Double slit interactive detector

[CHOP]

my understanding is that there has never been a double slit experiment with a detector at the slit, where that detector's state was changed as a result of a particle being at that slit. if true, then if such a schema was possible and tried, then there would be no interference, and the reason there would be no interference is because the 'which-path' info exists in nature (particularly, in the fact that the detector was changed). is all of that correct?
thank you

 

[DrChinese]

my understanding is that there has never been a double slit experiment with a detector at the slit, where that detector's state was changed as a result of a particle being at that slit. if true, then if such a schema was possible and tried, then there would be no interference, and the reason there would be no interference is because the 'which-path' info exists in nature (particularly, in the fact that the detector was changed). is all of that correct?
thank you

:Welcome:

When you place a detector at a slit (something which has been done in many different ways), you do not get an interference pattern (just as you say). Also as you say, it does not matter if the detector is changed or not IF the which path info exists somewhere.

Note: this is my post 7000.

 

[CHOP]

Hi thanks very much for your response,
But if the slit detector was changed, that fact (by itself) would mean that 'which path' info is available. Correct?
So I don't understand why you specified that it does not matter if the detector was changed. It does matter because the change is the info being available (in principle). What am I missing?
Also, congratulations to you on 7k! And I guess, to me!

 

[CHOP]

Oh hang on, I think I got your point. You are saying that whatever is most directly connected to that particle (which is not the detector but the interaction with the particle which enabled the detector to detect) is how 'which path' info manifests. The detector merely responds to that manifestation, so its change is not relevant to the non interference (it is just a kind of spreading of the path info). Is that right? If that is right, then may I ask: Has there been any experiment of exactly that kind? Where something was applied by the slits which interacted with the particle (causing non interference)? If so, what experiment?