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IBM Tech Detects & Changes Spin of Single Electron
An anonymous reader writes "Looks like we have another step forward in Quantum Computing - IBM has discovered how to detect and change the spin of a single electron. Won't be long before we're all solving impossible encryption problems.
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IBM Detects and Changes Spin of Single Election.
Damn you Taco, and your politics section, it's corrupted my mind!
... are they certain?
If spin can be measured in a meaningful way, the entire future of politics is suddenly up for grabs. Imagine a "spin detector" built into the home television!
Wow. "You spin me right round, baby right round, like a record baby, right round, round round...."
The problem with quotes on the internet, is that nobody bothers to check their veracity. -- Abraham Lincoln
How can we know it's so?
Electron 1: Oh my god! they've found us! what can we do? we are doomed!
Electron 2: Oh stop being so negative
I am the lord of the pun. Dance Knave!
But they will have to dramatically increase the seek time of cats before this tech will be usable as a hard drive replacement.
You changed the outcome by measuring it!
It's good to see some tech companies actually innovate...
My website
Whew, okay. After I RTFA I realized they hadn't done the impossible, just the really hard. IBM can measured the energy required to change the spin of a single atom not a single electron. (A prerequisite of this, of course, is detecting the spin of a single atom; but that's not that difficult with electron microscopes.)
So what do we do if quantum computers can decrypt anything in almost real-time?
All I can think of is making the data streams uninterceptable, which leads us back to encoders/decoders built using quantum entanglement.
**TODO** Steal someone elses sig.
IBM has discovered how to detect and change the spin of a single electron.
Measuring the spin of electrons bound to atoms was first achieved in the famous 1922 Stern-Gerlach experiment, a key stage in the discovery and understanding of quantum spin.
However, to quote from this discussion of the experiment, the Stern-Gerlach technique cannot be used to measure free electron spin because 'The spreading of the electron wave packet washes out the separation effect due to the electron spin'. Therefore, it appears that IBM's discovery is significant.
Tubal-Cain smokes the white owl.
Won't be long before we're all solving impossible encryption problems.
Of course by then we'll all be using quantum encryption techniques.
Overspinning electrons to overclock systems?
Nope. SCO still owns that title and will for a VERY long time. It's just that now IBM can measure the spin and quantify it with a number.
I'm quite sure the cat knows as well.
A while back there was a proposal to have a public onetime pad system that worked like this. there is a server, perhaps a sattelite, that is streaming random numbers at say gigabytes per second. To encode a message you weakly encrypt a prior message to the recipient telling him a precise start time: say the message reads: start colleting your onetime pad at the first occurence of the first 5 digits of the number pi that come after 12 noon. you both then collect the data that comes at that time and treat ti as a shared one time pad.
you opponents may be able to decrypt the pre-message eventually but not it time to make the start time. thus they cant collect the onetime pad data. the data rate of the random stream is chosen so that no plausible storage system could retain more than say a few hours worth of the data, so no one could just record it all. As long as no one can crack your message on that time scale you can dsafely send the one time pad whihc no one can crack by technical means.
Some drink at the fountain of knowledge. Others just gargle.
This is the sort of situation where the Internet is more a hinderence than a help. Over time discussions such as this will polarize the lay community either for or against a particular area of research, wher two areas of research strive to achieve similar goals.
Public Opinion greatly influences funding of research, so I hope that premature dabates of which technology is superior, won't shape decisions to fund one or the other, since ther is the possibility that one or the other area of research might hit a brick wall at some time in the future, at which point it wll be nessecery to pursue the other area of study. It would be bennefitial to all to have continued both areas of research in parrelel. Don't get me wrong. I don't believe that discussions like this alone will influence the course of research, but merely that the colaborative enviroment the Internet offers will promote (suprisingly) colaboration to the point where only one research path will be pursued by both teams, working together, rather than competing, as it were.This is an area whewre competition is a positive thing in academic research. I merely question the degree to which the Internet actually contributes to this.
Were he still alive, Andre the Giant would have something to say about this sentence.
Obliteracy: Words with explosions
Won't be long before we're all solving impossible encryption problems.
Who's this "we"? I still can't get my VCR to stop blinking 12:00...
"Was it a millionaire who said 'Imagine No Posessions?'" -- Elvis Costello
Green acres is the place to be
Farm living is the life for me
Land spreading out so far and wide
Forget Manhatten, just give me that country side
No need to thank me.
That is the degenerate or lowest energy state. If the only thing in the universe is two electrons, that is.
Materials are grouped according to how they respond to external magnetic fields as follows:
paramagnetic materials tend (usually strongly) to line up such that their spins are opposing the existing magnetic field, and therefore attracted to it. In classical terms, magnetic field lines permeate this material and cause attraction.
diamagnetic materials tend (usually extremely weakly) to line up such that their spins are aligned to the existing magnetic field, and therefore opposed to it. This effect is so small it usually can't be measured without very strong magnets or a carefully balanced system. Water is one of the most diamagnetic materials; if you're careful you can see the effect in one of those glitter lamps; let it settle down and still and hold a very strong magnet to the side, you can see the flow as the glitter moves away.
ferromagnetic materials tend, like paramagnetic materials, to line up such that their spins are opposed to external magnetic fields. However, they also tend to retain that orientation when the magnetic field is removed.
EVERY single material is one of the above. There's a proof (I forget who wrote it) saying that no static combination of electric, magnetic, and gravitational fields can be stable; that is, there is no combination of the above forces where something can be seen to levitate and balance the forces perfectly. The proof is almost correct; he didn't know there was such a thing as materials with a negative magnetic permeability (even though the permeability is slight it's enough in extreme circumstances)
Couple cool tricks:
1. If you've got a hugely strong electromagnet, you can float low size organic material in it. I once saw a video of a frog in a bubble of water levitating in apparent microgravity.
2. Certain kinds of graphite are strongly diamagnetic. The dust isn't, but the graphite layers are. You can shave flat little disks off and watch them float over an array of magnets.
3. Using bismuth and a couple neodymium magnets with a clever little gadget to help in positioning, you can make a frictionless bearing. Google if curious.
For those curious in playing around with strong magnets... forcefield.com is your friend...
I am disrespectful to dirt! Can you see that I am serious?!
This is a big step forward in spintronics, not in quantum computing. Quantum computing is predicated on the idea that solutions to the Schrödinger equation can be a linear combination of several single-state equations; this is the case with any higher order differential equation. By detecting or explicitly setting the spin, you force the solution to be only one of these equations, and the quantum magic goes away. Great news for spintronics (using spin, not charge transporation to carry information), not news at all for quantum computing.
`which fortune`
Okay, one answer is that CmdrTaco got it wrong. He said, "IBM Tech Detects & Changes Spin of Single Electron". He should have said, "IBM Tech Detects & Changes Spin of Single Atom". Huge difference.
--
Bush's education improvements were partly fraud
Won't be long before we're all solving impossible encryption problems.
Nothing impossible to solve is solvable, and nothing unsolvable is possible to solve.
I think the word you are looking for is intractable.
just = (My)Opinion.toCents();
Yes, but it's more general.
In QM, you measure a property of an object by applying an "operator" (you put in a function, and it spits out another function) to its wavefunction. Heisenberg said[*] that certain pairs of operators don't commute (meaning order is important - AB != BA), and so some pairs of properties can't be measured together.
"Position and momentum" is a particular example of a pair, as is "different components of angular momentum" (L_x and L_z, say). I can't remember how 'spin' fits into things, though ...
[*]Pedantry: Yes, I know Heisenberg talked about matrices, Schrodinger about operators.
Heisenberg is driving his car, when he gets pulled over by a cop. The cop asks him "Do you know how fast you were going?"
To which Heisenberg replies "No, but I know where I am!"
Spin is basically a quantized angular momentum intrinsic to many particles (electrons are spin 1/2, photons are spin 1).
From classical mechanics (and quantum mechanics as well), linear momentum is the generator of translations and angular momentum is the generator of rotations. So linear distance and linear momentum would be canonical variables for Hamiltonian dynamics, just as well as angle and angular momentum would be.
There are some differences, though, by noting that translations in different directions are Abelian, while rotations are non-Abelian (Abelian operations are independent of the order of the operators). You can easily see this by taking any object and rotating along the X axis and then the Y axis. You'll get a different resulting configuration than if you rotated along Y first, then X. However, if you translate in the X direction first and then the Y direction, you are in the same place as if you translated Y first, then X.
Anyway, the generalized uncertainty principle relates the minimum uncertainty one can have through a combination of two non-commuting operators. The commutator for operators A and B is defined as [A,B]=AB-BA. The generalized uncertainty relation states that if [A,B]=i C for Hermitian operators A,B, and C (the i=sqrt(-1) is necessary for making everything Hermitian work out properly), then the product deltaA×deltaB=1/2|deltaC |(where deltaA is the uncertainty of that operator on the wavefunction (ie, deltaA=sqrt(A^2-A^2). The expectation value X is the normalized integral of the operator acting on all values of the wavefunction, giving an effective average value expected if infinitely many observations were measured.
For example, one of the primary consequences of quantum mechanics in one dimension state that [x,p]=ihbar (I might be off by a sign here). Plug this into the generalized uncertainty relation, and you get the well-known result deltax×deltap=hbar/2. Note, this is only true if x and p are acting in the same direction. If they're in orthogonal directions, the operators commute, and the total uncertainty product can be as small as zero.
Angular momentum operators, on the other hand, have the commutation relation [Lx,Ly]=ihbarLz, where Lx is the angular momentum operator in the x direction, and so on. What this means is that you cannot simultaneously know the x, y, and z components of the spin vector. In other words, you don't know exactly where the vector is pointing in space. For a single particle, you would be able to simultaneously know it's x, y, and z positions, but not its angular momentum. And you can see deltaLx×deltaLy=hbar/2Lz.
So while you cannot know exactly the angular momentum of a particle, you can know a little more about it than hinted above. The operator L^2, which is a measure of the total angular momentum, commutes with the other angular momentum operators. Ie, [L^2,Lz]=0, and similar for Lx and Ly. So for a system with angular momentum, one CAN simultaneously know the total angular momentum as well as the z-component of the angular momentum. A vector in 3D space needs 3 independent components to know it exactly, but for angular momentum we can only know two exactly. So there is effectively a cone of uncertainty that any particle with angular momentum (or spin) points along.
For the curious (if anybody even read this far) - if you studied chemistry and remember the quantum numbers for the periodic table, you'll recall n, l, m, and I think s. The l refers to the measure of total angular momentum and the m refers to the z-component of that angular momentum.
make world, not war