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Time-dep perturbation theory

  1. Nov 16, 2007 #1
    while I`m reading the griffiths` textbook..

    got my curiosity from "Typically, the diagonal matrix elements of H` vanish"

    i.e. <a|H`|a>=0 in general..

    If V(x) does not have an angular dependence..

    the selection rule implies <a|H`|a>=0 (since Δl=0)..yes..

    but what if it does?

    what it(vanishing diagonal element of H`) means
    physically (in view of the perturbation theory)

    sorry for my bad english..
  2. jcsd
  3. Nov 16, 2007 #2

    Dr Transport

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    Gold Member

    If the diagonal elements of the perturbation didn't vanish, then they wouldn't perturb the system but be a small addtion to the unperturbed eigenvalue or another eigenstate.
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