Twenty years before most scientists expected it, a commercial company has announceda quantum computer that promises to massively speed up searches and optimisation calculations. D-Wave of British Columbia has promised to demonstrate a quantum computer next Tuesday, that can carry out 64,000 calculations simultaneously (in parallel "universes"), thanks to a new technique which rethinks the already-uncanny world of quantum computing. But the academic world is taking a wait-and-see approach. D-Wave is the world's only "commercial" quantum computing company, backed by more than $20 million of venture capital (there are more commercial ventures in the related field of quantum cryptography). Its...