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Free particle wavefunction represent a fixed profile= wavepacket?

  1. Nov 3, 2013 #1
    Why the Griffiths book says : any function of x and t that depends on these variables in the special combination (x±vt) represent a wave of fixed profile, traveling in the -+x direction at speed v...
    I don't really get the reason why from 2 terms of wavefunction can become only one term?

    Please help.

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  3. Nov 3, 2013 #2


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    Griffiths means that your wave function is either of the form [itex]\psi(t,x)=f(x-v t)[/itex] or of the form [itex]\psi(t,x)=f(x+v t)[/itex]. Obviously the shape of the wave stays the same for each time, but it's moving to the right or left, respectively.
  4. Nov 3, 2013 #3
    How do you know there are two form of wavefunction?
    By drawing out a graph of wavefunction against x? To see they are actually two superposition of two traveling wave?
    Those information are from the wave function? How do you know? Do I miss any wave knowledge? Where should I study these?
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