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

Dispersion relation and Photonic Energy and Momentum Equations in QM

  1. Feb 7, 2010 #1
    Hi All,

    In quantum mechanics, related to photon, we have these two equations as valid ones:

    E = h x f

    p = h / lambda

    But we have in vacuum the dispersion relation c = lambda x f.

    1) How these relations change when the dispersion relation change ?

    2) Is it universally correct to write p = h x f / c ?


    Thanks ALL

    Best Regards

    DaTario
     
  2. jcsd
  3. Oct 10, 2010 #2
    Or still, is it correct to write:

    E = h c / lambda ?

    Best wishes

    DaTario
     
  4. Oct 11, 2010 #3

    DrDu

    User Avatar
    Science Advisor

    Yes, but at least c should be understood to mean not the vacuum velocity but the velocity of the wave in the medium.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook