Can Teleportation Become a Reality?

[TriKri]

Hi,

I hear a few years ago about an experiment in which some scientists had succeeded to teleport a photon a short distance. Is this really possible? In that case, how does it work, and what theory do you have to use to make teleportation possible? In which speed does the teleported object travel while being teleported?

 

[sbrothy]

While you wait for a physicist to give his or hers 2 cents here's an informative and quite entertaining article explaining it in some detail:

http://lightlike.com/teleport/

Oops forgot.. I found it here (last external link): http://en.wikipedia.org/wiki/Quantum_teleportation

 

[g33kski11z]

Here is another recent article regarding teleportation of particles.

http://www.scribd.com/doc/31712725/Experimental-Free-space-Quantum-Teleportation-WWW-OLOSCIENCE-COM

.. the article is a bit over my head, so I too, am waiting for a 'laymans' explanation..

 

[PhilKravitz]

Watch out there is a trick in the language. There is
1) teleportation
2) quantum teleportation

Quantum teleportation is defined by some as the transmission of the full quantum state of a particle from point A to point B using standard communication mechanisms. This does not mean transporting the particle from location A to location B only the information about the full quantum state.

 

[haael]

This does not mean transporting the particle from location A to location B only the information about the full quantum state.

That will suffice. You can annihilate a massive particle, turn it into photons carrying information about its quantum state, send them to some other planet and use them to re-create the original particle. This will allow transportation of massive objects at light speed, provided that the necessary energy is already at the destination point.

So, "teleportation" as seen in Star Trek is at least theoretically possible, except there is no means to copy the transported object, and the effects of disturbing the communication signal would be less pleasing.

Technical difficulties to overcome:
1. You have to annihilate a whole human body, so you have to prepare some bit of antimatter.
2. You have to be annihilating it so slowly, so that the heat does not destroy the teleporter or the planet.
3. You have to be annihilating it so fast, so that the untouched parts don't move relative to the already annihilated parts (or perhaps freeze it near 0 Kelvin before the teleportation).
4. You have to collect all information of the system (every damn photon) and store it in some quantum computer.
5. You have to send the data to other planet with virtually no interference from anyting.
6. You have to have big amount of energy at the destination point, ready to use before the teleportation and quantum-entangled with the antimatter used to annihilate the body.
7. You have to re-create the matter from received photons, getting back the body and the original antimatter.

This seems complex, but is possible in principle. Laws of physics allow as to turn matter into massless information, send it away and turn back to matter. So, it's only the matter of time before people start sending themselves to distant places through network :).

 

[K^2]

Quantum teleportation is defined by some as the transmission of the full quantum state of a particle from point A to point B using standard communication mechanisms. This does not mean transporting the particle from location A to location B only the information about the full quantum state.

What you are saying is nonsense. Teleporting state of a particle is the same thing as teleporting a particle. All particles are indistinguishable. You cannot tell if particle A is here and particle B is at Alpha Centauri, or if it's particle B here and A there. What makes them different is their states.

Suppose I have an electron in the state a|+> + b|->. I want to use teleportation to swap it with another electron that has state c|+> + d|-> and is located elsewhere. The wave function is going to be something like:

φ(x₁)(a|+> + b|->) * ψ(x₂)(c|+> + d|->) - φ(x₂)(a|+> + b|->) * ψ(x₁)(c|+> + d|->)

If I swap particles, I must swap φ and ψ which give locations of the two particles.

ψ(x₁)(a|+> + b|->) * φ(x₂)(c|+> + d|->) - ψ(x₂)(a|+> + b|->) * φ(x₁)(c|+> + d|->)

Now let's swap the particle spin-states instead.

φ(x₁)(c|+> + d|->) * ψ(x₂)(a|+> + b|->) - φ(x₂)(c|+> + d|->) * ψ(x₁)(a|+> + b|->)

Exactly the same thing except for the overall sign change. Note that the overall phase is undetectable and will never make a difference. If you use bosons instead, even the sign stays the same.Now consider complex multi-particle systems. The relative "locations" of particles are also just quantum states of the system. You quantum-teleport these, and it's the same thing as teleporting the system. You just have to make sure you have elementary particles to build stuff out of, and these are the same elementary particles in any part of the universe.

Quantum Teleportation is teleportation. No qualifiers needed.

 

[pallidin]

Could be wrong, but I think the OP is asking if, say, an electron which exists at location (a) can be teleported to location (b) which previously had no electron. And, that the electron at location (a) ceases to exists after this "teleportation"

If this is correct, this is very distinct from quantum entanglement.

 

[haael]

Could be wrong, but I think the OP is asking if, say, an electron which exists at location (a) can be teleported to location (b) which previously had no electron. And, that the electron at location (a) ceases to exists after this "teleportation"

Yes, it is possible, with the light speed.

If this is correct, this is very distinct from quantum entanglement.

This is all thanks to quantum entanglement.