Earlier quoted context omitted.
"The key point is that the potential, rather than the field, has an observable effect. In classical gauge theories, the potential itself is not considered to be observable; only the field (the gradient of the potential) is. However, in QM, the potential itself can have observable effects." That comment is short, succinct and understandable, it's the best summary of the physics involved that I've heard in so few words…
> in QM, why exactly does potential have observable effects? The simple answer is that it's right there in the Hamiltonian, and the Hamiltonian is the central operator in QM, the one that determines time evolution. The fact that the EM potential appears there has been known almost as long as QM itself. Much of the recent QM experimentation in gravitational fields has been making use of recent technological advances t…
It's a while since I last looked at Aharonov and Bohm's '59 paper but if I recall your point about the Hamiltonian is covered there. My understanding is that in this paper the key difference from the earlier work to which you also refer is that their new solution to the Hamiltonian now involves a phase factor.
The point I should have made was that I wasn't thinking so much about the mathematical explanation of the Aharonov-Bohm effect but in more general terms where perhaps this new experimental work may reinvigorate interest in the subject and in related areas.
Whilst QFT provides us with an exquisitely accurate mathematical account for the purposes of calculation, it says little about the underlying physics per se. Thus, it seems to me that we stil have a limited understanding about the nature of say virtual particles, ZPE, etc. and essentially no understanding of why the electric, magnetic and fine structure constants and others are the values they are.
Research into the Aharonov-Bohm effect, could eventually lead to a deeper more fundamental understanding of the subject although, given past history, I fully accept that coming up with a major breakthrough in the near future is probably unlikely. (It's even more unlikely that we'll resolve the constants problem anytime soon, if at all.)
It seems to me that the most significant aspect of this work is that we now have more than just a theoretical framework that connects EM and gravity/the gravitational field at a QM level (or seemgly so). Tenuous it may be but it seems like a good start.
For my part, I still worry about why, say, the electric and magnetic constants have the value they do or why our understanding of ZPE is seemingly at odds with reality given the ludicrous value of the calculated zero-point radiation of the vacuum. But then, this is more about philosophy than it is about physics.