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

If bosons don't interact, then how can gravity affect the path of light?

  1. Dec 29, 2012 #1
    One says that bosons do not interact with one another. However, the presence of a gravitational field, and hence of gravitons (bosons) (assuming they exist), changes the probability of where a photon (boson) appears, which is the same sort of interaction as two fermions, no?
    And, the contrary: mass-energy tells space how to bend, and this bending of space is essentially the gravitational field, so isn't this an interaction of photons and gravitons?
     
  2. jcsd
  3. Dec 29, 2012 #2

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    "One says that bosons do not interact with one another."

    Who says?
     
  4. Dec 29, 2012 #3
    Perhaps what one means is that bosons do not obey the Pauli exclusion principle.

    This needs to be compared with fermions: Even non-interacting (i.e. no many-body interactions) fermions repel each other due to the Pauli exclusion principle. Bosons on the other hand do not repel in case of no many-body interactions.
     
  5. Dec 29, 2012 #4

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Let's not guess what the OP means; let him explain it himself.
     
  6. Dec 29, 2012 #5
    I think there should be a feynman diagram for it?
     
  7. Dec 29, 2012 #6

    Bill_K

    User Avatar
    Science Advisor

    Sure. One choice for the electromagnetic Lagrangian is

    L = - ½ Aμ,νAμ,ν = - ½gμσgντAσ,τAμ,ν = - ½(ημσ + hμσ)(ηντ + hμσ)Aσ,τAμ,ν

    from which one can pick out the vertex that couples two photon lines and a graviton.
     
  8. Dec 29, 2012 #7
    Oops, my apologies to all who responded; I misread an article ( "The Computational Complexity of Linear Optics", by Scott Aaronson and Alex Arkhipov), which outlines experiments using non-interacting bosons -- and I misread the way this phrase to mean that all bosons were like that. But after the challenge by Meir Achuz, I re-read it and understood my mistake. My thanks to Meir Achuz (like mea achuz~100%?), Regel, Vanadium 50, adrien, and Bill K.
    :blushing:
     
  9. Dec 29, 2012 #8

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You have outed me. Now you know my test score, and my safah.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: If bosons don't interact, then how can gravity affect the path of light?
Loading...