Teleportation?

Discussion in 'Science' started by Fatmantan, Jun 22, 2009.

  1. Fatmantan

    Fatmantan Member

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    http://www.news.com.au/technology/story/0,28348,25669608-5014239,00.html

    Realistically, would it be possible to make this happen?
     
  2. Ashpool

    Ashpool Member

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    Not quite sure what is has to do with teleportation?
     
  3. abadonn

    abadonn (Taking a Break)

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    The 'teleportation' thing is thrown in there as an aside, with no further details or elucidation. I dont think they're evisaging teleporting in the sense of 'beam me down scotty'. The problems associated with going from transferring a bit of data to a matter teleportation system are astronomically huge. Dont get too excited yet.

    paulh
     
  4. hlokk

    hlokk Member

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    They have teleported things before (e.g. photons or more recently atoms), and it relies on quantum entanglement. So, by developing a simpler method of establishing/maintaining quantum entanglement it could mean teleportation is easier. The article is really about simpler quantum entanglement.

    (When talking about teleportation, it is usually a transfer of quantum entanglement. I.e. You can start with say an atom at one end, then transport the quantum state to another atom a distance away, such that the atom ends up the same, essentially making an exact (down to the quantum level) of the atom. If you could do that with all atoms within an object, then you've essentially teleported the object, though we're a long long long way away from that)
     
  5. Fortigurn

    Fortigurn Member

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    That sounds like a replicator. Is that what you're actually doing? And where do the atoms come from at the other end? You just buy a 'Bucket 'O Atoms' from Costco or something?

    This sounds strangely close to a book we had at home which I used to read avidly when I was very young. It was a children's book on technology, and near the end it made all kinds of extraordinary projections about what kind of technology people might use in the future. It was written in the late 70s or early 80s, and didn't project further than about 2030.

    One of the projections it made was a suggestion for interplanetary travel by teleportation. You would walk into a booth, and your body would be copied by the machine which would then send your information at light speed to your destination. At the destination the information would be used to replicate you using a vat of 'stuff'.

    The book was diplomatically silent as to exactly how you addressed the fact that your original 'self' was still at the point of 'departure', and what you did about the fact that every time you wanted to go somewhere you would be cloning yourself. Presumably the original would be 'disposed of' in some quick and efficient manner, perhaps to be recycled for 'incoming' copies. I'm reminded of 'The Prestige'.
     
  6. Gullenager

    Gullenager Member

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    Have you teleported it, or essentially just copied it's charateristics completely? Heavy mindbender man.
     
  7. OP
    OP
    Fatmantan

    Fatmantan Member

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    That's true. :shock:

    It's not really teleporting, just replicating.

    Will it "kill" the original copy of you from one end and "create" a copy on the other?
     
  8. UB3R

    UB3R Member

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    i think they might be more referring to teleportation of information, not of people... but thats just a wild guess.

    i.e. an application may be say it takes 30min for a radio signal to reach mars, well instead with these two in phase pairs perhaps you could send a message and the instant you sent it to one entangled device the other replicates that information without the need for it to actually be transmitted?

    i'm guessing teleportation of energy or matter would require more than just replication of information?

    wild guess
     
  9. Fortigurn

    Fortigurn Member

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    That's the way it seems to me, which is why this looks more like a replicator than a teleporter.
     
  10. hlokk

    hlokk Member

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    Its 'quantum teleportation', its not quite the same as teleportation you see in movies/tv.

    Technically speaking, it copies the quantum state of the particle. I.e. in any possible way you could describe that particle, they are identical. So you arent really transferring matter (or energy for that matter.... damn unavoidable pun). Sending the actual particle to the other location would probably destroy the quantum state anyways. You cant really send the info or even read the info either. Basically what you do is use two quantum entangled particles (called qubits*) then 'apply' the actual particle you want to transfer. The particles 'merge' and the location particle takes on properties of the merge. Though, due to the combination there are 4 options at the receiving end. So then you send a 2 bit data to the location telling you which state it is (measuring destroys the two qubits). From that info you then do some more stuff and end up with the quantum particle you sent (perfect down to the quantum level).

    I.e. you take a particle, apply it to quantum entanglement, then get that particle (quantum perfect) at the other end. The original particle is changed/destroyed. So what you did was take a particle that cant be sent (well, unlikely to survive with its quantum state intact), cant have its quantum data sent (cant broadcast quantum data), cant be measured then duplicated, and 'sent' it to somewhere else. Its not really the same particle, but it has all the exact same quantum states (i.e. is exactly the same). Though, even in some movies/tv the person is scanned then duplicated anyways.

    The entanglement happens instantaneously (doesnt matter how far you are away) which would make you think that it would make FTL possible, but unfortunately you still need to send (via conventional means) which state it is in, making it no faster than standard communication unfortunately.

    *a qubit is like a binary bit, but instead of being 0 or 1 it can be 0, 1 or both (welcome to the weird world of quantum mechanics)


    Theres a saying in quantum theory: If you think you understand quantum theory, you dont understand quantum theory.


    Edit: technically speaking you cant copy quantum states.
     
    Last edited: Jun 22, 2009
  11. Ashpool

    Ashpool Member

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    So i was reading a bit last night. And I got to thinking about indeterminism which has a lot to do with quantum mechanics. Hesienburg and all, shcrodingers cat etc.

    And I was wondering about computationablity. And the fact that certain self referencing statements can't be computed and also the halting problem. It has me philosphising that this inherent problem with self reference was somehow related to the uncertainty associated with quantum theory.
     
  12. Fortigurn

    Fortigurn Member

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    So as some of us have said, it's more like reduplication. And in the process the original is conveniently destroyed. How does the entanglement happen in the first place?
     
  13. hlokk

    hlokk Member

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    In "classical teleportation", its usually two things. Either the matter is physically shifted (perhaps through some wormhole or alternate spacetime or whatever), or the person is scanned, then duplicated on the other end and the original copy destroyed after or during the process. You cant copy or duplicate quantum states, so no "original copy is destroyed".

    Quantum teleportation isnt either of these. The particle merges with the entangled pair, then to extract from the other you need to read the state at the sending location, and reading quantum states changes the state (i'm not sure if the particle itself is destroyed, but the quantum state is lost). So its like merging with yourself on the otherside, then getting stuck halfway in limbo until the key from one location gets sent to the other :p. Its not really comparable in terms of 'destroying' the original, because as soon as you merge the particles you have a superposition of both, so you loose the particle before even 'sending' it.


    (Usually you get entangled particles from the decay of other particles)
     
  14. Fortigurn

    Fortigurn Member

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    Ok that made even less sense than before. Now I have no idea what is being entangled with what, and how anything gets anywhere. And apparently you lose it before you've sent it. :confused:
     
  15. Tapek

    Tapek Member

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    The bit that always confuses me with quantum science is if the entanglement is broken when you read the changed state at the receiving end, how do they use it to make super fast computers?

    Would it be millions of entanglements transferring at light speed inside the cpu, with 1 entanglement per bit of data or something along those lines?
     
  16. hlokk

    hlokk Member

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    Two particles are entangled. Another particle is applied to one of them, which changes the state of the other (as they're entangled). If we measure what the combining did at one end and send the results to the other end, then that other end can then determine what the particle being sent was (and end up with a quantum perfect copy).

    Imagine a particle can be described by half a deck of cards. Entangled particles are two particles with complementary half decks (i.e. one has half, the other has the other half). Now, quantum fluctuations means the decks are constantly being shuffled. At any point in time you may get different cards. With entangled particles, as you shuffle the cards around, the other particle has the opposite cards (so pause at any time and you''d get a full deck between the pair).

    So entangled particles have opposite states. Now, to teleport a particle, if i 'merge' it with one entangled pair, the same thing happens at the other end instantaneously. But when they merge, it can merge into 4 states. At the other end the person the person doesnt know which of the 4 states to look at. So the person at the sending end, reads their merged particle which destroys the particle and the entanglement (i.e. the link, and one set of particles was destroyed, so the other particle is still fine at the other end). The sending person then tells the receiver which state their particle is in. Now that the receiver knows what state it is in, they apply an operation that gets rid of the previously entangled particles data, leaving you with a particle with the quantum data of the particle you sent only.


    Quantum computers dont really run like normal computers. They dont use entanglement as some transfer method within the normal computer process. Basically what you do is setup a system that results in a probability waveform distribution. Then you read your waveform (which destroys entanglement) and you end up with a list of probabilities. From that you then pick your answer (e.g. the highest probability).

    Edit: this video explains it a bit simpler: http://www.spike.com/video/how-do-quantum/3003435

    So basically quantum computers can perform the same calculation on different numbers at the same time because it works on probability (rather than individually checking each number as traditional computers). Dont worry, i'm still a bit confused myself.

    Its obviously a lot more complicated, and I cant say I completely understand it, but basically quantum computers deal with probabilities.
     
    Last edited: Jun 24, 2009
  17. crag_v

    crag_v Member

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    hlokk, your explanations are a delight to read.
     
  18. Tekin

    Tekin Member

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    thanks - I was also looking for a way of saying "that was really interesting, and i understood none of it"

    Hlokk - delightful reading as always.

    Also: one of the proposed uses for "quantum computing" is for forecasting/simulations. Think of things like nuclear weapons simulations, or weather pattern migration. You're never going to have an "answer" that can be programmatically generated, however you are goign to have a staggering number of "probabilities". A current limitation of standard programming is that each of these probabilities must be mapped discretely through to the end - while this is a quick process for a very fast computer, the sheer number of possibilities makes the process time consuming.

    Quantum computing is, in theory, better able to manage multiple path probability mapping which should move the focus away from a massive super computer able to process each probability line discretely, to a quantum computer able to process all probabilities simultanously.

    That said - a large majority of "quantum computing" theory is based around the physics of how it works, rather than the logistics of how you actually program for it!!
     
  19. hlokk

    hlokk Member

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    Damn, thats not what I want (well, the second part).


    Spot on for the bit about quantum computing.
     
  20. gobbledegook

    gobbledegook Member

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    Each bit in traditional computers is either 'on' or 'off'. In a quantum computer, each qubit is on and off at the same time. So as the quantum computer expands its power increases exponentially.

    I think that's the simplest way it can be explained without explaining anything :D
     

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