provide here a general no-go rule showing that the latter stays true even if arbitrary sequential measurements are allowed. On the other hand, we prove a positive result showing that already a single trusted qubit is enough for quantum theory to produce a self-testable extremal point within the corresponding set of no-signaling assemblages. This result opens up the possibility for security proofs of cryptographic protocols against general no-signaling adversaries.
