Electron in the double-slit experiment

[ueit]

I think we can say at this time, with a high degree of confidence, that in a double slit experiment the electron passes through one slit. This experiment has been reproduced at macroscopic scale by Yves Couder and Emmanuel Fort. Take a look at this article:

Single-Particle Diffraction and Interference at a Macroscopic Scale
Phys. Rev. Lett. 97, 154101 – Published 13 October 2006

https://hekla.ipgp.fr/IMG/pdf/Couder-Fort_PRL_2006.pdfThe relevance of Couder's experiment to quantum mechanics is theoretically justified here:

Emergence of Quantum Mechanics from a Sub-Quantum Statistical Mechanics
Gerhard Grössing, Int. J. Mod. Phys. B, 28, 1450179 (2014)

https://arxiv.org/pdf/1304.3719.pdf

A movie depicting the experiment can be found here:



Too bad Feynman didn't live to see this.

Andrei

 

[edguy99]

If they would have put detectors at each slit would the diffraction patterns have been observed on the detection screen?

That would be a great experiment to see.

Also, is the observed scatter of electron positions on the detection screen caused by the uncertainty in the electrons momentum which was inducted when the experiment attempted to localize the particle when it went through the slit?

The phase of the electron is what causes the pattern. The wavelength of an electron (how quickly the pattern repeats) is a function of the speed of the electron. Think of the electron as going through periodic changes as it flies through space. How much it "diffracts" around corners is a function of the "phase" (where it is in the wave function) of that electron.

 

[Nugatory]

I think we can say at this time, with a high degree of confidence, that in a double slit experiment the electron passes through one slit. This experiment has been reproduced at macroscopic scale by Yves Couder and Emmanuel Fort.

That is not in any meaningful sense a "reproduction" of the quantum-mechanical double-slit. It's a completely different physical system governed by completely different physical laws and that happens to display interestingly similar behavior so is interesting as an analogy. Considering the ubiquity of the wave equation in physics, it is not surprising that such analogies exist - but an analogy is never the real thing. Thus, you may feel a high degree of confidence, but you shouldn't expect others to share it.

The relevance of Couder's experiment to quantum mechanics is theoretically justified here:

"Justification" is also much too strong of a claim. There's nothing wrong with Grössing's suggestion that quantum mechanics might emerge from a realistic non-local hidden variable theory of the sort that he is considering (although without a candidate theory there's only so far it can be taken), and Couder's analogy suggests one picture of what such a theory might look like. But that's not a theoretical justification, it's an idea about one possible area of exploration.

 

[ueit]

That is not in any meaningful sense a "reproduction" of the quantum-mechanical double-slit. It's a completely different physical system governed by completely different physical laws and that happens to display interestingly similar behavior so is interesting as an analogy. Considering the ubiquity of the wave equation in physics, it is not surprising that such analogies exist - but an analogy is never the real thing. Thus, you may feel a high degree of confidence, but you shouldn't expect others to share it.

I think you are downplaying this a lot. Sure, interference experiments based on waves have been performed since Newton's time, but this is the first experiment to show interference effects with single particles outside quantum physics. Feynman thought it was impossible to imagine a classical mechanism for obtaining such a result, yet there it is.

"Justification" is also much too strong of a claim. There's nothing wrong with Grössing's suggestion that quantum mechanics might emerge from a realistic non-local hidden variable theory of the sort that he is considering (although without a candidate theory there's only so far it can be taken), and Couder's analogy suggests one picture of what such a theory might look like. But that's not a theoretical justification, it's an idea about one possible area of exploration.

I was under the impression that Grössing's proposal is local after all and what he calls "systemic nonlocality" does only refer to the influence of boundary conditions upon the particle. But it seems you are right, so I will retract my claim regarding the importance of his work in regards to Couder's experiments.