Re: Has FTL communication really never been tested in this way?
- From: Andreas Most <Andreas.Most@xxxxxxxxx>
- Date: Tue, 30 Oct 2007 21:11:59 +0000 (UTC)
scerir wrote:
"PostReplies":
Here's another page I found explaining
his experiment and a very interesting
earlier experiment which was encouraging:
http://www.paulfriedlander.com/text/timetravel/experiment.htm
There is an interesting quote,
about Dopfer experiment, from that link.
"The important conclusion is that,
while individual events just happen,
their physical interpretation
in terms of wave or particle
might depend on the future"
[A.Zeilinger]
Now it seems to me that the key word
is "interpretation". Meaning that
from a *single* spot, on the two-slit
screen, produced by one photon passing
through the interferometer, one cannot
realize if that *single* spot is part
of an inteferential pattern *or* part of
a smooth pattern. One can realize precidely
that only after he measures, in the future,
the position *or* the momentum of the other
photon entangled with the first one.
(The third possibility, that one doesn't measure,
in the future, the position or the momentum of
the entangled photon is interesting but it is not
relevant here).
But the problem I see (since long time) is this.
Imagine there is not a *single* spot (produced
by one photon) on the two-slit screen, but 1000
distinct spots (produced by 1000 distinct photons).
Can we still say that nobody can realize whether
these 1000 spots form an interferential pattern *or*
a smooth pattern, untill one measures,
in the future, the position *or* the momentum
of all the other distinct 1000 photons, each one
of them entangled with a photon producing the spot?
Yes, we can say this. Without any coincidence unit you will
not be able to see an interference pattern. Actually, by
involving the correlation with the entangled partner you choose
about 500 of the 1000 initial photons. The way you perform the
selection, either momentum or position measurement, determines
whether there is an interference pattern or not. What is actually
disturbing is that it does not depend on when you perform the
measurement on the entangled partner. But that is the way it is in
quantum mechanics.
I think Cramer is wrong in assuming he could send a signal backwards
in time because the interference pattern occurs when the correlation
between the two entangled photons has been established (and of course
roughly 500 events have been rejected) and not the moment the photons
hit the screen.
Andreas.
.
- References:
- Has FTL communication really never been tested in this way?
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- Re: Has FTL communication really never been tested in this way?
- From: Marc Millis
- Re: Has FTL communication really never been tested in this way?
- From: scerir
- Re: Has FTL communication really never been tested in this way?
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- Re: Has FTL communication really never been tested in this way?
- From: scerir
- Has FTL communication really never been tested in this way?
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