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Eigenvalue plots Tannoudji's Quantum Mechanics Vol. II

  1. Sep 23, 2009 #1
    Hi guys,

    probably that's the wrong forum, but I was just curious about
    the plot (Figure 1 Chapter XI A./1. page 1097 / Volume II) of the eigenvalues


    If I calculate them they are supposed to be straight lines with positive or
    negative slope i.e.:

    [tex]E(\lambda) = E_n^0 + \lambda \epsilon_1^j[/tex]

    in first order perturbation theory.

    Am I missing s.th. or are these curves just ment to be realistic measurement curves
    (and if so why isn't there any hint in the text) ?
    Last edited: Sep 23, 2009
  2. jcsd
  3. Sep 23, 2009 #2
    If you calculate higher order corrections to the energy you will also have term of order [tex]\lambda^2[/tex] and higher. So the exact value of E(lambda) is not given by a straight line, but some curve instead. The plot gives an example of what the exact value of E(lambda) might be.
  4. Sep 23, 2009 #3
    Thank you very much, it's all about detail :smile:
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