Scientists Find Method To Reliably Teleport Data

An anonymous reader writes "Scientists at the Kavli Institute of Nanoscience say they've managed to reliably teleport quantum information stored in one bit of diamond to another sitting three meters away (abstract, pre-print) . Now, their goal is to extend the range over a distance of a kilometer. '[R]eliability of quantum teleportation has been elusive. For example, in 2009, University of Maryland physicists demonstrated the transfer of quantum information, but only one of every 100 million attempts succeeded, meaning that transferring a single bit of quantum information required roughly 10 minutes. In contrast, the scientists at Delft have achieved the ability "deterministically," meaning they can now teleport the quantum state of two entangled electrons accurately 100 percent of the time. They did so by producing qubits using electrons trapped in diamonds at extremely low temperatures. According to Dr. Hanson, the diamonds effectively create 'miniprisons' in which the electrons were held. The researchers were able to establish a spin, or value, for electrons, and then read the value reliably.'"

Comments

This research should receive enormous funding.

[Anonymous Coward]

Can you imagine the boner the high speed traders would have if someone figured out a way to communicate information from New York to Chicago or London instantaneously?

Re:This research should receive enormous funding.

[TeknoHog]

You can't use quantum teleportation to transmit information faster than light. QT requires a classical information channel (like fiber optic cables) on the side to actually work. The point about QT is being able to transfer a quantum mechanical state, i.e. the wavefunction with its full phase information. You cannot do that with classical means, because you'd need to measure the state, thereby collapsing it into a classical state.

Re:This research should receive enormous funding.

[fuzzyfuzzyfungus]

At least poor Erwin can finally bring his cat with him when he travels.

Re:This research should receive enormous funding.

[barlevg]

I realize you were making a joke based on a perception common in popular culture, but the truth is that the Schrodinger's Cat paradox has a simple resolution: the cat *cannot* be both alive and dead because the detector (which detects whether the decay has occurred and which triggers the release of the poison if the decay occurred) collapses the wave function of the particle. There's no such thing as a passive detector. So while a subatomic particle could indeed exist in a superposition of "decayed" vs. "not decayed," the second you go about asking the particle whether it's decayed (that is, when you set up the detector), the wave function collapses, and no superposition is possible.

Re:This research should receive enormous funding.

[fuzzyfuzzyfungus]

I think that that was more polite and informative than my fairly feeble joke deserved. My thanks.

Re:This research should receive enormous funding.

[NotDrWho]

Anyone remember the movie "Mystery Men"? One of the characters in that movie summed up my feelings on modern quantum physics pretty nicely. He was "Invisible Boy." But he could only become invisible when no one was looking (not even himself), and no cameras were on him. The second that anything that could actually verify his ability tried to do so, he became visible again. This led to the obvious question "How do you know you have this power at all?" to which he relied "Well, I just feel it."

Re:This research should receive enormous funding.

[skids]

The double slit experiment. Even when you slow down the rate of photons going through the slit so no two can possibly interfere, they still present a self-interference pattern. If the function was "already collapsed" it could not interact with itself.

Re:This research should receive enormous funding.

[barlevg]

Basically, we know that superpositions exist because we can perform experiments in which, if a particle were always in one state or the other, the results would be different. See: double-slit experiment. If photons didn't exist in a superposition of states, then the distribution of light you'd get with the double slit would be the distribution you get from having one slit covered plus the one you'd get from covering the other one. But you don't--the distribution is completely different, which means that a single photon somehow travel though *both* slits and "interferes with itself." It's more than a little batshit.

Re:This research should receive enormous funding.

[Charliemopps]

I realize you were making a joke based on a perception common in popular culture, but the truth is that the Schrodinger's Cat paradox has a simple resolution: the cat *cannot* be both alive and dead because the detector (which detects whether the decay has occurred and which triggers the release of the poison if the decay occurred) collapses the wave function of the particle. There's no such thing as a passive detector. So while a subatomic particle could indeed exist in a superposition of "decayed" vs. "not decayed," the second you go about asking the particle whether it's decayed (that is, when you set up the detector), the wave function collapses, and no superposition is possible.

You're presenting your interpretation as fact, and it's not. It's a possible scenario, but this thought experiment is designed explicitly to show a paradox that we have yet to resolve. What you describe is the "Copenhagen interpretation" which was proposed by Niels Bohr, Werner Heisenberg and others in 1924 to 1927. It states that quantum states are not fixed but probabilities. Just as you said, once any measurement is made the wave function collapses and the state is fixed in the classical sense. If this interpretation is true, then you are correct. But there are many other interpretations that have any equally valid chance of being correct.

In the "Many-Worlds" interpretation, the cat really is both alive and dead. When you open the box you become entangled with the cat (not literally, that would hurt) and one version of you perceives it as alive and another perceives it as dead. Both results occur, you experience both, but you remain unaware of your duplicate and he of you.

Einstein himself supported an entirely different interpretation called the "Ensemble interpretation" which basically just makes the entire thought experiment irrelevant. It's wacky and hard to explain so I'll just link to it: http://en.wikipedia.org/wiki/E...

Anyways, I recommend reading up on Schrödinger's cat via Wikipedia or some other source. You're only incorrect in that you thought your explanation was the only one.

Oh, and full disclosure, I'm not a scientist, I just find this stuff incredibly interesting. Also it makes me sound smart at parties. Actually I don't get invited to parties... they say I ramble on about nonsense. Thank God for the many worlds theory... at least I'm popular somewhere.

Re:This research should receive enormous funding.

[Gr8Apes]

I used to be called a tinfoil hatter. But Edward Snowden proved that even *I* wasn't paranoid enough.

You'll note that there has been a dearth on tinfoil hatter jokes since Snowden.

Re:This research should receive enormous funding.

[barlevg]

I didn't come up with this.

Re:This research should receive enormous funding.

[barlevg]

You're presenting this response as if the Copenhagen Interpretation were not still the standard interpretation of QMech nearly a century after its formulation. In all the academic circles in which I've run (I have a Ph.D in physics, although my field was pretty far from quantum mechanics), Many World is considered an interesting idea with little practical consequence, and almost everything Einstein said regarding Quantum Mechanics has turned out to be disproved (though I'm not familiar with this specific interpretation).

Re:This research should receive enormous funding.

[rgbatduke]

Please excuse my absolute ignorance, but I was under the impression that classical information channel was only required to transmit one of the entangled photons. If one of the entangled photons (or what ever it is that is entangled) was transported elsewhere (truck, fiber optics, what-not) the two entangled would still maintain the same state (spin etc) and information could then be transmitted faster than light by changing the state of one and reading the state of the other.

Information cannot be transmitted faster than light as far as we know in standard physics today (barring extreme relativistic things like white or black holes and I doubt even those unless/until experiment verifies any claim that they can).

Quantum theory doesn't get around it. You cannot choose the direction to "collapse" or "change the state" of one of the two entangled spins, because the instant you measure it, it "collapses". You might now be able to predict the state of the other end of the channel, but the person there can't because he doesn't know what you measured, so if he measures up or down when he tries (again, supposed "collapsing the wavefunction") he won't know what you measured at your end or (since the two spins are no longer entangled as soon as a measurement is made at either end) what you do to it subsequently.

But the real problem (the "paradox" bit of EPR) is much worse than that. Suppose the two "entangled" electrons are separated by some distance D. Non-relativistic naive stupid quantum theory states that when one of the two electrons is measured, the wavefunction of the whole thing collapses. But suppose that D is nice and large -- in gedanken experiments we can make it a light year, why not? In the "rest frame of the Universe" (the frame in which the cosmic microwave background has on average no directional doppler shift) experimenters on both ends simultaneously perform a measurement of the spin state of the two electrons. This (simultaneity) is a perfectly valid concept in any given frame but is not a frame invariant concept. Neither is temporal ordering a universally valid concept. But given a simultaneous measurement of the two spins, which measurement causes the wavefunction to collapse and determines the global final state, given that the entropy of their measuring apparatus (which is responsible for the random phase shifts that supposedly break the entanglement, see Nakajima-Zwanzig equation and the Generalized Master Equation) is supposedly completely separable and independent?

By making D nice and large, we have a further problem. I said that the measurements were simultaneous in "the rest frame" (and even gave you a prescription for determining what frame I mean), but that means that if we boost that coordinate frame along one direction or the other, we can make either measurement occur first! That is, suppose the spins are in a singlet spin state so that if one is measured up (along some axis) the other must be measured down. Suppose that in frame A, spin 1 interacts with its local measuring apparatus first and is filtered into spin down. This interaction with its local entropy pool -- exchanging information with it via strictly retarded e.g. electromagnetic interactions -- supposedly "transluminally", that is to say instantaneously in frame A -- "causes" (whatever you want that word to mean) spin 2 in frame A to collapse into a non-entangled quantum state in which the probability of measuring its spin up in that frame some time later than the time of measurement in frame A is unity. In frame B, however, it is spin 2's measurement that is performed first, and as the electron interacts with its entropy pool you have a serious problem. If you follow any of the quantum approaches to measurement -- most of them random phase approximation or master equation projections that assume that the filter forces a final state on the basis of its local entropy and unknown/unspecified state -- it cannot indep

I think this was reported the other day

[jareth-0205]

http://www.smbc-comics.com/?id...

Re:I think this was reported the other day

[Anonymous Coward]

And may the comments in your code always be one word too long to fit on a single line.

Headline

[slapout]

"Scientists Find Method To Reliably Teleport Data"

Scientist found the internet?

Re:Headline

[slapout]

Ok, so they switched from Comcast...

Why not 1000 km?

[NotDrWho]

If it's real "quantum entanglement," that should be not different than 3m or 1km.

Re:magic?

[MRe_nl]

The whole universe is local. It turns out all spells are actually ranged touch attacks. This will cause a massive disruption in the Unseen University at about lunch-time.

Re:magic?

[giltwist]

Like I'm 5, please.

Oh my god, where are your parents?

Sorry, but that is just incorrect

[Anonymous Coward]

Unfortunately this got modded up to +5 quickly, but is completely wrong.

. There's no such thing as a passive detector.

A larger part of quantum mechanics is there is no such thing as any interaction being passive. You're detector could consist of a photon bouncing off of a particle or the interaction between two particles. Until you make a measurement on that second particle, or it interacts with the environment, then you've created an entanglement between the detecting particle and the thing being measured. Any dependent interaction within a sealed system, whether called a detector or not, results in an entanglement of states, not breaking the superposition.

If instead we accepted what is said in the parent post as true, then entanglement could not exist, and you could go as far as to undermine all of quantum mechanics by finding issues with Bell's inequality, etc.

Ignore previous reply

[barlevg]

Sorry. Linked to the wrong section. This is the relevant answer, and it's as old as the paradox itself:

However, one of the main scientists associated with the Copenhagen interpretation, Niels Bohr, never had in mind the observer-induced collapse of the wave function, so that Schrödinger's cat did not pose any riddle to him. The cat would be either dead or alive long before the box is opened by a conscious observer.[6] Analysis of an actual experiment found that measurement alone (for example by a Geiger counter) is sufficient to collapse a quantum wave function before there is any conscious observation of the measurement.[7] The view that the "observation" is taken when a particle from the nucleus hits the detector can be developed into objective collapse theories. The thought experiment requires an "unconscious observation" by the detector in order for magnification to occur. In contrast, the many worlds approach denies that collapse ever occurs.

Re:Ignore previous reply

[Anonymous Coward]

But a Gieger counter sitting on some table is well coupled to the lab and environment around it and would allow for coherence as with any other interaction outside the closed system under consideration. If you could construct a way of isolating a cat from the environment, you could use the same method on a gieger counter, and then the effects of "unconscious observation" would go away in a closed system. Things like this have been tested on a smaller scale using detection methods that can be isolated or not, and in the isolated cases superposition returns.

If information can't be sent faster than C.....

[mark-t]

.... then I'm not sure what the real difference is between teleporting data and simply sending it. Can somebody please explain?

Re:If information can't be sent faster than C.....

[Zalbik]

IANAP (I Am Not A Physicist), but as I understand it, the information is sent instantaneously (teleported), but can only be "read" via the use of a measurement taken at the source location & sent (via classical channels) to the target.

i.e.:
2 entangled particles exist. One at A and one at B
Measurement is take an A. This results in a change of state to both particles
Unfortunately, due to quantum funkiness, the state at B cannot be determined without the measurement from A.
Measurement is sent from A to B (via classical channels)
B can then determine the state of their particle (which matches the state at A)

Please excuse any butchering of the science that may of occurred due to my ignorance :-)

Re:How fast is the data transmitted?

[selectspec]

The problem with the articles is that they use a misleading term "information". The quantum information is transmitted instantaneously. However, quantum information is not the same as classical information. Classical observers at either end of the experiment cannot set the quantum information that is transmitted. Therefore the no-communication theorem is not violated. Superluminal communication of classical information (what you and I think of as data) is not possible. The best way to think of this (as another slashdot user pointed out) is that you have a random number generator at two points separated by a distance. Both points generate the same random number regardless of how far away from each other they happen to be in space.

The practical application of this is not transmitting classical data faster than the speed of light (as that is not possible.) However, it could be used for an encryption mechanism that is unbreakable. This is done by taking the random numbers generated and using them to encrypt classical data, which is then transmitted by conventional means (radio etc) and then decrypting on the other end with the same set of random numbers. Nobody can decrypt the data unless they have the other entangled particle of which there can only be one.

Additional funding

[PsyMan]

DeBeers have announced additional funding as long as they can't do it with artificial diamonds.