One thing that isn't clear in this article is whether they really teleportated it, meaning that they were able to transfer information instantaneously from point A to point B (which would go against Einstein's relativity law that states that nothing can go faster than the speed of light), or if they just transported a light beam from one point to another with regular means of communication.
It sounds more like it's the later case, and the word "teleportation" here is probably more a link bait than anything else.
And in any case, the title in the article is horrible: "Scientists teleport Schrodinger's cat"
This is not FTL no, that's still impossible and if they'd done -that- this would be a big deal indeed.
What this allows is simply transmitting "quantum information" from one place to another with any reliability at all, by packing it with classical information that helps accomplish that (being the macro-object/light packet).
It's explicitly clear in the article that this isn't "instantaneous" travel. As much as I hate the analogy, they basically were able to copy the box, the cat, the Geiger counter, and the radioactive trigger wholesale and transmit the copy somewhere else. Normally the process of copying would mean someone had to look in the box. This time they were able to copy the package without finding out if Heathcliff was alive or dead.
It would appear that they did. The abstract of Lee et Al's report states:
"We report on the experimental quantum teleportation of strongly nonclassical wave packets of light. To perform this full quantum operation while preserving and retrieving the fragile nonclassicality of the input state, we have developed a broadband, zero-dispersion teleportation apparatus that works in conjunction with time-resolved state preparation equipment. Our approach brings within experimental reach a whole new set of hybrid protocols involving discrete- and continuous-variable techniques in quantum information processing for optical sciences." [1]
The abstract as a whole is a little beyond my knowledge of physics, but the way I read it seems to support that they did actually teleport - but in the quantum sense (ie they destroyed and recreated something in the same quantum state, not that they moved in instantaneously).
Another Science article in the same issue supports my reasoning "Such exotic quantum states can now be prepared in the lab, and even better, they can be teleported—that is, destroyed in one place and recreated in another one, as shown by Lee et al. (1) on page 330 of this issue." [2]
Quantum teleportation just means reproducing the entire quantum state of the system without physically transporting it. It's interesting to note that you can't do this without destroying the original (http://en.wikipedia.org/wiki/No-cloning_theorem).
and the word "teleportation" here is probably more a link bait than anything else.
One thing I like about HN is that if I see a link that sounds too, umm, bait-y, I can just look at the comments here and avoid wasting my time (or at least getting excited without cause).
"Teleportation" is a precise term in the field of quantum information; it wasn't the choice of the news article. Yes, the term was chosen to sound sexy, but it's not an unreasonable term for what it describes even if it can't quite live up to Star Trek.
A better word for non-quantum-physicists would be "transport" here. It's very difficult to move quantum bits from one place to another at all. The light beam is used to increase the reliability of that process.
This doesn't affect how -classical- information is transmitted or make it any better. It makes -quantum- information transmission reliable, which is actually pretty significant. This should allow for quantum computers of larger sizes than the super-tiny ones that have been created so far to actually work.
http://en.wikipedia.org/wiki/Quantum_teleportation (what is being done in this experiment) What the breakthrough is is a way to do quantum telportation reliably -and- quickly (which had both been done before)
Why are people assuming that 'teleportation' means instantaneous travel?
To me, teleporting has always meant transferring the information that describes an object to another location, where the object is reproduced. This transfer of information occurs via light/radio waves or similar.
I hate to post what is nearly a "me too", but I'd also like to ask that question, with the clarification that I do not mean it as a rhetorical equivalent of "No, of course it's not instantaneous, duh", I am genuinely curious where the sheer confidence of the definition of "teleportation" as "instantaneous in violation of relativity" suddenly came from. Is there some scifi show on TV that I'm not watching that is promulgating this interpretation or something? I've seen the belief that entanglement can be used for FTL communication going back unto yea the very beginnings of the internet but this solid and shared definition of instantaneous is new to me vs. even the iteration of this whole argument I saw a few months ago. (Fringe maybe? Haven't started that yet.)
This confusion comes up every time there's a popular article about quantum teleportation.
In a certain interpretation of the unambiguous mathematics, quantum teleportation does feature an instantaneous transfer of the quantum state. It's just that this state is useless for sending messages unless accompanied by a few bits of classical information. Since this classical info flows at less than the speed of light, there's no conflict with special relativity.
It may not be the word "teleportation" that triggers it. A lot of popular science fiction, e.g. the Commonwealth Saga, uses quantum entanglement as a plot device for instantaneous communication.
I'm assuming this due to modern fantasy borrowing the term from sci-fi (ie, "teleport" as a way to magically whisk someone/thing from one location to another instantaneously)... which popular culture has adopted wholesale.
I have a vague impression from articles read in the past that quantum entanglement could allow for a signal to be transferred over an arbitrarily large distance, instantaneously, because somehow a change at point A was 'magically' reflected at point B. I admit that this doesn't necessarily have anything to do with teleportation (I honestly don't understand their usage of the word).
By the way, a quick Google search shows that I am not alone in my thinking, and that I am wrong. :-)
Teleportation is a misnomer here. Nothing is being teleported or transmitted rather information is being measured in two different locations simultaneously as if it were teleported. What I believe is that information is showing up in two different locations simultaneously. This term, entanglement, I think means that every quantum spin has an equal and opposite quantum spin at some other location that always exists. In other words, there's an opposite "thing" of our "thing" and when we adjust our "thing" we can now see or measure the opposite "thing" adjusting oppositely.
It sounds to me like it's an incremental improvement on existing technique, which the researchers are justifiably excited about, and through the Mighty Power of Mass-Market Science Journalism (TM) it becomes something that has never been done before, instead of it "merely" being done better than ever before. Photons have definitely been "teleported" before, as have individual atoms [1]. Though I scare-quote the word because it doesn't really precisely correspond to what people think of when they hear the term.
It's interesting, but it's not a breakthrough, nor does it herald any sort of advance in anything resembling Star Trek transporters, though to its credit I think this is the first Mass Market Science Journalism (TM) article on quantum teleportation I've seen that managed to avoid that faulty comparison, so points for that I guess.
Quantum optics is outside my realm of expertise; to be honest my eyes kind of glaze over whenever these guys give a talk. The real life applications of this are not really teleportation in the "beam me up sense" but more along the lines of encryption.
If your transmission is based on quantum entangled photon states, it is physically impossible to eavesdrop without giving yourself away, since the act of eavesdropping 'collapses the quantum superposition' (like when you open the box with Schrodingers cat). They've actually already rolled out systems based on this technology in various places in the world, but there is a lot of work to improve bandwidth and so forth.
I won't say too much more as I'm well outside the field and will probably garble it.
Minimum round trip time between San Francisco and Tokyo is about 60ms due to the speed of light, which means in practice FPS games are unplayable across the ocean.
If they manage to implement this shit, we'll be able to have FPS games hosted anywhere in the world!
Can anyone explain what quantum teleportation is? Wikipedia does not help, aside from assuring me that it is not what I thought it was:
Quantum teleportation, or entanglement-assisted teleportation, is a process by which a qubit (the basic unit of quantum information) can be transmitted exactly (in principle) from one location to another, without the qubit being transmitted through the intervening space. It is useful for quantum communication and computation. It does not transport the system itself, nor does it allow communication of information at superluminal (faster than light) speed. Neither does it concern rearranging the particles of a macroscopic object to copy the form of another object.
I found it best described as such: you put a white marble and a black marble in separate paper bags. You send one to a friend. As soon as you open the bag, you instantaneously know what color the other marble is. That doesn't mean you can instantaneously communicate with your friend.
They entangled a q-bit with a packet of light, and then sent it from one place to another (presumably using fiber optic or something), without breaking entanglement.
This is important because it gets you the ability to route quantum information to different places.
Presumably a quantum bus in a computer or a quantum fiber-optic line.
I'll try to explain from what I understood in quantum physics class years ago.
When you're dealing with things on the quantum level, observing a particle affects it. Remember Schrodinger's cat? The cat is both dead and alive, until someone opens the box. The opening of the box gives the cat its new state of deadness or aliveness.
Quantum teleportation works through entangled particles. Entangled particles are, in some sense, the same particle in two places. An action on one entangled particle will instantly affect the other particle, including observation of the particle.
Suppose Alice and Bob share an entangled particle. Alice observes the particle on her end, collapsing it into one of four states. Which state it collapses into is and always will be completely random.
Bob's particle was instantaneously affected in one of four ways corresponding to those states. Trouble is, he doesn't know which way, and he can't do anything with his particle until he does.
Alice has to communicate to Bob in any regular way, through light, telephone or internet, what she observed on her end, so that Bob knows what exactly happened to his particle, and what to do with it.
So in this way, it really was instantaneous over a distance, but at the same time nothing useful happened faster than the speed of light.
Can someone please explain what the term "teleport" mean here? I'm not getting why this is an amazing scientific breakthrough (but I'd love to learn why it is).
If it doesn't mean information travelling instantaneously or faster than light, then did the reporter (or the scientist) put the word "teleport" in the title just so it's attention grabbing?!
Anyone found the DOI link yet? The explanation in the article is, I agree, awful, and I want to read what they actually did! If it was only moving a bit of information from RAM to a register (or the quantum equivalent) which it sounds like...then yea, no biggie.
Does this conflict with the notion of the speed of light being a universal maximum speed? If teleporting information causes bi-directional communication to be instant, aren't signals being propagated at faster than the speed of light?
Downvotes probably due to people thinking that your comment adds nothing to the conversation, not necessarily disagreeing with you (I would think that the pic would be cooler if it were higher res; as it is, I can't make much sense of it).
[+] [-] gregschlom|15 years ago|reply
It sounds more like it's the later case, and the word "teleportation" here is probably more a link bait than anything else.
And in any case, the title in the article is horrible: "Scientists teleport Schrodinger's cat"
[+] [-] burgerbrain|15 years ago|reply
"It does not transport the system itself, nor does it allow communication of information at superluminal (faster than light) speed." https://secure.wikimedia.org/wikipedia/en/wiki/Quantum_telep...
I doubt this is different.
[+] [-] Saavedro|15 years ago|reply
What this allows is simply transmitting "quantum information" from one place to another with any reliability at all, by packing it with classical information that helps accomplish that (being the macro-object/light packet).
http://en.wikipedia.org/wiki/No-teleportation_theorem explains why transmission of quantum information is difficult.
http://en.wikipedia.org/wiki/No-communication_theorem explains why quantum effects do not enable FTL transfer of classical information.
[+] [-] geuis|15 years ago|reply
[+] [-] ElliotH|15 years ago|reply
"We report on the experimental quantum teleportation of strongly nonclassical wave packets of light. To perform this full quantum operation while preserving and retrieving the fragile nonclassicality of the input state, we have developed a broadband, zero-dispersion teleportation apparatus that works in conjunction with time-resolved state preparation equipment. Our approach brings within experimental reach a whole new set of hybrid protocols involving discrete- and continuous-variable techniques in quantum information processing for optical sciences." [1]
The abstract as a whole is a little beyond my knowledge of physics, but the way I read it seems to support that they did actually teleport - but in the quantum sense (ie they destroyed and recreated something in the same quantum state, not that they moved in instantaneously).
Another Science article in the same issue supports my reasoning "Such exotic quantum states can now be prepared in the lab, and even better, they can be teleported—that is, destroyed in one place and recreated in another one, as shown by Lee et al. (1) on page 330 of this issue." [2]
[1] - "Teleportation of Nonclassical Wave Packets of Light" - http://www.sciencemag.org/content/332/6027/330 (Science 15 April 2011: Vol. 332 no. 6027 pp. 313-314) [2] - "Make It Quantum and Continuous" - http://www.sciencemag.org/content/332/6027/313.full (Science 15 April 2011: Vol. 332 no. 6027 pp. 313-314)
[+] [-] jnhnum1|15 years ago|reply
[+] [-] invalidOrTaken|15 years ago|reply
One thing I like about HN is that if I see a link that sounds too, umm, bait-y, I can just look at the comments here and avoid wasting my time (or at least getting excited without cause).
[+] [-] jessriedel|15 years ago|reply
[+] [-] baddox|15 years ago|reply
[+] [-] Saavedro|15 years ago|reply
This doesn't affect how -classical- information is transmitted or make it any better. It makes -quantum- information transmission reliable, which is actually pretty significant. This should allow for quantum computers of larger sizes than the super-tiny ones that have been created so far to actually work.
http://en.wikipedia.org/wiki/No-teleportation_theorem (why it is difficult to transmit quantum information)
http://en.wikipedia.org/wiki/Quantum_teleportation (what is being done in this experiment) What the breakthrough is is a way to do quantum telportation reliably -and- quickly (which had both been done before)
[+] [-] bmunro|15 years ago|reply
To me, teleporting has always meant transferring the information that describes an object to another location, where the object is reproduced. This transfer of information occurs via light/radio waves or similar.
[+] [-] jerf|15 years ago|reply
[+] [-] jessriedel|15 years ago|reply
In a certain interpretation of the unambiguous mathematics, quantum teleportation does feature an instantaneous transfer of the quantum state. It's just that this state is useless for sending messages unless accompanied by a few bits of classical information. Since this classical info flows at less than the speed of light, there's no conflict with special relativity.
[+] [-] Deestan|15 years ago|reply
[+] [-] r00fus|15 years ago|reply
[+] [-] georgieporgie|15 years ago|reply
By the way, a quick Google search shows that I am not alone in my thinking, and that I am wrong. :-)
[+] [-] Blunt|15 years ago|reply
[+] [-] CoffeeDregs|15 years ago|reply
[+] [-] jerf|15 years ago|reply
It's interesting, but it's not a breakthrough, nor does it herald any sort of advance in anything resembling Star Trek transporters, though to its credit I think this is the first Mass Market Science Journalism (TM) article on quantum teleportation I've seen that managed to avoid that faulty comparison, so points for that I guess.
[1]: http://www.livescience.com/7647-teleportation-milestone-achi... (which I would note fails the Star Trek test)
[+] [-] flashingleds|15 years ago|reply
If your transmission is based on quantum entangled photon states, it is physically impossible to eavesdrop without giving yourself away, since the act of eavesdropping 'collapses the quantum superposition' (like when you open the box with Schrodingers cat). They've actually already rolled out systems based on this technology in various places in the world, but there is a lot of work to improve bandwidth and so forth.
I won't say too much more as I'm well outside the field and will probably garble it.
[+] [-] fragsworth|15 years ago|reply
If they manage to implement this shit, we'll be able to have FPS games hosted anywhere in the world!
[+] [-] hammock|15 years ago|reply
Quantum teleportation, or entanglement-assisted teleportation, is a process by which a qubit (the basic unit of quantum information) can be transmitted exactly (in principle) from one location to another, without the qubit being transmitted through the intervening space. It is useful for quantum communication and computation. It does not transport the system itself, nor does it allow communication of information at superluminal (faster than light) speed. Neither does it concern rearranging the particles of a macroscopic object to copy the form of another object.
[+] [-] teej|15 years ago|reply
[+] [-] ohyes|15 years ago|reply
This is important because it gets you the ability to route quantum information to different places.
Presumably a quantum bus in a computer or a quantum fiber-optic line.
I can see the marketing pamphlets now!
[+] [-] hanibash|15 years ago|reply
When you're dealing with things on the quantum level, observing a particle affects it. Remember Schrodinger's cat? The cat is both dead and alive, until someone opens the box. The opening of the box gives the cat its new state of deadness or aliveness.
Quantum teleportation works through entangled particles. Entangled particles are, in some sense, the same particle in two places. An action on one entangled particle will instantly affect the other particle, including observation of the particle.
Suppose Alice and Bob share an entangled particle. Alice observes the particle on her end, collapsing it into one of four states. Which state it collapses into is and always will be completely random.
Bob's particle was instantaneously affected in one of four ways corresponding to those states. Trouble is, he doesn't know which way, and he can't do anything with his particle until he does.
Alice has to communicate to Bob in any regular way, through light, telephone or internet, what she observed on her end, so that Bob knows what exactly happened to his particle, and what to do with it.
So in this way, it really was instantaneous over a distance, but at the same time nothing useful happened faster than the speed of light.
[+] [-] tyng|15 years ago|reply
If it doesn't mean information travelling instantaneously or faster than light, then did the reporter (or the scientist) put the word "teleport" in the title just so it's attention grabbing?!
[+] [-] tehwalrus|15 years ago|reply
[+] [-] unknown|15 years ago|reply
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[+] [-] raheemm|15 years ago|reply
[+] [-] fragsworth|15 years ago|reply
[+] [-] unknown|15 years ago|reply
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[+] [-] sorbus|15 years ago|reply
[+] [-] victorantos|15 years ago|reply
so what's new?
[+] [-] CamperBob|15 years ago|reply
[+] [-] bradharper|15 years ago|reply
[+] [-] guelo|15 years ago|reply
EDIT: The pic is not cool?
[+] [-] sorbus|15 years ago|reply
[+] [-] cbarnardo|15 years ago|reply