For a classical channel, neither the Shannon capacity, nor the sum of conditional probabilities corresponding to the cases of successful transmission can be increased by the use of shared entanglement, or, more generally, a non-signaling resource. Yet, perhaps somewhat counterintuitively, entanglement assistance can help and actually elevate the chances of success even in a one-way communicational task that is to be completed by a single-shot use of a noiseless classical channel. To quantify the help that a non-signaling resource provides to a noiseless classical channel, one might ask how many extra letters should be added to the alphabet of the channel in order to perform equally well without the specified non-signaling resource. As was observed by Cubitt, Leung, Matthews, and Winter, there is no upper bound on the number of extra letters required for substituting the assistance of a general non-signaling resource to a noiseless one-bit classical channel. In contrast, here we prove that if this resource is a bipartite quantum system in a maximally entangled state, then an extra classical bit always suffices as a replacement.

翻译：对于古典频道来说,无论是香农能力,还是与成功传输案例相对应的有条件概率总和,都无法通过使用共同缠绕或更一般地说,非信号资源来增加成功的可能性。 然而,也许有些反直觉的纠缠援助可以帮助和实际上提升成功机会,即使是单向通信任务,而单向使用无噪音古典频道完成单向通信任务。为了量化非信号资源为无噪音古典频道提供的帮助,人们可能会问道频道的字母字母字母中应增加多少个,以便在没有指定非信号资源的情况下同样顺利地运行。正如库比特、良、马修斯和温特所观察的那样,将一般非信号资源的援助替换为没有噪音的古典频道所需的额外字母数量没有上限。与此形成对比的是,我们在这里证明,如果这一资源在最紧密缠绕的状态下是双向量子系统,那么额外的古典部分总是足以替代。