I know that the Englert-Greenberger-Yasin Duality Relation states that as the predictability of finding a photon at a slit in a double slit experiment increases, the visibility of the interference patterns decreases. Now, how exactly is the predictability varied in a double slit experiment?

  • $\begingroup$ the predictability varies as you like, it's an experiment parameter. After it is defined, you can use the duality relation. $\endgroup$ – user46925 Dec 23 '15 at 6:45

As you change something in the experiment to better predict a photon at one slit, the interference pattern looks more and more like just the sum of the patterns of each slit taken independently. That is, the extreme case pattern would be the sum of the patterns taken with one slit covered and the other slit covered.

  • $\begingroup$ I understand that. My question is just how practically, that is in an experiment, can you build an apparatus in which the predictability of finding a photon at a certain slit can be altered $\endgroup$ – Clement Decker Dec 22 '15 at 23:11
  • $\begingroup$ Of course one can build such an experiment, but it won't back up a failed particle interpretation of quantum mechanics any more than any other experiment. False is false and one should let got of it. $\endgroup$ – CuriousOne Dec 23 '15 at 0:23
  • $\begingroup$ What do you mean? I am confused by what you are saying $\endgroup$ – Clement Decker Dec 23 '15 at 4:16

Let us look on the double slit from the end of the history. Suppose one would shot photons on a screen with two slits and he want to know, how near he could place this two slits together and "hit" the slits separately. He starts with a big distance and wide slits and directed his photon source or to the first or to the second slit.

As he is an attentive observer he will see on the observer screen a) that every single photon he shot in the middle of the wide slit will arrive the screen and still will be a photon and b) after a while in the area of the geometrical shadow he will see fringes (intensity distributions), the first fringe is going partially behind the border of the geometrical shadow.

Now he wants to direct the photons from the source as precisely as he could to one edge of the slit. In the result he still see fringes. He tries it with monochromatic light, he make the source pointlike putting into the beam path a mask. He get the fringes more or less sharp, but they still exist.

To get the process he put the observer screen closer and closer to the edge. Photons still there are, but the fringes mutate more and more to a chaotic distribution. Doing this with two slits from the classical experiment, the observer gets the same results. He concluded that photons are indivisible and very real particles. And he concludes, if the photons are going behind the geometrical shadow there has to be an influence between the photons and the material of the edges. The final conclusions I leave you.

  • $\begingroup$ That is interesting but I don't think you know what I am asking. I am wondering if you were to do an experiment how exactly you might vary the predictability of finding a photon at a certain slit. I imagine that you could do this by varying the relative widths of the slits. But are there any other experimental methods for varying probability? $\endgroup$ – Clement Decker Dec 23 '15 at 7:15
  • $\begingroup$ @Clement If you have the possibility to do experiments, try to lay an electric potential to the slits edges. This will change the density of the surface electrons. Please don't forget to inform me about the results. $\endgroup$ – HolgerFiedler Dec 23 '15 at 8:02
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    $\begingroup$ I am not in the position to do such an experiment. I am wondering simply because I have realized that I can arrive at the EGY duality relation simply through a classical understanding of physics by looking at the case in which the amount of light passing through each slit is different. I was wondering if there are other methods besides simply varying the relative amounts of intensities passing through each slit and whether I could derive the EGY duality relation in these circumstances by only using a classical understanding of light. $\endgroup$ – Clement Decker Dec 23 '15 at 8:08
  • $\begingroup$ @Clement Nice. I'm with you. Have you tried to read my elabations about complex one-dimensional structures and about photons as composed particles. Both availible in English and German. $\endgroup$ – HolgerFiedler Dec 23 '15 at 9:01
  • $\begingroup$ No I have not. I am a high school student and can not access them because I am not a published researcher. $\endgroup$ – Clement Decker Dec 23 '15 at 19:39

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