Double Slit Experiment No Mystery

de Broglie-Bohm has the same problems as usual for such theories. I wrote an article once [0] about such things and I'll just quote from it.

> To understand the working physicist’s position, it is useful to consider pilot wave theory. This alternative to the Copenhagen interpretation is often championed by realist philosophers, who would prefer that measurable properties, such as the position of a quantum particle, should always be well-defined. In this interpretation, the wavefunction is a classical field, like the electromagnetic field, called the pilot wave. Every particle always has a definite location, but it is “guided” by interaction with its pilot wave, allowing it to perform feats impossible for ordinary classical particles, such as quantum tunneling. Hence, the subtlety of quantum mechanics is dispelled by describing a quantum particle as both a classical particle and a classical field, in a literal interpretation of wave-particle duality.

> For those who have struggled with the subtleties of quantum mechanics, this simple story sets off alarm bells. For one thing, where is the probability? If the electron really has a definite position, then why is it measured to be seemingly random, even after the electron settles into its lowest energy state? The answer is that the pilot wave is postulated to unpredictably shuffle about the location of the electron until its position reaches “quantum equilibrium” and matches with the predictions of the Copenhagen interpretation. This shell game is assumed to occur too quickly to detect. Worse, once it is over, the electron is predicted to hover in midair, perfectly still. Velocity measurements indicate otherwise, so pilot wave theory simply assumes they are all mistaken. Apparently, there is a real velocity, but it cannot be measured, and any attempt to do so yields something else. These ad hoc fixes allow pilot wave theory to avoid contradiction with the empirically verified uncertainty principle.

> The pilot wave itself also has strange properties. We expect to be able to measure classical fields, but the pilot wave cannot be directly measured. Classical fields were introduced to avoid nonlocal “action at a distance”, but when the particle is measured, the pilot wave instantly collapses. The collapse is postulated to be faster than light but coincidentally completely undetectable, making pilot wave theory almost impossible to reconcile with relativity. Furthermore, “Bell test” experiments confirm that this problem cannot be removed in any refinement of the theory.

> The reason most physicists are hesitant to accept pilot wave theory is that it appears to have the ether’s flaws. In exchange for the classical intuition of definite particle trajectories, the theory drastically increases the complexity of our world. It suggests many natural questions about the nature of the pilot wave and particle, then gives them unnatural answers which are hidden from observation. That is why, when physicists working on quantum foundations were polled at the 2011 conference Quantum Physics and the Nature of Reality, precisely zero vouched for the pilot wave. The interpretation is like an art teacher who sings the praises of creative freedom, yet berates any who draw outside the lines.

I don't personally have anything against Bohmian mechanics except for one thing: its supporters consistently ignore all of these well-known issues and present it as if it's a completely perfect quasi-classical model for the world, only kept down by conspiracy. This leads to all kinds of crazy narratives that I think are actively harmful to the field. At the very least, people who go out and talk about the many worlds interpretation face the weirdness of quantum mechanics head on, and honestly.

0: https://knzhou.github.io/#writing

> Admittedly there’s still a bit of mystery left. How does periodicity in space quantize momentum (I think if it as a sort of resonance phenomenon). But it’s hardly an impenetrable, soul searing mystery that makes you question reality itself.

I don't find this to be true. What's left is the key issue. The entire mystery is left. The old QM worked exactly like that explanation: you take a classical explanation and postulate that some quantity in it is quantised. This is ad-hoc and not a general approach. A major breakthrough in the new QM was an explanation why things are quantised. And yes, it's a resonance phenomenon. Resonance of what? Probability amplitude waves. Once you have that explanation you can do away with the classical+quantised part of the explanation, because it becomes superfluous.

Here we go. Throwing around internet titles. You do realize he has a PHD in math. I will trust his math work over your "theories"

Let's see some papers you have published?

I'm not saying anything about whether it is true or not.

I'm saying there is a completely different class of reasoning between talking about how the two-slit experiment might not be mysterious, and describing the use of the scientific method to validate it, versus attributing the obscurity of a result to a systemic bias problem in science.

I completely accept that science has human bias problems... The community is made of people, after all. I personally subscribe to the idea that it is systemically sexist.

So I do not argue that there is a bias, I only state that the transition from one kind of discussion to the other was jarring in this post.

I waled away from the article not sure if it was primarily about a theory I hadn't heard of, with a footnote about why I hadn't heard of it, or if it was primarily about a systemic coverup of a theory, with some introductory material about the theory presented to understand why it would be covered up by the establishment.

One can say, "Why not both?" But truly, good writing has a focus, and an essay really doesn't have a lot of room to stray too far from a single, primary message.

It could be that one good essay is about how the grand mystery isn't that mysterious, and another good essay is about how Science with a capital S is biased towards the mysterious and inscrutable.

It wouldn't take much editing for this essay to be transformed into either of those. And perhaps this is a matter of taste, but I would prefer one of those essays to this one.

But that being said, whatever else I might think about its focus, I'm glad it introduced me to something intriguing about the two-slit experiment!

> Well I don't believe that's what he intended.

Agreed. Remember he started by saying the double slit experiment has been performed on much larger molecules at this point. People who come across this will go "wait a second?!" and question what they've been told.