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Quantum Computing: A view from the enemy camp

Posted by chrisd on from the to-be-or-entropy dept.

SIGFPE writes "There seems to be an unthinking acceptance by many people that quantum computers are now on their unstoppable way up and before too long we'll be cracking RSA and simulating protein folding on complex quantum computers. However there is another point of view that considers quantum computers to be as difficult to make as perpetual motion machines - and for much the same reason: entropy. As an antidote to all the successes that have been reported on /. here is a just published and highly readable preprint by a sceptical mathematical physicist."

1 of 36 comments (clear)

  1. Achieveable accuracy by tony_gardner · · Score: 3, Informative

    An interesting article, but it seems to rely on several strange arguments. I wouldn't agree that the accuracies required in manufacture and operation are not achieveable. It would seem to me that a fabrication accuracy of 1 part in 10^5 is scarcely unachieveable, especially since we have everyday devices, for example LCD monitors in which less than 1 pixel in 1 million is dead, and those are consumer products.

    I don't necessarily buy his argument about the inherent fault-intolerence of quantum computing either, since it relies on the idea that a simple computer with no fault tolerence built in is fault intolerant! Scarcely a surprise. He didn't make a convincing argument that building in fault tolerance is impossible, only that it isn't being done in the simple designs he notes. Maybe I've misunderstood, but it would seem that this is an avenue for more research, rather than less.

    It seems to me that in the end the whole of his argument relies on the engineering argument that we don't at present have any way to measure large numbers of single spin states (or indeed any single spin state). This would seem again to be an argument for more research, rather than less, since engineering serendipity is not a predictable mathematical process.

    I understand his frustration that quantum computing is taking a lot of research funding from other areas, but I'd be a little more cautious than he is about saying that it definitely _can't_ work.