IBM Tech Detects & Changes Spin of Single Electron 334
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.
"
Misread this... (Score:5, Funny)
Damn you Taco, and your politics section, it's corrupted my mind!
Re: (Score:2, Funny)
Re:Misread this... (Score:5, Funny)
Hmmmm. (Score:2)
Re:Hmmmm. (Score:2, Informative)
As I recall, Heisenberg states the impossibility of measuring both the position and momentum of a particle at the same time. I don't think that affects changing its spin.
Re:Hmmmm. (Score:2)
Re:Hmmmm. (Score:5, Informative)
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.
Stupid question? (Score:3, Interesting)
The bigger use I see for this new technology isn't encryption, it is end-to-end communication without the possiblity of interception. In this event, you simply don't need to encrypt the transmission because it is impossible to in
Re:Stupid question? (Score:3, Informative)
It doesn't. Who ever put that in the article leader was an idiot. First, there are very few truly "impossible" encryption problems. The one-time pad is one example of a cipher that is impossible to break. Quantum computing will not help us to break those types of ciphers. They truly are impossible to crack.
What QC will help with is solving nearly impossible problems. I.e., problems which can only be solved through brut
Re:Hmmmm. (Score:5, Informative)
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.
Oh, but tinkering is entirely accurate? (Score:2)
Heisenberg said you cannot know both the position and momentum [aip.org]. But, you can tinker with more minor attributes with complete accuracy?
I'm also hoping someone will explain this.
--
Bush: Spending money the U.S. doesn't have [brillig.com] to make his administration look good.
CmdrTaco mistake. (Score:5, Informative)
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 [cbsnews.com]
Re:CmdrTaco mistake. (Score:3, Informative)
To reverse an atom's spin, one must influence the spin of the electrons. This technique does just that.
Re:This does not answer the question. (Score:3, Informative)
Things change spin all the time. Bang on an iron slug enough times with an iron hammer, and you'll start to magnetize both objects, just from the impacts.
IBM is an applied science lab. They found no value in making Hydrogen reverse its spin, and nobody but a particle collider holds onto one free electron; they're always on the move. IBM found value in measuring the required energy to apply to a certain metal used in their products, to make that metal reverse its overall spin.
Well (Score:4, Funny)
Re:Well (Score:4, Funny)
No (Score:5, Funny)
Re:No (Score:5, Funny)
Re:No (Score:3, Funny)
Politicians everywhere are terrified! (Score:5, Funny)
Wow. "You spin me right round, baby right round, like a record baby, right round, round round...."
Re:Politicians everywhere are terrified! (Score:5, Funny)
I HATE YOU. This is stuck in my head for the rest of the day now. DAMN YOU
I'll help you get it out (Score:5, Funny)
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.
So is IBM (Score:3, Funny)
Re:So is IBM (Score:5, Funny)
Re:So is IBM (Score:2)
I'm uncertain about the article. (Score:4, Funny)
Simple. (Score:2)
I heard it is locked in a box somewhere, but that may or may not be so. ;)
Interesting.. (Score:5, Funny)
Electron 2: Oh stop being so negative
Re:Interesting.. (Score:2)
Yes,yes,yes,yes,yes
Positivity YES
Have U had your plus sign 2 day?
Positivity YES
Do we mark U present, or do we mark U late?
Re:Interesting.. (Score:5, Funny)
The second atom says, "Are you sure?"
The first atom says, "Yes, I'm positive."
Re:Interesting.. (Score:2)
Re:Interesting.. (Score:3, Funny)
To which the barman of course replies "to you, no charge!"
Thankyou, here all week, veal, etc etc . .
P
Heisenberg gets stopped... (Score:5, Funny)
To which Heisenberg replies "No, but I know where I am!"
Which leads to MY favorite joke... (Score:2)
The other sodium atom says "What's the matter?"
The first sodium atom replies "I think I just lost an electron!"
"Are you sure?"
"Yes, I'm positive."
Re:Interesting.. (Score:3, Funny)
A third electron comes strolling by, kinda tired, and asks "hey fellas, mind if I sit down and rest for a minute?"
The two electrons, indignant, reply "OF COURSE NOT... what do we look like, a pair of BOSONS?!"
Re:Interesting.. (Score:3, Funny)
This could lead to incredibly high storage density (Score:5, Funny)
Re:This could lead to incredibly high storage dens (Score:2)
But seriously... Look at the OTHER stuff they did (Score:3, Interesting)
But seriously: Did you notice some of the other related experiments from the same group, listed at the bottom?
One struck me: The inclusion of a single ferromagnetic impurity atom in a semiconductor, with its magnetization state producing a srong and extremely localized effect on the electronic properties of the semiconductor.
This might lead to a RAM where the storage element is a transistor with a single magnetic atom embed
NO FAIR! (Score:5, Funny)
Re:NO FAIR! (Score:2)
You changed the outcome by measuring it!
No, just the two.
Innovation (Score:5, Insightful)
Re:Innovation (Score:5, Informative)
Re:Innovation (Score:2)
I'm sure there IS a good reason, I just wonder what it is.
Re:Innovation (Score:3, Interesting)
While I don't KNOW, I can speculate:
1) Silver oxidizes (tarnishes) very easily. Silver oxide is NOT such a great conductor. Given the extremely small size of the interconnects, this could lead to chips with EXTREMELY short service lives - like minutes. (Aluminum - copper's predecessor - oxidizes, too, but the oxide has about the
Re:Innovation (Score:3, Interesting)
Just looke it up, and it appears I've been confused about the purple plague. Actually it's not electromigration of gold into silicon, but an effect of ultrasonically bonding
Re:Innovation (Score:3, Informative)
Re:Innovation (Score:5, Interesting)
Doubly so since it didn't have to happen.
Bell Labs was originally intended to be a boondoggle, since part of the deal for Bell's original monopoly was that they could set phone rates to make a particular profit (6%?) on every dollar they spent on building the phone system, including research. So they set up a R&D arm that was mandated to spend as much money as possible on research with some vuage connection to telephony, in the expectation of being able to make 6 cents on every dollar spent.
It was a "failure" from the first year: They were PROFITABLE, earning/saving more money from using and licensing the results of the research than they spent on doing it. On the average, basic research pays off big-time (even if you can't tell in advance what any particular project might produce). Example: The transistor.
Unfortunately, after the dissolution of the monopoly, the successor to Bell Labs became infected with the "Harvard Business School" style of short-term milking: Cut R&D (which costs money now and pays off later), creating a temporary boost in the profit figures followed by a collapse. Declare that you're a genius, cash out and move on to the next sucker company, leaving your successors to take the blame when the house of cards collapses.
Fortunately, IBM has learned both of these lessons of Bell Labs, big-time (as well as the Labs' UNIX lesson of how {essentially} giving away source code leads to lots of business for computer companies) and has become a worthy successor.
Spin doesn't come in pairs of electrons? (Score:2)
I thought electrons were always tied with another one of opposite spin: if one is up, the other is down.
Re:Spin doesn't come in pairs of electrons? (Score:5, Informative)
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...
Re:Spin doesn't come in pairs of electrons? (Score:2, Funny)
"He's got the upside, I got the downside."
Re:Spin doesn't come in pairs of electrons? (Score:4, Informative)
In a molecular system, this is not necessarily the case. (Otherwise things wouldn't be magnetic)
Impact? (Score:3, Interesting)
Not Electrons (Score:5, Informative)
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.)
Re:Not Electrons (Score:4, Interesting)
Re:Not Electrons (Score:3, Informative)
"IBM scientists have measured a fundamental magnetic property of a single atom -- the energy required to flip its magnetic orientation."
That is what the article is about. In the course of measuring the energy, they flipped the spin of the atom (not of an electron, nor of the components of the atom). The article doesn't even mention the spin of electrons or the components of the atom.
What happens if encryption becomes impossible (Score:5, Interesting)
All I can think of is making the data streams uninterceptable, which leads us back to encoders/decoders built using quantum entanglement.
Re:What happens if encryption becomes impossible (Score:2)
Hmm.., how about thinking about NOT having anything to hide?
Re:What happens if encryption becomes impossible (Score:3, Insightful)
Re:What happens if encryption becomes impossible (Score:3, Insightful)
use quantum computers to encrypt everything to start with. I'm sure an algorithm can be written that would take a quantum computer a very long time to decrypt - it just may have to be run on a quantum computer to start with.
Re:What happens if encryption becomes impossible (Score:2)
Re:What happens if encryption becomes impossible (Score:2)
AHHHHHH! I just had a visualization of inbound pigeon SPAM.
Stern-Gerlach experiment (Score:5, Informative)
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 [wikipedia.org], a key stage in the discovery and understanding of quantum spin.
However, to quote from this discussion of the experiment [phys.rug.nl], 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.
Re:Stern-Gerlach experiment (Score:2)
(If you're sitting in front of a CRT you have such a beam in front of you, behind the glass)
What IBM did here was flip the spin of an individual electron. That's what's new.
They did not determine the spin in three dimensions. (That is what they are referring to in your quote.) If you measure the Z component of an electron spin, you destroy the X and Y c
Re:Stern-Gerlach experiment (Score:3, Informative)
No. The (traditional) SG experiment does not measure the spin of electrons bound to atoms. It measures the spin of a beam of electrons in a magnetic field.
Wrong. The SG experiment was applied to a beam of silver atoms, which have a single electron in their outer shell. It cannot be practically applied to a beam of free electrons, due to the spread of the electron wavefunctions under the action of the uncertainty principle (see my original post, and also the discussion here [cornell.edu]).
And then quantum encryption (Score:5, Insightful)
Of course by then we'll all be using quantum encryption techniques.
What's next? (Score:5, Funny)
SCO Has Been Quoted as Saying (Score:2, Funny)
Mine mine! All mine! Your ideas are all mine!!!
the key to rebecca (Score:5, Interesting)
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.
Re:the key to rebecca (Score:2)
"How do you generate gigabytes of one-time pad?" (Score:3, Interesting)
or if you prefer "better randomness" (sic) use HotBits cesium decay generated random numbers [fourmilab.ch] and pipe...maybe not gigabytes of data ( (about 30 bytes per second, to be precise, sucks...but then...
Mix both obtained key with the obscure, non repetitive algorithm of your choice (a simple XOR will be enough) and you
duh (Score:2)
do we have gigabyte per second data links right now? yes. so just make the delay from the pre-message as large as need be to assure no plausible storage device will work.
Finally if this delay approaches the speed of decryption then stack the encrypted message with another layer of encryption inside.
if that is still not good enough then send the mathematical algorithm in english for decryp
Breaking Encryption? (Score:5, Insightful)
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.
You keep using that word (Score:5, Funny)
Were he still alive, Andre the Giant would have something to say about this sentence.
Re:You keep using that word (Score:2, Funny)
Perhaps something along the lines of... (Score:3, Funny)
Original poster: Won't be long before we're all solving impossible encryption problems.
Andre the Giant: As long as someone knows where they left all the mob gems!
Stop that rhyming, I MEAN IT!
Re:Perhaps something along the lines of... (Score:2)
Re:You keep using that word (Score:2)
Re:You keep using that word (Score:3, Informative)
Were he still alive, Andre the Giant would have something to say about this sentence.
Yeah, like it was Inigo Montoya who said the line you're thinking of [imdb.com]
What IBM doesn't relize... (Score:2, Funny)
don't underestimate the importance of this! (Score:2)
Replicator:
Today, we know how to create microchip circuits and experimental nanometer-scale objects by "drawing" them on a surface with a beam of atoms. We can also suspend single atoms or small numbers of atoms within a trap made of electromagnetic fields, and experiment on them. That's as close as the replicator is to reality. Making solid matter from a pattern as the replicator appears to do,
Re:don't underestimate the importance of this! (Score:2)
If you can detect and change the spin of an electron, and can entangle them, why can't you communicate using this?
Tell me when.. (Score:3, Funny)
But... (Score:4, Funny)
Not so young anymore... (Score:3)
Over the past 15 years, Eigler has led a group of young scientists who have pioneered the use of atom manipulation in wide-ranging experiments aimed at building and understanding of the properties of atomic-scale structures and exploring their potential for use in information technologies such as digital logic and data storage.
Let's see... if they were 25 when Eigler started, they're now 40! Not so young anymore!
(it's a joke. laugh.)
Re:Not so young anymore... (Score:2)
Won't be long? (Score:4, Funny)
Who's this "we"? I still can't get my VCR to stop blinking 12:00...
NSA... (Score:2)
How much you want to bet that the NSA already has this technology, and already solve impossible encryption problems?
Been awhile since I was in physics.... (Score:2)
Spintronics, not Quantum Computing (Score:4, Informative)
How do you solve the impossible? (Score:5, Informative)
Nothing impossible to solve is solvable, and nothing unsolvable is possible to solve.
I think the word you are looking for is intractable.
Wrong. (Score:4, Interesting)
Step 1. Get a 1-bit quantum computer working
Step 2. Wire 1,024 of them together
Step 3. Break 1,024-bit encryption!
In reality, you now have the capability to solve 1,024 separate 1-bit problems. To solve a 1,024-bit problem, the electrons carrying each qubit need to be entangled with each other.
Keeping things in a state of quantum entanglement is extremely difficult. The most I've ever read about was 7 qubits entangled for less than a microsecond. Note that as the number of entangled objects (particles or molecules) increases, the operation gets exponentially harder. As the time to complete an operation increases, it also gets exponentially harder. Quantum computing boosters won't tell you this, but it is not just a matter of getting a prototype working and then making it bigger.
Sure it will (Score:3, Insightful)
Sure it will. Right after I receive my new, wall-sized television in a poster tube, unroll it, and hang it on my wall -- as I've been promised will happen any time now for the last 20 years.
RTFA (Score:3, Informative)
It's about a single ATOM
A-T-O-M
not
E-L-E-C-T-R-O-N
I tried to repeat their experiment... (Score:3, Funny)
10 jokes modded up and not one encryption comment? (Score:3, Insightful)
Private-key encryption will still be just as safe (most likely).
Public key encryption based on factoring will be the first casualty.
Given the fact that patches, fixes, and reimplementations are developed and administered all the time, there's no reason to think that fixing vulnerable systems won't be a fairly trivial re-implementation of some sort. Even if a bunch of systems are left unpatched, it's a long way from IBM labs to some script kiddie's Quantum iPod.
There will be market-hyped hysteria, and a massive cottage industry of re-implementations of security protocols. Think Y2K but worse.
gears? we don't need no stinking gears [usrnull.com]
Re:so now that we can spin one electron (Score:2, Funny)
The Dept. of Homeland Security will be visiting you shortly.
Re:so now that we can spin one electron (Score:2)
Really? Because spinning trillions and trillions of electrons is easy. Just apply a big magnetic field. That's very old news indeed.
The novelty here is the manipulation of a single electron spin. That is difficult and remarkable. Manipulating lots of them is easy.
Re:Consumer Quantum Computers (Score:3, Insightful)
So the question here is: Why would they replace traditional computers? There is no real reason to think that they will replace conventional computers, except for in the areas in which they are better.
(and that's not likely to be every area)
Quantum computers are inherently much more complex than traditional ones. Thus, they will likely always
Re:Consumer Quantum Computers (Score:2)
You can buy an electric or hybrid car now if you want. You can also buy a horse, or walk. You don't need an order from the President to junk your gasoline car and get an electric one.
Cathode-ray tubes for data visualization.
In five years they will be replaced with LCDs. Already new desktop computers come with LCDs (and all notebooks :-) CRT manufacturing is expensive, dirty and it will be phased out.
Nearly all elevators still use ordi