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Do photons pass through each other?

  1. Nov 7, 2014 #1
    If I am not wrong, Feynman is claiming that photons can pass through each other. Isn't it?

    This thread is started with the interest of the thread "Does electron has definite path?": https://www.physicsforums.com/threads/does-electron-has-definite-path.780047/page-2#post-4905563
  2. jcsd
  3. Nov 7, 2014 #2


    Staff: Mentor

    Why do you think the issue is can they pass through each other rather than having a probability of scattering? In other words why do you assume the language you are using is the appropriate one for the situation?

    The answer is they have a probability of scattering:

    Added Later:
    As I alluded to in the other thread lay explanations and what really is happening are two different things. See post 4 of the following:

    Now its not normally an issue. But if you want to use it to challenge well known QM facts such as electrons having an observable path then sorry - you are going into much more advanced territory.

    Last edited: Nov 7, 2014
  4. Nov 7, 2014 #3


    User Avatar

    Staff: Mentor

    He is claiming no such thing. He is stating the fact "light is crisscrossing" without interference.

    If you think a beam of light is a stream of photons, you might infer from this that photons can pass through one another. However, this inference would wrong because your premise that a beam of light is a stream of photons is incorrect.

    Some of your comments in the thread from which this one was spawned (for example, the bit about a volume so small that all the space within it might be occupied by a photon) reflect a similar misunderstanding of what a photon is.

    I don't how strong your math and science background is. If you've been through a few semesters of quantum mechanics already, you could give "Quantum Field Theory for the Gifted Amateur" a try. Feynmann's "QED: The strange theory of light and matter" is a good start if you haven't.

    But in any case, it is futile carrying on discussions based on misconceptions about what a photon is, so I am closing this thread.
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