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Scientists Dubious of Quantum Computing Claims 107
Dollaz wrote with a link to the International Business Times, which questions the authenticity of D-Wave's Quantum computing. We discussed the 'Sudoku playing' computer yesterday, but scientists in the field have expressed a lot of distrust of the company's findings. The machine was not available for inspection during or after the demo, and even if the technology was working as intended there is some doubt that it can be scaled. The article points out that "notwithstanding lofty claims in the company's press release about creating the world's first commercial quantum computer, D-Wave Chief Executive Herb Martin emphasized that the machine is not a true quantum computer and is instead a kind of special-purpose machine that uses some quantum mechanics to solve problems." Good to see people in the field questioning 'breakthroughs'.
I Knew It! (Score:2, Funny)
And then when it coughed and 'had to take a smoke break.' I knew there was a reason no one could look at it.
Reply button missing (Score:5, Interesting)
This is an odd statement, because that's generally what people "in the field" do. The author says this as though it's unusual to see anybody questioning lofty claims. In fact, it's very common. The first slashdot article about this was met mostly with skepticism.
Note: Replying to this post, because I am not getting a "reply" button for the story itself. Anybody else experiencing this bug?
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There's a Reply link in the floating thingy. [sic]
Mod modding +1 funny.
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Stick that in your Sudoku and smoke it.
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That wasn't the author, that was Zonk. In a summary, anything not in blockquote tags was written by the posting "editor". Apart from that, I agree, that's the way it's supposed to work - someone makes a claim, experts in the field scrutinise and challenge it. The claim is either upheld, or refuted. That's science. Duh.
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Lofty Goals (Score:2)
A quantum computer is a new sort of being.
Well DUH (Score:5, Funny)
Yes
I kid, I kid. I think...
Re:Well DUH (Score:5, Funny)
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Re:Well DUH (Score:4, Informative)
Don't confuse the uncertainty of quantum collapse with the uncertainty of the Uncertainty Principle. They are two different concepts. The uncertainty principle derives from a mathematical truth (it would be true even if the world was not governed by quantum physics), whereas the uncertainty associated with wavefunction collapse is a true quantum effect unrelated to the Heisenberg uncertainty principle.
(The Uncertainty Principle is a consequence of the fact that momentum and position are dual-spaces of each other -- similar "uncertainty" principles arise, for the same reasons, in more mundane fields such as signal processing)
Can't....resist....straight line....must fight... (Score:2, Funny)
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bloody url didn't work
http://en.wikipedia.org/wiki/Uncertainty_Principl
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Re:Well DUH (Score:5, Funny)
Re:Well DUH (Score:4, Funny)
If it's a Schrödinger box then the cat's included all right... the open issue is that you may or may not be having burgers for lunch.
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I think "Pick a box" may actually have been the first quantum game show, wadya reckeon?
Re:brilliant (Score:1)
Maybe I don't understand... (Score:2)
So, can't they just put together "just marketing hype", then turn their backs, close their eyes, and shoot the marketers who actually understand the hype, so it'll uncollapse into a probability field again, then turn around and have a chance of it being finished?
You know, kind of like how the finite probability driv
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for instance, if the probability function was a gaussian distribution, You could think of "collapse" as reducing the width until it became a delta function. [wolfram.com]
Re:Well DUH (Score:5, Funny)
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There is a further universe somewhere in which the GP post was modded funny instead of insightful. Some luckier copies of all of us live there. Oh, and some more insightful moderators too
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Link 1 http://video.google.com/videoplay?docid=8033280380 582597891&hl=en/ [google.com]
Link 2 http://video.google.com/videoplay?docid=-687784917 8932916346&hl=en/ [google.com]
Thats my problem with the press release, too: (Score:4, Informative)
Well, _any_ mosfet based transitor uses quantum mechanics to solve problems (you get real problems explaining band-formation and the influence of substrate doting classically). That statement is trimmed down to be as slippery as possible.
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Here is my take on their quantum computer,
They have a device which contains a collection of cells of liquidy stuff.
They start each cell out at a different temperature to represent the different states in the input array.
They then drop the temperature further and see where the collective group ends up.
Wave height or combined temperature or something other measurable (measuring though interrupts the cells hence making another measurement inv
How to verify their claims? (Score:2, Interesting)
I'm legitimately curious. Such a device has never been built, how do these guys prove they have one? They say themselves they aren't certain if it's quantum-ing up the sudoku.
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Re:How to verify their claims? (Score:4, Insightful)
Re:How to verify their claims? (Score:5, Insightful)
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As someone once said... (Score:2)
Uncertainty? (Score:5, Funny)
Time to check the cat.
He kind of has a point... (Score:2, Insightful)
puzzles (Score:2)
They're more interested in the power to do stuff they can't right now.
They should get the Sudoku books with the easier puzzles!
Re:He kind of has a point... (Score:5, Interesting)
Solve any problem polynomially reducable to SAT/3-SAT (http://en.wikipedia.org/wiki/Boolean_satisfiabil
without the use of heuristic algorithms. Further, show it being done in polynomial-time with respect to the problem size.
Naturally, the machine and program would also have to be subject to inspection to show that it wasn't just spitting out a canned response to a problem already worked on and answered by a team of supercomputers elsewhere....
Fortunately, checking the result won't take too long. The check should be calculable on a conventional computer in polynomial-time.
Re:He kind of has a point... (Score:4, Interesting)
You have your reducibility direction mixed up: even really easy problems (like sorting, or outputting "2") are reducible to SAT. It's the hard problems that SAT reduces to.
Not that this matters, because quantum computing is very unlikely to be able to solve NP-complete problems. It does seem to help with very structured problems like factoring, though. No, factoring is (almost definitely) not NP-complete.
Further, show it being done in polynomial-time with respect to the problem size.
Polynomial-time is an asymptotic notion. It can't be verified for a particular problem size (or finite set of problem sizes). It is purely an analytical concept, not an experimental/testable one.
Re:He kind of has a point... (Score:5, Informative)
I went to the Vancouver demo of this yesterday and it is pretty clear why they couldn't have it available for inspection at an event like this. It is located in a specially shielded room in their lab to reduce signal noise with a cooling system that cools a portion of the computer down to 4mK (extremely close to absolute zero).
Besides, even if I or anyone else there was able to inspect it, do you really think that we could look at it and say "hey, I don't see any quantum effects"
Uncertainty? (Score:4, Funny)
Good blog responses (Score:5, Interesting)
They didn't do what they said they did (Score:5, Insightful)
What did they do? Nobody knows. They were very careful to evade the important question: what did they actually accomplish? They never mentioned qubit decoherence times, fidelity, nothing. These are things they can claim without compromising the trade secrets. They gave a lot of emphasis to saying that the computer is part a classical computer, and part a quantum computer, something that nobody really cares about. What is important is to spell out exactly what was the part of the problem the quantum computer solved.
The CTO has a blog, and he sounds very competent in it. I'm guessing that he just had a lot or pressure from the investors to show *something*. It was just a big show to get some Venture Capitals. Pretty graphics and tech demos are cool for getting fans for videogame consoles and getting VC only, not so much as to make scientific claims.
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Misconceptions about NP-Completeness (Score:5, Interesting)
For a problem that actually can't be solved, try the Halting Problem.
Now, the cool thing about NP-Complete problems is that any other problem that's known to be in NP (meaning we can solve them, just some instances will take a ridiculous amount of time to do so) can be efficiently transormed, meaning transformed in polynomial time, into an NP-Complete problem. This means if you can really solve general instances of Sudoku in polynomial time, you can take an instance of the 3SAT problem, efficiently transform it into an instance of Sudoku, then efficiently solve the Sudoku problem and then transform the answer into a solution to the 3SAT problem. If they have really built such a machine, this is a big deal.
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Mod the parent up! (Score:1)
Quantum Computing Blogs (Score:2, Informative)
See also the Quantum Pontiff [dabacon.org]
Marketing department at work... (Score:3, Interesting)
You could pick any device that returns different numbers at different times. It could be a microphone, a geiger counter, a clock og a quantum device
Now pick the quantum device, and call the whole device a "Quantum computer"
This is normal in marketing departments. The only unusual thing here is that they got the engineering department to go with them.
Maybe, but... (Score:4, Insightful)
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If you write that you have a quantum computer it is bad if you have none.
If you dont claim it it does not matter.
If you stampede as the companies founder in his blog over the "gate model" and implicitly claim that the rest of the community does not get it right because they are trying complicated things to get qubits working, while you use a quick and dirty "simple" approach (which in QC usually can never work), the level of authenticity which the community demands from your Experiments *will be higher* tha
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You realise that a computer was originally the name given to a person who worked out the mathematics of a set problem. There used to be rooms full of "computers", scratching away with pencils on paper. So really, any problem solving device is a true computer. And by that definition, an electronic problem solving machine is a true computer. So, what do *you* mean by "true" computer ?
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The problem is the direction it is a step in may be a dead end. I don't entirely understand why, but it seems that the technology they are using is fundamentally limited in certain ways, such that there are entire classes of useful quantum algorithms (most notably Shor's al
Don't worry everything is cool (Score:2, Offtopic)
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Dubious Scientists (Score:2)
Hey, if you're not anal retentive, you have no business being a programmer.
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In fact, it's a perfectly cromulent word.
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The scientists were unsettled in opinion (2)
http://www.m-w.com/dictionary/dubious [m-w.com]
Future Slashdot Editors? (Score:1)
I've been saying for ages it's a scam (Score:5, Interesting)
So the first part of the scam is this: even if this device wasn't a quantum device at all it would still work to some extent because when you allow systems to cool they fall into lower energy states. If the 'quantum' aspect of things works then it might find that state faster, but without careful monitoring there's no way of telling if the 'quantumness' had anything to do with what it did. In fact, for large systems we know that it won't be very 'quantum' at all because it will interact with its environment and decohere. But it's a perfect strategy for designing a machine that you can claim is quantum, when it isn't. It stinks of scam.
Secondly: suppose you want to solve a challenging problem with this device. For example you want to search some space for a miniumum of some sort. For this machine to be effective the state space must be pretty large or else you could use a regular classical computer. Consider a billion state problem (quite small really for combinatorial problems). You have to be able to get a system to settle into the minimum energy state despite the fact that there are a billion states nearby all of which have almost the same energy. Just the tiniest input of energy and it'll jump up from that minimum. There is absolutely no way that they can search a large enough state space and still have the minimum energy state sufficiently far from other states.
BTW This device is quite different from what is conventionally meant by a 'quantum computer', it's more like a quantum, analog computer.
Real and useful 'digital' quantum computers are a long way off. I expect that the size of quantum computers will grow by a bit or so per year at the most. (When I say 'bit' I mean total memory, not the size of the bus.)
Sudoku (Score:2)
I'm very skeptical about the whole concept of utilizing quantum effects to solve problems. It's an interesting idea, utilizing the structure of the universe to tell us what we want to know, but it may not be at all practical. Nature doesn't seem to have utilized the method, and since it evolves molecule-sized structures it ought to be in the position to do so.
I think that, when we're done playing
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How fast can it run an infinite loop?
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I thought they already had a conventional algorithm that could solve Sudoku without utilizing quantum effects?
Quantum computers can only solve problems that conventional algorithms can solve. Potentially, they could solve them faster.
Nature doesn't seem to have utilized the method
There are a lot of useful things nature hasn't discovered, like wheels (macro sized) and transistors. The nervous system doesn't take advantage of ANY molecular scale computation, so how could it build a quantum computer?
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If the claims were accurate, then the solving of a Sudoku puzzle is an excellent choice for a demonstration. Especially if it's a 100x100 sudoku, which (if designed properly) no human or computer could solve in the amount of time left in the unive
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it better work (Score:1, Funny)
Article makes things seems worse (Score:2, Interesting)
Also, while the article claims it might not be a "true quantum computer", it never really says how that's different from a "computer that uses quantum mechanics to solve certain problems", and given its audience, can't possibly expect its readers to know. To me, this just sounds like journal
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So, is this the right place.... (Score:4, Informative)
:)
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drama queen media doing its thing again (Score:2)
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Anything for the VC.
Quantum Love (Score:1)
Quantum Love [thedialogs.org]
bad science? (Score:2)
Well, have there been any peer reviewed papers published in journals with good reputation? If not, we have here the number one sign of bogus science [chronicle.com]: The discoverer pitches his claim directly to the media and questioning is the only reasonable attitude. For me, they lost it when they announced that the presentation was going to be remote, that the actual machine would not be in the room where the presentation was held. Yeah, so you haven't actually
Uncertainty (Score:1)
Gee, You Think? (Score:2)
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And still, even if they were on-site, if they wanted to cheat, how would you check that its really the QC that does the calculations? Even if there is a cable going into it, who says the real data didnt elsewhere? Or somebody put a laptop somewhere inside the QC?
There is simply no way to verify the claim without taking the whole assembly apart, which of
They didn't hire me so they must know something (Score:4, Interesting)
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I've done a lot of smoke and mirror shows myself, and this demo did not smell funny at all.
The headline "Scientists Dubious of Quantum Claims" is rather sensationalist for what they're actually saying in the article.
Can you really fault them for not wanting to move a computer that has to be housed in a special chamber, cooled to near absolute zero, and be havily shielded from any outside interference?
Besides, judging by the questions people asked, not a single person in the au