Superdense coding is a paradigmatic protocol in quantum information science, employing a quantum communication channel to send classical information more efficiently. As we show here, it can be understood as a particular case of a prepare and measure experiment, a scenario that has attracted growing attention for its fundamental and practical applications. Formulating superdense coding as a prepare and measure scenario allows us to provide a semi-device-independent witness of entanglement that significantly improves over previous tests. Furthermore, we also show how to adapt our results into self-testing of maximally entangled states and also provide a semidefinite program formulation allowing one to efficiently optimize, for any shared quantum state, the probability of success in the superdense coding protocol.

中文翻译：

---

超密编码中纠缠的半设备无关证书

超密集编码是量子信息科学中的一种范式协议，它利用量子通信通道更有效地发送经典信息。正如我们在此处显示的，可以将其理解为准备和测量实验的特殊情况，这种情况因其基本和实际应用而引起了越来越多的关注。将超密集编码表述为准备和测量方案，可以使我们提供与半设备无关的纠缠见证，与以前的测试相比有明显改善。此外，我们还展示了如何使我们的结果适用于最大纠缠态的自测试，还提供了一种半确定程序公式，该公式可以使任何共享的量子态有效地优化超稠密编码协议中成功的概率。