Two-Slit & n-Slit Experiments: Explained

[RandallB]

Wallin; What, your complaining about a lay answer because it is not technical enough?
If you just want to know how “photon detectors” work use google.

Thanks for your reply. I can see how such a test would work with balls, …

NO, the test will not work with balls to produce interference because going though a single hole balls do change direction with the needed dispersion.

What's more, if I understand the double slit experiment correctly, if photons and electrons are sent through the slits one at a time, they still interfer with each other.

I was wrong you do not understand the rest of the issue. The point is because we know they go through the slits one at a time we know it is impossible for them to “interfere with each other” (edit: to produce the pattern we find).

I have been reading … All … done to prove the point that the act of observation collapses the probability wave. ….
So I guess what I'm really asking is how does an electron or photon detector work?

NOT when you assume a “probability wave” is real and has the ability to “collapse”. You are no longer dealing with your original question when you do that. The principle logic of how to select particles going undisturbed through just one slit is the important part of the test, and described in lay terms by the ball example.

Once you assume or open the question of what is happening from event (slits) to observation (detection screen); you are on a new topic with a large selection of views that are open to argument as you can see in the other posts. None of those various speculations are required by the HUP math used in OQM Theory. QM might be matched by other ideas but science has accepted nothing as more complete than QM yet.

 

[Wallin]

Wallin; I was wrong you do not understand the rest of the issue. The point is because we know they go through the slits one at a time we know it is impossible for them to “interfere with each other”.QUOTE]

I'm confused again (easily done!). I thought that if photons or electrons were "shot" singly through double slits with detectors turned off, they do produce an interference pattern. Its only when the detector(s) are turned on, that the interference pattern disappears. We can know the particles/waves are going through the slits one at a time without knowing "which slit." Its when we know "which slit" that the probability wave collapses. And I'm not saying the probability wave or its collapse is real. I'm not even saying the particle/wave is real. Talking about what's real and what's not real in QM seems a precarious exercise.

Sorry I wasted your time with the question about detectors, but Google is not always an ideal or efficient source of information. I'm not trying to buy a detector, I'm trying to understand how it interacts with the things it detects. I've looked on Google and haven't found a good explanation of how the apparatus interacts with its subject. Guess I'll keep looking.

 

[RandallB]

Not a waste of time, but IMO (in my opinion) the real problem you are working on in your mind has more to do with understanding what is meant by the Bohr “completeness” of QM or what Feynman called “shut up and calculate”. (Terms all easy to find with simple searches.) And how QM Theory does not need or even expect a ‘tangible’ description like “collapse” to describe the theory.

Actually, IMO experimental proof that “superposition” and its “collapse” is real would falsify QM completeness as defined by Niels Bohr using HUP. And I doubt a better technical understanding of photon or electron detection will help you in understanding these issues.

Science only uses statistical mathematics (like HUP) to resolve this paradox, NOT what you might call common sense. No scientist claims it does or demands that a description like collapse, multi dimensions or guidewaves are required.

 

[Wallin]

That's fair. If I knew how, I would shut up and calculate! But being a very poor mathematician, I must resort to questions. Perhaps I'm trying to find sense and meaning in a physical phenomenon which by nature is inexplicable. Is that what your trying to tell me?

 

[reilly]

Yes! Thank you reilly, the Davidsson-Germer experiment is exactly the kind of thing I would have hoped to find out about with my question a few comments back!

So do the electrons refract as well as diffract within a crystal? Do they resolve into a spectrum at all? If so what property of each electron determines its place within the spectrum? The speed / energy of the electron?

Captain, sir!

Yes. electrons can refract inasmuch as it is a consequence of scattering, highly dependent upon superposition of momentum states. Within matter, an electron passing through will bounce around a bit, slow down, and can also scatter away from the surface of the matter. Best place to start is to review the propagation of light through materials,and of charged particles through matter. Jackson and other E&M authors do the first, older books on atomic or nuclear physics do the latter --- particularly those with an experimental twist.
Regards,
Reilly Atkinson