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Do virtual particles interact?

  1. Mar 20, 2012 #1
    (First off, I'm not sure that I'm asking this question in the right area, but there does seem to be other questions associated with the topic, so hopefully I'm ok, but if I'm wrong, apologies.)

    I understand that virtual particles are.... virtual, a mathetical construct that is used to describe certain scenarios, but does the math allow virtual particles to interact with each other / ordinary particles? For example, within a vacumn, virtual particle / anti-particle pairs are constantly being "created"and "destroyed", so does the math allow for "collision" (changing the virtual / mathetical trajectory) between the virtual particle of pair A and the virtual particle of pair Bs, and does the math allow the virtual anti-particle from pair A to "destroy" the virtual particle from pair B?

    Thanks for your help,

  2. jcsd
  3. Mar 20, 2012 #2
    In a manner of speaking, certainly. Various vacuum loop diagrams could be interpreted something like you describe. In the end it all just contributes to the picture of what the vacuum itself is though. As for interacting with normal particles, well they do this all the time, otherwise we would not know they existed. Even just two electrons scattering off each other exchange virtual photons, which are clearly interacting with the real electrons.

    Perhaps I am not really understanding your question though.

    edit: I scoured google images for a nice picture of some vacuum bubbles, but the best I found was this:


    The last diagram shows some vacuum bubble affecting the propagation of a (say) photon, which perhaps is something like what you are thinking about?
    Last edited: Mar 20, 2012
  4. Mar 21, 2012 #3
    Thanks Kurros. That's exactly the info that I was looking for. It can be difficult to seperate the real / virtual elements in what I read generally on the subject. It's great to have a perspective on a specific question.


  5. Mar 21, 2012 #4
    The vacuum bubble above was first calculated by Uehling ( E.A. Uehling, Phys. Rev. 48, 55 (1935)), also by Serber in same issue. In bound muonic and pionic atoms (where pions or muons replace an atomic electron), this is called vacuum polarization. This has been confirmed to high accuracy by measurement of the atomic transition energy level shifts of muonic and pionic x-rays. This correction can shift atomic energy levels by several percent.
  6. Mar 21, 2012 #5
    Thanks Bob. I'm afraid that your description is a big bit above my current knowledge level! Do you know of a lowbrow article / forum that I could use to help me get started?


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