Superluminal Light Propagation, Higgs, Graviton Rings, etc.

[aargh! I type too slow...Here's the post I meant to write before]

For the short answers to your questions: 1)Yes. 2)It actually could be any speed. 3)You are are correct.

Teleportation (and collapsing of quantum entanglement) can be essentially instantaneous! Unlike the courteous information that always obeys the speed (of light) limit, teleportation does not have to, because by itself it can not convey information.

As you mention, teleportation requires the pre-making of some quantum object. Consider two people: Alice and Bob. One day they are hanging out in the Einstein Cafe and create a pair of quantum particles with unique properties. If one particle is pointed "up" then the other will always be point "up" as well. If one is "down", the other will always be "down" with 100% probability. The quantum trick is that before measuring the particles they are simultaneously up and down so measuring either one will give a 50% probability of getting a specific result. Of course once one is measured the other can be instantly determined since we know about the correlation between the particles even if we don't know anything about a specific particle. This type of "quantum entanglement" I describe is very counter-intuitive, and I don't know what to say other than it has been shown to exist in experiments. If I continue with the story however, perhaps I can convince you that no information is transmitted in the process of this instantaneous determination.

So after having a couple of drinks at the bar, Alice and Bob part ways and head for opposite ends of the galaxy. Quite some time later (on a pre-determined schedule), Alice measures her particle. At that exact instant, Bob's particle is also determined by the quantum mechanical laws I stated earlier. Unfortunately Bob has no way of knowing what Alice's result is. As far as Bob is concerned, the particle could still be up or down with equal chance, although the uncertainty now rests on classical ignorance instead of any quantum property. Alice knows what the result is, but it would take a regular message sent at the speed of light before she could communicate that information to Bob.

The real key to this system that prohibits faster-than-light communication is the inability of Bob or Alice to measure their particle without affecting it. The same strange rules that allow one to create correlated (entangled) particles prevent us from measuring a particle without disturbing it. Until he receive's Alice's message, the outcome of Bob's measurement will appear random to him, and thus convey no information. He will know his result is the same as Alice's, but because the result of her measurement was random, no information can be communicated. For the outcome to contain any information at all, Bob has to wait for that speed-of-light message to reach him.

As a side note, I mentioned at the beginning that the collapse of entanglement can be at any speed. A fascinating area of research in quantum mechanics revolves around a "weak measurement" where we only get partial information about a quantum object. The result is that the state of the object only partially collapses. In fact, you can think about any quantum measurement as a continuous process of gaining information. The more information gained about the quantum state, the more we have forced the quantum object to take a specific value. So the collapse of entanglement you talk about can actually be at any speed. The "instantaneous" ones tend to have the most dramatic results though.

smith

I 'teleport' information every day ..... using my fax machine.
I involve a macroscopic atomic object containing alot more than thousands of billions of atoms ..... my secretary.
( I use the local phone lines as a waveguide and paper as a storage medium )

Oddly - and this might be a difficult concept for CNN - this is simply because the topics have nothing to do with each other ( except that someone chose to label them with the same word ). Note to CNN: StarTrek is a fiction franchise, while the Danish guys are optics researchers.

They have used light to coherently communicate using entanglement properties of said photon's ( which are produced by the process that spawns them ). The important factor is that one can detect eavesdropping - because essentially a 'copy' is kept using the other photon, and quantum mechanics puts a lower limit on any level of disturbance used to read it. There is no 'action at a distance', or 'superluminal' transfer, or 'non-locality' at all - because the whole bloody arrangement is preset by methods using boring sub-light stuff ( and is meaningless without such preparation ). You can always run the 100m in as fast a time as you like, by starting the stop-watch late - for instance after the first 95m have already been run....

Entanglement is not always quantum mechanical - you can do it clasically too - even in your own home. Let's say Bob and Alice ( the eternally entangled communication duo ) agree to always gainsay each other - Bob says YES when Alice says NO, and vice versa. Then when Bob sends Alice a Birthday card proposing/alleging some truth, Bob knows Alice will disagree. There may be some excitement perhaps in awaiting the opening of the envelope. But when done, one will 'instantaneously' know where the other stands. Spooky ...... :-)

Hint: the sublight bit happened whenever they agreed to gainsay .... or possibly when they compared notes later to see if each kept to their gainsaying bargain.

Cheers, Mike.