Does the Double Slit Experiment Change When We Observe Particle Paths?

[calinvass]

I would like to show you my own opinion about DSE. I might be silly but I suspect data filtering issue.
Let's suppose we have a detector DA for slit A, DB for slit B and a interference detector D0.
If we consider the photon a wave pulse it means it will go either through a slit or through both. If we don't watch detector A and B we will plot all D0 photons (pulses) and some of them will interfere and create the interference pattern. When we open our "eyes" and watch detectors we correlate DA and DB with photons on D0. If we filter pulses on D0 that are not correlated we obviously won't get a diffraction pattern. DA and DB I believe , can't detect a pulse if it is not full energy. On the other hand D0 will almost always detect the recombining wave.
Waves don't interfere when we don't have the knowledge which slit they went trough. They interfere when they pass through both slits
That's all

 

[vanhees71]

It doesn't make sense as long as you don't explain how you want to build such detectors concretely. Note that it is not so simple to have an experiment, where you have both interference and which-way information at the same time. You never can have interference for the same ensemble of photons that has which-way information and vice versa. A very illuminating experiment is the famous "Delayed-Choice Quantum Eraser Experiment" by Kim et al:

Yoon-Ho Kim, R. Yu, S.P. Kulik, Y.H. Shih, Marlan O. Scully, PRL 84, 1 (2000)
https://arxiv.org/ct?url=http://dx.doi.org/10%2E1103/PhysRevLett%2E84%2E1&v=d0a2ac7d
https://arxiv.org/abs/quant-ph/9903047

A real experiment (including a very understandable treatment of the underlying theory) can be found at

S. P. Walborn, M. O. Terra Cunha, S. Padua, C. H. Monken, PRA 65, 033818 (2002)
http://dx.doi.org/10.1103/PhysRevA.65.033818
http://arxiv.org/abs/quant-ph/0106078

 

[DrChinese]

I would like to show you my own opinion about DSE. I might be silly but I suspect data filtering issue.
Let's suppose we have a detector DA for slit A, DB for slit B and a interference detector D0.
If we consider the photon a wave pulse it means it will go either through a slit or through both. If we don't watch detector A and B we will plot all D0 photons (pulses) and some of them will interfere and create the interference pattern. When we open our "eyes" and watch detectors we correlate DA and DB with photons on D0. If we filter pulses on D0 that are not correlated we obviously won't get a diffraction pattern. DA and DB I believe , can't detect a pulse if it is not full energy. On the other hand D0 will almost always detect the recombining wave.
Waves don't interfere when we don't have the knowledge which slit they went trough. They interfere when they pass through both slits
That's all

calinvass, you are new so you are likely not aware of forum rules. Placing forth your own personal speculation is not appropriate here. However, because questions about double slits are so common, I will address it anyway.

1. Your speculation varies from the standard quantum theoretical explanation. Individual quantum particles - which display double slit interference behavior - do not possesses a property called "full" energy. Either a particle is detected, or it is not. The only thing that is "partial" are the odds it will be detected at a particular spot when observed. That chance varies from 0 to 100%. Please note that this is true of individual particles of light (photons), electrons, ions, and even entire molecules. (There is no such thing as a "weak" individual molecule any more than there is a "weak" photon.)

2. Your idea is falsified in experiments with light. You can attach polarizers near each of the slits. When the polarizers are aligned parallel, the pattern shows interference. When the polarizers are perpendicular, there is no interference pattern. This is explained because it is possible to use polarization information to determine which slit the light passes through ONLY when the polarizers are perpendicular.

I would encourage you to read more about the basics of light and quantum physics before attempting to fashion your own counter hypotheses. The field is rich with detail, and there are many existing experiments to learn about. I am sure you will find them fascinating.

 

[calinvass]

Alright, thank you and sorry for this post

 

[DrChinese]

Alright, thank you and sorry for this post

Glad you have come here. I might suggest that you read up a little more on the subject. Then return and ask a question. I think you will find that leads to very fruitful discussion of quantum behavior, and you will gain a lot from the process.

 

[calinvass]

It doesn't make sense as long as you don't explain how you want to build such detectors concretely. Note that it is not so simple to have an experiment, where you have both interference and which-way information at the same time. You never can have interference for the same ensemble of photons that has which-way information and vice versa. A very illuminating experiment is the famous "Delayed-Choice Quantum Eraser Experiment" by Kim et al:

Yoon-Ho Kim, R. Yu, S.P. Kulik, Y.H. Shih, Marlan O. Scully, PRL 84, 1 (2000)
https://arxiv.org/ct?url=http://dx.doi.org/10%2E1103/PhysRevLett%2E84%2E1&v=d0a2ac7d
https://arxiv.org/abs/quant-ph/9903047

A real experiment (including a very understandable treatment of the underlying theory) can be found at

S. P. Walborn, M. O. Terra Cunha, S. Padua, C. H. Monken, PRA 65, 033818 (2002)
http://dx.doi.org/10.1103/PhysRevA.65.033818
http://arxiv.org/abs/quant-ph/0106078

Thank for the links. There are very useful articles.
If we consider the "Delayed-choice quantum eraser", to confirm the coincidences a second BBO before the slits could be placed and an additional detector Dc. This way any photon landing on any of the D0,D1,D2,D3 or/and D4 should be correlated with a detection on Dc. For example a detection on Dc and D0, with no detection D3 and D4 would mean a pulse passing through both slits and would result in diffraction pattern.