Wiring up quantum circuits with light: Researchers entangled microwave and optical photons for the first time

The number of qubits in superconducting quantum computers has risen rapidly during the last years, but further growth is limited by the need for ultra-cold operating temperatures. Connecting several smaller processors could create larger, more computationally powerful quantum computers -- however doing so poses new challenges. Researchers have now demonstrated quantum entanglement between optical and microwave photons that could lay the foundation for such a future quantum network.