Understanding QM..

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I'm going to explain a few things as I understand them, and I want someone correct me where I'm wrong. I don't know the correct terminology for everything, so bear with me.

 

Assume we have a box with three (for the sake of simplicity) mirrors set up inside of it. There is a mirror right inside the entrance of the box that is coated so that the photon has a 50% chance of reflecting at a specified angle, and a 50% chance of passing through the mirror. There are further mirrors within the box which ensure that the photon will emerge from the box on the other side at the same position no matter which path it takes after encountering the first mirror.

 

From what I understand, when the photon is initially fired into the box it has a wave function which dictates the probability of finding the photon at points in space (this wave function actually covers the entire universe, most of which has a probability of near 0). When the photon encounters the first mirror, it has a 50% chance of passing through and a 50% chance of reflecting. At this point, the wave function will show an equal probability of finding the photon in each pathway. When the wave functions recombine at the end of the box, they display typical wave interference, with patterns of high and low probability. This accounts for the wave pattern that would be detected if the experiment was carried out several times with the same photographic plate at the end of the box.

 

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Now let's assume have two entangled photons which originate at a single source and are travelling away from each other. <--p1-- (source) --p2-->. If I understand this correctly, these photons have a two-particle wave function that describes their positions (and other properties). Thus, measuring the position of one will collapse the wave function of both of them. So let's say one of the entangled photons is directed towards the box I described above. If we do this with several pairs of entangled photons, the banding pattern characteristic of waves will show up, correct? Now let's say we do it again, except this time we measure the position of the photon which will not enter the box. This collapses the wave function of the photon which is entering the box and thus the banding pattern will not show up, right?

 

I'm trying to get a grasp on this whole concept. Almost everything I've read on the subject has been way over my head or simplified so much that's it not technically correct.

[RICHARDBATTY]

But at least this might get the attention of someone who has.