Transfer of Quantum State

  • Thread starter Harmony
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  • #1
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An experimenter, A, has prepared four photons with known polarization states. In another lab, experimenter B has prepared four photons with random orientation.

Is it possible, for the photons prepared by B, to take the polarization states of the photons prepared by A, without B knowing the orientation of the photons prepared by A?
 

Answers and Replies

  • #2
It depends on wheter the photons were pre pared from the same source that is if A and B have got entangled product then yes.Even if A knows B and B knows A and they know what the other is doing and their labs are not very far away again the answer (maybe) is yes.
 
  • #3
yes,it will b
 
  • #4
Is the uncertainity which heisenberg talk of a result of complex interconnections between a particle to the rest of the universe all it is the inherent property of nature?
 
  • #5
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Hmm..that means if they aren't entangled before, there isn't anyway to make them entangled? Meaning that, if the photons are not prepared from the same source, there is absolutely no change for the transfer to occur?
 
  • #6
No Its not that.If you exchange one photon from set of A to that of set set of B still there will be an entanglement.
Also If A performs experiment first or B, and tell the latter about his/her result still there will be entanglement due to B's (or A's)conciousness
 
  • #7
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Hmm....so would it be safe to say that, experimenter B can't "steal" the information from A without exchanging the photon or ask the information from A like you said?
 
  • #8
They should also be situated far away so much so that their fields can't interact.Also their should be no third person knowing about them and their nature or else he/she shall collapse their wave function.Complete Sheilding (imposible in reality and might be in principle also.)
 
  • #9
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They should also be situated far away so much so that their fields can't interact.Also their should be no third person knowing about them and their nature or else he/she shall collapse their wave function.Complete Sheilding (imposible in reality and might be in principle also.)

Thanks for your help, I really appreciate it. The reason i ask about the transfer of states, is because that I plan to write a story which involved a "stolen" quantum states ie experimenter B steal the quantum states of photons from A and make the original photons randomly oriented.

I am aware that this might not be possible to do in practice, but i suppose there isn't any physics laws that forbids the re-entanglement of two set of photons which comes from different source (at least, base on current knowledge), since you said that in principle their field might interact?

I don't wish to write a science fiction story which is forbidden by the laws of physics, that's why i post in this forum for expert's advice...:)
 
  • #10
K^2
Science Advisor
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What you are asking about is called quantum teleportation. Look it up.
 
  • #11
Sorry to state this Sir Harmony I'm not an expert.I just took up quantum mechanics few weeks ago.
And K^2 I wasn't talking about quantum teleportation (by the way what is it?) I just gave what I interpret from quantum mechanic which is that the experiment which I perform at quantum level has a considerable dependence upon my intentions.
Sir Harmony please confirm from experts like A.Neumaier or tom.stoer
or our Mentor Doc Al
 
  • #12
K^2
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I was replying to OP. Sorry, I can see now that it was ambiguous.

Quantum teleportation is a method for transfering quantum state using classical channel without performing a projective measurement on the state in question. You do need a pre-fabricated maximally entangled pair, however.

So, say Alice has an electron with some unknown spin state. She wants to send that spin state to Bob. They can use optic fiber to prepare a pair of entangled electrons in their respective labs. Alice can then perform a Bell-basis measurement of the pair of electrons she now has and send result of the measurement, which is two bits of information, to Bob via any convenient channel. Bob can use that information to restore the state of the original electron in Alice's lab. The original state is, of course, destroyed in the Bell-basis measurement, fulfilling requirements of the no-cloning theorem.

If you want the details of the algorithm with all the math, Wikipedia article covers all the basics, and links to relevant articles.

By the way, this has been experimentally confirmed on simple 2-state systems.
 
  • #13
Thanks K^2 :-)
 

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