Most people hear about the wave-particle duality of light in high school and quickly run the other way, concluding that physicists must be crazy. Others are intrigued and may even follow the problem all the way to a career in physics, where they fall down the rabbit-hole of quantum mechanics and loose any notion of the universe being a rational place. Now an article from Quanta Magazine that was republished in Wired reports on experiments that may bring rationality back into the argument.
The experiments use oil droplets moving over waves on a fluid surface to reproduce effects analogous to those of quantum mechanics: tunneling through barriers, spontaneously arising or annihilating, and occupying discrete energy levels. Some researchers believe these experiments suggest that quantum objects are as definite as droplets, and that they too are guided by pilot waves; in the case of quantum mechanics, the pilot waves are undulations in space-time. It turns out this is nothing new, French physicist Louis de Broglie presented the earliest version of pilot-wave theory back in 1927. However, the idea was essentially washed away on the tide of more popular theories of quantum mechanics at the time. These new experiments have resurrected pilot-wave theory.
I am particularly intrigued that some think the pilot-wave approach could indeed be the key to resolving the long-standing conflict between quantum mechanics and Einstein’s theory of gravity, which clash at infinitesimal scales. I think of the infinitesimally curved dimensions of M-theory (or string theory if you’re old-school) and can’t help but consider how perfectly they could work as the space-time wave carrier that is necessary for pilot-wave theory. If M-theory could be demonstrated to provide the mathematical framework of pilot-wave theory, Einstein’s dream of a complete unified field theory might finally be at hand. This would expand our understanding of the underlying nature of the universe dramatically, and do it in a way that was blessedly rational.