Single slit experiment and HUP

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Discussion Overview

The discussion revolves around the single slit experiment in quantum mechanics (QM) and its relationship to the Heisenberg Uncertainty Principle (HUP). Participants explore how the width of the slit and the thickness of the slit walls affect the resulting Gaussian distribution of light on a screen, while also debating the implications of these observations for the validation of HUP.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • One participant notes that as the slit width decreases, the Gaussian distribution on the screen widens, questioning whether the thickness of the slit walls contributes to this effect.
  • Another participant suggests that with a narrower slit, more light is spread out wider, and theorizes about the effects of an infinitely thin wall on photon behavior.
  • A participant challenges the assertion that the single slit experiment validates HUP, arguing that the same wide distribution can be observed classically with multiple photons, complicating the interpretation of the results.
  • Further, it is claimed that the single slit experiment does not serve as proof of HUP, with a focus on the EPR-Bell experiments as more relevant for validating HUP, though there is disagreement on the conclusiveness of those experiments.

Areas of Agreement / Disagreement

Participants express disagreement regarding the interpretation of the single slit experiment in relation to HUP. Some argue that it validates HUP, while others contend that this interpretation does not hold and that classical explanations can account for the observed phenomena.

Contextual Notes

Participants highlight the complexity of explaining the results of the single slit experiment classically, particularly when considering the behavior of individual photons versus multiple photons. There are unresolved questions about the role of slit wall thickness and the assumptions underlying the interpretations of the results.

Chaos' lil bro Order
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In QM a photon with wavelength comparable to the width of a slit, will pass through and create a 'Gaussian Distribution' on a screen. As the slit width is decreased (gets thinner), the 'GD' on the screen will counterintuitively INCREASE (aka. widen). My question is it possible that the slit wall thicknesses themselves are the cause of this effect? How does slit wall thickness effect the GD on the screen when all other variable are held constant?

ty
 
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With or without HUP as the slit becomes narrower, more of the total light going though it is spread out wider.
How wide can be limited by the thickness of the “wall”. A razor thin wall with a very thin slit say 3 to 4 wave lengths wide, should produce some photons “turning” 600 or more. A full ½-pi turn in theory could be produced by an infinitely thin wall.

For a fun applet on the single and double slits where the screen observations are measured in radians (for a curved screen):

http://www.physics.northwestern.edu/vpl/optics/diffraction.html"

It assumes a infinite thin wall, and allows some light to go through even if the wave length is larger than the slit width, neither of which is realistic, just the formulas to the extremes.
 
Last edited by a moderator:
RandallB said:
With or without HUP as the slit becomes narrower, more of the total light going though it is spread out wider.
QUOTE]


That experiment is a validation of HUP, so saying with or without HUP is meaningless and makes not sense.
 
Chaos' lil bro Order said:
That experiment is a validation of HUP, so saying with or without HUP is meaningless and makes not sense.
NO the idea that the single slit experiment some how provides validation of HUP is what “makes not sense”. You’re not understanding the experiment if you think that.

You get the identical wide distribution of light with lots of photons going thought the one slit together (explain that classically without HUP) as you do when you send one photon at a time though the slit – not so easy to explain that one classically.
A weird and unexplainable result, that HUP is used to explain!
To turn around and then claim the same result you were explaining is proof or validation of the explanation doesn’t cut it.

The only experiments that can be looked at as a validation of HUP-QM are the EPR-Bell proofs. And not everyone agrees that those are conclusive, but the majority do accept them.
Other experiments are just paradoxes resolved by accepting the HUP-QM interpretation.
 
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