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Expectation value in a linear superposition

  1. Jan 15, 2012 #1
    In a linear superposition, what is the relationship between expectation value of, say, energy and the amplitude coefficients of the eigenfunctions?
  2. jcsd
  3. Jan 15, 2012 #2

    Ken G

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    Gold Member

    That depends on what it is a superposition of. Normally, if you want to know the expectation value of some observable, you express the superposition in terms of "eigenfunctions" of that observable, meaning a superposition of states of a definite value for that observation. When you do that, the expectation value is a weighted average of those values, where the weights are the squared magnitude of the coefficients of the superposition.
  4. Jan 15, 2012 #3
    thank you :)
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