Slashdot Mirror
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.
Is this a case where D-Wave was fraudulently trying to pass something off as quantum when they knew it wasn't, or did they really and truly not know. How could they not know?
This could mean that D-Wave isn't quantum. Or it could mean that quantum computing in general isn't faster than normal computing. I seem to recall some physicist making a bet that quantum computing would be proved equivalent to classical computing.
(T>t && O(n)--) == sqrt(666)
I've been surprised time and again that D-Wave has kept afloat as long as it has. It *will* fail in the end, the only question is how much of that investment money Geordie Rose got safely stashed before the collapse. Their approach is fundamentally not quantum computing.
This could mean that D-Wave isn't quantum. Or it could mean that quantum computing in general isn't faster than normal computing. I seem to recall some physicist making a bet that quantum computing would be proved equivalent to classical computing.
I propose the following experiment.
1. Place a radioactive source, a detector and and this supposed quantum computer in a closed opaque box.
2. Attached to the computer are 2 vials. Vial 1 contains oily secretions of a serpent. Vial 2 contains bovine excrement.
3. After a certain time the computer will open one of the vials. If radiation is detected it will open vial 1. If not it will open vial 2.
4. Now sniff the box.
" 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 "
That is algo design 101. Why has it taken so long for somebody to test it this way?
This is when the lawsuits start flying. And we get to discovery and see what makes this computer and company tick.
That is unless the agencies and universities don't want to reveal themselves as being gulible by going to court.
Well if its a system of switches/links between qbits, and you set it up and run it, then its an analogue computer on a chip.
https://en.wikipedia.org/wiki/Analog_computer
And if it's not showing any 'quantum entanglement effect' then its big selling point is lost, because otherwise you're simply dealing with an analogue computer.
But the makers of the computer can't find a single problem it solves well. Why is that?
Learn to love Alaska
Wait, I have an idea...they should overclock the quantum chip. By the way, that's twice as funny if you know how it works.
So invent some. I remember some bullshit about how they had all the equations if only a quantum computer existed...
As long as they have enough wealthy believers at this early stage to fund development, there's no need to ignite the pending explosion of competing startups with something as unwise as a publically proven quantum computer. If would-be competitors' investors are discouraged by D-Wave's apparent lack of proof, this is to D-Wave's strategic advantage.
An ordinary $1000 i7 laptop or Xeon server? Or an ordinary $10million mainframe (if you can still spend that much for a mainframe)?
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Originally I meant to bet with Matthias Troyer if the D-Wave machine was truly a quantum annealer. At the time Matthias wrote me:
""Actually, we can't bet anymore since I know the results that we're going to publish and we'll say yes to quantum :-). We should have done the bet a year ago."
So we decided to bet if the current crop of D-Wave machines can already beat conventional computing.
Obviously I lost that bet, but not by much.
It will be interesting to see how the next chip generation will fare, there is still lots of room for higher qubit integration. In comparison to conventional CMOS the D-Wave chip structures are huge.
Conventional chip design doesn't have lots of room at the bottom any more. D-Wave on the other hand still has plenty of room at the bottom.
That's why I will continue to bet on them.
That's been the big question with D-Wave all along. What does it really do, how does it really work, what's it good for, is it real?
Everybody knows what a universal quantum computer is good for - running Shor's algorithm to do factoring and totally wrecking public-key cryptography, plus whatever other problems people care about in the real world. But general-purpose quantum computers so far can't keep enough qbits entangled together to factor numbers bigger than 21 = 3x7, and if anybody's figured out how to do significantly bigger than that, they're keeping it Really Well Hidden (either because they're a government, or because a government will want them to do stuff, or because a government will want them killed.)
Meanwhile, D-Wave has 512 qbits that they claim they'll be able to do something with, and maybe it'll have a chance of being cool or useful. And maybe if you kick in enough megabucks to get a non-disclosure agreement, you'll be able to get some information beyond vague quantumy handwaving. They are the only game in town, after all.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
.... 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.
So they tested a so-called quantum computer that doesn't work very well, and got a Science paper out of it. Color me unimpressed.
As noted, the D-Wave was never sold as being for anything except quantum annealing. Slashdot and the rest of the tech rags, of course, were only too happy to call it a "quantum computer". Just because "everybody knows" what a universal quantum computer is good for doesn't make it one.
Its sole purpose is optimization, and specifically optimization problems that are amenable to quantum annealing. Furthermore, it can only really be useful on problems that are amenable to quantum annealing but not to other optimization methods (simulated annealing and friends). So it's absolutely feasible that it doesn't outperform a conventional processor on problems that aren't hard enough to be problematic for simulated annealing.
Whether the class of problems that can be solved by QA but not SA actually contains anything useful (or anything at all) is another matter altogether, of course.
They wired the computer into Deepak Chopra's quantum consciousness and all it produced was a stream of pseudoscientific gobbledegook.
But the makers of the computer can't find a single problem it solves well. Why is that?
Aside from profit, why is that question even relevant? It took a century for the geocentric model to give more accurate results than the old heliocentric model. Here we appear to have quite a few independent observers who know quantum annealing when they see it, I am not one of them. Sure it could be a scam but so far I have seen zero evidence supporting that hypothesis.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
The manufacturer pitches its machine as the world’s first commercially available quantum computer. Critics initially considered this a nonsensical claim. Has the mood now turned?
The experts were sceptical at first, but the question now is no longer whether it’s bogus. The tests at Lockheed Martin and Google have shown that the machine works and uses quantum mechanics in the process. This is an accomplishment. But can quantum mechanics help solve optimisation problems? This is now the exciting, unanswered question.
So can D-Wave really be described as a quantum computer?
It’s more of a physics experiment, a prototype that solves specific problems using some quantum mechanics. The device is not a universal quantum computer that can do anything. But as a specialised device, it can be referred to as a quantum computer. It’s like the controls in a car, toaster or refrigerator that solve only one specific problem but can also be called computers.
You're mixing up your geos and helios.
It took a century for the geocentric model to give more accurate results than the old heliocentric model.
But the "benefits" were immediate. The geocentric model was complicated and incomplete. The heliocentric was "better" day-1 for some things. But the accuracy was more a limit of the measurements at the time. It also took time for others to come on board. People were afraid that if they admitted the heliocentric model was better, they'd be sent to Hell.
Learn to love Alaska
Alot of hype about these quantum computers, D-Wave in particular making claims.
Theres a limited class of problems that that type of computing is applicable to and thses things are not the equivalent of a general purpose computer.
Way too easy? Well let them supply a spectrum of appropriate quantum problems (and not just the subset their hardware's quantum like effect can handle) so that it can be properly demonstrated.
Obviously, the D-wave performs differently when it is observed. If anything, this proves that it is a Quantum device.
People were afraid that if they admitted the heliocentric model was better, they'd be sent to Hell.
This Galileo worship tripe again.
Copernicus had no trouble with the Catholic Church and had a better heliocentric model than anything Galileo came up with, before Galileo was born. The reason it didn't catch on was because there was no advantage in real life to either model. Except for a very small few scientists, no one paid close attention to the exact rate of movement of Jupiter over the years, nor did anyone have reason to. The typical population in that timeframe was really not concerned with the finer details of anything with less direct influence on earth than the sun and moon. Crops were important, weather was important, tides were often important, and for sailors, stars were important. Planets were a curiosity, and a detail that comes out to less than 0.003% variation in the least consistent of stars when you're using a sextant with 5% error is completely meaningless.
What we need to know about is the existence or non-existence of unfair comparisons, i.e., problems that favor the putatively "quantum" computer.
Since I don't expect a quantum computer to be faster at everything, then finding a bunch of solutions to problems that aren't any faster on the "quantum computer" doesn't prove anything, even if the problems look like the kind of problems you'd hope would be quantum-computery. There's not much more you can do than point to the absence of evidence when the burden of proof isn't on you.
The burden of proof is on the vendor here, and standard of "proof" is conceptually simple at least: demonstrate that for some task this device offers any practical advantage whatsoever over the best available conventional technology. That could be in absolute performance against the best available tech(e.g. ASICs and supercomputers), in relative performance over similarly priced systems, or in some practical measure other than performance, such as power consumption. Any clearly identifiable and verifiable advantage counts as positive proof the vendor has something worth paying attention to.
Of course even comparable performance by a novel architecture on some class of problems is interesting, because of the huge advantages a mature technology enjoys. Performance of a new design even in the same ballpark as a mature design suggests future improvements might be in the works. But it's only a suggestion.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
They're not qbits, they're just bits, that's what this test demonstrated.
If you put the quantum computer in a box, how will you know if it's at run level 5 or not?