Saturday, November 19, 2011

An alternative interpretation of quantum mechanics

In 1952, well respected physicist David Bohm published 2 important papers in the prestigious journal Physical Review:

http://prola.aps.org/abstract/PR/v85/i2/p166_1
http://prola.aps.org/abstract/PR/v85/i2/p180_1

The ideas he presented here are an extension of de Broglie's (the same guy responsible for the de Broglie wavelength and the concept of wave-particle duality) 1928 "pilot wave theory". He showed that the gradient of the quantum mechanical wave function can be interpreted as a particle momentum. Hence, the wave function is like a "source field" that steers the particle into certain trajectories, but in a random fashion somewhat like Brownian motion. These trajectories have probabilities that are proportional to the square of the magnitude of the wave function, consistent with experimental results. I think all physicists and anyone interested in quantum mechanics should read these papers.

Curiously, hardly anyone is aware of these ideas. They are certainly not taught in school! After 80 years since the development of quantum mechanics, the only concept of the wave function that we have is the so called "Copenhagen interpretation", developed by Niels Bohr and others. In this interpretation, the wave function is an abstract mathematical probability function, which "collapses instantaneously" into a single point (like a Dirac delta function) upon a "measurement" by an observer. However, even today we still do not have a good idea of what constitutes a measurement or how this collapse process comes about. In my opinion, Bohm's physical interpretation makes a lot more sense.

Has this "source field" been detected? If I may speculate a bit, I think the zero point field is a good candidate to have the properties of a source field. See, for instance:

http://www.springerlink.com/content/t0847g0x6u756m0g/