Nobel Prize-winning physicist Richard Feynman has been quoted as saying that it’s safe to say “that nobody understands quantum mechanics.” But even though the study of the quantum world may be counter-intuitive (read: brain-explodingly insane), there is apparently a theory of atomic and subatomic dynamics that doesn’t require such an enormous stretch of the imagination: It’s called the “pilot wave theory,” and it’s described with exceptional clarity by Veritasium’s Derek Muller.
In the video above, Muller—a science educator and entertainer with an incredible science CV and penchant for making topics like laser hair removal fascinating—uses a petri dish of silicone oil atop a speaker to demonstrate a peculiar phenomenon. He shows how, thanks to a little layer of air, the droplets of silicone oil can continuously bounce on the surface of the pool beneath them without being absorbed. But even though the droplets don’t directly connect with the pool beneath them, they still make waves, and then interact with those waves, resulting in a forward momentum.
While this experiment isn’t on the quantum scale, it does help to demonstrate the way quantum-scale particles may operate according to the pilot wave theory. And for any lay people who’ve struggled with grasping why things are so strange on the quantum scale according to the standard interpretation, this pilot wave theory—proposed by Louis de Broglie in 1927—provides a far more palatable framework for understanding quantum mechanics.
One of the highlights of the video is the way the pilot wave theory explains the findings of one of the bedrock quantum mechanical experiments, the double-slit experiment. In the double-slit experiment, electrons are fired through a pair of slits at a screen. With the standard interpretation of quantum mechanics, those electrons only have a probability of hitting any particular spot on the screen, and it’s only when we measure—when we look—to see where the electrons hit the screen — do they actually hit the screen. Therefore, before we measure where the electrons went, they didn’t actually go anywhere. That’s a kind of reality we most definitely do not observe in our normal, non-quantum world.
But Muller points out that with the pilot wave theory, we can do away with the idea of the electrons not having definite positions before we measure them; that we can account for the wave pattern that electrons demonstrate in the double-slit experiment because of their interference with their own waves. And boom, suddenly, the quantum strangeness that makes an observer critical to determining what “really happened” in quantum-scale events disappears.
However! Muller does point out that this theory is only a competing explanation of quantum mechanics, and does not supplant the standard interpretation, as these pilot waves have not been detected. Still nice to know the world of the very small may not be all that crazy though, right?
What do you think about the pilot wave theory? Let us know in the comments below!