D-wave claims to have built 128 qbit quantum computers which are commercially available?

What I don't understand is that have they really been able to do this given that the scientific community is still struggling to make a quantum computer realizable (from what I have gathered)?

If yes, then it means that they have solved many problems and have actually hit a milestone. Isn't that a really big event?

If no, then how has Google and NASA ordered a 512 qbit quantum computer from D-Wave? Corporations like Google will not invest $10 million if it didn't see something in it. Lokheed Martin bought the 128 qbit one for roughly the same price. How has nobody opened it up and shown that its not a quantum computer (maybe this is a naive question, but nevertheless)?

Also see: http://spectrum.ieee.org/tech-talk/computing/hardware/google-and-nasa-buy-a-dwave-computer

The related question What can the D-Wave quantum computer do? is not in the light of the recent events which seem to give D-Wave more credibility, does not discuss why this is or is not a big event in the scientific community and was asked at a time when critism was all that was there. Quoting the wikipedia page on D-Wave:

"MIT professor Scott Aaronson, self-described "Chief D-Wave Skeptic", originally said that D-Wave's demonstrations did not prove anything about the workings of the computer. He said that a useful quantum computer would require a huge breakthrough in physics, which has not been published or shared with the physics community. Aaronson has since updated his views on his blog, announcing that he was "retiring as Chief D-wave Skeptic" in 2011, and reporting his "skeptical but positive" views based on a visit to D-Wave in February 2012"

  • $\begingroup$ I hope I can ask this here on this forum, since it is a physics-news question. I know that there is no better place to ask. The question seems to be important! $\endgroup$
    – Man
    May 27, 2013 at 15:14
  • 1
    $\begingroup$ Note that NASA also has a "scientist" on their payroll who is building a warp drive/time machine. Government spending is by no means an indication of intelligence. $\endgroup$
    – user10851
    May 27, 2013 at 15:51
  • $\begingroup$ Certainly not my work, but this should be the "canonical answer" to this question: scottaaronson.com/blog/?p=1400 ... In fact, though, I think it's author has posted here from time to time; paging Dr. @ScottAaronson :) $\endgroup$
    – wsc
    May 27, 2013 at 15:58
  • $\begingroup$ What do you mean by "work"? They certainly can't factor any number too large to be factored by classical computers. They do seem to be doing something like what D-Wave claims they are doing; D-Wave calls this quantum annealing, and it is very time-consuming to simulate classically (for stochastic Hamiltonians, which is all that D-Wave's machines can do so far, it may be polynomially simulible, but with a huge blow-up in time). However, whether this gives them the ability to solve any useful problems faster than classical computers is still an unanswered question. $\endgroup$ May 27, 2013 at 18:31
  • $\begingroup$ @ Peter Shor: by work I mean use the principles of quantum computing for running, have the advantage that we expect as compared to a classical computer having same number of qbits. $\endgroup$
    – Man
    May 27, 2013 at 18:47

1 Answer 1


I think the current opinion is that D-Wave have demonstrated some quantum computing abilities but not all the features that a Quantum computer could be capable of. Their current system also performs the specific calculation ( a simulated annealing) slower than a conventional computer can.

That said - they are a genuine effort and certainly not cold-fusion/perpetual motion snake oil con.

Remember when government organisations like Nasa and pseudo-government outfits like major defense companies invest in something it can be for more political reasons that the actual deliverables. Or less cynically, that they are investing in the future.

  • $\begingroup$ Investing in the Canadian future >_> $\endgroup$
    – wsc
    May 27, 2013 at 16:00
  • $\begingroup$ @wsc if they think that buying a useless machine now means the company will be around to produce a workable machine later might make sense. But in more general term - don't assume that Nasa investing in tech X means that it's rocket-scientist approved ! $\endgroup$ May 27, 2013 at 16:02
  • $\begingroup$ I get the argument (and I'd also point out that I don't really care what rocket scientists think about quantum computers; wake me up when the Station Q folks buy one), My point was if it was a cynical political calculus, NASA would get American vendors to make a knockoff of DWave's machine. The point you make in your comment is probably a bit closer to reality (and in LM's case, being a "ground floor" investor in the technology). This was probably what you meant in the first place though. $\endgroup$
    – wsc
    May 27, 2013 at 16:12
  • $\begingroup$ @wsc =- assuming the senator in question knew that DWave was Canadian ;-) $\endgroup$ May 27, 2013 at 16:15

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