In the infamous double-slit experiment of quantum mechanics, it appears that particles whether massless particles of light, photons, or charged electrons, fired at a pair of slits will pass through and form interference pattern on the other side, as if they are behaving like a wave, even when only one particle is passing through a slit at a time. It’s as if, so the Copenhagen interpretation of QM goes, the particle is in both places at once, passing through both slits and a “decision” only being made at the point the observer looks/measures the interference pattern.
It really always seemed silly that the observation itself could alter the “choice” made by a subatomic particle passing through one of a pair of slits. Click the diagram for details of the experiment.
However, an alternative explanation might be that it is not the particles but a pilot wave, an energy field exuded by the particles is what creates the interference pattern, carrying particle after particle through in such a way that the pattern emerges naturally without an observer effect. This is the Bohmian interpretation of QM. It sounds a lot more plausible to this chemist’s brain and much more common sensible than the Copenhagen idea mocked by Einstein. And, now, there is experimental evidence as reported in Quanta magazine.
As Dan Falk puts it in his excellent article:
“The electrons act like actual particles, their velocities at any moment fully determined by the pilot wave, which in turn depends on the wave function. In this view, each electron is like a surfer: It occupies a particular place at every specific moment in time, yet its motion is dictated by the motion of a spread-out wave. Although each electron takes a fully determined path through just one slit, the pilot wave passes through both slits. The end result exactly matches the pattern one sees in standard quantum mechanics.”