Oh no not another thread on the 2 slit experiment

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Discussion Overview

The discussion revolves around interpretations of the classic double-slit experiment in quantum mechanics, exploring various theoretical perspectives beyond the Copenhagen interpretation. Participants express curiosity about alternative explanations, including Bohmian mechanics and Many Worlds Theory, while questioning the nature of particles and waves in quantum mechanics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants inquire about interpretations of the double-slit experiment beyond the Copenhagen interpretation, mentioning Bohmian mechanics and Many Worlds Theory.
  • One participant suggests that the act of observation interferes with the wave, causing it to behave like a particle, reflecting on the nature of measurement in quantum mechanics.
  • Another participant argues that electrons should not be strictly classified as waves or particles, proposing that they may represent something entirely new.
  • Concerns are raised about the limitations of the Many Worlds Theory, particularly its lack of new predictions compared to the Copenhagen interpretation.
  • Some participants express skepticism about popular representations of quantum mechanics, criticizing oversimplified analogies like describing electrons as "tiny marbles."
  • Several links to external resources are shared, including articles and websites discussing Bohmian mechanics and interpretations of quantum mechanics.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretations of the double-slit experiment, with multiple competing views and ongoing debates about the nature of quantum mechanics and measurement.

Contextual Notes

Participants express uncertainty about the implications of different interpretations and the nature of quantum phenomena, highlighting the challenges in understanding measurement and inference in quantum mechanics.

Schrodinger's Dog
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http://www.fortunecity.com/emachines/e11/86/qphil.html

I was wondering if anyone knows of any other interpretations of the classic two slit experiment other than the Copenhagen interpritation, I've heard there there is a Bohmian interpretation(anyone know anything about how the wierdness is explained in this) but I can't seem to find any other ideas, although this article mentions a few. Anyone got any whacky ideas of their own, or interpritations that might explain this wierdness in different ways. For example you could say that the act of observing the wave itself interfers with it and makes it behave in a particular fashion(If you'll pardon the virtual pun:smile:) the "colision" or detection disturbing it and making it behave as a particle? Anyone seen any other interesting interpritations even if they are as far fetched as the many worlds one or my one?
 
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grrr.. the article says "photons... are like particles and like waves..."

No they are neither. They are described by ket vectors in a hilbert space! And all physical observables are represented by Hermitian operators acting on that space.
 
http://www.upscale.utoronto.ca/GeneralInterest/Harrison/DoubleSlit/DoubleSlit.html

This is probably a better web site.

The whole thing is pretty bizarre in that you can never really exactly see what is going on without destroying the interference itself. So in a science so used to inference, even the fundementals have to be infered, for all we know it may be not just be neither a wave nor a partice nor a warticle but something even more bizarre than that? But how could we be sure?:eek:

EDIT: honestly I ask because I can't find descriptions of other interpretations on the net, or at least not very good ones, if someone can enlighten me, I'd apreciate it.
 
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Schrödinger's Dog said:
http://www.upscale.utoronto.ca/GeneralInterest/Harrison/DoubleSlit/DoubleSlit.html

This is probably a better web site.

The whole thing is pretty bizarre in that you can never really exactly see what is going on without destroying the interference itself. So in a science so used to inference, even the fundementals have to be infered, for all we know it may be not just be neither a wave nor a partice nor a warticle but something even more bizarre than that? But how could we be sure?:eek:

EDIT: honestly I ask because I can't find descriptions of other interpretations on the net, or at least not very good ones, if someone can enlighten me, I'd apreciate it.

I agree with masudr's point of view. If we try to think of electrons as either a wave or particle, we just get lost. Thinking of them as something completely new is probably the better way to look at it.

I've never heard of a "Bohmian" interpretation...I'll have to Google it. There is, as you mentioned, the Copenhagen version. The only other one I know of is "Many Worlds Theory" which unfortunately (as far as I know) gives EXACTLY the same answers as the Copenhagen. (Quick rundown: Every time the Universe makes a quantum level "decision" the entire Universe splits into as many copies as there are quantum options. The electrons interfere in the 2-slit essentially due to the interference of two similar Universes being right next to each other, or some such argument.) I don't find it to be a good theory in that regard, because it doesn't make a new prediction. However there HAS been a flurry of activity in recent years over parallel universes, so maybe...

-Dan
 
Schrödinger's Dog said:
http://www.upscale.utoronto.ca/GeneralInterest/Harrison/DoubleSlit/DoubleSlit.html

This is probably a better web site.

The whole thing is pretty bizarre in that you can never really exactly see what is going on without destroying the interference itself. So in a science so used to inference, even the fundementals have to be infered, for all we know it may be not just be neither a wave nor a partice nor a warticle but something even more bizarre than that? But how could we be sure?:eek:

EDIT: honestly I ask because I can't find descriptions of other interpretations on the net, or at least not very good ones, if someone can enlighten me, I'd apreciate it.
Here's a good general page on Bohmian mechanics:

http://plato.stanford.edu/entries/qm-bohm/

Wikipedia entry on Bohm's interpretation:

http://en.wikipedia.org/wiki/Bohm_interpretation

This one talks a little about how Bohm's interpretation would analyze the double slit experiment:

http://www.mathematik.uni-muenchen.de/~bohmmech/Poster/post/postE.html

This page talks about how you'd understand the Aspect experiment with Bohm's interpretation:

http://home.sprynet.com/~owl1/qm.htm#IV
 
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I don't find it to be a good theory in that regard, because it doesn't make a new prediction. However there HAS been a flurry of activity in recent years over parallel universes, so maybe...
If I may attempt to respond (and then be subsequently corrected by Vanesch! :smile:)...

MWI attempts to take QM seriously -- if a particle is in a superposition of states, then fine, it's in a superposition of states. Any realistic "measurement" should subsequently wind up with the measuring device being entangled with the particle.

The hypothesis that a measurement "collapses" the wave function to provide a definite outcome is simply an ad hoc patch to the theory for people who like definite outcomes! (Or, more accurately, a mathematical tool for computing conditional probabilities)

Note that there are things that we can describe quantum mechanically that act like measuring devices, (e.g. a quantum computer), and they do get entangled with whatever they're measuring. So why should a "classical" measurement be any different?
 
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The annoyingly enthusiastic voice also tries to initially pass of electrons as "tiny marbles if you like." Furthermore, the video showed each individual electron as a particle at all times -- of course this is ridiculous, and we should all know the electron has no well defined position unless it's in a position eigenstate, and also that the electron is described by kets.
 
Thanks guys this was exactly the sort of thing I was looking for :approve: :smile:
 

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