Teleportation

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rwald
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Post by rwald » Tue Jun 22, 2004 9:58 am

If I'm not misaken, Tez (sorry about the name thing earlier), one important element still not in your system is that you can't just look at the paper and get a rough idea of where the dot is without changing the paper. In theory, with the setup you've currently given, one could just look at the paper and note the exact time the dot moved; the time could be the signal. However, I believe that with the real QM, you couldn't even get a general idea of where the dot was without affecting the paper, something you wouldn't want to do until you had the two classical bits to work with.
For the record, I don't actually know anything. Not even this.

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Tez
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Post by Tez » Tue Jun 22, 2004 10:11 am

rwald wrote:If I'm not misaken, Tez (sorry about the name thing earlier), one important element still not in your system is that you can't just look at the paper and get a rough idea of where the dot is without changing the paper. In theory, with the setup you've currently given, one could just look at the paper and note the exact time the dot moved; the time could be the signal. However, I believe that with the real QM, you couldn't even get a general idea of where the dot was without affecting the paper, something you wouldn't want to do until you had the two classical bits to work with.
Read my post rwald, I did explain this in excruciating detail.

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Abraxas
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Post by Abraxas » Tue Jun 22, 2004 11:13 am

Ditto on the analogy, Tez. I don't teach any high level physics, but if I did (or do in the future) I at last have a semi-decent grasp of entanglement. Like a lot of physics, it did my head in for a bit.

Abraxas
'There is a mask of theory over the face of nature,' William Whewell

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Sorgoth
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Post by Sorgoth » Tue Jun 22, 2004 8:34 pm

Tez wrote:
Good point, I should have been a bit more careful. What actually happens is that the two entangled pieces of paper are not initially blank - they each have a dot on them. The crucial point is that this initial dot is completely randomly placed on the paper. After the measurement, the dot moves to one of the 4 positions as I described above.

SInce the initial dot is random, Bob cannot tell whether Alice has performed her measurement or not.
Ah, and when you're dealing with quantum particles, observing them changes them, rendering any results you may get worthless, communication-wise.

Oh well, it was worth a shot :)

Heh..where was it that I read (Or heard):

Guy: So now you can go across the galaxy in seconds! Amazing, you've finally gone faster than light!

Scientist: No, of course not, that's impossible. We made light go faster!