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Homework Help: Quantum particle in a 2 dimensional box

  1. Jun 5, 2007 #1
    1. The problem statement, all variables and given/known data
    I need some help :cry:

    http://www.fysik.uu.se/kurser/1tt306/filer/TentKF06+short-answers.pdf [Broken]

    On task 4 a) i don't understand why they have two solutions, one for odd n and the other for even n.
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Jun 5, 2007 #2


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    Hi there, I also study @ Uppsala ;) physics..

    It has to do with the parity of the wave functions. Look on the symmetries around x=0. Ground state has zero nodes, 1st excited has one etc. Skiss the potetial and search for symmetry points.
    Last edited by a moderator: May 2, 2017
  4. Jun 6, 2007 #3


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    Note there's no qualititative difference between the x and y directions. You could write the wavefunction more symmetrically as:

    [tex] \psi_{nm} = C \sin \left( n \pi \frac{x-(-A)}{A-(-A)} \right) \sin \left( m\pi \frac{y-0}{B-0}\right) [/tex]

    They just used some trig identities to rewrite this.
    Last edited: Jun 6, 2007
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