Electron two-slit experiment in classical electromagnetism

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There is a theoretical problem, whether you can see it or not. There is no way to reconstruct quantum behaviour using EM fields.
An assertion without evidence. Empty words.
The aberration is yours, not that of the mainstream theoretical physics.
Well, then show me that mainstream paper where classical EM has been found incompatible with the two-slit experiment. Please, don't show me bulets and billiard balls!

This is why the quantum computer is relevant. Because ultimately you'd have to explain all QM phenomena using classical EM.
Let's take one example at a time!

Imagine going to a lab that has built a quantum computer and trying to persuade them that you see no theoretical problem with building such a computer using classical EM theory.
I see no theoretical problem. It's just a bunch of charges going around. What problem is there?

They are either going to say that you are mad or suggest you go and build one yourself. What they are not going to do is waste their time trying to build one and failing, just to prove you wrong.
They build it from atoms. The building process has nothing to do with the nature of the electrons. They are what they are. Are you saying that if you believe the electrons are classical you would fail to build a quantum computer?
 
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PeroK
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I see no theoretical problem. It's just a bunch of charges going around. What problem is there?
That probably sums up your view of theoretical physics!
 
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Imagine going to a lab that has built a quantum computer and trying to persuade them that you see no theoretical problem with building such a computer using classical EM theory.
Let me clarify this a little bit. My hypothesis here (a hypothesis I would like to see tested by direct calculations or a rigurous argument) is that QM might be for classical EM (with or without some modifications) what QM is for Newtonian mechanics. If you want to build a bridge you aren't going to use quantum mechanics, you would use an approximate theory that makes calculations easy and gets the job done. QM's description of the two-slit experiment is simple, the equivalent description in terms of all those interacting charges is unbelievable complex. Such a calculation would still be interesting for theoretical reasons. Practically, nobody would do it that way. So, if you want to build a quantum computer you would use QM, not classical EM, even if classical EM would work in principle.

In my first reply I intended to convey that I see no theoretical contradiction between classical EM being right and the existence of quantum computers, not that it would be practical to use classical EM in this case.
 
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Lord Jestocost
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QM's description of the two-slit experiment is simple, the equivalent description in terms of all those interacting charges is unbelievable complex.
In case I correctly follow your line of thinking: One could try to simulate electron and neutron diffraction at simple periodic lattice structures. This should be more easily manageable.
 
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vanhees71
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It is a well-established fact that classical electromagnetism is an approximation to the more comprehensive quantum electrodynamics. You have to quantize both "particles" as well as "radiation"/"fields" to get a consistent picture in accordance with the observations. There is no classical way to describe diffraction of electrons a la Davisson and Germer or their use in electron microscopes, which are direct applications of the wave properties of electrons as described by QED.

Also the electromagnetic field has to be quantized. The most simple evidence for this is spontaneous emission and the Bose-Einstein statistics as demonstrated by black-body radiation, the very phenomenon where the discovery of quantum theory started on Dec/14/1900. Today there are many more amazing experiments with single photons demonstrating the necessity for field quantization.

So neither phenomena concerning electromagnetic fields nor those concerning matter and their mutual interaction are completely describable within classical electrodynamics.
 
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vanhees71
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In case I correctly follow your line of thinking: One could try to simulate electron and neutron diffraction at simple periodic lattice structures. This should be more easily manageable.
But it's impossible to describe these phenomena in terms of classical particle mechanics!
 
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Let me clarify this a little bit. My hypothesis here (a hypothesis I would like to see tested by direct calculations or a rigurous argument) is that QM might be for classical EM (with or without some modifications) what QM is for Newtonian mechanics.

In my first reply I intended to convey that I see no theoretical contradiction between classical EM being right and the existence of quantum computers, not that it would be practical to use classical EM in this case.
This personal theory depends on ignoring all the experimental evidence to the contrary. As in your other posts, we are debating under the bizarre assumption that no experiments have been carried out that contradict classical EM.

Even something as simple as the magentic moment of the electron is different under QM than classical EM: it's approximately twice what it should be under classical EM:

https://en.wikipedia.org/wiki/Electron_magnetic_moment

Modern QM is so far beyond classical EM that it's absurd that we even debating this. Trying to pretend that classical EM could produce an alternative to QCD and the quark-model, the weak force and nuclear decay is blind personal theorising. You yourself even noted that the neutron has a magnetic moment:

The neutron is neutral in the same sense the barrier is neutral. It contains an equal number of positive and negative charges. It has a magnetic moment, too.
Where does that come from in classical EM? Where are the quarks, where is the strong force? Where is colour confinement? Those are all quantum mechanical models.

Finally, particle scattering experiments, when modelled using QT, produce different results from classical EM. The experiments have been carried out and shown that the classical Coulomb's law breaks down at high energies. Reduce the energy and the classical formulas are seen as an approximation to the quantum formulas.

These are not isolated experiments. All of high-energy physics for the last 100 years has been non-classical - all of it! The fact that you are aware of none of it is irrelevant. I'll pick one example from yesterday:

https://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.110.213001

This is where modern QM physics has reached. It's 150 years beyond Maxwell. His theory was groundbreaking in 1865. But, that is the physics of 1865, not of 2021.

And don't ask: where's the evidence for this? The evidence is the entire body of 20th and 21st century experimental high-energy physics, from the photoelecetric effect, to electron diffraction, Compton scattering, particle scattering, experimental confirmation of the standard model of particle physics, the Higgs boson, and everything else.
 
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berkeman
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Thread closed for Moderation.
 
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Was there any study of this experiment in the context of classical electromagnetism?

No - because classical electromagnetism does not describe the election. Attempts were made early on to do it, but they all ran into difficulties. For example, if it was a classical particle, it should spiral into the nucleus. Only by assuming it is a quantum particle can the double-slit using electrons be explained, as well as the spiralling issue:
https://arxiv.org/pdf/quant-ph/0703126.pdf

A big issue in physics is that models must explain the phenomena being looked at and others. If not, it is not worth pursuing.

With my moderator's hat on, it is important discussions like this proceed on that basis. It will not get anywhere otherwise, and like this may be shut down.

Thanks
Bill
 
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After a Mentor discussion (and some other actions), thread will remain closed.
 
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