Forgot your password?
typodupeerror
Science Technology

Programmable Quantum Computer Created 132

Posted by Soulskill
from the four-out-of-five-ain't-bad dept.
An anonymous reader writes "A team at NIST (the National Institute of Standards and Technology) used berylium ions, lasers and electrodes to develop a quantum system that performed 160 randomly chosen routines. Other quantum systems to date have only been able to perform single, prescribed tasks. Other researchers say the system could be scaled up. 'The researchers ran each program 900 times. On average, the quantum computer operated accurately 79 percent of the time, the team reported in their paper.'"
This discussion has been archived. No new comments can be posted.

Programmable Quantum Computer Created

Comments Filter:
  • The researchers ran each program 900 times. On average, the quantum computer operated accurately 79 percent of the time, the team reported in their paper.

    20% of the time it got it wrong, and 1% of the time, someone looked in the box and it wasn't there. 79% accurate. That's pretty useless. I've got a pair of dice that can do just as badly.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      My dice are 100% accurate. I ask them for a random number, and every time that is what they return.

      • by Fizzl (209397)

        int rand()
        { return 3; } //Chosen with a fair dice roll

        (Old joke, yeah.)

      • Re: (Score:1, Funny)

        by Anonymous Coward
        Someone will put linux on it, and it will be able to crack RSA, but people won't be able to figure out how to get their printers to work with ti.
        • Re: (Score:1, Funny)

          by Anonymous Coward

          Someone will put linux on it, and it will be able to crack RSA, but people won't be able to figure out how to get their printers to work with ti.

          ...Or their keyboards.

      • by tomhudson (43916)

        My dice are 100% accurate. I ask them for a random number, and every time that is what they return.

        I can fix that for you with a bit of sandpaper (dice that are slightly sanded on one or more faces are called"flats [metal-express.net]", and come up non-random).

    • by Timothy Brownawell (627747) <tbrownaw@prjek.net> on Thursday November 26, 2009 @01:12PM (#30238042) Homepage Journal

      79% accurate. That's pretty useless.

      Not useless at all, just have it solve the same problem 5 or 15 times and go with the answer that it gives most often. Plus, for some problems it's much easier to verify an answer than to come up with it -- for those problems, just pair it with a normal computer to check the answers, and keep trying until it says the answer is right.

      • Re: (Score:3, Informative)

        79% accurate. That's pretty useless.

        Not useless at all, just have it solve the same problem 5 or 15 times and go with the answer that it gives most often. Plus, for some problems it's much easier to verify an answer than to come up with it -- for those problems, just pair it with a normal computer to check the answers, and keep trying until it says the answer is right.

        One of the classic examples of that last one is prime factorization. In general it's very hard to come up with the two primes that were multiplied to create a very large number, but if the quantum computer coughs up a candidate it's downright trivial to check whether that's a solution.

      • by RudeIota (1131331)
        There's still room for error there though, and that is simply unacceptable based upon how we use our computers today.

        This means that quantum-based processor will either become useful for a certain niche (something that doesn't require precise results) or we'll find a way to make them useful for everyday stuff... like outfitting classical processor technology with quantum capabilities to solve specific types of problems more efficiently.
        • by LKM (227954)

          There's still room for error there though, and that is simply unacceptable based upon how we use our computers today.

          Well, no. Computers can always be wrong. Repeat the calculation often enough, and you'll be better than your average PC. Besides, as RudeIota notes, sometimes the calculation is hard, but verifying the result is trivial (that is often the case in cryptography, for example). In those cases, you can just repeat the calculation until it's correct.

        • There's still room for error there though, and that is simply unacceptable based upon how we use our computers today.

          This is why everybody uses only ECC memory in their desktop machines and all filesystems in common use support checksumming for data integrity.

          • by tlhIngan (30335)

            There's still room for error there though, and that is simply unacceptable based upon how we use our computers today.

            This is why everybody uses only ECC memory in their desktop machines and all filesystems in common use support checksumming for data integrity.

            Or uses floating-point hardware. Regardless of how many bits you use, floating-point computations are always approximate (mostly because the range of numbers that can be represented is larger than the number of possible numbers a given bit length can r

      • by mugurel (1424497)

        So I guess in the near future we will be seeing things like:

        >>> 1 + 1

        2 (p < .001)

      • by Device666 (901563)
        The programmable quantum computer is 100% accurate all the time, it always prints 42.
        • how can it always say 42 unless it knows the question? if the question is known, then we cease to exsist since the question and the answer cannot be known in the same universe at the same time... unless someone else in a parrallel universe knows the question, then the programmable quantum computer is a space time travelling machine, for which would be epic!
      • by volpe (58112)

        Plus, for some problems it's much easier to verify an answer than to come up with it

        Yes. They're called "NP Complete" problems.

        • Plus, for some problems it's much easier to verify an answer than to come up with it

          Yes. They're called "NP Complete" problems.

          Maybe [wikipedia.org]:

          If f is a one-way function, then the inversion of f would be a problem whose output is hard to compute (by definition) but easy to check (just by computing f on it). Thus, the existence of a one-way function implies that P != NP. However, it is not known whether P != NP implies the existence of one-way functions.

          I'm not certain exactly what this means, but part of it seems to be that "one-way" != "NP-complete" (because that would result in a much shorter explanation). But it does at least seem to me

    • 79% accurate. That's pretty useless. I've got a pair of dice that can do just as badly.

      You may be interested in purchasing this chip I have here. It has a very nice fdiv routine. Since we're so good friends, I'll give you a 100.00001353% discount.

    • by ShakaUVM (157947)

      >>79% accurate. That's pretty useless. I've got a pair of dice that can do just as badly.

      79% accurate? That's good enough for government work!

    • A factoring algorithm that gives the correct answer with 50% probability (in a short enough time) would be very useful.
      Since you can check the answer with a single multiply, you keep trying until you have the correct answer.

      This is one of a set of problems labeled "NP" - a characteristic is that you can verify an possible answer in polynomial time.
      Any of these problems can be solved with a polynomial time algorithm that gives the correct answer 50% of the time.

    • Re: (Score:3, Informative)

      Actually quantum computing is, by design, probabilistic. Every specifically quantum algorithm (even Shor's infamous factoring algorithm) gives incorrect results by design for the simple reason that it's really not possible to have quantum algorithms which succeed all the time (unless you forgeo their quantum properties). So long as the probability of a correct answer is strictly greater than 0.5, however, one only has to repeat the computation a constant number of times to get the probability of success arb
      • by CTachyon (412849)

        Actually quantum computing is, by design, probabilistic. Every specifically quantum algorithm (even Shor's infamous factoring algorithm) gives incorrect results by design for the simple reason that it's really not possible to have quantum algorithms which succeed all the time (unless you forgeo their quantum properties). So long as the probability of a correct answer is strictly greater than 0.5, however, one only has to repeat the computation a constant number of times to get the probability of success arbitrarily close to 1.

        Nitpick: though this is true for the most familiar quantum algorithms, i.e. the ones in BQP (Bounded-error Quantum Polynomial-time), there are also some quantum algorithms that give exact answers with 100% certainty, such as EQP [stanford.edu] (Exact Quantum Polynomial-time).

    • /me stirs berylium ions and tastes...

      /me announces "needs more cats!"

  • So is that 21% of the time is was both correct and incorrect ?
  • by jaggeh (1485669)

    79% of the time they work every time

  • Were any cats harmed in the running of the programs?
  • by Shivinski (1053538) on Thursday November 26, 2009 @12:54PM (#30237898) Homepage

    On average, the quantum computer operated accurately 79 percent of the time,

    Well, its better then anything Microsoft can come up with...I'll take 10!

    • Re: (Score:1, Flamebait)

      by DiegoBravo (324012)

      And is better than the probability of total Linux hardware support for any random pc/laptop!

  • Since it's a Quantum Computer, shouldn't reading the results actually mess up the results? Or at least that's what I understood from that Futurama racing joke.

  • by WED Fan (911325) <akahige&trashmail,net> on Thursday November 26, 2009 @01:11PM (#30238030) Homepage Journal

    In some alternate universe, there's a guy who is riding a bus, a thought pops into his head, "Pick a number between 1 and 100. Now, add 3. Now, divide by 13...". 99% of the time, he does the problem in his head, 79% of the time he finishes it. 1% of the time, he says, "Screw it". 100% of the time, he wonders where the hell these things are coming from and decides to check himself into the nearest mental ward.

    Quantum computing is screwing up someone's day.

    • And that's by having only one quantum computer in a single universe... now imagine what would happen if all the other universes would start inventing such computers!

      • By the way, who would be able to claim the invention when the universes merge? Hmm, intriguing concept, prior art in a parallel universe...

        • by WED Fan (911325)

          I've already patented "A Quantum Method for Parralel Copyright, Trademark, and Patent Registration".

          (Note: I assert that this comment is now prior art in all Universes and proof of my ownership of said patent, including Universes that contain no processes or concepts of copyright, trademark, or patent.)

  • How do they know? (Score:3, Insightful)

    by jpmorgan (517966) on Thursday November 26, 2009 @01:26PM (#30238150) Homepage

    I'm curious how they could possibly know that it operated correctly 79% of the time, since the underlying quantum state isn't observable. You could say it produced the 'correct' results 79% of the time, but that's not the same as saying it operated correctly 79% of the time; it's very possible for a quantum computer to operate incorrectly and still produce the right result, through sheer random chance.

    I suppose I could read the paper.

  • Ha ha (Score:2, Insightful)

    by cefek (148764)

    Can you imagine the accuracy of a Beowulf cluster of that?

    • Again 79%. size does not matter
      • Or, you get more combinations of right, wrong, and other as answers. Now, what happens when one unit in the cluster suddenly starts throw the right answer 100%?

        Or, goes 100% wrong?

        Or, goes 100% OTHER?

        What if it taps something we cannot comprehend?

        What if it hits "other" just once. And as a result, somewhere in the timeless Eternity, God freezes, bends over, and monkeys fly out of His ass?

      • Re: (Score:1, Informative)

        by Anonymous Coward

        not if they are parallel. computations that are done on each node where the majority of the answer is the right answer (as long as it's accurate past 50%). won't increase speed but will increase accuracy.

      • Re: (Score:3, Funny)

        by dem0n1 (1170795)

        Again 79%. size does not matter

        That's what she sighed as she patted him on the knee and then walked out of his life never to be seen again.

    • by Sulphur (1548251)

      21% of the time Beowulf accidentally shakes Grendel's hand.

  • How long until they get it to factor huge numbers?

  • Experimental physicist Boris Blinov says that one of the most exciting things about the new study is that the quantum computer may be scaled up. “What’s most impressive and important is that they did it in the way that can be applied to a larger-scale system,” says Blinov, of the University of Washington in Seattle. “The very same techniques they’ve used for two qubits can be applied to much larger systems.”

    Pretty soon they will be able to calculate the US budget with accuracy heretofore unmatched by any recent administration.

    • by daveime (1253762)

      You don't need two quantum states for that, one will suffice.

      In The Red, until the end of the universe (where I hear there's a very nice restaurant).

      • by hwyhobo (1420503)

        You don't need two quantum states for that, one will suffice.

        Funny +1

        In The Red, until the end of the universe

        Insightful +1

        Too bad I cannot moderate in the same thread I post in.

  • by Temujin_12 (832986) on Thursday November 26, 2009 @02:28PM (#30238608)

    do {
        solveProblem();
    } until (getPhotonPosition() && getPhotonVelocity());

    • actually that's not an infinite loop. you can actually get both position and velocity of a particle.
      the result of getPhotonPosition() and getPhotonVelocity() just has to be a function, not a single number...

      So you could get for example two gaussian functions as result. And then you use some fuzzy logic.

      PS: the velocity of a photon is often the speed of light (in vacuüm)
    • by inflame (1339495)
      i think you meant electron
    • do {
              solveProblem();
      } until (getPhotonPosition() && getPhotonVelocity());

      In vacuum Photon Velocity will be a rather famous constant.

      The photon momentum, on the other hand, depends on the photon's energy ( i.e the colour ). Thus you can't break the uncertainty principle using photons, even though their velocity is always the same.

      Now in before some smartass points out it is gluons that have colour.

  • by Cytlid (95255)
    The old 80-20 rule. The other 21% of failures caused the first 79% to be correct.
  • You know what they say... 79% of the time, it's correct every time.

  • That's all well and good, but the important thing is: Will it be able to run Crysis 2?
  • Get out into the Beyond [wikipedia.org], and you can reasonably expect 100% efficiency out of your quantum computers. Keep going into the Transcend, and you can reasonably expect better than 100% efficiency -- or at least that's what it looks like to merely-human minds.

    Just don't open any unsigned JAR files.

    • by argent (18001)

      Hexapodia is the key insight.

    • by arethuza (737069)
      Somehow I don't think a digital signatures will work too well in the Beyond or the Transcend. And we think security is tricky here...
  • Can it run Linux?
    • by md65536 (670240)

      I think a machine like that is better suited for Windows, because it can offer an improvement. Users found that it would only crash reliably about 79% as often as expected.

    • This is the first computer that can and can't run Linux at the same time!

Never put off till run-time what you can do at compile-time. -- D. Gries

Working...