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Silicon Buckyballs = Quantum Bits?
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."
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.
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...)
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.
bp
It seems a little like supersonductors... you just have to keep trying new materials.
There is a good article about BuckyBalls from First Science here as well.
However, this is purely based on assumptions. I could be completely wrong. I still do math using my 10 fingers.
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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.
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.)
...or maybe not.
How many Quibits to a Q*Bert?
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.
If god had intended you to be naked, you would have been born that way.
They were also discovered (I think) by scientifical-types who were shooting lasers at graphite , 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 on popular science has some details about that.
Brant
Brant
Argle. Bargle.
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
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.
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Next thing you know, they'll be making Buckyballs out of hummus!
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/ This is a little more technical, but still worth a look.
Please.
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C60 was first discovered by some chaps studying interstella chemistry/chemical physics. One of them Prof Harry Kroto 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.
:-)) Japan, and the US.
:-)
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
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)
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.)
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Hmm, still sounds a bit rude, though.
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Power in the hands of the accountable.
Now, with an arc welder and a two sticks of graphite, you too can create buckyballs!
Isolating them is an entirely other beast, though.
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.
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.
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