[extropy-chat] Precognition on TV

[scerir]

Damien:
> Dr. Evan Harris Walker and others did something along these lines, 
> trying (as I recall) to modify interference fringes; there are 
> disputes in the literature over the outcome, but I'm inclined to 
> think that no such effect was seen. 


Ah, well.

The electron interference (electron wavefunction entering
both slits of a Young interferometer; electron wf
choosing both paths in a Mach-Zehnder interferometer;
etc.) is, in principle, more interesting than photon 
interference.

Because, with electrons, the interference pattern also 
depends on the (possible) existence of a magnetic field,
inside the interferometer. Even when this field
is completely and perfectly shielded, the amplitudes
of the electron can feel, nonlocally or via action
at a distance, the existence of a magnetic field, 
and the interference pattern changes. There are
several problems, or difficulties, with the principles
of conservation here, due to that action at a distance, 
but this is another story. (I'm not sure, but the young 
Zeilinger perhaps performed neutron interferometry 
experiments, and found that the interference pattern 
depends on the gravity field).

Having two beams of entangled electrons, and two
interferometers, and two shielded magnetic fields, 
it is possible to check that the second order 
interference (the output of one interferometer versus 
the output of the other interferometer) depends 
on the difference between the two magnetic fields,
even when the two interferometers are in separated 
regions (spacelike separated also I suppose). This 
is a sort of double nonlocality, that is two say EPR 
nonlocality + Bohm-Aharonov nonlocality.

But I do not think that pre- or retrocognition
implement tricks like the above.