From: scerir (scerir@libero.it)
Date: Sat May 11 2002 - 08:15:14 MDT
Hal:
> For what it's worth, I found a sci.physics posting from early 2000
> asking about essentially the same experiment, but unfortunately no
> one replied.
Chiao, Kwiat, et al. performed several experiments, using 2
interferometers and 2 beams of entangled photons. They
did not use Michelson-type interferometers, but the Franson
'set-up', that is to say 2 identical Mach-Zender interferometers,
*but* with arms of different length.
They were *not* interested in the first order interference
(interference inside each interferometer) but in he second
order interference. The second order interference is between
the outputs of each of those special interferometers: photons
both passing through the long arm or photons both passing through
the short arm, of course each photon inside his own interferometer).
As far as I remember they found a correlation between photon 1
(going up, passing through interferometer 1) and photon 2
(going up, passing through interferometer 2) or an
anticorrelation (depending on the actual set-up, i.e. length
of wavepackets vs. lenght of different arms of each interferometers).
That is to say: they could manage to obtain a correlation,
or to obtain an anticorrelation. They realized that the entangled
photons (bi-photon) behave non-locally (each one knows what
the other is doing).
Shih et al. performed a different experiment, this way.
|> >
| source of | >
<---|<------ two entangled ------->| > >
| ph.1 photons ph.2 | >
|> >
D S
ph.1 = photon 1
ph.2 = photon 2
D = a double slit
S = a screen
Photon(s) 1 just passes through a double slit D, that's all.
Photon(s) 2 reaches the screen S where *it* (which did not
cross a double-slit!) draw a weird interference pattern.
If you remove the D from the first beam, the interference
pattern on S vanishes.
But, ok, those experiments are a bit different from that
one described above (sci.physics).
s.
This archive was generated by hypermail 2.1.5 : Sat Nov 02 2002 - 09:13:59 MST