AI 中文总结
研究纠缠辅助通信中，虽跨信道使用相关性不提升最终速率，但能增强可靠性。通过证明Petz-Rényi信道信息对特定α严格超可加，实现纠缠辅助随机编码错误指数多副本增强，且无需传输系统间纠缠。
AI 中文摘要
量子信道的纠缠辅助容量具有单字母加性特征，这意味着跨信道使用的联合编码不会提高最终通信速率。但本文表明这种加性情况不适用于通信可靠性。具体而言，证明了对于每个α∈[1/2,1)，Petz-Rényi信道信息可以严格超可加，这产生了纠缠辅助随机编码错误指数的真正多副本增强，尽管纠缠辅助容量仍是加性的。对于测量信道已通过分析确定了此现象，其是纠缠破缺且有无辅助加性容量的。值得注意的是，这种严格超可加性由可分离的、经典相关的双副本信道输入边缘见证，表明传输系统之间无需纠缠。我们的结果表明，虽然跨信道使用的相关性不会提高纠缠辅助通信的最终速率，但可以增强其可靠性。
英文摘要
The entanglement-assisted capacity of a quantum channel admits an additive single-letter characterization, implying that joint encodings across channel uses cannot increase the ultimate communication rate. Here, we show that this additive picture does not extend to communication reliability. Specifically, we prove that the Petz-Rényi channel information can be strictly superadditive for every $α\in[1/2,1)$, yielding a genuine multi-copy enhancement of the entanglement-assisted random-coding error exponent, even though the entanglement-assisted capacity remains additive. We establish this phenomenon analytically already for measurement channels, which are entanglement-breaking and have additive unassisted capacity. Remarkably, this strict superadditivity is witnessed by a separable, classically correlated two-copy channel-input marginal, demonstrating that no entanglement between the transmitted systems is required. Our results show that, although correlations across channel uses cannot increase the ultimate rate of entanglement-assisted communication, they can enhance its reliability.
