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Science Hardware Technology

Triple E Entanglement Lends Hope to Quantum Computer 135

Posted by Hemos from the building-the-machine dept.
tinrib writes "New Scientist reports that a new semiconductor-based technique for entangling multiple electrons could mark a significant step towards the development the first fully-functional quantum computer. The new technique involves using electrons rather than the more traditional photons and ions, and so far they have managed to entangle three electrons. "
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Triple E Entanglement Lends Hope to Quantum Computer More

Triple E Entanglement Lends Hope to Quantum Computer

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  • MMm Hmm (Score:4, Funny)

    by Raul654 ( 453029 ) on Monday March 03, 2003 @10:31AM (#5423774) Homepage
    Entangled electrons? Well, it might be early in the morning, but I'm always up for hearing about electron bondage :)

  • Repost. (Score:3, Informative)

    by waytoomuchcoffee ( 263275 ) on Monday March 03, 2003 @10:33AM (#5423783)
    Repost. [slashdot.org]

  • And if they entangle a fourth (Score:5, Funny)

    by Genyin ( 415163 ) on Monday March 03, 2003 @10:34AM (#5423790) Homepage Journal
    And if they entangle a fourth, maybe they'll be able to factor 15.

  • Triple E Enlargements (Score:5, Funny)

    by gricholson75 ( 563000 ) on Monday March 03, 2003 @10:34AM (#5423792) Homepage
    Am I the only one who saw TRIPLE E enlargements, and didn't think at all about electrons?

  • How big? How many? (Score:3, Insightful)

    by rhs98 ( 513802 ) <`ku.oc.taobatisi' `ta' `89shr'> on Monday March 03, 2003 @10:34AM (#5423795) Homepage Journal
    How many entangled's are needed to make a usable device?

    Physically how big are the "box's" containing these 3 entangleds
    • the question is the same as "How many logic gates/bites etc do you need to make an electronic usable device?" depends on the application!

    • Scales exponentially with the number of entangled (Score:4, Informative)

      by mmacdona86 ( 524915 ) on Monday March 03, 2003 @10:50AM (#5423887)
      The computing power (for certain applications) is supposed to scale exponentially with the number of entangled qubits. If they ever get 16 qubits entangled, that would certainly be an interesting basis for future research. Anything less is kind of a toy. You'd probably need 32-64 before you start getting to the point of actual usefulness for specialized applications. Of course, when people talk about instant codebreaking, they are envisioning ~1000 qubits entangled. Of course, the difficulty of getting n qubits entangled probably scales exponentially with n as well, so I think the whole notion of quantum computing will remain theoretical. Keeps some physicists in grant money, though.
      • If they ever get 16 qubits entangled, that would certainly be an interesting basis for future research. Anything less is kind of a toy.

        16??!?! Jeebus, but every sunday-school student knows that Noah's ark was 40-qubits, and that was thousands of years ago!

        You'd think that modern science would be getting better at this, not worse.
      • don't put anything passed human inovation. it migth be dificult to do, but so what...it is not impossable...now of cource as n approaches infinity then you have problems, but 1000 is a long way off from infinity.
      • Of course, the difficulty of getting n qubits entangled probably scales exponentially with n as well, so I think the whole notion of quantum computing will remain theoretical. Keeps some physicists in grant money, though.

        Indeed. One reason to keep funding them, at least until hard limits to the problem are determined, is that the payoff is potentially enormous. Quantum codebreaking could revolutionize the CIA and NSA's job for a while, putting them back to the golden era in WWII when they had cracked German codes like Enigma, without the knowledge of the Germans.

        Quantum computing will be almost the exact opposite of ordinary computing: today, the difference in computing power available to the average joe, compared to large corporations and governments, is not that great. Quantum computing will change this balance - it'll only be available to the big guys, at least for a good long time. It'll potentially be an enormously profitable tool, which could confer great power to those who control it.

        It's like the information-age equivalent of the atomic bomb - once the possibilities were understood, it didn't make sense *not* to work on it, because the possibility of one's enemies/competitors having it when you didn't was horrible to contemplate.

    • Argh. It's painful how few people understand quantum computing.

      First, the advantages of quantum computing. It is well established that there are quantum algorithms for which there are no known efficient classical algorithms. That is, there is a known efficient quantum algorithm for breaking RSA, and no known classical algorithm. Complexity theory still hasn't been able to determine if P belongs to NP, so there may theoretically be an efficient classical algorithm that breaks RSA. Only time and lots of math will tell. However, it is possible (and some say likely) that the space of problems that quantum computers can tackle efficiently is strictly greater than the space of problems classical computers can solve efficiently.

      In a physical quantum computer, noise is a problem. That is, your qubits will become entangled with the environment and you lose the information encoded in them. Several others have noted this problem. What they have not noted is that there exist techniques for overcoming the problem of noise using additional qubits. The math is complicated, but the outcome is that quantum computers can be made sufficiently reliable and stable to perform computation at realistic conditions (i.e. well above absolute zero. like room temperature). However, this increases the number of qubits one would need to perform computation with.

      For instance, the number of qubits needed to break RSA grows with the log of the size of the key. This is very encouraging. However, the number of qubits necessary to provide sufficient error correction grows this number significantly. That said, a reasonable piece of quantum hardware that could break 1024 bit RSA would require something on the order of 10^3 qubits, subsets of which would need to be entangled to perform the computation.
      • Note that the above numbers are for a application specific quantum circuit designed solely to break RSA. To my knowledge, no one has proposed a design for a general purpose quantum computer, though it has been proven that it is possible to build one. There are lots of technological (not mathematic or physical) problems associated with designing a general purpose quantum computer. Merely having a large quantity of entangled qubits is not sufficient.
    • IIRC it is not the entangled particles(electrons in this case, photons in more common cases) that do the computations. The entangled particles are used to etch the materials used in making the chips. For some reason, after you entangle the particles, they can etch the surface of the die at a smaller size than their width. In other words, they can make a cut in something less than thier size (and it gets smaller as the number of entangled particles increases). However, I could be totally wrong, in which case I hope that this didn't help :)

  • What is Quantum Computing? (Score:3, Insightful)

    by whoisvaibhav ( 654143 ) on Monday March 03, 2003 @10:36AM (#5423800) Homepage
    Just like the subject says: What IS Quantum Computing?

    • Re:What is Quantum Computing? (Score:4, Informative)

      by Grr ( 15821 ) on Monday March 03, 2003 @11:05AM (#5423989)
      This site [qubit.org] managed to explain it to this programmer with only a moderate starting knowledge of particle physics.
    • All I really know that in my field (information security) it spells the death-toll for all current encryption algorithms. Infeasible math problems will cease to exist.

    • Re:What is Quantum Computing? (Score:2, Informative)

      by Anonymous Coward
      Quantum computing is a way of entangling quantum bits (or qbits) so that they can perform complex calculations instantaneously. Because classical computing requires a particle to be in only one state at any one time a program must be executed as a series of commands which is a time consuming business. quantum physics (as defined by Einstein) allows particles to be in all states simultaneously which means that all elements of the calculation can be done in parallel with the associated performace increase that this involves. As a result calculations which were quite complex to perform using classical methods (such as Fermat's last theorum) can be trivially solved. And as another poster pointed out this will mean that all encryption (yes even quantum encryption) can be broken.
    • If you enjoy your research in the form of good hard science fiction, Robert J. Sawyer [sfwriter.com] currently has a trilogy, with the second book just in bookstores, regarding an alternate world where Neanderthals survived while Humans died out, and includes details on privacy, quantum computing, and different extinction selections and how they affect the same world. Really interesting read.

    • Re:What is Quantum Computing? (Score:5, Informative)

      by wass ( 72082 ) on Monday March 03, 2003 @02:10PM (#5425303)
      Quick answer.

      Classical computing deals with bits which are exactly in one of two states, 0 and 1.

      In quantum mechanics, the 0 and 1 state are two eigenstates for a single qubit. However, each qubit can be in a linear combination of these two eigenstates (state must be normalized to 1). If you measure whether the state of a single qubit is a 0 or 1, then you've collapsed the wavefunction, and the particle is forever in that specific state (if no future interactions occur).

      That in itself isn't too interesting. But if you make a system of several qubits, you can overlap the wavefunctions, or entangle the qubits, in such a way that an operator acted on the system relates to a specific process you're trying to measure (ie, factoring a number), and the multi-qubit eigenstates of that operator. This means that the intermediate qubits, which are in linear combinations of the states 0 and 1, interact amongst each other, and measurement of the entire system yields a value of the measurement operator by letting the qubits interfere nearly simultaneously. This is why many apparent operations can happen in parallel in a quantum computer.

      I don't know the specifics of how to apply Shor's algorithm or any other quantum computing algorithms, but that's the basic gist of it. Interference of the wavefunctions of several individual qubits can do some interesting things.

      That said, there are several ways of creating a qubit. One way exploits the fluxoid quantization of a superconducting loop. Any loop of a superconductor MUST have a total magnetic flux through it equal to an integer multiple of the fundamental flux quanta. So, if you apply a magnetic field such that you are applying exactly half this value, superconducting currents must thenflow around the loop to give extra magnetic flux (Ampere's law) to make the total flux an integer multiple of the flux quanta. These currents can flow to either enhance the applied field, giving 1 flux quanta, or they can destroy the applied field, giving 0 flux quanta. However, until the current is measured, it isn't known whether it flows clockwise or counterclockwise. The state of this qubit is thus in a state 1/sqrt(2)[clockwise] +1/sqrt(2)[counterclockwise].

      Other ways to make a qubit make use of spintronics, which use the two spin states of an electron as the basis for the two qubit states. This is an upcoming approach, as spintronics research is really taking off quickly now.

      People have also used NMR to produce the qubits, which I don't know the details of. But IIRC, this was the method used by the group that prime factored 15.

  • Once again, the extreme depth of our knowledge about semiconductors, as a result of their usefulness in computers over the past few decades, lends itself to a rather novel and unrelated use.

    Cool!

  • important for multi bit computing (Score:5, Informative)

    by Anonymous Coward on Monday March 03, 2003 @10:40AM (#5423832)
    Electrons are highly mobile and relatively easy to handle, but so far there has been a lack of good ways to handle them well. By entangling several of them you get more degrees of freedom and can build a quantum computer with more bits.

    If these techniqes can be extended, it might be possible to build an effective quantum computer with eight or even more bits. And remember that quantum bits aren't directly comparable to bits in traditional microprocessors, so eight is really very good.

    The next big challenge is miniaturization; a quantum computer is tiny, but the equipment to monitor and interpret computations is massive.

    • Re:important for multi bit computing (Score:1, Informative)

      by Anonymous Coward
      1. You dont MOVE electrons. It's like the example of the iron balls hanging from strings: the first one hist the second and the force is propagated to the final ball while all the others are still. This is why current moves with the approximate speed of light, while electrons in general move at mush lower speeds and towards random directions.

      2. For some people, quantum computer is hype. Over here at MIT, research on quantum computing has been abandoned (well, typically at least)

      3. What does miniaturization has to do with quantum computing which is supposed to make faster chips?

  • Cannot resist... (Score:4, Funny)

    by HiQ ( 159108 ) on Monday March 03, 2003 @10:43AM (#5423843)
    Exploiting such quantum weirdness, a quantum computer would be able to perform many computations at once, making it vastly more powerful than a conventional computer.
    I'm sure the masters of code bloat will hog up such a computer as fast as you can say 'Schrodinger'. The main advantage of doing multiple computations at once will be that while your quantum computer BSOD's, Clippy will come walking right through that asking if you need help.

  • White Paper (Score:3)

    by Gyorg_Lavode ( 520114 ) on Monday March 03, 2003 @10:43AM (#5423848)
    Does anyone have a PDF white paper by the researchers on the subject? I'd like to read alot more.

    • Re:White Paper (Score:3, Informative)

      by dracken ( 453199 )
      This site is for searching CS publications based on citations and other criteria. There are numerous papers [nec.com] on quantum computing many of which provide an excellent introduction. Ofcourse the webpage of faculty and their lecture notes ( here [berkeley.edu] and here [berkeley.edu]) provide an excellent introduction. I would recomment going through the lecture slides before attacking a few of the more readable and fundamental papers.

  • a good idea but doomed to failure (Score:4, Informative)

    by Anonymous Coward on Monday March 03, 2003 @10:44AM (#5423854)
    I'm not realy an expert on quantum computing but I think there's a good reason to assume that this approach will be doomed to failure.

    the problem is not entangling the photons in the first place but keeping them in that state, the slightest disturbances (lorries going past, the old woman next door doing the hoovering etc etc) can cause them to become untangled, and so for this reason the whole system must be cooled to absolute zero.

    Unfortunately the method described in the article does not easily allow for this as the technique only allows for adiabatic cooling to be used as opposed to the more efficient direct pressure systems used on compteting technologies. Without this it is likely to be far too expensive to be brought into general use

    • Re:a good idea but doomed to failure (Score:5, Informative)

      by QEDog ( 610238 ) on Monday March 03, 2003 @10:55AM (#5423926)
      for this reason the whole system must be cooled to absolute zero.

      That is not true. You don't need then to be entangled for the rest of the eternity, just for a few nanoseconds, so you can compute with them, and then reset them back to its entangled state for a new computation.

      The problem with /. reposting news is that I'm so stupid that I read the comments again, they usually end up being the same questions, and I end up answering them again.

    • If you can entangle 5 qubits, you can encode a single qubit worth of information with quantum error correction (such that if any 3 of 5 qubits maintain coherence, the state is preserved), provided you can maintain coherence long enough to perform a quantum error correction cycle. So all you need is 5 times as many qubits as you need to perform your calculation, and you can perform arbitrarilly long calculations.

      It's theorized that solid state QC's have a very good chance of scaling to large numbers of qubits, enabling such quantum error correction algorithms to be used and thus solving the decoherence problem.
    • [ the problem is not entangling the photons in the first place but keeping them in that state, the slightest disturbances (lorries going past, the old woman next door doing the hoovering etc etc) can cause them to become untangled, and so for this reason the whole system must be cooled to absolute zero. ]

      As some other people have pointed out, there are quantum error correction codes that allow you to perform quantum operations given that your error rate is below a certain threshold (I don't remember the right number, but I think that you need to be able to perform about 10^4 operations before your system dephases in order to have a "fault tolerant quantum computer". Besides, there are several proposals that look to minimize the dephasing problems.

      Other point is that entangling photons is not that difficult (altough not that easy either...). However, entangling electrons in a controlled way in a solid state sample is much more difficult. That is really cutting edge research.I am *really* interested in looking at their scientific paper.

      Just as a note, quantum computers are not around the corner and won't be for quite a while, but I don't think we'll ever get a refrigerator so good that reaches absolute zero (unless Lisa Simpson invents it).

      Pablo B.
  • I realize its early Monday morning, but I could have sworn that the headline read:
    "Triple E Enlargement Lends Hope to Quantum Computer"

    Needless to say I was both baffled and erotically curious.

  • 3 entangled electrons... Which one is Michelle Pfeiffer ?

    Steve

  • New Scientist != Science (Score:3, Interesting)

    by gr8_phk ( 621180 ) on Monday March 03, 2003 @10:54AM (#5423913)
    I've read a number of articles at that site linked from /. stories and none of them were about really solid scientific findings. In this case, these guys are probably advertising a weak concept to get grant money. If not, they would probably keep quiet and go for patents or at least publish in a respectable journal.

  • DMCA Lawsuit (Score:3, Insightful)

    by Greyfox ( 87712 ) on Monday March 03, 2003 @10:56AM (#5423932) Homepage Journal
    The DMCA lawsuit won't be pretty, since every company on the planet that makes a living off encryption (From the MPAA to Verisign) will sue these people for making a device capable of breaking copyright protection. The advent of the first working quantum computer will be followed shortly by the makers of that computer being sued into oblivion.
    • Or quite frankly it will be illegal to possess, as such a powerful decryptor would be considered a weapon.

    • Re:DMCA Lawsuit (Score:4, Informative)

      by enjo13 ( 444114 ) on Monday March 03, 2003 @07:10PM (#5428009) Homepage
      For the love of GOD how does this get rated as 'Insightful'.

      In order to be illegal under the DMCA the devices PRIMARY USE must be to circumvent copy protection. No one outside of the RIA and MPAA would argue that a quantum machine was anything remotely close to that.

      The effect of Quantum machines in terms of military intellligence (and the populaces right to own them) will surely be debated, but there is nothing in the DMCA that can be used to prevent the spread of Quantum machines.
      • I'd be willing to bet that any of the aforementioned entities will try and given the amount of money they can bring to bear, I expect they'll have a good amount of success in court. If they don't have a good amount of success in court, they'll just buy a few more congressmen and have some more laws passed.

        In short: No quantum computer for you.

  • 3 electrons? (Score:3, Funny)

    by ZorMonkey ( 653731 ) on Monday March 03, 2003 @10:59AM (#5423958)
    3 entangled electrons hey? I think they're starting to hoard them... Could this be the reason we have a power shortage? Soon, they'll have all the electrons entangled, and we'll really be hurting. ::scampers off to hoard his own electrons::

    • Re:3 electrons? (Score:1, Funny)

      by Anonymous Coward
      You already have 10^30 of them at least...stop hoarding already!

  • Quantum Computer Eh? (Score:3, Insightful)

    by The Original Atrox ( 449206 ) on Monday March 03, 2003 @11:07AM (#5423996) Homepage
    Yes, this is a very small baby-step twards a quantom computer.... But, I personally view each such step with a little trepidation. Once the first quantom computer is made... all our present encryption will be... useless against it. Because of its prime factoring ability. Its one of those things, that every time a piece of technology gets something to move a little itsy bit closer to that, I regard it like every little bit closer to the A-Bomb that the Manhatten Project got... viewed with trepidation. The biggest problem with the quantom computer is that... initially, and for many many years, only a select few (those with the -big bucks-) will ever have one, or access to one. This.... this privacy we hold so neer and deer online will perish. Unless there is a form of encryption that can be achieved by PCs, that can boggle a quantom computer... which... I dont see as comeing any time soon. And no... I'm not paranoid, everyone just thinks I am ;)

    Microft
    -Beware of he who would deny you access to information, for in his heart, he dreams himself your master.
    • I make no claim to being an expert on such matters but, until someone corrects me, I think it is an exaggeration to claim that unbrakeable cyphers will not be possible. For sure, the computational power of a true, large scale, quantum computer will be immense. However, it will not be unlimited. In essense, it will operate as a massively parallel computing device. The degree of parallelism will not be infinite.

      What this implies is that messages encrypted using techniques common today, such as IDEA with 128-bit keys, will be easily broken. It will, of course, have no effect on messages encoded using one-time pad techniques. Further, I assume that current public key methods with long enough keys will still be safe in practice.

    • But, I personally view each such step with a little trepidation. Once the first quantom computer is made... all our present encryption will be... useless against it.

      To modify an old phrase: What quantum physics giveth, and it taketh away.

      Quantum encryption makes it impossible for wiretappers to snoop on transmissions. As long as the communication endpoints are secure (this includes physical security), transmissions over quantum channels are completely secure, quantum computers NOTwithstanding.

      The problem with completely secure crypto isn't technical, it's economic and political. You need special equipment (and a direct fiber link) to do quantum crypto. Unless you can afford (and are legally allowed) to buy this equipment, your communications will be vulnerable to governments and powerful corporations who have quantum code cracking computers.

    • heres a good form of encryption.

      step one: make up your own alphabet/language.
      step two: write a letter in it on paper
      step three: bite the bullet and pay the 40 cents to mail it.

      as long as you don't leave your rosetta stone lying around your good. :)
    • Don't you worry, Atrox; your dismal view of quantum computing's future won't come to pass. And if this really does bother you, I'd suggest reading up on quantum computing someplace besides /.

      There are only around a half dozen algorithms anyone's come up with for a quantum computer that are good for anything; one of them is for factoring primes, which makes RSA encryption (to my understanding) more or less trivial to break.

      If, suddenly, people gain access to quantum computers.... we'll start using other encryption schemes. It's not an "end to privacy"; it's an "end to RSA encryption".

      So sleep well at night; the big bad QC's aren't coming to get you... and for the love of God, don't get your education on anything with the word "quantum" in it from here!
      • I stand corrected... a QC would be a risk to public-key cryptography only. So... I suggest we start finding ways to get ourselves some one-time-pad systems going... Some way to distribute keys 'not in the open'. So yea... either that, or work on non-RSA ways for clients to agree on a session key. OGR is one such tech that is looking promiceing.

        Microft

  • All about Quantum Computing (Score:5, Informative)

    by infolib ( 618234 ) on Monday March 03, 2003 @11:08AM (#5424000)
    here [qubit.org]

    Especially recommended are the tutorials [qubit.org] where you can pick up material corresponding to your current understanding of quantum mechanics.

    For this article, you might be looking for the Kindergarten explanation of entanglement [qubit.org]

  • Great! An infinite number of ways to crash! (Score:3, Funny)

    by HarveyBirdman ( 627248 ) on Monday March 03, 2003 @11:25AM (#5424125) Journal
    So not only can I have bus errors and memory errors and network errors, but my processor's entanglements can collapse at any moment.

    I can see it now. "Dr. Watson reports answer hazy. Try again later."

  • what are the differences between quantum computing and quantom processing. Is quantum processing theoretically impossible while we already found out that quantum computing is possible?

  • Well of course they're triple entangled (Score:4, Funny)

    by kfg ( 145172 ) on Monday March 03, 2003 @11:38AM (#5424248)
    I *told* them keeping a kitten in the lab was a bad idea, but would they listen to me? Nooooooooooooo!

    "It's so cute," they said.

    "It won't be any trouble," they said.

    "It'll keep the mice out," they said, trying to prove it was working animal instead of the fact that they were just a bunch of softies.

    Now all I want to know who's going to sit here all day and untangle this mess, 'cause it sure as hell ain't gonna be me.

    Maybe I'll get lucky and the damned furry little vomit ball will go curl up in the "warm spot" in the cyclotron.

    KFG
    • I *told* them keeping a kitten in the lab was a bad idea, but would they listen to me? Nooooooooooooo!

      In quantum information, kittens are important. In order to get the entangled states to survive long enough to do any useful work, we must offer cats to the Great God Schrodinger. If Schrodinger is pleased with the sacrifice, the cat dies and the computer works. If Schrodinger is displeased, the cat lives and the computer fails. Sometimes the cat dies AND the computer fails, but that's just experimental error.

      The sacrifice of cats is quite essential, and a well-respected scientific procedure. Please don't tell the animal rights people, they won't understand.

    • Didn't anyone ever tell them not to leave the electrons lying on the floor? ;-)

      LOL funny post KFG

      SB

  • Quantum grandad (Score:5, Insightful)

    by pubjames ( 468013 ) on Monday March 03, 2003 @11:45AM (#5424298)
    My grandfather was a professional photographer, and when I went to see movies with him at the cinema he used to love to explain to me how the special effects were done (painting scenery on sheets of glass, that type of stuff). Then one day we went to see something - (Close Encounters or Star Wars or something) and the film made him kind of sad because he couldn't explain the effects to me. I remember thinking that that must be a defining moment in one's life - when you start to find things in your own profession that you don't understand because it has quicker than you've been able to keep up.

    I'm only 32 and I've been into computers since I was a kid. But I can't get my head round this quantum stuff at all. At least my grandad was in his late sixties before he started not understanding things. Seems like our generation aren't going to be so lucky. Or perhaps everyone else understands it and I'm just dim. Ho hum.
    • Whether at 60 or 30 we will all find current technology escaping us when we cease to keep up with the pace.

      If you choose to "bow out" of the race why be sad about it? Be happy that others are forging ahead in your absence and that you can now enjoy the technological "magic" along with the rest of the civilians.

      PS Quantum doesn't need to be very complicated. Superposition seems complicated when they throw the math at you but its really just this:

      The universe hasn't yet decided the outcome of certain quantum events so all possibilities exist at time zero. A quantum calculation involves forcing the universe to resolve the uncertainty at time one. Programming a quantum calculation involves setting things up so that the universe will select or sort for the outcome you are looking for given a range of inputs.
      • PS Quantum doesn't need to be very complicated. Superposition seems complicated when they throw the math at you but its really just this:

        The universe hasn't yet decided the outcome of certain quantum events so all possibilities exist at time zero. A quantum calculation involves forcing the universe to resolve the uncertainty at time one. Programming a quantum calculation involves setting things up so that the universe will select or sort for the outcome you are looking for given a range of inputs.

        [Slaps forehead] Oh, now I understand! It's all so simple! At a quantum level, all possibilities exist and all we are doing is forcing the universe to resolve uncertainty! Piece of cake!

        • Re:Quantum grandad (Score:5, Interesting)

          by Hentai ( 165906 ) on Monday March 03, 2003 @02:15PM (#5425341) Homepage Journal
          It's more fundamental than that.

          Quantum mechanics unravels deterministically, while it is sampled stochastically. What this means is that the universe is computing the outcomes, and we're sampling random values within those outcomes.

          In layman's terms, the idea is to tap into the biggest, fastest, most powerful physics computational engine ever created, and setting up bizzare interactions of objects, because the particular bizzare interactions will happen to result in a state that we can read to get an answer to a math problem - simply by the nature of the laws of physics, which are mathematical. If we know, for example, that EM is an inverse square law, then the simplest way to compute the inverse square of X is to convert X into the distance from a light source to a sensor, and just read the sensor.

          Using the fundamental laws of physics to do math is the idea behind the abacus, in an extremely abstract sense. It's also the idea behind the Babbage computer, in a slightly less abstract sense, and behind the electronic computer, in an even less abstract sense. The quantum computer just continues the de-abstraction trend, and gets the computation as close to the bare-level of the actual physics engine as possible.

          Think about it - if you have a itty bitty calculator that can do 3 calculations per second, any calculations you want, or a huge honkin' physics simulator that can do 3x10^30 calculations per second, so long as they're all four-dimensional tensor calculations, what's easier - punching in sixteen trillion equations by hand into the hand calculator, or finding a way to convert those equations into four-dimensional tensor calculations and throwing them at that enormous physics computational engine?

          Now, what's the biggest physics computational engine we have access to? (hint: You're soaking in it.)

    • Re:Quantum grandad (Score:4, Interesting)

      by Mahrin Skel ( 543633 ) on Monday March 03, 2003 @12:28PM (#5424594)
      It makes my head hurt, but I sort of understand it. Quantum computing ties into the theory (now seeming pretty well proven) that at a sub-atomic level, all of the things that *can* happen, do happen, until someone actually observes them and forces the system to assume a fixed state. Electrons have "spin", and one of the properties of that spin is that it *must* be either up or down (don't worry what "up" or "down" means, think of it like flipping a coin). A "quantumly entangled" electron may have either up or down spin, and as long as you don't look at it directly it will behave like it has both (you flip the coin and catch in in your fist, you don't know whether it is heads or tails, even though it must be one or the other).

      In QC, you set things up so that the "quantum entanglement" is going to do a calculation for you, in effect you're not only using the computer you built, but all of the computers it might have become. Then you observe the results in such a way that only the "potential" computer that achieves the right result is remaining.

      If you really want to give yourself a headache, think of it this way: To find out if the cat in the box is alive or dead, you ask the cat.

      --Dave

      • If you really want to give yourself a headache, think of it this way: To find out if the cat in the box is alive or dead, you ask the cat.

        I don't think I can get my head around poking my computer with a stick to get an answer...

      • Nah.. thats only semi-decidable since you'll never get a response from a dead cat..
        The trick is to find out how to ask the box!
    • Well, as yet quantum computing has a lot more to do with low-temperature physics than computer science, so it's not surprising that even if you were "into computers since you were a kid" you wouldn't be up on quantum computing.

      There has been information-science work on how a quantum computer might be applied, but it has naturally been purely theoretical now, so again if your interest in computers hasn't extended as far as information-science theory you shouldn't be surprised not to be up on quantum computing.

      It's not like Oracle is going to be advertising "Oracle 11i with Quantum Query extensions" any time soon..."

    • Re:Quantum grandad (Score:1, Insightful)

      by Anonymous Coward
      Funny, I feel the same way.

      Or perhaps everyone else understands it and I'm just dim.

      Here's the scarier, and even more likely reality : NOBODY understands it fully, but everybody understands their little piece well enough to be able to collectively put something together.

      This exponentially increasing requirement of trust keeps me up at night.
    • Don't worry, you're not dim; this stuff isn't easy. I've taken five semesters of quantum mechanics classes, and I'm just now starting to gain some intuition for what's going on down there.

      If you really want to understand the stuff in the news about quantum computing and nanotechnology, I'd recommend going to a bookstore near your local science/engineering college, and peruse the used textbooks for a good one on quantum mechanics. Some of them introduce quantum with a telling experiment (Stern-Gerlach or photon polarization); I find that this is the easiest way to attach some physical significance to the ideas discussed in the news (keep in mind that most journalists don't know any more about this than you, so take what they write with a grain of salt!).
  • There is a great book called Entanglement:The Greatest Mystery in Physics [216.18.4.194]

    The the author Dr. Amir Aczel was interviewd by Quarks and Quarks [radio.cbc.ca] (a CBC radio show).

    The interview aired on the December 14, 2002 show [radio.cbc.ca]
    You can listen to the the author in mp3 [radio.cbc.ca] or ogg [radio.cbc.ca]!

    I highly recomend the book. It is technical, but very readable for anyone with a little math/physics background.

  • Electrons.. for computing? Now that's a truly radical idea!
  • Not being an English speaker nativelly, I needed to look at what exactly was the meaning of Entanglement.
    Well, I've made a quick lookup in the dictionary [reference.com] and I think, after having read the article, that the second
    definition must be the most accurate one.

    1. To twist together or entwine into a confusing mass; snarl.
    2. To complicate; confuse.
    3. To involve in or as if in a tangle. See Synonyms at catch.
    • In Russian, there are two possible translations of entangled, e.g. as in entangled states:
      1. Zaputannye sostojanija
      2. Pereputannye sostojanija
      The researchers I met commented that when one talks about this, one picks the translation that best describes his understanding of the subject :)
  • Big deal, Slashdot quantum entangles posts all of the time: http://science.slashdot.org/article.pl?sid=03/02/2 6/2345203&mode=thread&tid=134
  • It's not foolproof, but an interresting explanation of quantum mechanics:

    A cat is placed in a sealed box with a device which releases a fatal dose of cyanide if a
    radioactive decay is detected. In this state the cat is neither alive nor dead but a ghostly mix of the two possibilities.

  • Do I now need to upgrade all of my encryption keys to 1048576 bits, so they aren't cracked in a millisecond?
  • Here [spacedaily.com] is a better page with a link to the actual paper, and here is another one [umich.edu] To actually get the published paper, it requires free registration though...

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