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Test: Quantum Or Not, Controversial Computer No Faster Than Normal
sciencehabit writes The D-Wave computer, marketed as a groundbreaking quantum machine that runs circles around conventional computers, solves problems no faster than an ordinary rival, a new test shows. Some researchers call the test of the controversial device, described in Science, the fairest comparison yet. "...to test D-Wave’s machine, Matthias Troyer, a physicist at the Swiss Federal Institute of Technology, Zurich, and colleagues didn't just race it against an ordinary computer. Instead, they measured how the time needed to solve a problem increases with the problem's size. That's key because the whole idea behind quantum computing is that the time will grow much more slowly for a quantum computer than for an ordinary one. In particular, a full-fledged 'universal' quantum computer should be able to factor huge numbers ever faster than an ordinary computer as the size of the numbers grow." D-Wave argues that the computations used in the study were too easy to show what its novel chips can do.
GP is actually correct. This is not even a full quantum computer.
"The D-Wave machine is not a universal quantum computer, however, but a more limited "quantum annealer."", which according to wikipedia seems to mean some sort of global minimum finder (given how to find all the local minimum solutions, find the lowest one).
With a mere 512 quibits available on the D-Wave device I'm more than willing to believe they may be still in the area of small inputs where an O(n) algorithm can still beat an O(log n) algorithm (e.g. http://cse.csusb.edu/dick/cs20... )
Do you know how to use a search engine?
Are you aware of scholar.google.com?
It's really not hard to find papers like this or this.
And yes, the Matthias Troyer who co-authored the first paper is the same guy who conducted the performance study that the /. blurb references.
That D-Wave performs quantum annealing can be regarded as settled. The only question that remains is how useful this may be.
Eight years ago everybody (myself included) thought D-Wave was a scam or just crazy. As new facts emerge smart people (such as Matthias) adjust their judgment.
It is not gate based universal quantum computing but special purpose quantum annealing.
If you accept this as a valid approach to quantum computing has certainly been the subject of much debate.
.... maybe the slahdot stub should have had a link to hear from the horse's mouth?
In this interview Matthias Troyer puts his team's results into the correct context.