Paths in Two-slit Experiment?

I just read an article of Jacques at all (2006), which starts with explaining the well-known double slit experiment, and its modern version with interferometer and single photon pulses. Wheeler is cited, saying (when interference has been shown) "each arriving light quantum has arrived by both routes�. Why cannot you say that the photon has taken one route, though it is unknown which route is taken, but that the probability wave has followed both routes.
- Bert Garssen (age 72)
Groningen, The Netherlands

Great  question. If only the ordinary two-slit experiment were involved, you could say that there was a wave that went through both slits but guided a point-like particle that wen through just one. That is in fact exactly the idea developed by David Bohm. The sets of possible trajectories for this theory are quite interesting.

That original Bohm theory was in the broad class of "local realist" theories, in which predictable outcomes have causes that are located where the events occur. John Bell realized that such local realist theories have some implications (Bell Inequalities) that disagree with the predictions of quantum mechanics in slightly more complicated experiments. Those experiments are routinely done now, and the results show that all the local realist theories, including Bohm's, are wrong.

Mike W.

(published on 04/24/2018)