Fatally linked photons. A new scheme allows such pairs to be reused in interactions that would normally destroy their entanglement. Researchers have dreamed up many other uses for quantum entanglement, including computers that use quantum states instead of ones and zeros. All such schemes destroy the entanglement that they process. With such recycling, maneuvers in quantum computing or cryptography might require fewer entangled pairs in order to operate.
Entanglement is an important aspect of quantum weirdness.
Two entangled particles exist in a single quantum state even though one measures them as separate particles at different locations. They are correlated like two coins which somehow always come out opposite one another, even though each coin flip is completely random by itself. For example, researchers can create a pair of photons in which one photon is horizontally polarized and the other vertically polarized, but in which they can't predict the state of a specific photon. Most of these schemes require fully entangled pairs of photons or other particles. Alice and Bob can apply the catalyst to each partially entangled pair and convert more of them to full entanglement than they could without the catalyst, so they waste fewer pairs.