Can someone explain Quantum Entanglement as it relates to Teleportation?

Question

I've been researching this for a while now and still have a hard time understanding it so I'd really appreciate explainations in your own words.
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I've looked at the wiki articles and joop so unless you have a really amazing, easy to understand link, I'd rather just have you explain it as best you can.
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Also, I think I understand the quantum entanglement part: what it is on its own. What I need help with is understanding how QE is used to actually "teleport" something.

Thanks :D

Answer 1

The main problem here is with the use of the term "teleportation", which is typical overhype. What can be achieved with quantum entanglement is not what from science fiction you in any sense or under any circumstances would understand as teleportation.

Here is an easy way to understand quantum entanglement.

Lets say I give you two identical boxes. In one you put a red ball and in the other you put a blue ball. Then you mix them up and I take one of them to the moon. You have no idea what colour ball is in my box or your box.

You now open your box and it has a blue ball in it. You instantly know that I have a red ball in my box. Relativity is not violated here because I still have no idea what colour is in my box until either I open it or you tell me what was in you box - and you cannot get that information to me faster than the speed of light.

The reason for this very obvious instantaneous transfer of information is that the rules of the system - our two boxes - allowed their states to be entangled with one another. In other words, if one box contained a blue ball the other must contain a red ball - no other reality was possible.

Now it happens in quantum mechanics that this is exactly how some systems behave. For instance, take two electons in a single box (so a single system) and cool them to the lowest possible energy - this is called the ground state. The rules electrons (which are fermions) obey say that no two can be in the same state, and when they both have the lowest possible energy the only difference between two of them can be that one has its spin up and the other spin down (spin is just a rather misnamed property of electrons - don't worry about what actually causes it). If they both had the same spin, one would have to have higher energy.

Now we have prepared our box with these two electrons their quantum states are entangled. However far we separate them - in other words however long we make the box - one is in one state and the other is in the opposite state, but we have no idea which is which.

Imagine measuring the spin of one electron at one end of the box. You instantly know the spin of the other one.

This information transfer is what is being referred to as teleportation. It is possible to construct entangled systems that replicate the state of electons or other particles remotely.

You are not really moving an electron from A to B - you are just using the fact that all fundamental particles are indistinguishable (they do not have labels saying this is electron Fred, and this is electron Jim). All that can be said about them is their state.

This is a far cry from transporting the information about a complex system like even a single atom.

Answer 2

You've read the sci fi stories about identical twins who feel what the other twin is feeling...that's quantum entanglement. Two quanta (e.g., two photons) actually dance together and pass on their characteristics to each other; so they become identical twins.

A long time later (maybe a nano second) the two identical photons separate and travel on their merry, independent ways. But, whatever photon A encounters, its twin, photon B also instantaneously (no speed of light limits here) encounters.

So here's the teleportation deal...suppose the entangled quanta have upward spins of 1/2, for example when they separate from their entanglement dance. Now suppose, we have quantum A in a chamber in, say, San Francisco and we have B in a similar chamber in NYC.

Now we give A some energy to give it spin -1, what happens to B according to entanglement theory? That's right, some 4,000 miles away, B suddenly gets spin -1. In fact, you can't tell A from B; so in every sense of the word A has teleported to NYC.

Experiments have shown this to be possible. In fact, they are now working on actually sending messages via teleportation of entangled quanta. [See source.]

Answer 3

i think of this is going against heisenbergs uncertainty thought. That pronounced - I incredibly disagree that entanglement won't be able to be used to transmit information, otherwise quantum teleportation could be impossible. considering the fact that experimentally teleportation has been executed - it incredibly is feasible to transmit the quantum information, on the rate of destruction of the 1st particle and dropping the entanglement interior the process the teleportative journey. i think of. save interpreting technology - permit's resolve the international's problems with perception. don't be like George W. Bush - A hater of technology and the worst President in cutting-side American background.

Answer 4

Dr Richard Feyman, whose textbooks I had both the joy and terror of using, made it a little easier when he told us, "Don't worry if you don't understand quantum mechanics - nobody understands quantum mechanics."

That one remark kept me from going completely nuts when first studying this stuff (note the word "completely").

Feynman was hilarious as well as a genius in the same league as Einstein. He dictated two books which appeal to just about everybody, titled "Surely You're Joking, Mr Feyman!" and "What Do You Care What Other People Think?" There's no physics in them, just stories and thoughts from a guy who could have done standup if he wasn't so busy with the Manhattan Project during WW II.