Slit Experiment vs Schrodinger's Cat

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Discussion Overview

The discussion centers on the relationship between the double slit experiment and the concept of quantum superposition, particularly in relation to macroscopic objects and distances. Participants explore the implications of quantum "fuzziness" and how it manifests in both microscopic and macroscopic contexts.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants question why quantum fuzziness is considered not to scale to macroscopic objects like a cat, while macroscopic distances can still exhibit this fuzziness in the context of the double slit experiment.
  • There is a proposal that the photon detected at points A and B in the double slit experiment suggests it is "spanning" the distance between these points, raising questions about the nature of probability in quantum mechanics.
  • One participant expresses confusion about the interpretation of the double slit experiment, suggesting that it demonstrates a photon being in two places at once, while others clarify that a photon is detected at a single point, and its behavior must be understood as a superposition of states.
  • Another participant mentions recent experiments, such as those conducted at Delft and Stony Brook, which reportedly show macroscopic scale effects of superpositions involving large numbers of particles.

Areas of Agreement / Disagreement

Participants express differing interpretations of the double slit experiment and its implications for quantum fuzziness. There is no consensus on the relationship between macroscopic objects and distances in the context of quantum mechanics.

Contextual Notes

Some statements reflect uncertainty regarding the definitions and interpretations of quantum phenomena, particularly concerning the nature of superposition and detection in the double slit experiment.

sanman
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I've always been told about how that joke about whether Schrödinger's Cat is alive or dead was merely intended to highlight the fact that "quantum fuzziness" does not scale up to macroscopic objects like a cat.

But when we do the slit experiment and observe that the photon is detected at both A and B, then aren't we seeing the "fuzziness" extending across a macroscopic distance? (ie. the photon is jumping/spanning across the distance between A and B)

Why is macroscopic object a no-no for showing the fuzziness, but macroscopic distance is fine for showing the fuzziness?
Are we saying that distance doesn't count at all, when it comes to tunnelling?

What is the probability of finding the photon anywhere in the space spanning between A and B?

Can we say that a wave object is an object of infinitely low density, since it is supposed to be spanning across the entire universe?
 
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sanman said:
But when we do the slit experiment and observe that the photon is detected at both A and B, then aren't we seeing the "fuzziness" extending across a macroscopic distance? (ie. the photon is jumping/spanning across the distance between A and B)
What do you mean when you say that "the photon is detected at both A and B"? In the double slit experiment, photons are always detected at a particular point.
 
Forgive me for my rusty memory, but I thought that the Double Slit Experiment was that the same photon shows up at both detectors (at points A and B)

I thought this is cited as proof of quantum fuzziness, so that the photon can be in 2 places at once.
 
sanman said:
I've always been told about how that joke about whether Schrödinger's Cat is alive or dead was merely intended to highlight the fact that "quantum fuzziness" does not scale up to macroscopic objects like a cat.

But when we do the slit experiment and observe that the photon is detected at both A and B, then aren't we seeing the "fuzziness" extending across a macroscopic distance? (ie. the photon is jumping/spanning across the distance between A and B)

Why is macroscopic object a no-no for showing the fuzziness, but macroscopic distance is fine for showing the fuzziness?
Are we saying that distance doesn't count at all, when it comes to tunnelling?

What is the probability of finding the photon anywhere in the space spanning between A and B?

Can we say that a wave object is an object of infinitely low density, since it is supposed to be spanning across the entire universe?

But there ARE experiments that are beginning to show "macroscopic" scale effects of superpositions. That is why the Delft and Stony Brook SQUID experiments are so important (do a search on here - a lot of water has flowed under those bridges). They showed superposition effects for at least 10^6 particles.

Zz.
 
sanman said:
Forgive me for my rusty memory, but I thought that the Double Slit Experiment was that the same photon shows up at both detectors (at points A and B)
No, the photon is always detected by a single detector. (Perhaps you are confusing the two slits with two detectors?)
I thought this is cited as proof of quantum fuzziness, so that the photon can be in 2 places at once.
What it shows is that the state of the photon, as it passes through this system, must be viewed as being in a superposition of single slit states. That's the only way to correctly predict the distribution of photons arriving at the detectors.
 

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