A silicon chip about the size of a penny that uses photons to run Shor's algorithm has been developed by a team of researchers at the University of Bristol in the United Kingdom. Up to now, laboratory-sized optical computers have been required to run the algorithm, which computes the two numbers that multiply together to produce a given figure. Factoring large numbers is impractical for traditional or classical computers, but quantum computers can execute this task easily, at least in principle.
Optical computing, in which photons, rather than electrons, carry information, has been promoted as a potential future for data processing. But photons also have quantum indeterminacy, which means they can represent multiple states concurrently. The Bristol team uses waveguides — channels etched into the chips that provide a path for the photons around the chips — to effect quantum factoring on a much smaller scale than has been required up to now.
"To get a useful computer it needs to be probably a million times more complex, so a full-scale useful factoring machine is still at least two decades away," says Bristol professor and team leader Jeremy O'Brien. "But this [chip] is one important step in that direction."
From BBC News
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