Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I Particle antiparticle creation

  1. May 18, 2017 #1
    When a particle and antiparticle pair is created are they created on the same position?
    If they weren't in the same position it would lead a problem on energy conservation, but they are fermions so they shouldn't be on the same position in space.
     
  2. jcsd
  3. May 18, 2017 #2
    No, they are distinguishable so that is not the the case.
     
  4. May 18, 2017 #3

    Nugatory

    User Avatar

    Staff: Mentor

    You may thinking in classical terms here.

    Quantum mechanically, the "position" of a particle is a rather dubious concept unless and until you've interacted with it in a way that localizes it (informally, "measured its position"). So consider an example of an interaction that produces a pair of fermions: an energetic gamma photon interacts with a heavy nucleus and produces a positron/electron pair: all energy conservation (and similarly for momentum) requires is that when the dust settles the sum of the energies of the nucleus, electron, and positron coming out is equal to the energy of the photon and the nucleus going in. The interaction itself should be thought of as a black box: some particles went in, some other particles came out, the energy coming out is equal to energy going in.
     
  5. May 19, 2017 #4

    A. Neumaier

    User Avatar
    Science Advisor
    2016 Award

    Usually a particle and an antiparticle cannot have the same quantum number, and hence can occupy the same position.
    When two photons (which are their own antiparticles) are created one cannot talk about their position and the question is moot.

    In any case, the particle concept becomes meaningless at distances that are too short, and ''the same place'' becomes a nonrelativistic fiction.
     
  6. May 19, 2017 #5
    Thank you A.Neumaier Nugatory andJilang for your answers they were really helpful
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted