Researchers at IST Austria have demonstrated for the first time the deterministic generation of entanglement between optical and microwave photons (arXiv:2301.03315). Together with their colleagues from TU Wien, they have verified quantum correlations between microwave photons inside a diluation refigerator and propagating optical photons. This is a first key step toward building scalable quantum networks where superconducting quantum process operated at mK temperatures are connected via optical fibers.
