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Science

Silicon Buckyballs = Quantum Bits? 101

Posted by timothy from the unceasing-wonders dept.
nachoworld writes: "Scientific American has reported that buckyballs have been made from silicon instead of carbon. Because the Si-Si bond is weaker and longer than a C-C bond, silicon was thought to be unable to form a buckyball-like structure. But Hidefumi Hiura and colleagues at the Joint Center for Atomic Research in Japan have been able to create a buckyball with a stabilizing tungsten core. Granted this core changes the properties of the Si buckyball, but Hiura suggests that they may serve as excellent quibits, which store single bits of information in quantum computers. The spin state of the metal atom could encode the bit, and the silicon cage would protect it from corruption."
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Silicon Buckyballs = Quantum bits? More

Silicon Buckyballs = Quantum bits?

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  • is a method of reliably -reading- these bits. Believe it or not, spin isn't the easiest measurement to make on a tungsten atom inside a silicon-60 cage.

  • Beverly Hills rejoices! (Score:5)

    by drin ( 83479 ) on Wednesday February 28, 2001 @06:55AM (#395125)
    And suddenly the plastic surgeons had a much more powerful tool than previously available... one large buckyball in each breast, and voila! Buckyboobs!

    (I know, it's silicon, not silicone, and it's definitely not saline, but I couldn't resist...)
  • what IS a buckyball?
  • With all the discussion of potential quantum "bits", I never see a discussion of how exactly they could be made addressable. It's not like they can all be made to stay in the same place, unless you isolate them in some sort of larger structure, which would defeat the purpose of using them in the first place.

  • How do the plan to read the spin state? (Score:3)

    by tcd004 ( 134130 ) on Wednesday February 28, 2001 @06:58AM (#395129) Homepage
    Can you imagine how delicate a processor of this nature would be. I would expect that the tiniest magnetic field could potentially disrupt the entire process. If we're talking quantum computing, then the spin state can represent a near-infinite number of positions, correct? If this is the case, the slightest fluxuation in the spin state would cause data-corruption.

    However, this is purely based on assumptions. I could be completely wrong. I still do math using my 10 fingers.
    tcd004 The heart of the Pentium 4! [lostbrain.com]
    The Microsoft Split, revisited! [lostbrain.com]
    The Stockphotos [lostbrain.com]

  • Re:stupid q: but WHat IS? (Score:3)

    by lithis ( 5679 ) <.gro.learhteh.gles. .ta. .ds.> on Wednesday February 28, 2001 @06:59AM (#395130) Homepage
    a buckyball is a specific arrangement of atoms so that they form a sphere (like a geodesic dome). they're named after r. buckminster fuller [netaxs.com].
  • If you really wanted to be helpful you`d hide a link somewhere in your post ;)
  • Ok, I've heard that one and/or/not gate is like 4-5 molecules in today's chips... How much smaller would a buckyball bit be than a regular J-K, T, D, whatever flip-flop ?
  • I believe the article is about using bucky balls to form cage like structures that house the atoms. That would be isolating them in very small structures wouldn't it?
  • These aren't really bucky-like structures as they are apparently incapable of being 'freestanding' - the cage structure depends upon the central metal atom for support, just as many other types of atom/ion are capable of ligand binding to a metal (usually, though not always a transiion metal) centre.

    The problem is that the article doesn't really give a huge amount of detail on the metal centre used, although if they are crowding 12 silicon atoms around it, I'd expect it to be fairly large. Nor is it explcitly stated that there are silicon-silicon bonds, although this is definitely implied by the diagram adjacent.

    Without reading the actual paper itself, the existance of silicon buckballs is definitely unproven for me.

    Elgon

  • How would you move THAT thing around a circuit board? It's f--in' HUGE!

    I think if quantum computing is going to work, it's going to be first done with electrons. They're just easier to deal with. We have more practice with them, anyway. (Maybe photons.)

  • There a are some people at CMU doing this. [cmu.edu] Their main interest is with Carbon-60 -- but they do work with other molecules such as samarium-cobalt, neodymium-iron-boron, cobalt-boron-silicon, tungsten carbide, silicon carbide, europium and gadolinium. They're right at the cutting edge, experimenting with all minds of materials that show any promise.

    It seems a little like supersonductors... you just have to keep trying new materials.

    There is a good article [firstscience.com] about BuckyBalls from First Science here as well

  • You can check them out at the Joint Center for Atomic Research [jrcat.or.jp] site. According to their organizational chart [jrcat.or.jp], they are working on some interesting things indeed!!

    _
  • Time for a little rant.

    The article says that these SiBuckyballs (suckyballs?) 'may' be able to serve as qbits. Interesting, yes. Fathomable to a dumb monkey like me? No. I mean, hell, I'm all about quantum computing. More better faster cheaper and all that, but the reason I read Popular Science and Discover magazine instead of Scientific American is that the articles in the former mags are *so* very much more comprehensible to me. I mean, I'm not a moron (really!) but I am also not a physicist, chemist, lawyer, doctor, lesbian or a Bhuddist. I have various knowledge in all of these fields, but no formal training. PopSci and Discover give so much more background and explination of basic concepts than does SciAm. I just wish that Popular Science would have more technical articles, but still explained in little words for dumbasses like me.
    Okay, I'm done ranting now. Panties are no longer in a metaphorical bunch.

    So how about them Knicks, eh?


    Brant
  • How many Quibits to a Q*Bert?

  • Re:stupid q: but WHat IS? (Score:4)

    by Chakat ( 320875 ) on Wednesday February 28, 2001 @07:04AM (#395140) Homepage
    A buckyball is the short name for the molecule given the name Buckminsterfullerine. This molecule usually consists of pure carbon and is spherical shaped. The molecules got their name from their resemblance to the geodesic domes of Buckminster Fuller (think soccer balls). Some of the interesting properties are that these molecules are superstable, and one of the things they're thought they'd be useful in is nuclear waste storage.
  • From the article:

    Thus, Hiura suggests that they may serve as excellent quibits, which store single bits of information in quantum computers. The spin state of the metal atom could encode the bit, and the silicon cage would protect it from corruption.
  • I know this Engineer guy, and he knows a lot, and he told me about these buckyball things. He said they are soccer balls. But if they start making soccer balls out of different materials, what will this do to the World Cup?

    First of all, you mean footballs, right? Here's a clue, if you're at a technical conference on the internet, and 90% of the attendees are calling it the internet, while 10% of the attendees are calling it The Microsoft Network with Internet Extensions, don't you think the 10% should change their naming scheme to conform to the common naming scheme?

    As for changes in the World Cup? Probably few, the winners would be Brasil, Germany or maybe Italy, definitely not USia.

    Ta-ta
  • BuckyBalls, from what I gather are pretty simple things (conceptually, at least!) -- it's just a fullerene molecule.

    But as this advances further than the Silicon counterpart, it paves the way for some huge research, specifically in Quantum Evolution. [surrey.ac.uk]

    I do quite a bit of study in Quantum Cryptography (I ain't no prof. though!) , and wonder how this all fits in.

  • Ooops, it's tungsten. Reasonably biggish as metal centres go: Plus it has available d orbitals to be donated into and to electrons to donate to the p orbitals of the silicon atoms. Hmmm.

    Elgon

  • While it is quite remarkable that scientists have created a silicon buckyball, silicon buckyballs have almost no real-world applications. C12 based buckyballs have promising electrothermic and chemical properties which may potentially make them useful in the engineering of quantum computers or superconductors, but due to silicon's higher atomic mass and lower isotropic stability, it is virtually useless for these type of applications. To achieve true, electron-tunneling superconductivity through a non-porous simiconductor media, you need a tight molecular bonding structure that silicon simply cannot provide. Until scientists perfect the laboratory creation of chemically stable dilithium-tungsten crystals, we're going to be stuck with carbon. While the article scores major points for it's cool factor, it sadly has no real-world merit.
  • They were also discovered (I think) by scientifical-types who were shooting lasers at graphite [ornl.gov] , for some reason. This somehow made buckyballs, adn they said to themselves 'this is nifty. I bet we could put a bunch of shit in here'.
    According to my semi-unreliable memory, buckyballs are fairly toxic, and make a fine black powder when they're together.

    Scientists have also found buckyballs filled with helium in the ground where comet/meteor strikes have occured. This article [popsci.com] on popular science has some details about that.


    Brant

  • Quantum spin in buckyballs (Score:3)

    by nqp ( 234709 ) on Wednesday February 28, 2001 @07:11AM (#395147)
    The remarkable thing about nuclear quantum spin is that it is very weakly coupled with the enviroment. Relaxation times (how long the spin takes to dissapear) is on the order of 100's of milliseconds in many materials.

    In this material it may turn out that nuclear relaxation times are of the order of hours ?? (in noble gases you can get relaxtion times of many minutes) due to the shielding of the nucleus from the enviroment by the silicon cage.

    The nice thing about single-quanta systems (i.e. a single atom) is that it is in a definite state. A spin-half system is has only two states (read 1 or 0 ). (Im not sure what spin the Tungsten nucleus has). As long as you "refresh" the spin before it relaxes with the enviroment (decays) you can use it like ordinary memory, but obviously at much higher densities...

    This Silicon cage is not really like fullerine which I think had 60 carbon atoms in a geodesic dome arrangement ? anyone know

  • Isn't it a particular molecure (fullerene) which is the buckyball?
  • These aren't going to be used in place of electrons, they're probably going to be used in the memory portions of a quantum computer. Remember, too, that quantum computers are still mostly well-funded thought experiments, and they're experimenting with what would be useful once they finally do build one.
  • No, a knee to the groin would just give them higher bandwidth...

    -----
  • Nobody tell Steeve Jobs, I can see it now "Buckyballs first on Apple!" they'll enclose said silicon in colored plastic.

  • More promising qubits (Score:4)

    by TeknoHog ( 164938 ) on Wednesday February 28, 2001 @07:14AM (#395152) Homepage Journal
    Superconducting loops with Josephson junctions seem much more promising candidates for quantum bits, where the 0 and 1 states are represented by opposite currents. Quantum superpositions of these currents - can you imagine current flowing both clockwise and anticlockwise simultaneously! - have been observed in numerous experiments, some (technical) links are here [nature.com] and here [tudelft.nl].

    The difficult part is that superpositions, which are the key requirement of qubits, are inherently destroyed when measurements are made. But some experiments, like the above, manage to sustain the superposition for a significant time, because the system is only weakly coupled to the measuring instruments.

    --

  • You can use Nuclear Magnetic Resonance (NMR) techniques to read nuclear spin.

    The decay of the spin depends on its coupling to the enviroment (T1 relaxation rate)

    For weakly coupled systems this can be from many seconds to minutes.

  • i don't know how they would read it, the article doesn't have much detail. however the spin exists in only two states, the ininite storage capability doesnt relate really, that other article about infinite storage was related to the infinite energy levels of an electron. the article does claim they are stable suggesting that the 'spin-state' wouldn't be changed by random radiation. i don't really know what spin state means, something about the spin of each particle in the central atom i suppose...
  • buckminsterfullerene i think, not -ine. just fyi.
  • Next thing you know, they'll be making Buckyballs out of hummus!

  • FYI: Physics Review Letters Reference (Score:5)

    by nickdog ( 133903 ) on Wednesday February 28, 2001 @07:25AM (#395157)
    The original PRL article is Hiura et. al. Volume 86, No. 9 pp. 1733-1736. Some may have access to PRL online at: http://prl.aps.org/ [aps.org] This is a little more technical, but still worth a look.
  • You really can't compare density to number of molecules. A buckyball is a single molecule with something like 50 atoms. The and/or/not gates in modern chips that you are talking about may be gigantic molecules made up of thousands of atoms. Remember, an entire strand of DNA is considered to be a single molecule. This could be up to 2 orders of magnitude smaller, although that doesn't take into account the peripheral equipment to detect the spin direction.
  • But..but...but...everyone knows dilithium is used to power warp drives! 'Core dump' takes on whole new levels of horror if they actually make computers out of that stuff!

    LEXX
  • "As for changes in the World Cup? Probably few, the winners would be Brasil, Germany or maybe Italy, definitely not USia. "

    Don't you mean Deutchland? ;)

    If I said Deutchland, the USian Slashbots would rush to correct me, saying the correct name is either Holland or The Netherlands.

    I didn't say Italia either.

    TG
  • then the spin state can represent a near-infinite number of positions, correct?

    actually, spins only have 2 positions.

    "just connect this to..."
    BZZT.

  • "Hey baby, are those quantum computers in your shirt, or am I just glad to see you?"

  • not a true buckyball (Score:1)

    by Anonymous Coward
    see title. a true buckyball is a geodesic structure. this is simply a body-centered structure, just like the body-centered structures found commonly in other intermetallic systems. the only innovation here is the use of the buzz word "buckyball". this seems to be the only item that qualifies this as news worthy.

    it never ceases to amaze me how journalists make hype by using words like "nano" and "buckyball". we all need to make a living, but be honest, wouldn't you all be better employed in the world of p.r?
  • Nope. Mr. Bucky designed and evangelized geodesic domes. The C60 molecules appearance resembles his architectural designs and were named in his honor. He was also something of a genius as well as a nutjob (in the finest tradition of genius nutjobs). Here is a pretty large FAQ about him: http://www.cjfearnley.com/fuller-faq.html

    -B
  • doesn't the article suggest that the tungston core makes the buckyball stronger while giving it trasport properties base on the spin of the tungston atom?

    ------------
  • Someone asked the Q in the subj, and Oztun repeats: "Hiura suggests...and the silicon cage would protect it from corruption."

    Well, that's what he suggests. He doesn't give the mechanism. Protect it from what sort of corruption? Onanism?

    Seriously, this is the point of basic research. Who knew that twisted ribbons of bubble walls in magnetic media could be used to create memories until someone poked around at it?

    Was it Einstein or Pauli who said "the only real science is physics, the rest are stamp collecting"? In chemistry it seems you need a new theory for every five or six materials. The pharmaceutical industry fleshes this out, trying every combination of molecule and malady until they find an effect they can sell, and not really caring about why unless there's a patent they need to circumvent.

    Likewise in materials for data storage. They found a toy that might be able to maintain a state. They need to find out if they can control the datum, if it is BIBO-stable to various kinds of perturbation, and if the entire memory apparatus can be built for a few bucks per gigabit. (Only geeks [slashdot.org] care what's under the hood, so the new technology has to compete on price/performance with the old one in some market, niche or broad).

    --Blair
  • Funny. I'm from the UK, and spent 20 years in Canada before moving to the US 5 years ago. I'm definitely not a 'Yank', nor am I so uneducated as to believe that silicon and silicone are the same thing. Your mileage, however, may vary.
  • no....a buckyball is a moleculare structure, a fullerene is a sub-atomic particle.

    two seperate size scales.
  • I would assume that they would be addressed by the mechanizm that created them inside the quantom computer. they would have to be sent in a physical direction by some sort of navigation device that shoots them in a streem of particals.

    but i AM MOSTLIKLY WRONG ON ALL ACCOUNTS :)
  • Please.
  • spin only has 2 states. if it had infinit states then QM would not be able to make predictions and would therefore never have been created.
  • Can you imagine how delicate a processor of this nature would be. I would expect that the tiniest magnetic field could potentially disrupt the entire process. If we're talking quantum computing, then the spin state can represent a near-infinite number of positions, correct? If this is the case, the slightest fluxuation in the spin state would cause data-corruption.

    Corporate Research Director, circa 1960, discussing invention of Integrated Circuit : Can you imaging how delicate a processor of this nature would be? The tiniest speck of dust could potentially disrupt the entire process. If we're talking digital computing, the superposition of all transistor outputs can represent a near-infinite number of positions, correct? If this is the case, the slightest fluxuation in substrate impedence could cause cross-talk and lead to data-corruption.

    Isn't it just amazing we can build GHz processors in sub 0.2 micron technology with 100s of millions of transistors on a single substrate, given the sorry state-of-the-art in 1960? I'm very skeptical of quantum computing (I'm even more skeptical of biological computing), but I think off-the-cuff dismissals of the technology is dangerous. People have a way of making such statements look really dumb 40 years on.

    However, this is purely based on assumptions. I could be completely wrong. I still do math using my 10 fingers.

    Try using your head, it works better. =)

  • Isn't it a particular molecure (fullerene) which is the buckyball?

    I believe that 'Buckyball' is a nickname given to a class of compounds called fullerenes. See other posts regarding the history of this class of compounds. Fullerenes are generally spherical molecules made of tetrahedral carbons (sp3 hybridized). They can be many different sizes; the most common being C-60. However, fullerenes can also be tube shaped molecules called 'buckytubes'. These molecules are be studied for possible use as 'micro-wires' in very small electrical devices.

  • If I were on speaking terms with a buckyball, I would address him as "Mr. Ball," or perhaps "Bucky" if we became good friends.

    OK, it's lame, sue me.

  • My goal is to get into the history books for making one of those brillant "the average consumer will never need any more than 64K of ram" statements!

    tcd004

  • I'm [ever | rather] upper class high society God's gift to ballroom notoriety I always fill my ballroom The event is never small The social pages say I've got The biggest balls of all

    CHORUS: I've got buckyballs I've got buckyballs And they're such buckyballs Dirty buckyballs And he's got buckyballs And she's got buckyballs But we've got the buckiest...balls of them all

    And my balls are always bouncing My ballroom always full And everybody cums and cums again If your name is on the guest list No one can take you higher Everybody says I've got Great balls of fire

    CHORUS

    Some balls are held for charity And some for fancy dress But when they're held for pleasure They're the balls that I like best My balls are always bouncing To the left and to the right It's my belief that my buckyballs Should be held every night

    CHORUS

    And I'm just itching to tell you about them Oh we had such wonderful fun Seafood cocktail, crabs, crayfish...

    Ball sucker.

  • Re:stupid q: but WHat IS? (Score:3)

    by IainMH ( 176964 ) on Wednesday February 28, 2001 @08:10AM (#395177)
    C60 was first discovered by some chaps studying interstella chemistry/chemical physics. One of them Prof Harry Kroto [sussex.ac.uk]had the bright idea of placing two carbon rods end to end in a vacuum a very small distance apart and putting a massive potential difference across them which yielded an arcing effect. They shoved the resultant black dust into a mass spectrometer and found massive peaks at 60 (x12) and 70 (x12) units. At first this was dismissed as contaminants, but then Kroto had the 'falling of the toilet and imagining the flux capacitor moment' of thinking about the Geodesic sphere created by R. Buckminster-Fuller at the Montreal expo 67 to which he went with his son.

    It was first isolated, by putting the black dust in benzene (J. Hare - then a research student of Krotos did this) which yielded a red solution that when dried yielded red C60 crystals.

    An explosion of research happened around the world, most notibly from the UK (Sussex Uni - guess where I studied :-)) Japan, and the US.

    There is loads of stuff on the web, and in a wierd way this is what got me into computers... Looking for papers 3 years ago turned me back to computers after I left them when my Amiga got packed away.... Then I realised that Chem grads got about 14,000 gbp a year in their first few years in Chem, and I was way too mercenry for that! :-)

    (Ex Chem geek)

  • I'm not sure, this is reasoning from analogy, but:

    I think that the spin states actually are "infinite", but when you read them you get one of the values. Which one you get depends on a combination of probability and the angle that you do the reading compared with the angle at which it is "spinning".

    And even then there are, as I remember, several different spins which are particle dependant. I don't know what you would read from a tungsten atom, but I believe that electron spins are half-integral. If you only measure one electron, perhaps the values would be + or - 1/2, but an atom has several electrons, so perhaps you could get some summation of the spins.

    Caution: Now approaching the (technological) singularity.
  • someone has an axe to grind ... ;-)
  • Well, the gates on high-speed CMOS transistors can be in the 10-20 atom range. The other parts of the transistor (source, drain) are usually quite a bit larger, since they are embedded in the silicon wafer, rather than built on top of it. Gates and wires are usually the limiting factors in semiconductor processing.

    --
  • But aren't Bucky balls are small enough that their position is non-deterministic?

    Boy, I'd hate to be a Bucky. :-)

    I think you'd still need to put them in a structure of some sort. How else would you be certain you're reading from the same bucky ball that you wrote to?

    The fact that these problems are barely considered tells me that we're a long way off from seeing quantum memory/computers.

  • Do Josephson junctions work at the temperature of the superconductor? Then perhaps the computer would only need to be submerged in liquid Nitrogen.

    This doesn't seem too practical for normal computers. Perhaps it could work well in a glass house enclosure. Otherwise this will need to wait on room-temperature superconductors.

    OTOH, I seem to remember that Josephson junctions need to be colder than merely superconducting temperature (I can't remember why I believe this, though). In that case the computer would need to be submerged in liquid Helium. I don't expect that to be a good choice outside of a lab, though one shouldn't underestimate what an engineer can do.

    Caution: Now approaching the (technological) singularity.
  • While neat science which probably has applications elsewhere, I really don't see this being at all beneficial to quantum computing. While the article doesn't state whether it is nuclear spin or electron spin that Hiura suggests using as the quantum bit (qubit), neither one would work well. Nuclear spin is an unpopular choice because it does not scale well to large-scale quantum computers. It is too difficult to engineer the exchange interactions between qubits to perform any reasonably sized calculations. As for electronic spin, being enclosed in this silicon cage would create a nightmare of interference. Not interference from outside particles, but interference between all the possible energy levels present due to the molecular bonds. As you get extra energy levels in a qubit, you find that the superposition from overlaying a large number of nearby energy levels creates an extremely irregular Hamiltonian that's not at all as nice as that for a single isolated electron spin. It is possible to emulate a single isolated electron spin in a complex system if you can distance (on the energy scale) the nearby energy levels sufficiently, but this is not always easy to do.

    So there would be a lot of work and a lot of calculations to be done before anyone could even reasonably talk about using such a cage for a qubit.

  • these SiBuckyballs (suckyballs?)

    That doesn't sound very flattering. I'd prefer "slickyballs."

    (Yeah, sounds rather rude, but then "suckyballs" could be construed as rude, too.)

    --

  • One of the more intersting things in that article is that the BBalls found at the impact site already held cargo: a foreign isotope of helium, which they use as evidence that the impact was extraterrestrial. Odd that this formation (buckyball) would be natural; most natural formations that I can think of do not have this apparent order to them.

  • Hmm, still sounds a bit rude, though.

    --

  • You Too Can Create Buckyballs! (Score:3)

    by searleb ( 168974 ) on Wednesday February 28, 2001 @08:24AM (#395187) Homepage
    Now, with an arc welder and a two sticks of graphite, you too can create buckyballs! [wisc.edu]

    Isolating them is an entirely other beast, though.
  • Josephson junctions attached to a high temperature superconductor will work at liquid nitrogen temperatures.
  • You are right, the standard buckyball has 60 carbon atoms and can have more in certain stable configurations. If carbon atoms are removed (from the 60 atom structure) the stability of the molecule rabidly decreases. The silicon cage that this article talks about has only 12 silicon atoms and very little in common with a buckyball.

    I know that researchers have also been able to trap atoms inside of buckyballs for quite some time, even the larger noble gases. What I would like to know is how the silicon cage in the article compares to a buckyball with a xenon atom trapped inside of it for use as a quibit.
  • >Interesting? I guess that's debatable. I've always thought any game that ostensibly lasts an hour and then takes 3 to play isn't particularly 'action-packed'

    Blame that on the commercials and other media/income related things. If you watch a high school football game, or non-mass-media-televised college game, it takes significantly less than three hours. I played soccer when I was younger (and somewhat through college), and football when my joints were healthier, and I'd definitely call football more action-packed than soccer. As for athleticism, that depends on the players, but football was far more physically taxing, with greater balance required in many cases. Soccer was always far less interesting to watch or play than baseball, and most people consider that slow, but (again, media-related extended time-outs aside) there's a heck of a lot more going on in baseball than soccer. Cricket is definitely omre exciting than soccer, too. I didn't start out trying to blast the sport, but it really does rank fairly low on the list... but it's the game where you really don't need very much equipment to play, and the intial skill level makes it easy (the ball just stays on the ground if you miss).

    The WWF/WCW isn't real, everyone knows it isn't real, and despite that, people still watch it (must be funny to see steroid-built guys wail o neach other).

    >Besides, we're not exactly dropping like flies every Saturday

    I can only assume you meal the XFL... not the highest talent level there, and not a great product... heck, if my back and knees were better, I could probably get on one of those teams, but I'd end up making less than I am at engineering, barring an amazing 'XFL championship'... bleh.

    --

  • Not like you'd think (Score:3)

    by Queueless ( 318282 ) on Wednesday February 28, 2001 @08:43AM (#395191)
    In quantium computing radio waves are used to affect and read the qubits. Something like a MRI machine. The "value" of the qubit is determined by the inference pattern created by the qubits when they are zapped with radio waves.
  • just scrape some soot out of a chimney or the container of a poorly burning candle. soot is formed when there is no oxygen present (otherwise it would have completely burned) and the carbon atoms bond with each other. This is almost identical to the use of high current and two sticks of carbon in an inert gas, just the source of the free carbon differs.
  • You're right. This discussion may (and will hopefully) seem silly in 40 years, but on the other hand, 40 years ago, they were saying we'd have fusion reactors in 40 years. Last I heard, they're saying we'll have fusion power in 40 years.

    You cannot really dismiss technical hurdles on the basis of the fact that technology will grow exponentially over the next X years. The fact remains that the problem of quantum computing devices (if it exists), still must be solved!

    Sure, we can laugh about those poor clods with their narrow ties and horned-rimmed glasses that had to suffer with transistors you could actually see with the naked eye, but they in fact were the ones that started the ball rolling for us to be able to sit around and guffaw at the fact that the Pentium IV performs as if it were a few hundred megahertz slower.

    I don't think the original poster was trying to dismiss the technology. He was just rightly pointing out a concern that a quantum computing device could be fragile.

  • Something struck me as I was reading one of the earlier posts, and it seemed ver important to the issue of quantum computing. Heisenberg's Uncertainty Principle basically says (in a nutshell) that the measurement of a particle will change the state of that particle. (I believe that's the upshot of being able to measure state or location, but not both. Physicists on the board, please correct me if I'm wrong!)

    That brought up the concern to me, then, of how quibits are supposed to be read. If I have 0x0BADBABE stored in a quantum memory register, and I use any means of reading that register, then either the location or the state is going to change of the quibits. Since one can't very well have registers flying all over the place not knowing where they are, (and if they are caged by buckyballs as mentioned in the article, then they won't be going anywhere) that would mean the state changes, making it useless. In fact, this sort of puts the kibosh on quantum computing completely.

    So why are top researchers putting so much time and energy into this field? What am I missing?

  • If you said *deutschland* then the "USian Slashbots" would probably assume (correctly) that you were referring to *germany*, since that is, of course, where deutschland refers to. Germany.
    Not the Netherlands. Not Holland. Nor Nederlandse, Italia, or Brasilia... it means Germany in the native German tongue. Grind your axe somewhere else (where you can pretend to know what you're talking about and fools actually believe you). If you were so hung up about it then you would have addressed the countries by their own names. (Just because the english speaking world calls China "China" doesnt mean that is how China addresses it ... and there's a hell of a lot more people calling it something other than China than there are people calling Soccer "Football").
    The MSN freaks will call it MSN. The Internet freaks will call it the internet. Nobody will give... not in their mind.
    A rose by any other name is still still a rose, and smells as sweet.

    ---
  • I agree, the graphic provided makes it look like graphite (layered 2D hexagons) with the tungsten just wedged inside, bonded to the silicon cage. Definately not buckyballs, where all the bonds are only to the other carbon atoms.

    Of course, I am not a Physicist or a Chemist.

  • No, Anonymous Cowards said both things. Perhaps you should learn to not jump to the too-obvious conclusion that two people posting as 'Anonymous Coward' are one and the same.

  • Yes, the normal buckyballs are made of 60 carbon atoms, arranged like the verticies on a soccer ball (hexagons and pentagons).

    Silicon and carbon belong to the same group on the periodic table. Both have a +4 charge on them, which is most likely why these researchers chose to use silicon.

    I know that carbon is a non-metal, and it bonds covalently with other atoms. Silicon is a transition metal (I think), and I think that it uses ionic bonds. Covalent bonds are much stronger than ionic ones - probably why they were having trouble assembling the cage. I bet the 60-atom silicon cages they tried to make fell apart, like the bridges of toothpicks I made back in second grade.

    I'm not sure what tungsten adds to the mix, or why it is chosen above all other elements. Perhaps it is because tungsten is resistant to temperature changes.

    ------------

  • And what other messes did I get into?
  • ok I fixed it. is you be happie? :p
  • Josephson junctions attached to a high temperature superconductor will work at liquid nitrogen temperatures.

    Provided the superconductor will work at that temperature :-). A Josephson junction is nothing more than a thin layer of insulator between two superconductors, usually some oxide. But interesting things happen because of the superconductivity. Current can flow across the junction without any voltage, if there is a phase difference in the quantum mechanical wave function that describes the motion of the electrons. This phase difference accounts for most of the weird phenomena in these loops.

    --

  • the measurement of a particle will change the state of that particle.
    So why are top researchers putting so much time and energy into this field? What am I missing?
    But after you've measured it, you don't care what state it assumes. The important thing is that you preserve the information from the measurement.

    Not stictly relevant to anything here, but..: a nice intro to quantum logic [uni-paderborn.de]
    --

  • It is true that a measurement will 'collapse' a quantum system into one of its basic states (ie 0 or 1 in a qubit) when measured. But this has nothing to do with Heisenberg's principle, which represents an inherent uncertainty in quantum systems even no measurements are made. It's hard to explain in simple terms, but many /. readers know Fourier Transforms so here goes. In QM, the momentum representation of a particle is the FT of its position representation. Any attempt to define the position accurately (making the wavefunction a narrow peak) will make the function wider momentum-wise, and vice versa. The effect of disturbing the system by measurement is a completely different postulate of QM.

    As of the practical use of qubits, attempts have been made to increase the 'relaxation time' of the system, so that the quantum state is preserved for a while even when it is connected to outside world for measurement. Currently, for superconducting loops (see my other comment [slashdot.org]) this is less a microsecond, but might be useful for some computation.

    Even when we have working quantum computers, the data will probably be stored in conventional memories. The real use of these qubits is in certain kinds of computation. IIRC the RC5-56 challenge would be solved in a matter of minutes. :-)

    --

  • oops!!! missed it :)
  • No doubt. But I referred to "fusion power"... right now the fusion reactors are a great way to use power, but there are still hurdles until it reaches the break-even point. My thesis in general here is just because something is trivial now (or in 40 years) doesn't mean it is trivial when it is first developed/discovered/conceived.

    I like the statement from the web roll computer technology piece a few weeks back. Paraphrased it went, "The first one will cost $500,000,000. The second one will cost $10."

    Nowadays, perspective drawing is something any mildly talented person can do. In the 15th century it was revolutionary.

  • OK!!!! sheesh. anything else.
  • I knew I was probably getting something mixed up, but I had no clue what. I am now enclued. ;) Thank you to all who answered my questions!
  • Why, just the other day, I was on Slashdot, trolling on about Buckyballs. I of course had no idea what the fuck I was takling about at the time, but I was hoping to attract someone nice to get laid.

    But the appearance of this article on Buckyballs only proves that I am not just a mere rambling, inane whore, but that I am also a powerful psychic! You should all fear my powers of advanced perception.

    I pledge that I shall not use my powers for anything other than trying to craft the finest trolls, in order to whore all the karma I can. I have heard that it is easier to get laid if one has accumulated a high amount of Karma.

    Please, when reading all of my comments, remember that I am a genius, and that I knew all before you ever could have due to my supernatural psychic abilities.

  • FYI (Score:1)

    by manyoso ( 260664 )
    FYI

    It was Ernest Rutherford who said "the only real science is physics, the rest are stamp collecting".
  • I studied the carbon buckyballs for a while once, and as the class was going through it I asked the question of if a buckyball could be used as an effective transistor. The professor was not positive, but he hypothized that the carbon shell would protect atoms inside too well, and would end up being far to unreliable to use as a transistor component. However, he said if carbon had a lesser electron affinity, it might work. Silicon fits into this category.

    Very nicely, it seems.

  • This all depends on the magnetic field. It can exist in two states, but without a uniform field its orientation would be completely random.... sandoz
  • Well, you have to know how well the spin states couple (ie - talk to each other). It is probably not practical to use a single molecule for a bit but you could use domains (clusters of aligned spins) to represent bits.
  • Actually, in the versions of the story I've heard, it was Dick Smalley who had the epiphany of the soccerball shape, rather than Kroto.

    Of course, I heard the stories when I was at Rice, and Smalley is generally regarded as a self-important jerk. Make of that what you will.
  • That's a run-on sentence. Either make it two sentences, or change the comma to a semicolon. :-)
  • And I always thought buckyballs were the University of Wisconsin's Mascot's genitals...weird..
    -----
  • Sorry to argue, but....last I checked, covalent bonding is stronger than ionic bonding. The covalent bond is a pair of shared electrons, you are right there. This bond involves an overlap of the orbitals of the two atoms involved, which leads to rather large bonding energy. Ionic bonds are the result of electromagnetic force between two oppositely charged ions, as you correctly mentioned. This bond, however, is weaker than the covalent bond, as the energies involved are lower. As its quite late, I won't go into the math involved here, but I will present an example. Compare the melting points of sodium chloride (which is held together by ionic bonds) and diamond (which is held together by covalent bonds); Sodium chloride melts at 801C, while diamond melts at 3550C. As the melting point is directly related to the strength of bonding in a solid, it is apparent that covalent bonding is stronger than ionic bonding.
  • Isn't there a slight problem with this method of address? You'd have to be really careful not to inadvertently excite an electron on the buckball to an excited state. If I remember correctly, the first excited state of a carbon-based buckyball is a 'cinched-belt' state (where the center of the ball shrinks in radius creating a two-lobed form). If there was something analagous in the silicon based structure, I'd worry about the integrity of the 'qubit' written to the tungsten core due to possibly enhanced interactions with the surrounding cage (which would now have a rather different electronic structure). Then again, this might not be a problem with radio frequency waves - their energy is probably far too low to excite the electron in the first place. But, on the other hand there are some weird low energy states that could be accesible in a metal-nonmetal system like this. Just a thought.
  • :>

    Ahh ha No, Quantum spins have only two positions clockwise or anti clockwise, its all very digital too, if it isn't going clockwise its going anti clockwise its either one or the other.

    What you thinking of is the fact that both spin states can exist simultaneously, which means the processing power increases exponentially as size of processor grows.

    The way they've done this so far is by using a large magnetic field and radio waves to control stuff, much like the way NMR (Nuclear Magnetic Resonance) works and they have managed to do calculations using algorithms using 4 molecules. (i think it was caffine or something.)

    The processors will be entirely unlike the ones we have today, its not going to be a block of silicon, it'll probably be a thin slime of gel trapped between two plates of glass, surounded by a massive magnatron or something equally strange.

    The thing to understand is that it probably isn't the best implementation for a chip because of the way it works, so expect to have an AMD 20000Mhz and a Quantum chip FPU
  • And I heard this story at Sussex :-)

    I know what you mean, everyone wants credit, thats the trouble when you give out the a gong that is the pinicle of any scientists' career to three people at once.

    Just as aside, Harry Kroto is a top bloke. He wasn't self important at all, like all the other faculty, he would sit in the tea room (there were no seperate rooms for staff) and chat to undergrads.

  • Thank God, it only takes 10^18 spins for NMR to be detectable.
  • The Z-component of a spin-1/2 particle has only to values.

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