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Commutative in Quantum Mechanics

  1. Apr 11, 2014 #1
    1. The problem statement, all variables and given/known data
    Calculate the commutative
    [P2,Lx]
    2. Relevant equations
    P2=P2x+P2y+P2z
    [Py,Lx]=-iħPz
    [Pz,Lx]=iħPy
    [Px,Lx]=[Py,Ly]=[Pz,Lz]=0
    3. The attempt at a solution
    [P2,Lx]=[P2x+P2y+P2z,Lx]
    =[P2x,Lx]+[P2y,Lx]+[P2z,Lx]
    =Px[Px,Lx]+[Px,Lx]Px+Py[Py,Lx]+[Py,Lx]Py+Pz[Pz,Lx]+[Pz,Lx]Pz
    =-iħ[Py+Py]+iħ[Pz+Pz]
    =iħ[P2z+P2y]
     
    Last edited: Apr 11, 2014
  2. jcsd
  3. Apr 11, 2014 #2
    First off, what is your question? Second off, your commutation relations are wrong. For example, [P2,L1]=-iħP3.
     
  4. Apr 11, 2014 #3
    Thanks, I was edited the given (miss-writing)
    The question is written in the first step
    Calculate the commutative [P^2,Lx]=?
     
  5. Apr 11, 2014 #4
    Yes, but what is the question you have about how to do this? You've fixed the typo, but you haven't applied the changes to your solution.
     
    Last edited: Apr 11, 2014
  6. Apr 11, 2014 #5
  7. Apr 11, 2014 #6
    As I said before, you've fixed the typos in your "Relevant Equations", but you haven't applied these changes to your solution.
     
  8. Apr 12, 2014 #7
    tman12321
    I was putted the relevant equation directly at the attempt part in the third step of solution.
     
    Last edited: Apr 12, 2014
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