Interference pattern inferencing

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Discussion Overview

The discussion revolves around the possibility of inferring the type of particle that passed through a double slit based solely on the observed interference pattern, without knowledge of the slit dimensions or the particle source. It explores theoretical implications, experimental setups, and the nature of interference patterns in quantum mechanics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that knowing only the presence of a double slit is insufficient to determine the particle type from the interference pattern, as the pattern's characteristics depend on both the slit separation and the wavelength.
  • Others argue that while the interference pattern provides information about the slit geometry, it does not directly reveal the type of particles involved.
  • A participant suggests an experimental setup involving a cylindrical mesh with adjustable slits to detect new interference patterns from unknown particles, questioning the feasibility of such an approach.
  • Another participant challenges the practicality of the proposed experimental setup, stating that there are simpler methods to discover new particles and emphasizing the complexity of quantum mechanical double slit experiments.
  • There is a discussion about whether the interference pattern can be considered a form of magnification, with some participants asserting that it is not, while others explore the idea of constructive and destructive interference affecting detection probabilities.

Areas of Agreement / Disagreement

Participants generally disagree on the implications of the interference pattern regarding particle identification and the concept of magnification in this context. The discussion remains unresolved with multiple competing views presented.

Contextual Notes

Participants express varying levels of understanding and assumptions about quantum mechanics and experimental design, which may influence their arguments. The discussion includes unresolved questions about the nature of interference patterns and their relation to particle detection.

roineust
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Is it possible to look at an interference pattern without knowing what was it's source, only knowing that there is a double slit in front of that pattern, not even knowing the double slit size and slits distance properties, only knowing there is a double slit there, and then only from examining that interference pattern tell what kind of particle was passed through the double slit?
 
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You need to know the distance from the slits and then the wavelength is easily found.
 
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The positions of the interference maxima depend on both the slit separation and the wavelength, and likewise the diffraction maxima depend on the slit width and the wavelength. Thus we cannot infer the wavelength from the pattern without knowing the slit dimensions.

The wavelength alone is not enough to infer the particle type, but that’s all we can ever get from the pattern. In practice of course we’ll know what the particles are from our choice of particle source and detectors.
 
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The level of beginners nonsense of the following question is probably high:

Did anyone ever try to envelop a particle accelerator, at the location where the particles smash against each other with a cylindrical adjustable mesh, where that mesh includes many double slits, that size and slits distance properties are adjustable, and then knowing the adjustable slits properties, executing many experiments with many different values of these adjustable properties, while smashing particles and then using the suite of sensors behind the smash location and behind the cylindrical mesh, in order to look for new previously unknown interference patterns of previously unknown particles?

At my naive and childish level of understanding physics, i would imagine that even if a suite of sensors are not tuned or able to sense a single particle because reasons such as smallness or weakness of that particle properties, it might be able to sense an interference pattern since it is some kind of magnification of a single particle influence on a suite of sensors?
 
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roineust said:
Did anyone ever try to ….. in order to look for new previously unknown interference patterns of previously unknown particles?
No. There are way easier ways to look for new particles, and as the previous answers should make clear the interference pattern tells us a lot more about the slit geometry than it does about the incident particles.

You should be aware that doing a quantum mechanical double slit demonstration (as opposed to the classical optics double slit experiment using light, which has nothing to do with quantum physics) is surprisingly difficult.
 
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roineust said:
it might be able to sense an interference pattern since it is some kind of magnification of a single particle influence on a suite of sensor?
The interference pattern is built up one detection at a time. Every particle passed through the double slit results in a single detection at a single point (that’s what particles are). We send many particles through so we get many detections - think dots appearing on a long-term exposed photographic film. Then we observe that we had more point detections in some places than others, and that’s the interference pattern.

So the interference pattern isn’t a magnifying effect, it’s the other way around. We need hundreds or thousands of successful detections before the pattern becomes apparent.
 
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Aren't the interference pattern areas where the particle is constructively in phase with itself a magnification?

And then isn't the accumulation of many particles in phase with themselves into a constructive and deconstructive interference pattern, yet another mode of magnification?
 
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roineust said:
Aren't the interference pattern areas where the particle is constructively in phase with itself a magnification?
Constructive and destructive interference of the wave function just means that the particle is more likely to land in some regions of the screen than others. But it has to land somewhere so nothing is being magnified, we’re just changing where the incoming particle is detected.
And then isn't the accumulation of many particles in phase with themselves into a constructive and deconstructive interference pattern, yet another mode of magnification?
It is not.
 
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The OP's question has been answered and the thread will be closed. Thanks to all that contributed.
 
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