FORGET Dolly the sheep, the hot topic nowadays is quantum cloning. Particles such as photons and electrons have quantum properties that, according to Einstein’s theories, can never be copied exactly unless you destroy the original in the process. That’s the basis of quantum cryptography—an eavesdropper can’t copy your message without disrupting it and alerting you to their presence.
Dik Bouwmeester and his colleagues at Oxford University will report in a future issue of Science that they have now copied a photon’s quantum state with 81 per cent accuracy, coming within a hair’s breadth of the theoretical limit of 83…
