

Experiment with faster-than-light "spooky" quantum effect at 18km - mojuba
http://www.physorg.com/news137937526.html

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mojuba
There's an old 1997 article that explains this kind of experiments and their
possible applications in a bit more detail:

<http://www.cebaf.gov/news/internet/1997/spooky.html>

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Allocator2008
I never got how this is supposed to be "spooky". To me it is common sense. To
whit:

If a spin 1 particle (say, a photon) is "tweaked" by adding energy to it in
some way, like say, being in the presence of a strong magnetic field, there is
a chance it could briefly decay into two spin 1/2 particles (say an electron
and an anti-electron). If the electron flies over to village A and is measured
to have an "up" spin, and the anti-electron flies over to village B, if the
electron had been measured to have an "up" spin in village A, why then
naturally it should come as no surprise that the anti-electron in village B
will be measured to have a "down" spin, due to conservation of spin laws. Spin
1 is decomposible into two spin 1/2 particles, so 1/2(electron) + 1/2(anti-
electron)=1(photon). The spin can be up or down, not both, so if one particle
has "up" spin, the other necessarily has "down" spin.

I have never understood why this is all supposed to be so "spooky". It is just
simple common sense based on known conservation laws. Spin is conserved. If a
spin 1 particle decays into two particles, and one is "up spin 1/2" then by
necessity, not by any kind of "spookiness" but by basic necessity, the other
particle will be "down spin 1/2".

Conservation laws are not "spooky". They are high school physics. So I really
don't understand sensationalist articles like this, other than to try to get a
"reaction" from the ill-informed.

~~~
mojuba
It is getting spookier with experiments where each photon, say, hits a semi-
opaque mirror and chooses a path randomly. The Geneva experiment was doing
precisely that:

 _You start with an ultraviolet photon and split it into two photons. One goes
one way and the other goes another way, both to identical interferometers.
Entering its own interferometer, each photon must make a random decision as to
whether it will travel a long pathway through the device or a short one. Then
you look for a correlation between the pathways taken by the photons in their
respective interferometers._

 _If the timing between the photons is exactly adjusted, each twin seems to
know what the other is doing and matches its choice of pathway to coincide
with that of its distant partner._ (upd)

From <http://www.cebaf.gov/news/internet/1997/spooky.html>

