In the
mid 1980s, a group from the University of Maryland, and a separate
group from the University of Munich carried out a version of the two
holes experiment (see Quantum Mysteries Parts
1-4). They used a beam of laser light that went through a
beam-splitting mirror. One of the split beams was phase-shifted and
then the two split beams were recombined to form the interference
pattern. Detectors known as Pockels cells were placed in each of the
split beams to monitor the passage of photons, and detectors at the
far end looked to see if it was producing interference or not. The
Pockels cells could be switched on or off within 9 nanoseconds. The
length of each path of light took about 15 nanoseconds for light to
travel that far, so the detectors could be switched on (or off) after
the light had passed the detectors. The decision of whether the
cells were on or off was made by a computer at random (with no human
intervention). Both groups found that the light behaved as particles
or waves depending on which choice was going to be made, even though
the decision had not been made when the light passed the detectors!
The universe seems to know what is going to happen before it happens.
For a
possible resolution to the mysteries in this series, see John
Gribbin's book Schrodinger's Kittens and the Search for
Reality.
Where shall we go from here? Shall I write a summary or resolution?
Was this series worth while or was it "old hat" and a waste of time for you?
Should I have posted all of it at once? Give me you views.