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X's expectation value in quantum physics

  1. Dec 11, 2004 #1
    When I'm in a dimension higher than 1, do I need to integrate over all space (V) or only the x axis?
    Thanks in advance.
  2. jcsd
  3. Dec 11, 2004 #2


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    Let's consider a QM system whose states are described by the wavefunction
    [itex] \psi (x,y,z) [/itex].You wish to calculate the expectation value for [itex]\hat{x} [/itex].That is nothing but the number.

    [tex] <\hat{x}> =\int\int\int_{R^{3}} \psi^{*}(x,y,z) x \psi (x,y,z) [/tex]

    I hope your wave function is normalized/normalizable.Else,you might encounter some problems with the integration above.

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