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Laser Links Give Aging Supercomputers a Second Wind

Free-space optics help old computers learn new tricks

3 min read
Laser Links Give Aging Supercomputers a Second Wind
Photo: iStockphoto

The speed of high-performance computing has soared from around 100 gigaflops in 1993 to over 50 petaflops today and is on course to hit the long-sought exascale (1018 floating-point operations per second) mark in the 2020s. Yet this remarkable supercomputing progress can be something of a super nightmare for the institutes and government agencies asked to invest the hundreds of millions, even billions of dollars that leading systems can cost.

“We are achieving a 1,000[-fold] improvement over 10 years, so after just 5 years a conventional supercomputer is no longer able to perform (at the necessary standard) and has to be trashed,” says Michihiro Koibuchi, a systems architect at Japan’s National Institute of Informatics, in Tokyo. Koibuchi and his colleagues think they have a solution that will let users get more out of older machines: free-space optics, lasers that link supercomputer nodes through the air.

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Quantum Error Correction: Time to Make It Work

If technologists can’t perfect it, quantum computers will never be big

13 min read
Quantum Error Correction: Time to Make It Work
Chad Hagen

Dates chiseled into an ancient tombstone have more in common with the data in your phone or laptop than you may realize. They both involve conventional, classical information, carried by hardware that is relatively immune to errors. The situation inside a quantum computer is far different: The information itself has its own idiosyncratic properties, and compared with standard digital microelectronics, state-of-the-art quantum-computer hardware is more than a billion trillion times as likely to suffer a fault. This tremendous susceptibility to errors is the single biggest problem holding back quantum computing from realizing its great promise.

Fortunately, an approach known as quantum error correction (QEC) can remedy this problem, at least in principle. A mature body of theory built up over the past quarter century now provides a solid theoretical foundation, and experimentalists have demonstrated dozens of proof-of-principle examples of QEC. But these experiments still have not reached the level of quality and sophistication needed to reduce the overall error rate in a system.

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