So I have learned in my QM classes that you can't tell one electron from another electron. They are indistinguishable. I also learned that the wavefunction of a particle includes the spacial part and the spin part. (There might be other parts I don't know! Please don't fault me for not knowing.)

I have also learned that it is possible to use the quantum teleportation protocol to retrieve exactly, 100%, the spin state of one particle in another particle after particular measurements. http://en.wikipedia.org/wiki/Quantum_teleportation

My question is, if you can teleport the spatial state and the spin state and whatever other state left there is that describes the particle, then wouldn't you be effectively teleporting the original particle?

A sub question directly related to this is; Is matter/particles just a changeable glob of stuff that acts differently, thus being a different particle, depending upon what quantum state its in? (This kinda sounds like string theory to me... Oh no!!)

Also, what's never answered is, What state does the original particle assume when its state is teleported to the new particle? Does the two particles, the original particle and the particle retrieving the quantum information, switch states?


the quantum teleportation experiments teleports for example the spin-state of the particle to be teleported with its superpositioned state intact, as you write. But the experiment is designed on the premise that the recipient has his/her own particle to imprint this superpositioned state on.

Since the "spatial state" of the particle involves the location of the senders lab, there would be no point in teleporting it. As you yourself suggest, it would be a null operation. On the other hand, if you want the particle to appear in the recipient lab, the spatial state obviously is NOT the same and hence you can't talk about teleportation at all in that case.

Subquestion: yes, the particles of the same type are interchangeable (given compatible quantum states) and actually this is always taken into consideration when calculating the superpositioned interactions in Quantum Field Theory - you need to consider all the ways the particles might get exchanged with each other during a process you are calculating, there are no "particle A" and "particle B" labels if their states are identical otherwise. With some stretch of words and imagination, the "glob" you are talking about is essentially the quantum field of the particle type.

Never answered question: The original particle's superpositioned state is destroyed in the quantum teleportation process. This is mentioned in the beginning of the document you link, actually. You can't clone the state without destroying the source - this is actually a theorem called the No-cloning Theorem.


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