Graivton quantization

  1. Theoretically, how much energy in particle accelerator would be required to quantize a graviton from a gravity field?
  2. jcsd
  3. mathman

    mathman 6,752
    Science Advisor
    Gold Member

    I doubt if anyone knows the physics behind your question.
  4. Probably somewhere around the Planck scale (10^19 GeV)
  5. Any reason why the graviton would require so much more energy to become quantized?
  6. tom.stoer

    tom.stoer 5,489
    Science Advisor

    This is the natural energy scale EPl; a theory of quantum gravity at a different scale EQG = xEPl with x << 1 would have to explain the smallness of x.
  7. Bill_K

    Bill_K 4,157
    Science Advisor

    Q. How much energy does it take to create a photon?
    A. ħω, where ω is the frequency of the photon.

    Q. How much energy does it take to create a graviton?
    A. Exactly the same, ħω.

    Q. Well then, how come particle colliders create scads of photons but no gravitons?
    A. It's not the energy that's the problem, it's the production rate. Photons are produced (primarily) by time-dependent electric dipoles. Gravitons are mainly produced by time-varying mass quadrupoles. You can crash two protons together and calculate their mass quadrupole moment as they collide, and then multiply that by the gravitational constant G to get the production rate. It's ridiculously small.

    Q. What does the Planck mass have to do with it, if anything?
    A. The Planck mass is the energy at which (presumably) gravitational interactions become comparable to the strong and weak interactions. So yes, you'd need a collider with that energy if you wanted to make the production rates comparable. But spacetime literally goes to pieces at that energy. If you really want to make gravitons, run at a much lower energy and be prepared to wait.
  8. If the production rate of a graviton is determined by the mass quadrupole * G, then wouldn't the graviton be much more likely to be detected if you placed a particle accelerator very close to a dense object, such as a neutron star or a black hole? (Since the value of the quadrupole function becomes larger as mass, and therefore gravitational attraction, increases). My bet is that there is an equilibrium near an event horizon, where gravitons are likely to be quantized.
Know someone interested in this topic? Share this thead via email, Google+, Twitter, or Facebook

Have something to add?