Based on the Double Slit Experiment and the Mach-Zehnder Interferometer is it reasonable that a single photon enter both eyes of one person?

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    $\begingroup$ Rather, each of two different copies of the photon enter two different copies of each person. $\endgroup$ Commented Jun 24 at 0:59
  • $\begingroup$ No, because there are no photons in the free electromagnetic field. "The photon" is the amount of energy that gets absorbed in your retina. In ONE of your retinas, that is, because the same amount of energy can not be absorbed twice. $\endgroup$ Commented Jun 24 at 1:53
  • $\begingroup$ No No No .... the EM field is everywhere, it guides the photons. The EM field is in both arms of the MZ, and it is in both slits .... the photon is dumb and just goes where the EM field tells it to. In an apparatus all electrons contribute to the EM field ... especially the excited electron in the source before emission. $\endgroup$ Commented Jun 24 at 16:13
  • $\begingroup$ Classical and old fashioned physics and people who want the the double slit to remain a mystery forever perpetuate the myth of the photon splitting .... $\endgroup$ Commented Jun 24 at 16:18

1 Answer 1


Theoretically yes, if the photon didn't interact with anything on the way that would cause the superposition to collapse. Of course that means that unless it doesn't interact with the eyes only one photon will be observed, but if you do interact with the photon via your eyes you will only see one photon because the absorption of the photon by your retina constitutes an "observation" in the quantum-mechanical sense.

  • $\begingroup$ Photon absorption by 11cis pi orbital would collapse the wave function yet create change in ion flow to the brain. Thus, observation occurs even if the brain does not have enough data for processing. It is 50% left and 50% right given transmission to orbital. If wrinkle exists in retina then photoreceptors may be misaligned resulting in destructive interference. Make sense? $\endgroup$
    – Bob S
    Commented Jun 24 at 1:30
  • $\begingroup$ @BobS what's important to recognize is that in the interaction with the retina, the photon can only appear in one place at a time. Passing through the slit, it can split up into two superpositioned states, but you can't ever observe or experience physical consequences of a superpositioned state because just as you do it collapses into one of the two states. You can only ever "see" one photon state. $\endgroup$ Commented Jun 24 at 2:12

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