From: scerir (scerir@libero.it)
Date: Sat May 11 2002 - 11:53:39 MDT
|> >
| source of | >
<---|<------ two entangled ------->| > >
| ph.1 photons ph.2 | >
|> >
D S
Ken wrote:
Isn't it true that the pattern at S does not become
detectable until a number of ph.2 have arrived?
And, isn't it true that the experiment did not measure
the minimum time after a change at D, that it is possible
to see the change at S?
--------
First question. Yes, of course, you need many photons,
otherwise you cannot detect that pattern (which is just
about 1 cm. wide).
Second question. To see a shift of the interference
pattern at S if you move D? You must wait some time
(few or many photons) otherwise you canot detect the
shifted pattern. (It is quite mind-boggling that
moving D, i.e. to a position where you have a
destructive interference, you just shift the *full*
interference pattern at S. The twin brother ph.2 seems
to *know* to much about what it is happening there).
But the ***main*** point, of course, is this. If one of the
photons (ph.1) is measured with a certain value (of positon,
of momentum, of energy, [of time]) its twin brother (ph.2)
must have been propagating with a well defined value.
Btw in the case of two entangled photons (bi-photon, actually
one particle) Popper suggested that also Heisenberg's principle
should break.
And Dr. Shih performed the experiment:
http://arxiv.org/abs/quant-ph/9905039
s.
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