1981年N.赫伯特提出了一个gedanken实验，以实现“第一个激光放大超光速连接”（FLASH）通过量子非局域性比光通信（FTL）更快。目前的工作报告了该提议的第一个实验实现，即通过光学参量放大属于纠缠EPR对的单个光子进入涉及5 x 10^3个光子的输出场。一个彻底的理论和实验分析解释了一般和结论性的确切原因，失败的FLASH计划，以及任何类似的超光速建议。
英文摘要：
In 1981 N. Herbert proposed a gedanken experiment in order to achieve by the ''First Laser Amplified Superluminal Hookup'' (FLASH) a faster than light communication (FTL) by quantum nonlocality. The present work reports the first experimental realization of that proposal by the optical parametric amplification of a single photon belonging to an entangled EPR pair into an output field involving 5 x 10^3 photons. A thorough theoretical and experimental analysis explains in general and conclusive terms the precise reasons for the failure of the FLASH program as well as of any similar FTL proposals.
A proposal for a feasible quantum-optical experiment to test the validity of the No-Signaling Theorem
受Greenberger [Physica Scripta T76，p.57（1998）]关于超光速信号的提议的启发，并受Zou，Wang和Mandel [Phys. Rev. Lett. 67，p.318（1991）]显示在没有符合检测的多粒子纠缠中的干涉效应，我们提出了一个可行的量子光学方案，该方案旨在表明远距离双方之间的信息超光速传输能力
One of the fundamental restrictions that quantum mechanics imposes is the "No deletion Theorem" which tells us that given two identical unknown quantum states, it is impossible to delete one of them. But nevertheless if not perfect, people have tried to delete it approximately. In these approximate deleting processes our basic target is to delete one of the two identical copies as much as possible while preserving the other copy. In this brief report, by using the No communication theorem (NCT) (impossibility of sending signal faster than light using a quantum resource) as a guiding principle,…
A crucial task for secure communication networks is to determine the minimum of physical requirements to certify a cryptographic protocol. A widely accepted candidate for certification is the principle of relativistic causality which is equivalent to the disallowance of causal loops. Contrary to expectations, we demonstrate how correlations allowed by relativistic causality could be exploited to break security for a broad class of multi-party protocols (all modern protocols belong to this class). As we show, deep roots of this dramatic lack of security lies in the fact that unlike in previous …
Recently, a group of experiments tested local realism with random choices prepared by humans. These various tests were subject to additional assumptions, which lead to loopholes in the interpretations of almost all of the experiments. Among these assumptions are fair sampling, no signaling, and faithful reproduction of a Bell-type quantum model. We examined the data from 9 of 13 experiments and analyzed occurring anomalies in view of the above assumptions. We conclude that further tests of local realism need better setup calibration to avoid apparent signaling or necessity of the complicated u…
