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Science Technology

Austrian Physicists 'Teleport' Light Over 600m 68

Posted by simoniker from the particular dept.
openSoar writes "The BBC is reporting that: 'Physicists have carried out successful teleportation with particles of light over a distance of 600m across the River Danube in Austria. When physicists say 'teleportation', they are describing the transfer of key properties from one particle to another without a physical link.'"
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Austrian Physicists 'Teleport' Light Over 600m More

Austrian Physicists 'Teleport' Light Over 600m

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  • Dear God (Score:4, Funny)

    by NickMc2000 ( 614182 ) on Thursday August 19, 2004 @02:08AM (#10009704)
    Haven't we learned anything from Half-Life or Doom? Teleportaion can only lead to some race trying to enslave humans. Ya, science is soooooo great.
    • You're forgetting about Brundle-fly. Be afraid. Be very afraid.
      • Your sig:

        If you reply, do so only to what I explicitly wrote. If I didn't write it, don't assume or infer it.

        Wow, here's a conundrum:
        Can I write in response to your sig? I mean, you did write it explicitly one time, but does every post constitute an explicit reiteration of the sentiments in your sig? Please advise so I know if replying to your sig is OK or not.

    • I, for one, welcome our new alien overlords...
      As long as I get to telefrag [urbandictionary.com] my boss, they can do anything they damn well want with Earth!
  • "The researchers were able to teleport three distinct polarisation states between Alice and Bob via the fibre-optic cable through the tunnel. The process is not instantaneous as it is limited by the speed of light."

    Doesn't sound like teleporting to me so much as uploading.

    Then again, I'm just grasping at straws hoping to get Canada its first gold medal in first non-anonymous post to have quoted an article done by a member without a Slashdot subscription.

  • Story title and summary all wrong (Score:5, Informative)

    by menscher ( 597856 ) <menscher+slashdotNO@SPAMuiuc.edu> on Thursday August 19, 2004 @02:18AM (#10009739) Homepage Journal
    Ok, as a physicist I initially thought these must be crackpots. A careful read made it clear that the science is good, it's just the slashdot title and summary that don't make sense.

    What they did NOT do is teleport particles of light. That just makes no sense. Light was used as the means of conveying the information used to teleport the quantum properties from one particle to another, without the particle having to travel.

    By the way, the reason this is called "teleportation" is that the particle effectively travels at the speed of light -- its properties can be transferred by light. If this could be applied to humans, for example, it would allow for light-speed travel, without all the nuisances of acceleration. It should be noted that this does NOT violate the universal speed limit.

    Oh, and before someone asks, this is entirely different from quantum tunnelling....

    • Re:Story title and summary all wrong (Score:4, Funny)

      by FLAGGR ( 800770 ) on Thursday August 19, 2004 @02:23AM (#10009759)
      Well, my spacetime folding machine works better, light speed travel is SOOOOOO 80's.

    • The researchers were able to teleport three distinct polarisation states between Alice and Bob via the fibre-optic cable through the tunnel. The process is not instantaneous as it is limited by the speed of light.

      I am feeling particularly stupid, I guess... But wouldn't the fibre-optic cable exist to transfer the entangled photons and the "spooky action at a distance" be performed between the entangled photons regardless of the existance of the fibre-optic cable?

      What does the cable have to do with thi

      • Sadly spooky action at a distance doesn't really work. Its really spooky actions between photon A and photon B, then B moves to C, in which spooky action occurs between photon B and photon C.

        Now the impressive part as I understand is that we've been able to do this with A and C being particles not just photons.

    • Re:Story title and summary all wrong (Score:4, Insightful)

      by noselasd ( 594905 ) on Thursday August 19, 2004 @04:00AM (#10010132)
      >By the way, the reason this is called "teleportation" is that the
      >particle effectively travels at the speed of light -- its properties
      >can be transferred by light. If this could be applied to humans, for
      >example, it would allow for light-speed travel, without all the
      >nuisances of acceleration. It should be noted that this does NOT violate
      >the universal speed limit.
      These folks did not "teleport" a single particle, they transferred the _properties_ of some particles to particles elsewere. Those properties were transported with the about the speed of light. So, I don't see
      quite how you could apply this to humans in the sence of teleporting an entire human somewhere else.

      • Re:Story title and summary all wrong (Score:4, Informative)

        by Anonymous Coward on Thursday August 19, 2004 @04:40AM (#10010249)
        Well, if you simultaneously transferred the _properties_ of every atom in your body to some atoms elsewhere, then you would have achieved teleportation of your body. The fact that your actual subatomic particles didn't move makes it seem kind of like "fake" teleportation, but in the strange quantum world we live in it is completely equivalent to and indistinguishable from "real" teleportation (whatever that means). That's why they call it teleportation even though the actual particles involved don't physically swap places. Of course, usable teleportation of everyday objects is infeasable because in order to get the same object out at the destination you need to have a supply of all the types of atoms in the original object plus the means to assemble them in the configuration of the original object.

        Basically you need to replicate the item first (roughly, ignoring the quantum states of the particles), then you can transfer its quantum state using quantum teleportation to complete the teleport. But you have to do every atom in the object at (about) the same time to avoid having the teleport process affect the object too much. The bandwidth needed to transfer the information held in even a small object dwarfs even theoretical limits on proposed futuristic communication channels. And assembling the replica in the first place is probably even harder; and if you've already made an almost perfect replica of the item then who needs the original anyway? Once you have replicator technology, teleporter technology seems less useful. (You might think it would still be useful for teleporting humans, but if we could do that it would imply that we could also replicate humans. Think of the consequences of that...)

        Wow, that ended up a lot longer than I intended. Some physicist person please come correct all the errors I probably made ;-)

        • Some physicist person please come correct all the errors I probably made

          No physics errors, and a very nice explanation. (And yes, IAAP. Just too lazy to write all that myself.)

          You might want to reconsider your statement "if you've already made an almost perfect replica of the item then who needs the original anyway?" Keep in mind that twins have the same physical makeup, but different personalities, knowledge, and experiences. Quantum teleportation would include those aspects (the part that makes us

        • I've always wanted to see one of the myriad Star Trek shows address the fact that the final step of teleportation is obliterating the original once the copy is confirmed successful. Anyone know of an episode where the writers acknowledge that there's a shredder sitting beneath the fax machine?

      • Re:Story title and summary all wrong (Score:5, Funny)

        by rikkus-x ( 526844 ) <rik@rikkus.info> on Thursday August 19, 2004 @04:51AM (#10010314) Homepage
        Indeed, this isn't so much teleportation as rsync.

        Rik

      • These folks did not "teleport" a single particle, they transferred the _properties_ of some particles to particles elsewere.

        And what's the difference between the two? If you transmit all the properties of a particle onto another particle for all intents and purposes you've transmitted the particle. The only difference between the two particles is the properties they posess. If you could do this to a huge number of particles (and somehow put them in the same order) you could teleport a person.

        Of cour
    • You know, it's actually good news, because this system works a lot more like what most people think is the process of teleporting people as seen in Star Trek: get on the transportation pad, and *BZTT* your physical form is carried away in a flash of light !

    • I'm under the impression (and IANAP), that you can somehow entangle two photons and then send them down seperate paths at light speed away from each other (say to two endpoints millions of km apart), at which point you can instantaneously transmit information from one photon to the other, by messing with the state of one and seeing a related change in the other. My understanding of this was you could have an entangled-photon generator at the centerpoint of a fiber link between two cities halfway around the
      • IANAP either, but I believe the uncertainty principle will muck it up. When you go to read the state of your entagled photon, you won't know if any change in the state is due to a change in the other photon or due to your attempt to read the state. My understanding is that action at a distance only occurs in situations where it conveys no information.
      • You're almost right. Yes, you can send photons down both directions. When you measure the polarization of one photon, it intstantly determines the polarization of the other photon. But you can't choose how to measure the polarization. It's random. Therefore you can't transmit information in this way.

        • Sounds like the whole thing is a lot of BS to me then. So like... if you replace "quantum entanglement" with "randomly-colored can of spraypaint", and "photon" with "tennis ball"... wouldn't you get the same effect? Blast two tennis balls with a single random color of spraypaint, shoot them in two direction, and when you observe one of them being puke-green [drum roll].. the other one is instantly determined to be puke-green!

          Where's the magic?

  • There was a physical link.. (Score:3, Informative)

    by kyhwana ( 18093 ) <kyhwana@SELL-YOUR-SOUL.kyhwana.org> on Thursday August 19, 2004 @02:19AM (#10009744) Homepage
    Err, there was a fibre link, ie a physical link. RTFA submitter?
    • It was the PROPERTIES of the particles that were teleported. Not the actual photons. You lose.
      • Yeah, I just "teleported" your post from the slashdot server into my retinas.

        See your words weren't transmitted, it was the bits that represent them being streamed across the internet, hundreds of miles, to a server, saved, sent to my computer, converted into an image which my monitor projected into my eyes.

        THE FUTURE IS NOW!

        • Re:There was a physical link.. (Score:5, Informative)

          by Rolken ( 703064 ) on Thursday August 19, 2004 @03:09AM (#10009948)
          Um, I'm not even entirely sure what you're getting at... but the point is, two photons are entangled, you move one far away, then mess with the first one and the second one instantly changes in the same way. The photons don't teleport, but their information does.
          • that's called quantum entanglement and is actually not what they did in this experiement. rtfa
          • rsync at the speed of light. ;)

            I could find some uses for that. My brother in law would like to rsync music collections for backup purposes for example. :D
          • You're wrong. If you mess with one, the other is not effected. What happens when particles are entagled is that they seem to rotate, flip, spin in the same pattern. It's like an Russian and a Scott being given the same instruction manual in France and both peple start exicuting the instructions at the same time, while they move back to their home countries. They will be doing the same thing at the same time, but if you slap the Scott in the face and give him a new set of in structions, the Russian does not

          • What is really happening (Score:5, Informative)

            by jgardn ( 539054 ) <jgardn@alumni.washington.edu> on Thursday August 19, 2004 @10:44AM (#10012383) Homepage Journal
            It's really more than that, because you have to remember that each photon is neither fully in one state or the other. It is a combination of the two. This is "quantum superposition", or the concept that a particle is really a manifestation of discrete possibilities.

            I think a good example of what is really happening is to imagine a pair of dice guaranteed by nature always to roll a 7. If you see a "3" on one die, then there absolutely must be a "4" on the other. Anything else would be a violation of several fundamental laws. Now imagine taking the two dice and seperating them by a large distance, and then rolling one of the dice. Even though there is a large distance, and even though the speed of light is the limit at which information may be sent, the other die will show the other number pair when measured. (Debate about whether one measurement happens before another is meaningless due to special relativity. In other words, one measurement cannot cause another to be so.) So if you roll a 3, the other die will roll (or has rolled) a 4. If you happen to roll a 1, then the other die will roll (has rolled) a 6. Spooky, huh? Welcome to the crazy world of quantum mechanics! Just when you thought you understood it all, nature throws a curveball.

            Now your first instinct is that somehow those dice decided on something befor they were seperated. This is not how quantum mechanics works. The two particles can't "decide" on anything until measurement. Every observation and every calculation tells you that the particles did not decide on a specific state beforehand. I could show you why this is so, but it's pretty complicated and involves higher level mathematics than the average slashdot reader can understand. If you're really interested, I suggest reading a QM textbook. They keep this topic in one of the last chapters, so you have a lot of studying ahead of you.

            Finally, your next reaction is going to be, "Wow, we can communicate at speeds faster than the speed of light!" Unfortunately, the way this works you can't "force" the particle to a particular state. If the particle comes in with a preference for one state or the other, then the complement will be true for the other particle. (By preference, I mean the chance of one state is 90%, and the other is 10%, or 99.99% and 0.01%, not something pre-decided. See the above paragraph.) And thanks to special relativity, it is fruitless to try and decide whether one measurement occured before or after another, so a causality link cannot be established.
            • That's not what this is though. They said specifically that it was not quantum entanglement. Quantum Entanglement is instantaneous, not at the speed of light. Nor does it require a fiber cable.

              What this does is send a funky photon from one molecule to another over fiber optics, changing the state of the 2nd molecule... Just another way to transmit data.

  • I was going to ask a dumb question, but... (Score:5, Informative)

    by benjamindees ( 441808 ) on Thursday August 19, 2004 @03:40AM (#10010061) Homepage
    I decided to do a little googling instead:
    How this relates to quantum computing: [arxiv.org]
    When a single photon is split by a beam splitter, its two `halves' can entangle two distant atoms into an EPR pair.

    How to entangle a photon pair: [astronomy.net] There are certain nonlinear (BBO) crystals, such as are used in optical parametric oscillators, that will supply entangles photon pairs.
  • don't know about you guys but i like the idea of teleportation

    we probably can't even imagine what would happen if people could finally get teleportation to work so it could teleport every kind of items, spaceprograms surely would have a great benefit from it, also every kind of transportation companies, except maybe bikecabs :) imagine that you could order food over teleportation :)

    althrough from the scientific point of view, this will be a huge effort even to get a single atom teleported from one place t

    • Re:teleportation ? be very afraid... (Score:1, Funny)

      by Anonymous Coward
      The idea of teleportation is a scary one...

      Imagine waking up in the middle of the night to find the US/Halliburton Army using satellite teleportation to move machinery into your backyard in their global search for oil...

      Teleportion will certainly have its pros and cons... and like all other technologies, its uses will be both beneficial and detrimental... think of its implications in drug trafiking... amongst other things...
    • Piss someone off at work.

      Does the word 'telefrag' mean anything to you? :P

  • Instant travel (Score:4, Informative)

    by laughing_badger ( 628416 ) on Thursday August 19, 2004 @06:38AM (#10010722) Homepage
    One interesting point to note is that, if it were possible to transport a person via this process, the trip would appear to be instantaneous. Although travel would occur at the speed of light, no time would appear to pass for the traveller. Cool.
    • "One interesting point to note is that, if it were possible to transport a person via this process, the trip would appear to be instantaneous. Although travel would occur at the speed of light, no time would appear to pass for the traveller. Cool."

      Duplicate stories on Slashdot would be a wonderful benefit to these heroic travelers!
  • Wouldn't it be wonderful if the latency between Earth and Mars rover could be eliminated? No more troublesome autonomous machines needed, just use remote control. Unless of course a fiber optic cable is a requirement - I don't see any fiber optic cables of that length being produced anytime soon.


  • > When physicists say 'teleportation', they are describing the transfer of key properties from one particle to another without a physical link.

    So some morning when you wake up with a suddenly teeny weenie, you'll know you've been had by a physicist.

  • Ok so why cant we? (Score:3, Interesting)

    by MortisUmbra ( 569191 ) on Thursday August 19, 2004 @07:13PM (#10018148)
    Since, obviously, you are not actually teleporting the photon itself, but rather its properties. Why can't we use this as a sort of limitless instantaneous data transfer method?

    I.E. Use the manipulation of these properties to single a sort of photonic 1's and 0's (or potentially much more, possibly instead of binary, it might be possible to make it trinary, or better).

    Think about it, you put a pack of these entangled photons into a sort of "storage" device, stick it on your next mars rover, and instead of there being a huge delay, your commands are sent instantaneously. Obviously eventually these entangled photons would be all used up (or could you continue to modify them after the first time?) but still, rovers, for example, are a consumable at this point too.
    • No, the communications would still go at the speed of light. this is non-negotiable.

      Also, I don't think reusable particles would be a problem, if you had a gram or so of entangled helium or something, that'd be about 10^20 bits ... of course, it'd be hard to get them in the right order...

      Reusing the particles is also non-negotiable. Once disentangled, only touching the particles together again in a specific manner would entangle them.

      Note: when I say non-negotiable, I mean it. It is not possible. At all.

      • Re:RTFS (Score:1)

        by n54 ( 807502 )
        i found the bbc article selfcontradictory or at best badly written as it says both "When physicists say "teleportation", they are describing the transfer of key properties from one particle to another without a physical link." as well as "...used an 800m-long optical fibre fed through a public sewer system tunnel to connect labs..." and "The link establishes a channel between the labs, dubbed Alice and Bob. This enables the properties, or "quantum states", of light particles to be transferred between the se
        • Sorry, but no. You can't just add up speeds of light to make stuff go faster, read up on special relativity. Yes, certain quantum effects can happen in two places at the same time, seemingly due to faster than light communications, but no information can be transmitted by this way. I mean it. I could be wrong, but I don't think there's any way to detect if a particle is still entangled without disentangling it, since the observation affects the particle. THe only way to use entanglement to transmit informa
          • Gah, stupid HTML formatting

            I VOTE FOR MANDATORY PREVIEWING!

            blah blah blah fuck you slashdot, if my post seems like yelling then it'll get modded down, you insensetive clods,

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