Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope
quantamagazine.org
quantamagazine.org
It is also important to understand that the reason these things are often conflated is that much of what is (or at least used to be before quantum computation became a thing) taught as quantum mechanics focuses on the special case of a single particle considered in isolation. In that one special case -- and ONLY in that one special case -- configuration space is the same as (or at least isomorphic to) physical space. But as soon as you add a second particle, that stops being true.
So the key to understanding QM is to START with the multi-particle case. This is actually easier than the single particle case because it forces you to set aside a lot of the things that make quantum mechanics difficult in general and focus on the thing that makes it hard to wrap your brain around: entanglement. But the reason that entanglement is hard to wrap your brain around is that it's weird when considered from the point of view of physical space. If you start with multi-particle systems, that forces you to start with configuration space, and that gets you past the hard part right from the start. After that it's just math.
It means that those things aren't really fundamental. What's fundamental is some other set of things that aren't too difficult to work with mathematically, but which don't correspond exactly to anything you're familiar with. The best you can do is to add in "probability functions", such that "state of the world X" means that you'd have some chance of detecting a particle here, and some chance of detecting a particle there, and so on.
It's that jump from one to the other that's awkward, and to be honest not 100% understood. But it's actually better understood than a lot of the woo-woo descriptions of quantum mechanics make it out to be.
Now, when I said that the math isn't too difficult to work with, that's a bit of a lie. It's all about Simple Harmonic Oscillation, except using complex numbers. That's really not too bad, but it's definitely new.
And both of those are among the details which can be safely ignored. The only math you really need in order to understand QM conceptually is linear algebra. (And actually, even the harmonic oscillators are not that difficult to understand. If you understand Euler's identity, you're 90% of the way there.)
How is that different from hidden variables?
One way to look at it is that every one of those pieces of configuration space apply to all of space and all of time. That's not forbidden. But it also means that these values aren't directly accessible. They can only be partially inferred.
I'd like to know more about this since I have never heard of this concept before and I feel like it has far-reaching implications
The unobservable parts are not really any different from indirectly inferred concepts like potential energy. It's just that even seemingly concrete notions like location turn out to be macro scale approximations of this phase space. They're not accessible only because you are a macro scale object. You can very much demonstrate that it's real by simple experiments. You just need to be able to take them seriously, which is unexpectedly difficult because classical physics seems so intuitively obvious.
gp's premise about learning with the multi-particle landscape first sort of blew my mind.
Right.
> Is this why string theory requires higher dimensions?
No. The higher dimensions of string theory are actual physical dimensions. Configuration space dimensions are pure mathematical abstractions, and there are potentially an infinite number of them, one for every degree of freedom in the system. Look up "Hilbert space" if you want the gory details.
Is there a resource (book, videos, ...) that takes this approach to teaching it (and accessible to/understandable by a motivated layman?)
AFAICT I am the primary proponent of the pedagogical significance of this idea, so maybe I should write something up. Watch my blog.
Exactly, how quantum collapse happens, or what quantum collapse even is, is one of the biggest mysteries of physics.
And I'll argue that as long as we don't have an explanation for that bridge between the "configuration space" and the "physical space" like you call them, the former may as well be magic.
Yes it would make learning and explaining the rules of magic a bit easier if you get into that mindset, but it still doesn't make it intuitive, but just easier to accept.
If anything, it does feel we could very well be living in a simulation governed by arbitrarily defined rules that exist on a different plane than other physical laws. Hmmm maybe we should give non-local hidden variable theories another look...
While I still feel just that, this post[1] and its reference to Scott Aaronson's lecture[2] on how QM can be seen as a "inevitable" generalization of probability theory did make quantum mechanics more... comforting? acceptable? Something like that.
[1]: https://www.physicsforums.com/threads/probability-theory-and...
And what of closer objects?
Would we be able to directly image the Apollo-landing sites for instance?
It strikes me that this could help establish or overturn such claims.
https://billwadge.wordpress.com/2019/10/25/double-slit-exper...
Any thoughts? Could it help to test it on a planet-sized scale?