Quantum Teleportation Achieved Over 7km of Cable (sciencealert.com) 189
An anonymous reader quotes a report from ScienceAlert: Quantum teleportation just moved out of the lab and into the real world, with two independent teams of scientists successfully sending quantum information across several kilometers of optical fiber networks in Calgary, Canada, and Hefei, China. Quantum teleportation relies on a strange phenomenon called quantum entanglement. Basically, quantum entanglement means that two particles are inextricably linked, so that measuring the state of one immediately affects the state of the other, no matter how far apart the two are -- which led Einstein to call entanglement "spooky action at a distance." In the latest experiments, both published in Nature Photonics (here and here), the teams had slightly different set-ups and results. But what they both had in common is the fact that they teleported their information across existing optical fiber networks -- which is important if we ever want to build useable quantum communication systems. To understand the experiments, Anil Ananthaswamy over at New Scientist nicely breaks it down like this: picture three people involved -- Alice, Bob, and Charlie. Alice and Bob want to share cryptographic keys, and to do that, they need Charlie's help. Alice sends a particle to Charlie, while Bob entangles two particles and sends just one of them to Charlie. Charlie then measures the two particles he's received from each of them, so that they can no longer be differentiated -- and that results in the quantum state of Alice's particle being transferred to Bob's entangled particle. So basically, the quantum state of Alice's particle eventually ends up in Bob's particle, via a way station in the form of Charlie. The Canadian experiment followed this same process, and was able to send quantum information over 6.2 km of Calgary's fiber optic network that's not regularly in use.
I Think this article might be a bit misleading.. (Score:5, Informative)
Someone explained this news to me recently, they said the scientists didn't send ~information~ over quantum entanglement, they sent the data across normal networking means and sent and a key to unlock the data via quantum entanglement. The method used has deep implications for security and encryption methods, but not faster than light data transfer. Just wanted to clear that up.
Re:I Think this article might be a bit misleading. (Score:5, Funny)
No. This article clearly means we'll be transporting ourselves to Mars before the week is out.
Re: I Think this article might be a bit misleading (Score:5, Funny)
Exactly. We just need to make sure no flies get into the pods before the doors shut.
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Exactly. We just need to make sure no flies get into the pods before the doors shut.
And since we are beaming ourselves over fiber, pray that backhoe fade doesn't hit while transporting....
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It also helps if the teleportation doesn't turn our insides out.
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Re:I Think this article might be a bit misleading. (Score:5, Funny)
Elon, at least log in if you refuse to take your pills.
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Scott us up, Beamie!
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No. This article clearly means we'll be transporting ourselves to Mars before the week is out.
It doesn't happen that fast. Based on news like this we've heard in the past, though, transporting to Mars is just 10 years away.
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Based on news like this we've heard in the past, though, transporting to Mars is just 10 years away.
And will continue to be for at least another 50 years.
Re:I Think this article might be a bit misleading. (Score:5, Interesting)
Given that none of the articles, as far as I saw, said anything about faster than light communication, and one explicitly disavowed the concept, I think you're projecting your own mistaken conceptions here.
And your friend is correct - quantum teleportation has nothing to do with faster than light communication, as you can neither determine to what form the waveform has collapsed, nor whether one side has already collapsed it. It's effectively** equivalent to having two identical letters containing a random message sealed in an envelope, taking them to different locations, and opening them at the same time. Both sides will get the same random message at the same time, but it provides no means for conveying information faster than light. It is however useful for keysharing.
** In the real world, what is written inside the "envelopes" isn't determined until it's actually observed. But it works out to the same net effect.
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There's no need to be a nerd about it. Some people mistakenly think this news is about fast internet speeds.
some people see "teleported their information" and skim the rest of the article.
Re: I Think this article might be a bit misleading (Score:5, Funny)
Umm, this is Slashdot!
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There's no need to be a nerd about it.
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If that random message is used as the key then it is transporting information since information is simply data that has a meaning or use.
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Data that to an observer is 100% random is not "transmitted information" in a physics context. Or in an information theory context either
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Data that to an observer is 100% random is not "transmitted information" in a physics context. Or in an information theory context either
Bullshit. It is transmitted along the fiber optic cable, at a fraction of the speed of light in a vacuum, to yield the same random value at both ends. By being unpredictable, it meets the definition of information.
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Well, fine, if you want to think of it that way, go ahead, Pretty much every single physicist would say you're wrong, but what do they know, with their "degrees"...
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Well, fine, if you want to think of it that way, go ahead, Pretty much every single physicist would say you're wrong, but what do they know, with their "degrees"...
If you want to count the length of the procedure from the time the entities at both end perform and evaluation, then fine. But that's skipping over the time for the entangled photons to get from hither to thon.
All this yields is a shared private key. Of course some one has already unrolled a reel of fiber optic from hither to thon. You could have just let them transport the key in their pocket.
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In a sense you could interpret it that way. But that's quibbling about terminology; it doesn't mean you can send messages that way, which is the important point.
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In a sense you could interpret it that way. But that's quibbling about terminology; it doesn't mean you can send messages that way, which is the important point.
Well you can, you just can't choose which message is sent, from the space of all possible messages sendable.
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Again it's quibbling about what "sending a message" means.
To most people "sending a message" implies two roles: the sender knows the content of the message before it is sent, but the recipient does not know the contents until it is received. So if you say "you can use this machine to send a message", that's what they'll picture, but it's not what is happening here.
And if you say message sending is "faster than light", they simply extend this model, picturing something like the Ansibles of science fiction.
H
Re:I Think this article might be a bit misleading. (Score:5, Informative)
It's effectively** equivalent to having two identical letters containing a random message
No. you're describing entanglement.
Teleportation is subtly different.
Teleportation consists of transferring the quantum state of one particle to another particle via the use of entangled particles (and a classical channel)
The beauty of this is that the entangled state can be set up in advance. You then give me a particle that you might or might not know something about its quantum state (but importantly, I do not know what you know about it so cannot measure that quantum state in advance). I can transfer the state of that particle to another particle that Bob has via some entangled particles we exchanged earlier *plus* some standard classical information that goes over classical channels (it's this classical information that limits the teleportation to the speed of light)
The particle that Bob ends up with is in an identical state the the one you gave me (and which I still have).
N.B. This is quantum teleportation, not quantum cloning which is not possible. The act of getting the quantum state to Bob affects my particle in a way that means I cannot also extract any information from it about the original state of your particle.
Re: God (Score:1)
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I don't know what else you saw but basically the entanglement leaves the target (teleportation) end in a superposition of four states, only one of which is the one you want the others are complementary states.
The sender makes a measurement at their end to determine which one of the four states is the correct one and then transmits it to the receiver. The receiver can then isolate the correct state from the others that would otherwise cancel out all knowledge of the original state.
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Sorry, I'm hopeless at explaining hence why I could never teach.
There aren't two identical "messages" in quantum teleportation. That would violate the no-cloning theorem. Instead there's one message that originally exists at point A and later exists at point B instead.
But - and this is the bit where it involves QM weirdness - there is no way to "read" a complete quantum state and record it classically. Think of it as a two bit word in a computer where every time you read one bit the reading circuit randomly
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Given that none of the articles, as far as I saw, said anything about faster than light communication, and one explicitly disavowed the concept, I think you're projecting your own mistaken conceptions here.
And your friend is correct - quantum teleportation has nothing to do with faster than light communication, as you can neither determine to what form the waveform has collapsed, nor whether one side has already collapsed it. It's effectively** equivalent to having two identical letters containing a random message sealed in an envelope, taking them to different locations, and opening them at the same time. Both sides will get the same random message at the same time, but it provides no means for conveying information faster than light. It is however useful for keysharing.
** In the real world, what is written inside the "envelopes" isn't determined until it's actually observed. But it works out to the same net effect.
It seems to me that they could very well use it for ftl communications. If you can change the state of one particle to a state that represents either a 1 or 0 then the other will change to match it so you just read the state of the recipient and then you have a binary stream. The bandwidth might not be especially great and on an earthly scale you'd probably still get a better data rate over traditional methods. Although I am not a expert in such fields, not even an amateur and there are probably a bunch of
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It seems to me that they could very well use it for ftl communications. If you can change the state of one particle to a state that represents either a 1 or 0...
That's just it; you can't do that.
You can only make measurements; you can't influence the result.
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The method used has deep implications for security and encryption methods, but not faster than light data transfer. Just wanted to clear that up.
The parent explicitly says that faster than light data transfer is not possible. It's really sad we are unable to capitalize on the 'spooky action at a distance' phenomena.
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I think in some sense, the particles are never actually separated, when though their x,y,z coordinates change in 3D space. It may make more sense to think of them as still actually connected in some domain, but that their projection in space has changed so that they seem to now be separated when only looking at spatial coordinates.
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If both parties are guaranteed to get the same information at the same time
Not "at the same time."
then at least one piece of information has been shared faster than light: both parties know the moment at which the other party received the information.
No they don't. All that can infer is that if - and when - the other party measured the photon - and if nothing has disturbed it beforehand - they will get the same result. They won't actually know what happened until they compare notes classically.
The other party may have made their measurement a hundred years earlier, or a hundred years later, or even at a point in spacetime which can not be said to be either earlier or later (thanks to relativity).
No information passes from A to B,
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Yeah. You can send random information faster than the speed of light.
No. You can't.
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No, you can't, and adding an expletive does not make you correct.
You cannot send random, or any other kind, of information faster than light. That's just not what entanglement/collapse does.
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What is being "communicated" FTL, without a non-FTL classical channel, is a random superposition of all the possible quantum states. That is not "random information", it's "no information". Without the classical channel you don't even know whether the holder of the other entangled particle is measuring the same quantum states, so no information is exchanged, not even information about the measured states of the entangled particles.
But sure, as a trivial special case, it is possible to exchange zero informat
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NOTHING is being transmitted FTL.
You entangle particles, separate them at speeds = c, then you measure them.
The information transfer is in the separation of the particles at speeds = c.
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Thank you. That is exactly what I said.
The only part of quantum entanglement that is "instantaneous" (or "FTL") is that when one party performs its measurement, the wave functions for both of the entangled particles collapse out of their superimposed states simultaneously, no matter how far apart they might be. However, this does not communicate any information by itself; for that the two parties still need a classical channel. As you say, nothing is transferred FTL. An observer cannot tell that the wave fu
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when one party performs its measurement, the wave functions for both of the entangled particles collapse out of their superimposed states simultaneously, no matter how far apart they might be.
I'm not sure that can be said to be true. There is no definite "simultaneously" for spatially separated objects.
If one person makes a measurement, then the other's state will have been collapsed. But I don't think you can make any statement about when it happened.
I know there have been experiments that put an lower limit of so many thousand times the speed of light on it, but I'm not really sure such numbers make proper sense.
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Once you are in the possession of them, I modify the state of my own particles, which will modify the state of the ones you have as well. You will detect those modifications instantly, when I make them. Or "faster-than-light".
Nope. You can't "modify" anything - you can only make a measurement. And I can't "detect" anything either - I can't tell whether or not you've made a measurement at a certain time (not least because "at a certain time" takes on an indeterminate meaning over distance).
All either of us can do is make a measurement. When I do, which could be before, after, or at a time with an indeterminate relation to yours (thanks to special relativity and relativity of simultaneity) I will find - upon comparing it to a clas
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so the key isn't data?
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A key is only information if it's a specific key. If you ask me for my key, you're requesting information. If you ask me for a key, then random data suffices.
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But you can't construct the key without communicating classically to collate your measurements. The key doesn't exist until that is done.
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Uh huh. Tell you what, I just sent you an instantaneous message. I will now send you via snail mail the key to decrypt it.
Exactly how fucking useful is that?
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Someone explained this news to me recently, they said the scientists didn't send ~information~ over quantum entanglement, they sent the data across normal networking means and sent and a key to unlock the data via quantum entanglement. The method used has deep implications for security and encryption methods, but not faster than light data transfer. Just wanted to clear that up.
Quantum Key Distribution: More expensive and less practical that putting the key on a USB stick and driving it to the other end.
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They key can't be constructed until the participants have communicated over a classical (even public) channel to compare how they made their measurements. Until then, they sort of haven't opened the box with the cat in it.
I may have mixed my metaphors somewhere along the way...
Quantum encryption not communication (Score:2, Offtopic)
The data is being send the traditional way. But the information is encrypted by the entangled particles then decrypted by its partner.
The real trick is to acutely time the communication delay and cache up the states of those times.
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Quantum Entaglement is not strange at all (Score:1)
I know there's a black and a white ball in a box. I pick one of them without looking at it and transport it 10km away, then I check what colour it is. Now I also know the colour of the other ball, but is it fair to say that checking the colour "affected" the ball I left in the box over the distance of 10km? Obviously it's absurd. Why would quantum entaglement be any more mysterious than this?
Re:Quantum Entaglement is not strange at all (Score:4, Informative)
That's not quite the trick.
You have a box with black and white balls. You take two, X and Y. You throw X without looking at it to Bob. "Hey Bob what's the color of your ball?", Bob says its black. You open your hand and look at your ball,..... amazingly it's black too. No matter what color Bob says, yours is linked to his color!
The claim: The act of Bob looking at the color *sets* the color of his ball, and because they are linked by a mysterious spooky distance effect, it also sets the color of your ball. The balls normally have no color.
The reality: You take a photograph of the balls. You throw one, Bob looks at his, you look at yours. The photograph is checked to see if it the balls have the same color? Yes? Then you count the experiment. No? Then you discard the experiment as a failed entanglement.
EVERY entanglement experiment includes this filtering stage. Since the information on whether the entanglement was a 'success' or 'not' is sent along another line, it follows that you cannot use this "faster than light" communication until the fixup information arrives via normal communications.
Bob does not know if his ball is a valid entanglement until details of the outcome of the photograph are sent to him.
For the purposes of this experiment, we downplay the photograph, and we never count the photograph as a "detection". When the ball is measure by Bobs eyes, we count that as a detection, when the ball is photographed, we don't count that as a detection until someone looks at the photograph. I kid you not.
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Oh shit. I thought you were feeding the cat.
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Re:Quantum Entaglement is not strange at all (Score:4, Insightful)
Not really, but if you want a completely descriptive analogy for quantum entanglement... well, there isn't one.
Alice and Bob have two different ways of measuring particles, and each way can give two different results. They might do a "brightness" measurement (analogy) which returns either black or white. Or they might do a "colour" measurement, which returns either red or blue.
The trick is that, although you might think the results are predetermind, and therefore fixed, they're not. If Alice does a brightness measurement and Bob does a colour measurement, there is now no way for Alice to get a colour measurement that will definitely match Bob's. The information is gone. It might match by chance, but it equally might not.
So Alice and Bob measure at random - sometimes brightness, sometimes colour. Later they compare notes on which tests they made on which photons (they can do this in public), and discard any results where they didn't use the same test. The remaining results are what they use to make up their key - a 0 for black-or-red, a 1 for white-or-blue.
If they do a test encrypt, and find that it doesn't work, that indicates someone else was intercepting their photons and screwing up the entanglement (because that person would have no way of knowing whether to test for brightness or colour).
At least, that's my understanding. I could be wrong, and probably am.
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At least, that's my understanding. I could be wrong, and probably am.
Well, you're right while no one is reading your post. Otherwise, it's wrong. Sorry.
Re: Quantum Entaglement is not strange at all (Score:1)
Alice has Bob by the balls. This is the only thing that really matters.
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The issue is that you can't know until data
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I know there's a black and a white ball in a box. I pick one of them without looking at it and transport it 10km away, then I check what colour it is. Now I also know the colour of the other ball, but is it fair to say that checking the colour "affected" the ball I left in the box over the distance of 10km? Obviously it's absurd. Why would quantum entaglement be any more mysterious than this?
What you describe here it the hidden variable theory, and it has been proven wrong using Bell's theorem.
Quantum entanglement really is mysterious. Mysterious enough to drive Einstein nuts. And while the maths work, there is currently no satisfactory interpretation.
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Bell's theorem rules out local hidden variables. There might still be non-local hidden variables, but that's just as weird, if not weirder.
Confused (Score:3)
Can someone spell this out for us lamens?
How does something teleport across a wire? By that logic, our current communication systems are "teleporting" information.
I thought Quantum Entanglement is instantaneous and void of any connecting wires, which fits my definition of "teleportation" a little better, but I still don't think of it as teleporting.
Re:Confused (Score:5, Informative)
Quantum teleportation is instantaneous, but first the entangled particles must achieve some distance between them, and this is subject to the usual speed-of-light constraints. In this case the photons achieved that separation over a length of fiber, rather than being sent through free space. Fiber is likely to scale considerably better than line-of-sight transmission.
Entanglement won't survive optical repeaters, so I'm not sure just how well this actually will scale in the real world. Still, 6.2km is a useful distance for some limited applications.
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Quantum teleportation requires the use of a classical channel. The entangled particles can be exchanged in advance (provided they can be stored without breaking the entanglement which is difficult in practice but trivial in theory)
The classical data can only be transferred at the time the teleportation is done - hence that limits the speed of the teleportation to the speed of light.
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FTA, there's another innovation not in the Slashdot headline or summary, except to say " the teams had slightly different set-ups and results."
One of those results seems to be that the team from China's method allows for quantum repeaters which can relay entangled particles:
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It's entanglement of "laymen" and "lamers".
Why Alice Bob and Charlie? (Score:2)
I always thought that it would be apropros to use Bob, Carol, Ted and Alice [wikipedia.org] as example names for sharing.
Re:Why Alice Bob and Charlie? (Score:4, Funny)
I always thought that it would be apropros to use Bob, Carol, Ted and Alice [wikipedia.org] as example names for sharing.
Ted and Alice broke up, though he doesn't know it yet.
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What about Rita, Sue and Bob too [wikipedia.org]?
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http://xkcd.com/1323/ [xkcd.com]
Fiber network? What fiber network? (Score:1)
"Calgary's fiber optic network that's not regularly in use."
Yeah no shit it's not in use. ISPs build the network and leave it there for years just to keep getting as much money out of their outdated tech... and when they finally give us fiber, they start with very low speeds (under 100Mbps), at ridiculous pricing, to gouge us even more.
I hate to break it to you ... (Score:2)
... but if you need a cable, it's not teleportation.
Just sayin'.
This is not teleportation (Score:1)
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Words can mean different things in different contexts.
Homeopathy (Score:1)
This layman needs further explanation (Score:2)
OK, slight background. Basic applied physics knowledge from 20+ years ago.
How does this qualify as teleportation if you have an optical particle, and a optical transport medium? Isn't this the photon hitting the surface of the fiberoptic transport medium, changing state to an optical waveform, traveling along the transport to the endpoint, exiting and changing state again, and then being detected as a photon?
Also somewhat confusing as photon's have no mass.
If this had been a neutron, or some other actual su
Ya know... (Score:2)
Alice, Bob, and Charlie show up a LOT in these types of discussions. Mucking around with quantum this and quantum that. Sending encrypted messages. Very suspicious. Why aren't they on some sort of watch list?
Explaining FTL non-information travel (Score:3)
My favorite way to explain the difference between something "happening" FTL and useful information not being able to travel FTL is this:
Imagine you've got a powerful laser aimed at a wall a few light-years away. You then sweep the laser beam along the wall's length. The illuminated area changes at several times the speed of light. But this is not information transfer, because each photon travelled a few years in a straigh(ish) line and hit the wall based on the angle of the laser at the time of emission. We "see" a moving spot, but what we're actually seeing is a progression of non-FTL arrivals. The photons carry information, but whatever knowledge is imparted at the point where the wall is illuminated is not transferred to any subsequently illuminated location.
Re:Explaining FTL non-information travel (Score:4, Interesting)
One could easily sweep the spot of a laser across the surface of the moon faster than a light-speed signal would do so.
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If you try sweeping the beam, you will see the spot on the moon stay where it was for 2.6 seconds (1.3 light seconds each way), then move to the next position.
A 2.6 second delay is not "faster than light", it is exactly what you would expect with light travelling at c.
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You've missed the point.
then move to the next position.
It (the spot) will "move" from the initial position to that "next position" faster than a light-speed signal could do so over the surface of the Moon.
Forget the delay. Just imagine that someone else is sweeping the laser pointer and you're just watching the result, so any delay from the Earth to the Moon is of no interest to you - in fact, maybe you don't even know it's someone on Earth doing it. What you would see is a spot "moving" across the surface of the Moon apparently faster t
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The impracticality of what the other guy suggested is neither here nor there; I posted my reply in protest, really, at your overly critical pedantry.
If you could do what he suggested, then the consequences would indeed be as he suggested. It's a thought experiment. It's meant to be an example, to help you understand the reality, not to prove something.
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Why should I believe you? Based upon what? Upon you saying so or other person saying so? How can anyone be sure about the exact outputs under so uncertain conditions?
Again, you are being too pedantic. Is there, possibly, some hitherto unknown physical phenomena that would stop the suggested idea working? Well, if there is, it has never shown itself.
Pulsars do the equivalent of what was suggested all the time. They are thousands of light years away, and they are sweeping signals around the entire 360 degrees of their view of the universe in fractions of a second. We've seen nothing interfering with them, so there is absolutely no reason to assume that the OP's thought ex
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PS: the speed of light is the fastest thing we know. Although it might be possible to go faster than that (why not? There is no solid justification for this being the absolute limit, other than our restricted perception and some old "I tell you so"s)
The "solid justification" is that anything faster than the speed of light would, in some reference frame, be equivalent to travelling backwards in time, which would break causality - a property our universe seems to hold with without exception.
Furthermore, the speed of light constant. To all observers. You can never reach the speed of light because light always moves away from you... at the speed of light. If you fly away from Earth at half the speed of light, any light you see will still travel at the spee
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The "solid justification" is that anything faster than the speed of light would, in some reference frame, be equivalent to travelling backwards in time, which would break causality
Which means nothing, since causality can only be determined in the reference frame where the action (i.e. the acceleration) is occurring.
The fact that causality may appear to be broken from some other reference frame is all very interesting, but ultimately irrelevant.
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Which means nothing, since causality can only be determined in the reference frame where the action (i.e. the acceleration) is occurring.
Yes, exactly. That was the whole point of bringing this up in the first place, as per the top-level post:
My favorite way to explain the difference between something "happening" FTL and useful information not being able to travel FTL is this:
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Sorry, ignore my other post. I could some confused idea about what you were replying to.
The fact that causality may appear to be broken from some other reference frame is all very interesting, but ultimately irrelevant.
It's not that it may appear to be broken, it's that it would be broken.
If something could travel faster than light in one reference frame, then it would, literally, be travelling backwards in time in some other reference frame. It's an inescapable and proven consequence of how spacetime is divided into space and time differently by different observers.
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By the way, I am perfectly aware about the speed of light value
Jesus. Stop acting so righteously offended. I wasn't being condescending. I wrote it out because I wanted to avoid saying "at the speed of light below the speed of light," that's all.
Despite having a quite strong opinion on this specific front, I don't want to discuss about any of this. I am not trying to be rude or to assume anything about your particular behaviour, it is just not seeing the point in continuing (some past experiences together with the reality of "I don't really care/need to convince anyone").
Then perhaps you should just keep quiet instead of starting arguments if you have no intention of concluding them.
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I think you misunderstand.
The experiments that are discarded are where the two end points don't measure the same quantum variable.
For photons, for example, you can measure whether linear polarization is up-down/left-right or diagonal-left-up diagonal-right-down/diagonal-right-up diagonal-left down.
If both ends measure the up-down/left-right state then one will get up-down, one left-right. If both measure the diagonal polarization then again they will get complementary results. But if one measures up-down an
Re:Coincidence circuit again, i.e. filtering (Score:4, Informative)
You got the first paragraph right. But then got sidetracked by tennis balls.
There are *two* complementary quantum states that you can measure. Measuring one destroys all knowledge of the other.
There is no classical system that behaves like this, therefore any analogy that doesn't invoke some magic artificial property of a classical object won't represent what happens in QM.
In your example you need tennis balls that randomly change colour when you measure their spin and can magically reverse spin when you look what colour they are.
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Particle could be anything, probably sub-atomic to actually work, so it barely matters what atom is actually SENT down the wire. Most likely a photon, though, in these cases though you can do it with electrons and similar.
Information is probably not much per attempt. Maybe as low as a bit each time. But that's enough to form a bitstream. Slow, but a bitstream. That means you can send a conventional PKE key or DH exchange using it because they are small but need to be transmitted securely.
You're measuri
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0 - 1
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\ | /
\|/
------- +
/ | \
/ | \
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Oh well. I tried to write a comment with a diagram but hit submit instead of preview :-(
Consider four directions on a plane. x axis (we'll call that |+>), y axis (we'll call that |->) y=-x (we'll call that |0>) and y=x (we'll call that |1>)
Modulo some constant factors, I hope it's obvious that you can build up some of those vectors from others:
|1> = |+> + |->
|-> = |0> + |1>
etc.
These are the directions of a plane polarized photon.
We setup some photons that are polarized in the |
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The system uses quantum teleportation as part of the communication system.
The title may be a little sensational, but only because most people think quantum teleportation means physical teleportation. No one who really knows what QT is thinks that it is a revolutionary breakthrough in FTL communications.
Quantum teleportation is cool, but not in the revolutionary way that physical teleportation would be.
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Was the message transferred FTL?
Nope, because the universe doesn't like it.
In this particular case the problem is that we don't know beforehand which particle is entangled with witch one. Some particles may not be entangled at all. The result is that by measuring his particles, Bob will only get random data.
The only way for him to find the "good" particles is by comparing his measurement with Alice's, but first, Alice has to transmit her results, and this can only be done the "slow" way.
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you could scan the particles and send signals through them
Nope. Doesn't work like that.