Searching for Quantum Mechanics Lecture on Delayed Choice Experiment

In summary, the conversation discussed a video about a quantum mechanics experiment with small and large envelopes, which may have been an instance of delayed choice. The video was of low resolution and the person speaking would like to find it again. Another person mentioned a Bayesian statistics problem, but clarified that it was not related to quantum mechanics. They also shared a link to a post discussing delayed choice and mentioned that it was one person's opinion. The conversation then shifted to discussing the best source for information on delayed choice, with some suggesting papers and others mentioning a physicist named Hossenfelder. There was some disagreement about her views and her value in the scientific community. Ultimately, the conversation ended with a discussion about open
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TL;DR Summary
Small and large envelops quantum mechanics experiment.
Hi everybody.
Some years ago I came across a video on youtube where they talked about an experiment with small and large envelops, when the small ones were placed into the large ones and then it resulted in something interesting.
It might have been an instance of delayed choice, but I am not sure.
The video was of a "popular" quantum mechanics lecture with a very low resolution.
I really like that example and would love to listen or read about it again.
Please let me know if you remember something like that.
 
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For "delayed choice" this is the best source :cool::

watch
 
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  • #4
tistemfnp said:
For "delayed choice" this is the best source :cool::

watch
No, it is not. It is one person's opinion.
 
  • #5
PeterDonis said:
No, it is not. It is one person's opinion.

Mhhh, just she uses the same argument (correlation) for the "interference pattern" (what it's actually not) that you just very used for explaining why there is no interference in entangled photons.

What's wrong about her "opinion", may I ask? (Actually I just understood your argument as I watched her video long before. It astonishes me to hear one argument in one context and have it ignored in a similar one.)
 
  • #6
tistemfnp said:
What's wrong about her "opinion", may I ask?
I didn't say it was wrong. I said it was her opinion. You should not be referring someone to a post that's one person's opinion and saying it's "the best source". The best source would be an actual experimental paper describing what was done and what results were obtained.
 
  • #7
PeterDonis said:
The best source would be an actual experimental paper describing what was done and what results were obtained.

@article{jacques2007experimental,
title={Experimental realization of Wheeler's delayed-choice gedanken experiment},
author={Jacques, Vincent and Wu, E and Grosshans, Fr{\'e}d{\'e}ric and Treussart, Fran{\c{c}}ois and Grangier, Philippe and Aspect, Alain and Roch, Jean-Fran{\c{c}}ois},
journal={Science},
volume={315},
number={5814},
pages={966--968},
year={2007},
publisher={American Association for the Advancement of Science}
}

@article{kim2000delayed,
title={Delayed “choice” quantum eraser},
author={Kim, Yoon-Ho and Yu, Rong and Kulik, Sergei P and Shih, Yanhua and Scully, Marlan O},
journal={Physical Review Letters},
volume={84},
number={1},
pages={1},
year={2000},
publisher={APS}
}

These are the papers. But they are only digestible with the explanations from Hossenfelder IMHO.
 
  • #11
tistemfnp said:
this is the best source

"Hossenfelder" and "the best" does not go along well together...
 
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  • #12
weirdoguy said:
Hossenfelder" and "the best" does not go along well together...

This is just because she actively reflects what others assume to be carved in stone. And some do not appreciate others thinking and like it more to reflect theories like repititions in a bible, what preserves them from developping own thoughts. Of course this is the opposite of science, which utterly depends on reflecting theory by continued verification and falsification and connected to that - discussion. I don‘t agree with everything she says and her over-confidence sometimes annoys me. But I think her presence is very valuable for scientific progress. The added smiley…
 
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  • #13
tistemfnp said:
This is just because she actively reflects what others assume to be carved in stone. And some do not appreciate others thinking and like it more to reflect theories like repititions in a bible, what preserves them from developping own thoughts. Of course this is the opposite of science, which utterly depends on reflecting theory by continued verification and falsification and connected to that - discussion. I don‘t agree with everything she says and her over-confidence sometimes annoys me. But I think her presence is very valuable for scientific progress. The added smiley…
You shouldn't confuse an open mind with a maverick position. Scientists who hold a mainstream opinion are not necessarily guilty of accepting science like "repetitions in a bible". An example of an original thinker who works very much within mainstream theory is Scott Aaronson. Included in this blog post are his thoughts on Hossenfelder's theory of superdeterminism.

https://scottaaronson.blog/?p=6215

In terms of making scientific progress, I favour Aaronson over Hossenfelder.
 
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  • #14
PeroK said:
Scientists who hold a mainstream opinion are not necessarily guilty of accepting science like "repetitions in a bible".
What I of course didn‘t state. Not criticizing Hossenfelder would be the bible position ;-). My point was about lowering people per se, just because they try to reflect.

Her stance on super-determinism isn‘t helpful. Personally I don‘t go along with it and think it‘s flawed.
 
  • #15
tistemfnp said:
What I of course didn‘t state. Not criticizing Hossenfelder would be the bible position ;-). My point was about lowering people per se, just because they try to reflect.

Her stance on super-determinism isn‘t helpful. Personally I don‘t go along with it and think it‘s flawed.
Okay, perhaps something was lost in translation.
 
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My favourite, from a didactical point of view, is

https://arxiv.org/abs/quant-ph/0106078v1
https://doi.org/10.1103/PhysRevA.65.033818

because for this the most complicated theory you need is an understanding of Fraunhofer diffraction of coherent light at a double slit and the workings of quarter-wave plates and polarization measurements and simple manipulations of bras and kets of a two-level system.

Here's my version for a lecture (given as my "habilitation colloquium"). It's understandable at the introductory QM level:

https://itp.uni-frankfurt.de/~hees/publ/habil-coll-talk-en.pdf
 
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FAQ: Searching for Quantum Mechanics Lecture on Delayed Choice Experiment

What is the Delayed Choice Experiment in quantum mechanics?

The Delayed Choice Experiment is a thought experiment in quantum mechanics proposed by physicist John Archibald Wheeler. It explores the counterintuitive nature of quantum particles, suggesting that the method of measurement can influence the state of a particle even after it has entered the measurement apparatus. This implies that actions in the present can seemingly affect the past state of a particle.

How does the Delayed Choice Experiment challenge classical intuition?

The Delayed Choice Experiment challenges classical intuition by demonstrating that quantum particles do not have definite states until they are measured. This contradicts the classical view that particles have predetermined properties independent of observation. The experiment suggests that the act of measurement plays a crucial role in defining the state of a quantum system, leading to the conclusion that reality is fundamentally probabilistic and not deterministic.

What are the key components of the Delayed Choice Experiment setup?

The key components of the Delayed Choice Experiment setup typically include a source of quantum particles (such as photons), a beam splitter, mirrors, and detectors. The experiment can be designed in various ways, but the essential idea is to delay the choice of measurement until after the particle has entered the apparatus. This delay can be achieved using fast-switching devices or by ensuring that the decision is made after the particle has passed a certain point in the setup.

What are the implications of the Delayed Choice Experiment for our understanding of time and causality?

The Delayed Choice Experiment has profound implications for our understanding of time and causality. It suggests that the conventional notion of cause and effect, where causes precede effects, may not hold at the quantum level. The experiment implies that future actions can influence past events, challenging the linear and unidirectional concept of time. This has led to various interpretations and debates within the field of quantum mechanics and the philosophy of science.

How do different interpretations of quantum mechanics explain the results of the Delayed Choice Experiment?

Different interpretations of quantum mechanics offer various explanations for the results of the Delayed Choice Experiment. The Copenhagen interpretation suggests that the wave function collapses upon measurement, creating a definite outcome. The Many-Worlds interpretation posits that all possible outcomes occur in separate, branching universes. The Transactional interpretation involves a time-symmetric process where waves travel forward and backward in time. Each interpretation provides a unique perspective on how measurement and reality interact in the quantum realm.

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