IT IS HARD to choose one moment as marking the birth of a technology. But by one common reckoning, quantum computing will be 40 next year. In 1981 Richard Feynman, an American physicist, spoke at a computing conference, observing that "Nature isn't classical, dammit, and if you want to make a simulation of nature, you'd better make it quantum mechanical, and by golly it's a wonderful problem, because it doesn't look so easy." Entering middle age, quantum computing is at last becoming a commercial proposition (see Science and technology section). Until recently the consensus was that practical applications would have to wait for large, stable machines, probably at least a decade away. Not everyone agrees. Venture capital is beginning to flow into companies built around quantum computers, as investors make a bold-possibly foolhardy-bet that even the limited, error-prone, unstable machines that make up the state-of-the-art today may prove commercially useful.
展开▼
