• Ook the Librarian@lemmy.world
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      1 year ago

      Since photons are indistinguishable, it’s hard to say too much concretely, but it some sense a diffracted photon is different photon. In order for a photon to interact with say, a diffraction grating, the interaction is done with “virtual photons”.

      So for a photon to change course, aka accelerate, it does it by absorbing a virtual photon and emitting another. Whether that is the “same photon” after the interaction is kinda more philosophy than physics, at least to me.

      Feynman diagrams are surprisingly accessible for how much information they contain. It’s one way to think about photon (and other particle) reactions.

      • ziggurism@lemmy.world
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        1 year ago

        There is no tree level photon-photon interaction. Photons scatter off electrons (or any other charged particle), not off neutral photons.

          • ziggurism@lemmy.world
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            1 year ago

            The electromagnetic field does have a force carrier. It is the photon.

            The photon mediates the force between electrically charged particles. It cannot mediate any reaction between two neutral photons.