Semantic Quantum Communication: Merging Semantic Extraction with Quantum Security for Efficient Secure Transmission.

Quantum secure direct communication (QSDC), a paradigm-shifting breakthrough in quantum communication, exploits quantum states for unmediated information transmission. Rooted in the inviolable fundamental laws of quantum mechanics, QSDC enables ultrasensitive detection of even the faintest eavesdropping attempts, guaranteeing true communication security solely when no interference exists. However, its practical scalability remains constrained by insufficient transmission rates. Semantic communication, which drastically boosts transmission efficiency by extracting core information features, nevertheless stays vulnerable to malicious intrusions. Integrating these paradigms promises to simultaneously enhance the equivalent data rate and security. Herein, we propose and experimentally validate a quantum semantic communication scheme, applying it to 3-dimensional point clouds. It achieves a 46.30-fold efficiency gain over direct transmission in the meaning domain, beyond the Wyner and Shannon capacity limits of syntactic communication. This breakthrough not only broadens the application scope of QSDC with limited bandwidth, but also marks a pivotal milestone in quantum information science.