FORGET Dolly the sheep, the hot topic nowadays is quantum cloning. Particles such as photons and electrons have quantum properties that, according to Einstein鈥檚 theories, can never be copied exactly unless you destroy the original in the process. That鈥檚 the basis of quantum cryptography鈥攁n eavesdropper can鈥檛 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鈥檚 quantum state with 81 per cent accuracy, coming within a hair鈥檚 breadth of the theoretical limit of 83 per cent. The next step is to test whether that would be enough to crack quantum crytography codes.
