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Homework Help: Need help with simple quantum problem

  1. Mar 26, 2004 #1
    Hi, I came across a problem which seems to be pretty simple, but I'm stuck :confused: .

    Given a Hamiltonian:
    [tex]H=\frac{\vec{p}^2}{2m}+V(\vec{x})[/tex]

    If |E> is a bound state of the Hamiltonian with energy eigenvalue E, show that: [tex]<E| \vec{p} |E>=0[/tex]

    -----------------------------------
    So I've been trying something like this:

    [tex]\frac{1}{2m}<E|\vec{p} \cdot \vec{p}|E> + <E|V(\vec{x})|E> = E<E|E> = E[/tex]

    but I have no idea how to proceed from here. I don't think I'm on the right track actually.

    Thanks in advance!
     
    Last edited: Mar 27, 2004
  2. jcsd
  3. Mar 27, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    FYI: This question has been answered in the quantum physics forum.
     
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