Natural Science Forum / Physics / Particle Physics / January 2006

It sounds like you're just quoting Afshar. His opinion of the importance of
his experiment is not shared by most other physicists.

-- Ben

I found the Transactional Interpretation intriguing, but if it was
true, then the absorption by your skin of a photon from a star 1
million light years away would have been predetermined, 1 million
years ago.

After thinking about this I decided it was too extraordinary to
believe.

Subsequently I came across the "Propagating Wave Interpretation". This
seems more straightforward than the other interpretations.
http://www.quantummatter.com/wave.html

It assumes that:
---QUOTE---
1. Elementary quanta of matter and energy exist as their wavelike
behavior suggests (wave packets), always.

2. Their time evolution is described by the Schrödinger equation (or
better yet, by the Heisenberg equation of motion for the density
operator).

3. Energy transfer, in quantum amounts, takes place locally. Thus,
when a photon is absorbed and measured, its energy is transferred at
only one point in space.
---END QUOTE--
(I believe the above mentioned energy transfer "at only one point in
space" might also be called "collapse of the wavefunction").

Returning to Afshar's paper:
http://www.irims.org/quant-ph/030503/Afshar%20Complementarity%20All.PDF

In the abstract he writes:
"Coherent laser light is passed through a dual pinhole and allowed to
go through a converging lens, which forms well-resolved images of the
respective pinholes, providing complete path knowledge."

In the light of the above assumptions, this would not provide
"complete path knowledge", because after passing equally through both
pinholes and then through the converging lens, the wave function of
each photon would have sharp maxima at the locations where we would
expect the images of the pin holes to be.

This would give each photon a 50/50 chance of being detected within
the image of one pinhole or the other.

According, although the wave function of each photon would pass
through both pinholes, the "collapse of the wavefunction" that occured
when the photon was detected, would force each photon to _appear_ to
have passed through only one pinhole.

This would reduce the "complete path knowledge" of Afshar's experiment
to the status of illusion.

In this way, the Propagating Wave Interpretation would seem to easily
cope with Afshar's experiment.

This may give it an advantage over the Copenhagen or Many Worlds
Interpretations.

Regards,
Peter