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Static Charge Photons

  1. Mar 25, 2008 #1
    What is the frequency/wavelength of the photons which mediates the forces between static charges? Are they exclusively low frequency photons, or is there a distribution of some kind? Also, in a slightly related question, is there a lower bound for photon frequency?
  2. jcsd
  3. Mar 25, 2008 #2


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    … where's my flak jacket … ?

    Hi ObsessiveMathsFreak! :smile:

    'spect I'll get shot down for this, but …

    I think they're just in mathematicians' imaginations … they help to simplify the perturbative expansion of the field … they have all possible frequencies and speeds … they're virtual photons, and virtual means not real, so they don't exist!
    :redface: … runs for cover … :redface:
  4. Mar 25, 2008 #3
    Wouldn't it depend on the energy that is actually exchanged in the interaction? For example, I think you could just determine the kinetic energy involved in the "collision" of two electrons, depending on their momentum, and using E=hf find the frequency of the virtual photon involved. Am I wrong?

    I've wondered this myself, or rather, wondered about the opposite question - is there an upper bound? Would it be a photon with a wave length equal to a Planck length? That'd be a very high energy photon!
  5. Mar 25, 2008 #4


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    Yes, you can do that - and the momentum of the photon is always larger than its energy, which means it's always faster than light.

    In fact, in the centre-of-mass frame of reference, the photon travels infinitely fast (I think this is why people talk of the "exchange" of a photon)!

    (Though I don't know how you'd work out the frequency. :confused:)

    Another reason for my not believing in them! :smile:
  6. Mar 25, 2008 #5
    And yet we do know that the EM force is transmitted _at_ the speed of light. So there is indeed something that is exchanged at a finite speed.
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