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Photon Creation and Light Generation

  1. Jun 15, 2010 #1
    I know people get tired of answering questions about photons, but I have a question regarding the best way to think of how light (i.e. E-M waves) are created.

    Several books and educational resources say that a light wave is created by "vibrating electrical charges."

    But my understanding of photons is that we don't have much of a model for how they are generated.

    If you don't like conflating/blending discussion of "photon"s versus "light waves," then I would put my concern this way: When an electron changes energy level and emits a photon, one cannot really say it "vibrates" in the way that we think of, say, a drumhead vibrating.

    How wrong is it to say that one can speak of short time envelope [a "delta t" in terms of the Heisenberg relationship] "between" the time when the electron was in one energy state and when it was in another, and during this time the light-wave/photon gestated?
  2. jcsd
  3. Jun 15, 2010 #2
    Oscillations of an electron are not the same as vibrations of the head of drum, of course, that is just an analogy to avoid a measure of math. You seem to be talking about two different things, the first being how and "when" a particle is emitted as being a time when it is created. If a medium absorbs a photon, then emits a photon, Photon1 is gone, and Photon2 which has been emitted was just created. How you place a time variable in there doesn't make much sense. Absorbers and Emitters just are not described in those terms AFAIK.
  4. Jun 15, 2010 #3
    I'm not talking about absorbing photons at all. Imagine [for the sake of our discussion], that an electron is in a higher energy state for some generic (unknown) reason. It could have simply been excited due to thermal collisions between atoms in a solid.

    Secondly, my point is that we are not talking about oscillations at all. An electron starts in one energy state and then goes to another. This is qualitatively different from, for example, E-M waves caused by alternating current in circuits. It is reasonable to describe those as coming from oscillations (or at least accelerations) of an electron, but photons generated by an electron changing states is different from this.
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