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D-Wave Large-Scale Quantum Chip Validated, Says USC Team

Posted by timothy on from the or-they-don't dept.

An anonymous reader writes "A team of scientists says it has verified that quantum effects are indeed at work in the D-Wave processor, the first commercial quantum optimization computer processor. The team demonstrated that the D-Wave processor behaves in a manner that indicates that quantum mechanics has a functional role in the way it works. The demonstration involved a small subset of the chip's 128 qubits, but in other words, the device appears to be operating as a quantum processor."

24 of 141 comments (clear)

  1. It Still Doesn't Mean Much... by tibit · · Score: 3, Interesting

    Yeah, quantum effects are directly noticeable in the way it operates. Yeah, yeah, whatever. The whole deal isn't about that. It's about whether those quantum effects are actually useful for something. Like, um, making it usefully faster than classical computers. I would be very happy even if they had shown "just" polynomial running time improvements, say executing an O(N^3) algorithm in O(N^2) time. Even that would be a big deal. Somehow, I'm very skeptical that anything of the sort will ever be shown for this particular architecture. I would so like to be wrong on that.

    --
    A successful API design takes a mixture of software design and pedagogy.
    1. Re:It Still Doesn't Mean Much... by tibit · · Score: 3, Informative

      You can't fight an exponential or even polynomial complexity merely by reducing constant factors. It doesn't matter what the constant factor is. All it takes is bumping, say, RSA from 4096 to 16384 bits. That's all you need to beat any conceivable reduction in the constant factor. Just think about it.

      --
      A successful API design takes a mixture of software design and pedagogy.
    2. Re:It Still Doesn't Mean Much... by firewrought · · Score: 4, Informative

      Why would a quantum computer would reduce the O notation?

      Because it's running in multiple worlds simultaneously? It's not just using 1's and 0's but superpositions of the two that are effectively in both states at once. Heh... I'm really don't understand this stuff, but the big deal about quantum computing is that it will make some previously intractable (e.g., non-polynomial) problems accessible to us. All problems in complexity class BQP become, essentially, polynomial on a quantum computer. If you've got enough qbits, among other things.

      --
      -1, Too Many Layers Of Abstraction
    3. Re:It Still Doesn't Mean Much... by cavreader · · Score: 2

      Exactly! I am glad just to know that someone is actually working on projects like this. It's not just another generation of current CPU technology it is something new and in time they will either master the technology or abandon the technology if things don't work out. But either way it is just nice to know there are people skilled and dedicated enough to attempt these advances.

    4. Re:It Still Doesn't Mean Much... by __aaltlg1547 · · Score: 3, Insightful

      No it hasn't.

    5. Re:It Still Doesn't Mean Much... by Anonymous Coward · · Score: 3, Informative

      Pedantic nitpick: Quantum computers cannot break public key (RSA) encryption in O(1) time; for a modulus N the time complexity is O(Log(n)^3).

    6. Re:It Still Doesn't Mean Much... by amaurea · · Score: 2

      Really? I thought it was 12,000 times slower than a normal computer when solving the one problem it does best, while costing approximately as many times more than said normal computer. That isn't exactly "incredibly fast" or "incredibly useful", is it? Scientists aren't too happy about it either, because the science, if it exists, is not being published.

  2. The question is by Anonymous Coward · · Score: 2, Interesting

    Can it help crack today's cryptosystems, in what way, and how fast.

    If it is able to do it then someone is doing it and we need to act.

    1. Re:The question is by MightyYar · · Score: 4, Informative

      Wrong kind of quantum computer. This does quantum annealing.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    2. Re:The question is by WaywardGeek · · Score: 4, Interesting

      Not too surprisingly, when a large US military contractor became a major purchaser of D-Wave equipment, all the company claims about being able to factor large integers vanished. D-Wave was going to have a blog series on it. I looked at it's architecture carefully, and yes, if the D-Wave machine has low enough noise, then a 512-qbit D-Wave machine should be able to factor integers close to 500 bits long. The next bigger machine could tackle 2,000 bit integers. The machine seems almost perfectly suited to this problem. The trick is dealing with noise. No one at D-Wave claims that their machine is perfectly coherent all the time during the annealing process. If 1 of the 512 bits suddenly drops out of quantum coherence, it will still act like a normal simulated annealing element until it re-enters coherence. Is noise like that enough to throw off detection of that one minimum solution? I don't know. I do feel that quantum effects will have a positive impact up to some temperature, after which it will just act like a normal annealing machine. I think there will be a phase change at some temperature where instead of qbits occasionally dropping out of coherence, just adding some noise to the solution, there will be so many out of quantum coherence that they will not be able to function at a chip-wide quantum level, and there will be no chance of finding that minimum energy solution.

      --
      Celebrate failure, and then learn from it - Nolan Bushnell
    3. Re:The question is by WaywardGeek · · Score: 3, Interesting

      I just went googling for my old posts about how to do integer factorization with D-Wave. Guess what? GONE! I thought I'd posted it in enough hard to scrub places... Anyway, all this machine is does is minimize an energy equation. I found somebody who had integer factorization coded as an energy equation as the sum of squared terms, but with the D-Wave machine, it does that naturally, and you don't need to square anything. I've got a lot going on at work, my mother is being sued, and I'm doing some genetics stuff. Do I really need to go back and recreate the integer factoring equation?

      --
      Celebrate failure, and then learn from it - Nolan Bushnell
    4. Re:The question is by BradleyUffner · · Score: 5, Funny

      I just went googling for my old posts about how to do integer factorization with D-Wave. Guess what? GONE!

      That's what you get for observing them.

  3. Great Scott! by Anonymous Coward · · Score: 5, Funny

    Great... now the NSA can record everything we do *and* everything we don't do in all possible parallel universes... Welp, the analog world was nice while it lasted I guess.

    -- stoops

    1. Re:Great Scott! by gweihir · · Score: 2

      For block-ciphers, the key-bits are halves. For example AES-256 remains completely secure even with a working general quantum computer. For AES-128, it would need a lot more than 128 bits and it would still need to break 64 bits. But constant factors do matter and there is reason to believe general quantum computers (if they ever work) will not be able to do many steps per second.

      RSA is a bit different, it could be in trouble. Bit there is always dlog crypto, and AFAIK, quantum computers do not help against that.

      --
      Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
  4. What about maintenance? by jennatalia · · Score: 5, Funny

    Are we going to need quantum mechanics to work on these chips and computers?

  5. Re:Was anyone really surprised by this? by timeOday · · Score: 4, Informative

    Well, I can tell you that no amount of computation will help for a one-time pad. That would be essentially the same as decrypting an empty sheet of paper. There is no information in either half of an OTP duo; only in the differences between the halves.

  6. Actually... by Black+Parrot · · Score: 2

    the device appears to be operating as a quantum processor

    Maybe it both is and isn't, until you have a look at it.

    --
    Sheesh, evil *and* a jerk. -- Jade
  7. Re:'incredibly' by Anonymous Coward · · Score: 2, Informative

    Fixed that for you, you left out the first/primary definition as shown below...

    incredibly
    Adverb

            1. To a great degree; extremely: "incredibly brave".
            2. Used to introduce a statement that is hard to believe; strangely: "incredibly, he was still alive".

    Synonyms
    unbelievably

  8. Re:2 Standard Questions to Evaluate any tech by guruevi · · Score: 4, Funny

    1) Yes
    2) No
    --next calculation--
    1) No
    2) Yes

    --
    Custom electronics and digital signage for your business: www.evcircuits.com
  9. Re:Was anyone really surprised by this? by the+gnat · · Score: 4, Interesting

    No, I mean the 439 benchmark just recently that absolutely destroyed classic computers. Mere seconds compared to over half an hour quicker.

    That was a terrible benchmark. They measured performance against possibly the most inefficient algorithm possible (using a third-party implementation) - not even remotely doing the same type of computations. That was where the "3600-fold" improvement came from. Some other computer scientists spent a bit of time optimizing an algorithm (also annealing, I think) for conventional computers in response, with the eventual result that their implementation was faster than the D-Wave. Which makes the entire effort sound like $10 million to avoid writing better software in the first place.

    It vaguely reminds me of all of the GPU benchmarks I've seen where single-precision floating-point performance on the GPU is compared to double-precision performance on the CPU. Except orders of magnitude worse.

  10. Re:This could be huge by the+gnat · · Score: 2

    there has been a fair amount of algorithm development done for quantum computers even though they are barely out of the concept stage

    As the AC above me notes, most of those algorithms won't run on this particular computer. Building a more general-purpose quantum computer is vastly more difficult - this is not even remotely my field of expertise, but from what I've read it has something to do with error-correction. D-Wave is essentially taking a huge shortcut to end up with a vastly less powerful (but probably still unique) technology. It's possible that this will turn out to have been a wise course; the best-case scenario is that their system is successful enough within its limited domain to promote more aggressive development of a more conventional machine - either by an expanded D-Wave or someone else with deep enough pockets.

  11. I don't get it. by xyourfacekillerx · · Score: 2

    I don't want to pay $32 USD for the paper. Am I the only one who can't figure out what they proved and how? The paper's abstract doesn't help much to balance the media's interpretation.

    1. Re:I don't get it. by the+gnat · · Score: 4, Informative

      I am pretty sure that this 7-month-old arXiv preprint corresponds to the Nature Communications paper. The titles and author lists are identical, but the abstract deviates, so who knows what changes it went through in revision (I don't have access to the official paper either, even at the university where I work). But presumably it covers the same ground, and it looks like all of the figures from the official are in the preprint.

      (Yo, fuck Nature Publishing Group.)

  12. Re:intel dead? by __aaltlg1547 · · Score: 2, Informative

    It won't become the thing for general computing use. There are specific applications where quantum operations can compute faster, but if it's a matter of what computers are normally used for, standard digital computing hardware is the thing.

    That said, quantum processor cores may become an accessory you can buy for your computer, complete with the software needed to set up quantum optimization problems, and high end scientific workstations might have them built in some day.