Optical switch protocol verifies entangled quantum states in real time without destroying them

The fragility and laws of quantum physics generally make the characterization of quantum systems time‑consuming. Furthermore, when a quantum system is measured, it is destroyed in the process. A breakthrough by researchers at the University of Vienna demonstrates a novel method for quantum state certification that efficiently verifies entangled quantum states in real time without destroying all available states—a decisive step forward in the development of robust quantum computers and quantum networks.