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Light-based Quantum Circuit Does Basic Maths

Stochastism writes "In yet another small step toward realistic quantum computing Australian researchers have developed a light based 4-qubit quantum computer. It has already calculated the prime roots of fifteen, three and five. 'The quantum circuit pioneered by the Queensland researchers involves using a laser to send "entangled" photons through a linear optical circuit ... The Queensland research group acknowledged that the theorised code cracking ability of quantum computers may be why Australian quantum computer research is in part funded by a US government defence intelligence agency, the Defense Advanced Research Projects Agency (DARPA).'"

46 of 198 comments (clear)

  1. How many maths does it do? by InvisblePinkUnicorn · · Score: 4, Funny

    Seven! It does seven maths!

    1. Re:How many maths does it do? by thatseattleguy · · Score: 2, Insightful
      Ever hear of "two countries divided by a common language"?

      one quick reference here
      There are various accepted abbreviations for the word mathematics, and one is as good as any other. In Germany, the abbreviation is "Mathe," in Britain and Canada, it is "maths," and in the USA, it is "math."

      /tsg/

    2. Re:How many maths does it do? by LiquidCoooled · · Score: 2, Funny

      When you are in the bathematics make sure you don't use all the hot waters.

      --
      liqbase :: faster than paper
  2. But... by SiriusStarr · · Score: 5, Funny

    More importantly, can it run Crysis?

    --
    Fear the penguin.
  3. having trouble with the conversion by User+956 · · Score: 2, Funny

    In yet another small step toward realistic quantum computing Australian researchers have developed a light based 4-qubit quantum computer.

    4 qubits? How much is that in furlongs?

    hectares?

    --
    The theory of relativity doesn't work right in Arkansas.
    1. Re:having trouble with the conversion by JeanBaptiste · · Score: 3, Informative

      1 qubit = 1 bit, I believe

    2. Re:having trouble with the conversion by snl2587 · · Score: 2, Informative

      Of course I get the joke, but for reference:

      Wikipedia: Qubit

    3. Re:having trouble with the conversion by LiquidCoooled · · Score: 5, Funny

      The similarity to bits only occurs once you open the box.
      Until that point a cubit represents a dead cat.

      --
      liqbase :: faster than paper
    4. Re:having trouble with the conversion by GeekZilla · · Score: 2, Funny

      Wasn't Noah's ark 300 qubits? Noah was the man! Take that Silicon Devil!

      --
      Veritas patesco per quaestio questio. Truth is revealed through questions.
    5. Re:having trouble with the conversion by Intron · · Score: 4, Funny

      -- Wanted --
      Schrödinger's Cat
        Dead or Alive

      --
      Intron: the portion of DNA which expresses nothing useful.
  4. Moore's law by pwnies · · Score: 3, Funny

    I wonder if Moore's law will apply to the number of qubits within a quantum computer as well. A 1024 qubit computer within the next 20 years would be nice.

    1. Re:Moore's law by moderatorrater · · Score: 4, Funny

      Nobody would ever be able to use 1024 qubits.

      -moderatorrater, 2007

    2. Re:Moore's law by SeekerDarksteel · · Score: 2, Informative

      Probably not. Moore's law is a very specific and narrow-focused trend regarding the number of transistors that can be placed on a chip to achieve the highest cost effectiveness. Any major shift in technology (i.e. away from traditional transistors) will have it's own completely different trend. There's no inherent trait in computing as a whole that gives rise to Moore's law.

      --
      The laws of probability forbid it!
    3. Re:Moore's law by GeekZilla · · Score: 2, Funny

      "Four Qubits should be enough for anyone."

      --
      Veritas patesco per quaestio questio. Truth is revealed through questions.
  5. Err by zsouthboy · · Score: 3, Interesting

    I was under the impression that we couldn't simply use PHOTONS as qubits - because while photons do have a quantum state, they get all...destroyed.

    Of course, the article doesn't help.

    Anyone?

    1. Re:Err by SeekerDarksteel · · Score: 5, Informative

      You can use ANY quantum mechanical system with two discrete states as a qubit, just as you can use any classical mechanical/electric system with two discrete states as a bit.

      Typically with photons, it consists of the direction of polarization of the electro-magnetic field associated with the photon. Straight up and down represents one state, horizontal represents the the second state, and the photon can be in a superposition of both of these states.

      Saying that photons get "destroyed" is irrelevant so long as we can measure the photon's polarization when it gets destroyed because as soon as we measure the polarization, the quantum state of the photon is destroyed anyway and becomes worthless to us. This is true of any quantum mechanical system, so whether the system representing the qubit sticks around or disappears after being measured (whether a photon, electron spin, or otherwise), is only a matter of logistics of the quantum computer, not of the actual computation.

      --
      The laws of probability forbid it!
  6. Re:MATH by LMacG · · Score: 2, Informative

    I dare you to take that umbrage to the UK or Australia.

    --
    Slightly disreputable, albeit gregarious
  7. Huh? by RecoveredMarketroid · · Score: 3, Funny

    It has already calculated the prime roots of fifteen, three and five.
    Prime roots of three and five? Boy, the quantum world is weird!...

    Parse error! Parse error!
    1. Re:Huh? by Fx.Dr · · Score: 2, Funny

      "Ask it to divide by zero or the cat gets it!"

      The cat was both shot, and not. It was half a tragedy. We all cried furiously, and didn't.

  8. Re:MATH by Dahamma · · Score: 3, Informative

    Sorry, wrong. Math and maths are both colloquialisms, and neither is more valid than the other. Just Britith vs American english tendencies, mostly.

    http://www.answers.com/maths&r=67

    Thanks fo the rant, though.

  9. Me too! by Daffy+Duck · · Score: 5, Funny

    It has already calculated the prime roots of fifteen, three and five.

    I, too, have already calculated the prime roots of fifteen, with nearly identical results. Where's my DARPA funding?

  10. Re:MATH by Anonymous Coward · · Score: 2, Informative

    I think you'll find those of us who learnt English (that's English, not American English) call it maths - as in Mathematics. Note that lovely S on the end.

    The only place in the world I've encountered the word "math" is in North America.

  11. Prime roots, eh? by bubbl07 · · Score: 4, Funny

    It has already calculated the prime roots of fifteen, three and five.
    -1 Redundant.
  12. Re:MATH by bosko0 · · Score: 2, Informative

    "Non-native English speakers"???

    Yeah, like those who live in England, who are sometimes called the English?

    In the US it is "Math", in the UK it "Maths". And non-native English speakers are taught British English, not American English, thus the affinity toward the way things are said in England.

  13. Re:MATH by Anonymous Coward · · Score: 2, Funny

    There's more Americans who speak English than there are British. Therefore, we win! Majority rule!

  14. Re:MATH by elFarto+the+2nd · · Score: 3, Insightful

    I've taken to just calling it just 'American' rather than English.

  15. Can't stop myself...oh the Humoranity! by GeekZilla · · Score: 5, Funny

    Q: What kind of room is it kept it?
    A: A Qubicle

    Q: How big is it?
    A: About four Qubit meters.

    Q: Qubit? Wasn't that an early arcade game with a little guy jumping around changing the quantum state of a bunch of Qubes?

    I have OBVIOUSLY had too much Qaffeine.

    --
    Veritas patesco per quaestio questio. Truth is revealed through questions.
  16. Re:MATH by SeekerDarksteel · · Score: 2, Funny

    Mathematical of course. Because this is English. We don't remove suffixes, we ADD them.

    (Pun only moderately intended)

    --
    The laws of probability forbid it!
  17. Re:MATH by SnprBoB86 · · Score: 2, Insightful

    If you are going to be a grammar nazi... don't. Your post is riddled with grammatical errors.

    "People who speak very good English"
    Should be: "People who speak English very well".

    "Almost as bad as "loose" instead of "lose", but non-native English speakers get a pass since they don't know any better."
    Should be two sentences without the "but". You have several similar errors involving the word "But".

    Additionally, please try to eliminate your use of run-on sentences.

    --
    http://brandonbloom.name
  18. Re:MATH by Anonymous Coward · · Score: 2, Funny

    Australia spoke English, last time I checked.

    You've apparently never taken a look at the lyrics to Waltzing Matilda.
  19. It's Obviously... by hyades1 · · Score: 2, Funny

    Computerized Australian Technology...until you take a good look at it.

    --
    I've calculated my velocity with such exquisite precision that I have no idea where I am.
  20. That's no big deal by p3d0 · · Score: 4, Funny

    I once new a guy who could compute the prime roots of 15 in his head.

    --
    Patrick Doyle
    I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
  21. Re:MATH by Samgilljoy · · Score: 3, Interesting

    Correction: Some non-native speakers of English are taught British English, not all. Moreover, British English has not been the standard worldwide for many years, so outside of Commonwealth countries and Europe, people do not, as a rule, gravitate towards British English.

    And no, all this has nothing to do with which dialectic is better. It's just sociolinguistics. American English is the premier language of commerce and political power. It's also the medium of a huge amount of popular culture and marketing. Sooner or later, the prestige will shift elsewhere, just as it started to shift away from Britain after WW2. Sic transit gloria mundi.

    We should also keep in mind that for some language groups, English s-plurals are particularly challenging, so the "maths" issue gets obscured by its similarity to a huge amount of genuine errors.

  22. It's obvious that by hyades1 · · Score: 2, Funny

    Computerized Australian Technology lives.....until you take a good look at it.

    --
    I've calculated my velocity with such exquisite precision that I have no idea where I am.
  23. DARPA by CompMD · · Score: 2, Insightful

    is not an intelligence agency.

  24. Re:Law of conservation of time by jrcamp · · Score: 2, Interesting

    One possibility is that we ask the 'computer' of the universe to do too much computation and end up in an infinite loop, crashed universe, 'dark' part of a mandlebrot-like fractal, etc.

    I think that the fact that we are here, almost 14 billion years after the universe began, is a good indication that it's not possible to "crash" the universe.

    The original numbers plugged in the Drake Equation estimated 10 intelligent civilizations in our own galaxy. Since there are more than 100 billion galaxies, that means there could potentially be more than 1 trillion advanced civilizations.

    I would bet at least 1 out of that trillion are much more advanced than us and have managed not to "crash" the universe. Whatever the hell that means.

  25. Correction by geekoid · · Score: 5, Funny

    -- Wanted --
    Schrödinger's Cat
        Dead and Alive

    --
    The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
  26. Re:Law of conservation of time by fredrikj · · Score: 3, Interesting

    Soon we will be able to test 2^N possibilities in 2N time, but my question is where does that information come from? There's a lot of hand-wavyness on how that actually happens...

    Phenomena like superposition and entanglement are not fully understood from the metaphysical point of view, and there is some hand-waving about that. But the mathematics agrees perfectly with experiment, and that's all we need to know to put the theory to use.

    One possibility is that we ask the 'computer' of the universe to do too much computation and end up in an infinite loop, crashed universe, 'dark' part of a mandlebrot-like fractal, etc.

    Another possibility is that the 'computer' of the universe will simply abort operations that take 'too long', the quality of our simulation will degrade, and our complex quantum math will result in randomish results.


    How do we know building a quantum computer won't break the universe? Well, the things that go on in a quantum computer are the same things that go on in ordinary matter all the time. A speck of dust consists of some 10^20 particles that continually interact with each other according to the same quantum-mechanical laws that govern the interaction of qubits used in integer factorization. Why should the universe care what purpose we use those interactions for?

    And in the end, a size/time-N quantum computation can be simulated with 2^N space and in 2^N time on a classical computer (I might be wrong about the exact form of those expressions). Would the universe collapse if we run a quantum algorithm on a PC?

    And then there is the possibility held by quantum researchers that somehow the universe can magically perform any amount of complex computation with no cost at all.

    This isn't true. Quantum algorithms have real costs that grow with the size of the problem, just like on ordinary computers. (Concretely speaking, we can simulate them on classical computers in deterministic time.)

  27. Re:Microsloth Windows Excalibur by Eli+Gottlieb · · Score: 2, Funny

    So basically, technology has given us quantum computers in the future, but users are still stupid enough to deliberately put Windoze on a Macintosh machine?

    That says something about life.

  28. Re:MATH by Anonymous Coward · · Score: 2, Informative

    In addition to the math/maths/mathematics issue, American 'English' has a good collection of other atrocities. I've converted a few of the ones I find odd/amusing to British English :

    check = cheque (as in money)
    tire = tyre
    sulfur = sulphur
    seeing eye dog = guide dog
    thru = through
    gasoline = petrol
    pissed (angry) = pissed (drunk)
    pavement = road
    sidewalk = pavement
    chips = crisps
    french fries = chips (sort of...)
    quarter of 5 = quarter past 5
    pedestrian crossing = somewhere cars line up to run people over,
                                  especially when turning right on red light whilst making a phone call...
                                  (I was injured last week by an SUV under exactly these circumstances)

    Not to mention dates with month and day the wrong way round (MM/DD/YYYY) and words with 's' replaced by 'z', color/colour etc.

  29. Re:Quantum Computing Is Pure Unmitigated Bullshit by Nazlfrag · · Score: 4, Informative

    Who to go with, the military funded scientists working on a solid foundation of one of the most tested and proven physical theories mankind's best and brightest conceived of and developed with working models or a random blogger who can't get his head around the uncertainty principle.

    Well, fair enough, Einstein himself quoted 'God does not play dice' on this very issue, before coming to terms with it. You might have the best of intentions but unfortunately you're off track. Regardless of what anybodies opinion is the quantum uncertainty model accurately predicts all available data, and theories that coincide with empirical evidence are useful and usable no matter how small or great an understanding we have of the underlying processes.

    Come up with a simpler theory that fits all the data and I'll gladly accept your claims of crackpottery, otherwise open your mind a little and realise that regardless of a deeper understanding, if the math fits, we can do it, ergo quantum computing is not just feasible, but is already happening as we speak in labs the world over, like the one in TFA.

  30. I'm in trouble... by E++99 · · Score: 5, Funny

    It has already calculated the prime roots of fifteen, three and five.

    CRAP! 15 was my RSA public key!
    1. Re:I'm in trouble... by MattskEE · · Score: 2, Funny

      I use the same combination on my luggage!

  31. Roots are not factors... by geekgirlandrea · · Score: 2

    s/prime roots/prime factors/, please. Sheesh.

  32. What's a "prime root?" by wickerprints · · Score: 4, Informative

    The article mentions things called "prime roots." This is not a standard mathematical term. Rather, considering the context, quantum computing, and its most discussed potential application--quantum cryptography--it is likely that what was actually computed were primitive roots.

    For the sake of completeness, a primitive root of a prime p is an integer r such that the smallest positive value of k such that p divides r^k - 1 is k = p-1. For large primes, finding primitive roots is not a trivial task. For example, r = 2 is a primitive root of p = 5, since the positive integer powers of 2 are 2, 4, 8, 16, 32, ..., and modulo 5, this becomes 2, 4, 3, 1, 2, .... The first occurrence of 1 is for 2^4, hence k = 4 = 5-1.

  33. Re:MATH by Aardpig · · Score: 2, Informative

    No truth. You're just the ignorant fuckwad who wasn't aware that the English say 'maths'.

    --
    Tubal-Cain smokes the white owl.