electron-photon interaction

Discussion in 'Physics' started by Mvjhoda, Jul 30, 2011.

  1. Mvjhoda

    Thread Starter New Member

    Jul 13, 2011
    I have studied feyman's charge- photon interactions which successfully explains repulsions between like charges, but can someone explain me attraction on basis of feyman's diagram,using charge-photon interactions?
  2. steveb

    Senior Member

    Jul 3, 2008
    This is usually done by invoking the uncertainty principle. For example, with an electron and positron, you can say that a virtual photon is emitted from the electron, thus carrying away a well defined momentum and allowing the electron to recoil towards the positron.

    However, due to the uncertainty principle, the position of the photon is very uncertain, since it's momentum is well defined. Poetically, you can say that the photon is blurry.

    A blurry photon traveling away from the electron might just as well be said to be on the other side of the positron/electron pair, and hence it can travel towards the positron and get absorbed by it, thus allowing the positron to recoil towards the electron.

    The end result is attraction since the electron and positron both move towards each other. This is just another example of how the quantum mechanical world is very nonintuitive.