## Quantum information: The promise

发布时间：2019-03-13 12:06:01来源：未知点击：

By Vlatko Vedral (Image: Volker Steger/Science Photo Library) Read more: “Instant Expert 33: Quantum information“ Processing information in quantum states, rather than in the electrical currents of conventional computer chips, exploits strange quantum effects such as superposition and entanglement to offer the prospect of peerlessly powerful, economical and secure number crunching. That is the well-developed theory, at least. The challenge is to make it a reality The decade or so after physicist Richard Feynman first floated the idea of a quantum computer saw the theory of quantum information bloom. 1981 Feynman argues that modelling the correlations and interactions of particles in complex quantum physics problems can only be tackled by a universal quantum simulator that exploits those same properties. 1982 The no cloning theorem threatens hopes for quantum computing. It states that you cannot copy quantum bits, so there is no way to back up information. The plus side is that this makes intercepting data difficult – a boon for secure transmission of quantum information. 1984 Charles Bennett of IBM and Gilles Brassard of the University of Montreal in Canada develop BB84, the first recipe for secure encoding and transfer of information in quantum states (see “Quantum security”, below). 1985 David Deutsch at the University of Oxford shows how a universal quantum computer might, in theory,