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Homework Help: Heisenburg uncentainty product

  1. Aug 14, 2010 #1
    1. The problem statement, all variables and given/known data
    Evaluate the heisenberg Uncertainty product (delta)p*(delta)x for any eigenstate of a particle confined to a box of width L
    hints:
    a] what do you expect <x> to be? justify this
    b] what do you expect <p> to be? justify this
    c] how is p^2 related to KE and to E for the particle?

    im not really sure how to approach this question but am i correct if a take the wave function of a particle in well of length L and find its expected value of <x> and <p> and then take there product and compare it with the hysenburg uncertainty??
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Aug 15, 2010 #2
    [itex]\Delta x[/itex] is not the same thing as [itex]\langle x\rangle[/itex]. So you can't just take the product of the two expectation values. In fact the definition of the uncertainty of a value is:

    [tex]\Delta x = \sqrt{\langle x^2 \rangle - \langle x\rangle^2}[/tex]
     
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