Genuine certification of incompatible quantum instruments through sequential communication tasks
Proving quantum devices work in fundamentally non-classical ways through message-passing games
Researchers designed communication tasks that can definitively prove when two quantum devices are genuinely incompatible — meaning they cannot both operate simultaneously in the same quantum system. The proof works without needing to know the internal details of the devices, and reveals a new way quantum systems outperform classical ones in communication tasks.
Certifying that quantum devices are truly incompatible is essential for building quantum technologies that exploit nonclassical effects. This method works even when the individual measurements and operations within those devices appear compatible on their own, catching genuine quantum behavior that simpler tests would miss. It provides a practical way to verify quantum advantage in real systems without assuming the devices work perfectly.