The Experiment:
One of the main problems with solving the measurement problem, is the
problem of quantum decoherence. This is a problem because it makes it
difficult to distinguish between whether it was the decoherence effect
or the act of measurement which caused the wave nature of particles to
disapear, in experiments such as the quantum eraser experiment. However
an experiment has been concieved which distinguishes between the two, in
order to determine the cause of wave function collapse.
It does so by controlling the process of decoherence(as best as
possible), and then observing the wave nature of the decohered system,
by virtue of diffraction, and then carrying out a measurement to see
whether the wave nature disapears or not. The exact experiment is a
modification of the davisson germer experiment. At the start of the
experiment, there will be a vaccum chamber containing a single proton,
and an electron gun which will fire electrons slowly into the system in
order to decohere the proton. It will be bombarded with about 5
electrons in order to decohere it, and once it has decohered, an anode
shall be switched on with a hole in the middle of it and the whole
object shall be fired towards a nickel plate, which leads to scattering
in various directions. The nickel target can also be rotated, in which
electrons can be deflected towards a detector on a mounted arc which
could be rotated in a circular motion. The detector, which would be used
during the experiment is a faraday cup. When the particle touches the
nickle plate in order to test whether measurement causes collapse, the
location of the proton shall be measured.
There will be two groups. The first group will not have the location of
the proton measured on contact of the nickle plate, whereas the second
group will have it’s location measured on contact with the nickle plate,
by virtue of a detector. Because the location of the proton has been
measured in group 2, it could affect the scattering of the decohered
particles, because the wave function has collapsed for that individual
particle(it would be different to those not measured), and so the
measurement problem could be solved by being able to see whether the act
of measurement has any affect on the scattering of the decohered
particles, and distinguish between whether it was decoherence which
caused it to behave classically because it has already decohered and
therefore the experiment would be testing the causality of measurement
on wave function collapse because we are able to measure the wave nature
of the decohered system and so any change upon measurement would be down
to the act of measurement not decoherence because it is being measured
via the diffraction of the particles.