Interference Pattern in Cascaded Experiments

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Discussion Overview

The discussion revolves around a thought experiment involving cascaded interference patterns generated by a series of interference experiments. Participants explore the implications of measuring particle positions at different stages and whether an interference pattern can still be observed at the final stage by an observer unaware of earlier measurements.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question the feasibility of cascaded interference, suggesting that any measurement of particle position would collapse the wave function and eliminate the interference pattern.
  • Others propose that if a photon has high uncertainty in position, it might still produce an interference pattern at later stages, despite earlier measurements indicating particle behavior.
  • A participant emphasizes that the collapse of the wave function occurs instantaneously upon detection, which complicates the interpretation of interference patterns at subsequent stages.
  • There is a suggestion that it is possible to have both which-way information and an interference pattern, but these are treated as separate events in the discussion.

Areas of Agreement / Disagreement

Participants express differing views on whether an interference pattern can be observed at the final stage after measurements have been made at earlier stages. No consensus is reached, and multiple competing perspectives remain.

Contextual Notes

Participants highlight limitations related to the assumptions of measurement effects on interference patterns and the implications of wave function collapse, but these remain unresolved within the discussion.

nouveau_riche
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"consider the same interference experiment,the interference pattern produced is used to illuminate the next source in series,which then produces a new interference pattern,this gets cascaded say 10 times and the final interference pattern is obtained on the wall.
now ,the observer, observing the final interference pattern is not known of the fact that there's another observer measuring the particle position in the first stage of interference,and viceversa

will an interference pattern b seen by the observer ,observing it at the last stage?
and if u think the experiment is not possible then provide a reason for the same
 
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no answers yet...
i think no one had an answer to that
 
Last edited:
nouveau_riche said:
no answers yet...
i think no one had an answer to that

still no answers,
i think there really is no certain answer
 
I question if anyone understands what you mean by cascaded interference. Basically, there is no superposition if it is possible to determine any which path information, regardless of the particular setup.
 
nouveau_riche said:
"consider the same interference experiment,the interference pattern produced is used to illuminate the next source in series,which then produces a new interference pattern,this gets cascaded say 10 times and the final interference pattern is obtained on the wall.
now ,the observer, observing the final interference pattern is not known of the fact that there's another observer measuring the particle position in the first stage of interference,and viceversa

will an interference pattern b seen by the observer ,observing it at the last stage?
and if u think the experiment is not possible then provide a reason for the same

the moment you measure the particle position in the first stage (or any stage or anywhere), the interference will disappear...starting with that particular photon...even if it has passed 2 or 5 or 10 slits already...(assuming we are sending photons one by one)...

thus this won't work...

or in other words

for whichever ("travelling/experimental/sample") photon(s) you do the measurement for...it's position would correspond to ...building a single blob pattern (non-interference pattern) instead of interference pattern...
 
San K said:
the moment you measure the particle position in the first stage (or any stage or anywhere), the interference will disappear...starting with that particular photon...even if it has passed 2 or 5 or 10 slits already...(assuming we are sending photons one by one)...

thus this won't work...

or in other words

for whichever ("travelling/experimental/sample") photon(s) you do the measurement for...it's position would correspond to ...building a single blob pattern (non-interference pattern) instead of interference pattern...

but if have a photon having high uncertainity in position then there might be the probability that localising the particle at say 2nd stage would produce an interference pattern at atleast 3rd stage regardless of the fact of being showing it's particle nature
 
nouveau_riche said:
but if have a photon having high uncertainity in position then there might be the probability that localising the particle at say 2nd stage would produce an interference pattern at atleast 3rd stage regardless of the fact of being showing it's particle nature

the "collapse of the wave function" is instantaneous, the moment you detect it, say at the 2nd stage, it "becomes" a particle...

however if it goes through slits on the 3rd stage and we don't find which-way...yes...you will get an interference pattern...

so now you have which-way in 2nd slit and interference pattern in screen at 3rd stage...

you now have which-way and interference pattern...so to speak/in a sense...however these are separate events...:)
 
San K said:
the "collapse of the wave function" is instantaneous, the moment you detect it, say at the 2nd stage, it "becomes" a particle...

however if it goes through slits on the 3rd stage and we don't find which-way...yes...you will get an interference pattern...

so now you have which-way in 2nd slit and interference pattern in screen at 3rd stage...

you now have which-way and interference pattern...so to speak/in a sense...however these are separate events...:)

so ..if i can get the interference pattern at later stages ...the problem become cumbersome..
the observer observing the interference pattern at last stage will never be aware of the fact the particle has shown it's particle nature to any observer i.e no effect of previous interaction of observer localising it
 

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