Letter: Quantum jump

Sir: John Gribbin ("Hey Presto! The quantum supercomputer", 19 November) is quite right about the enormous potential offered by quantum information technology.

But rather than lying "a decade or two down the line" quantum teleportation is a reality: the experiments, performed in Austria, were described in Nature two years ago. Similarly, our first quantum computer, a two bit device based on nuclear magnetic resonance techniques, was built in 1997, and similar devices with between two and seven bits are now being investigated all over the world.

Dr JONATHAN A JONES

Oxford Centre for Quantum Computation

Clarendon Laboratory

Oxford