It's a metaphor we can relate to far more easily than one of a dithering Universe.īut experimentally, the time wasn't right for de Broglie's simple idea. It has an actual position, but its destiny is in the hands of changes in the flow of the fluid that guides it.

The scattered patterns of lines and dots observed in experiments are just as they seem – consequences of waves rising and falling through a medium, little different to a ripple on a pond.Īnd somewhere on that wave is an actual particle.

And that isn't as easy to imagine.ĭe Broglie's idea of a hypothetical wave was meant to return some kind of physicality to the notion of probability. Now, physicists were proposing a flavor of probability that wasn't about our naivety. Mathematics merely puts our ignorance in order while reality exists with 100 percent certainty in the background. We can picture a stack of playing cards sitting upside down on a table, its hidden sequence locked in place. Prior to quantum physics, the mathematics of probability were tools for predicting the roll of a dice, or the turning of a wheel. Just what any of this means on an intuitive level is hard to say. These properties, he maintained, can only be said to exist once an observation has been made. According to Bohr, it was as if the Universe was yet to make up its mind on where to put a particle, what direction it should be twisting, and what kind of momentum it might have. This isn't merely the kind of uncertainty a lack of knowledge brings. What behaved like a wave was an inherent uncertainty at work. To theoretical physicists like Danish theorist Niels Bohr and his German colleague Werner Heisenberg, who set the foundations of the Copenhagen interpretation, the most economical explanation was to treat probability as a fundamental part of nature. The results were best explained by a new field of mathematics, one that incorporated probability theory with the mechanics of wave behavior. To better understand what a pilot wave is, it helps to first understand what it is not.īy the 1920s, physicists were baffled by highly accurate experiments on light and subatomic particles, and why their behavior seemed more like that of a wave than a particle. Yet something about De Broglie's surfing particles makes it impossible to leave alone, and over the past century, the idea continues to increasingly pop up in modern physics.įor some, it's a concept that could finally help the Universe make sense – from the tiniest quantum particles to the largest galaxies. Pilot wave theory, on the other hand, suggests that particles do have precise positions at all times, but in order for this to be the case, the world must also be strange in other ways – which led to many physicists dismissing the idea.

Today, the majority of physicists subscribe to what's referred to as the ' Copenhagen interpretation of quantum mechanics', which, generally speaking, doesn't give precise locations and momentums to particles until they're measured, and therefore observed. So, like any beautiful idea that falters in the face of experiment, it swiftly became a relic of scientific history. His hypothesis was the foundation of what would later become pilot wave theory, but it wasn't without its problems.

Quant theory