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Photon interection

  1. Aug 7, 2006 #1
    This is manish mehta I have a question regarding to photon
    why does interference between photons doesnot occur.A photon can only interfere with itself give an example
  2. jcsd
  3. Aug 7, 2006 #2

    Hans de Vries

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  4. Aug 7, 2006 #3


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    At the most fundamental level, photons can interact directly only with charged particles. From the point of view of Feynman diagrams, the only "vertices" that involve photons have two lines for charged particles and one line for the photon.

    However, there are second-order processes in which two photons can interact indirectly, by using virtual charged particles. A Feynman diagram for one such process looks like a square box (for the charged particles) with wavy lines entering two corners and leaving two corners (for the incoming and outgoing photons). This is the sort of thing that Hans is referring to. Since it's a higher-order interaction, its probability is very low which makes it difficult to detect.
  5. Aug 8, 2006 #4


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    There's also the scalar electrodynamics in which the "seagull" term involves 2 photonic lines in lowest perturbation order. However, such an interaction is not part of the Standard Model.

    But it's still possible.

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