Quantum Speedup Found for Class of Hard Problems

For computer scientists, solving problems is a bit like mountaineering. First they must choose a problem to solve — akin to identifying a peak to climb — and then they must develop a strategy to solve it. Classical and quantum researchers compete using different strategies, with a healthy rivalry between the two. Quantum researchers report a fast way to solve a problem — often by scaling a peak that no one thought worth climbing — then classical teams race to see if they can find a better way. This contest almost always ends as a virtual tie: When researchers think they’ve devised a quantum algorithm that works faster or better than anything else, classical researchers usually come up with one that equals it. Just last week, a purported quantum speedup, published in the journal Science, was met with immediate skepticism from two separate groups who showed how to perform similar calculations on classical machines. But in a paper posted on the scientific preprint site arxiv.org last ye ... Read full article.