Computing: Quantum bits and silicon chips.

Quantum computers offer a new kind of processing power. Silicon chips are easy to manufacture. Scientists are trying to take advantages of the two approaches through their combination. A materials scientist at University College in London, England, Marshall Stoneham is using his experience in semiconductors to marry the worlds of silicon chips and quantum computing. Like all quantum computers, Stoneham's design shares a common feature with conventional processors, both carry out calculations by manipulating bits of information, the ones and zeros of binary code. The simplest operation involves flipping the value of a bit, so that 1 becomes 0 or vice versa. More complex operations involve two bits. One bit may be flipped if the value of a second bit is 0, for example, but not if it is 1. In principle, quantum devices work in the same way. But they also take advantage of the rules of quantum mechanics, which say that particles can exist in two states simultaneously.