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Bra-ket Notation and Operator

  1. Oct 7, 2012 #1
    Hi
    If C is an operator such that C|1> = |1> and C|2>=|2>, then C^3 |1>= |1>|1>|1> =|1> ^ 3 ? If yes, then what does this C^3 represent?
    :confused:
     
  2. jcsd
  3. Oct 7, 2012 #2

    I like Serena

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    Welcome to PF, rsaad!

    If f is a function such that f(x)=x.
    And f3(x) denotes f(f(f(x))).
    What is f3(x)?
     
  4. Oct 7, 2012 #3
    OMG! That makes sense! Thank you soooo much!!!!
     
  5. Oct 7, 2012 #4
    f^3 x is a function again =)
     
  6. Oct 7, 2012 #5

    I like Serena

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    You're welcome. :wink:

    Yeah... which function?

    And is C^3 |1> = |1>|1>|1>?
     
  7. Oct 7, 2012 #6
    No. it is just |1>
     
  8. Oct 7, 2012 #7
    So that's an identity function
     
  9. Oct 7, 2012 #8

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  10. Oct 7, 2012 #9

    mfb

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    Your C is not the identity function!
    Try to calculate C^3 |2> to see the difference.

    Edit: Ignore that post, see below.
     
    Last edited: Oct 7, 2012
  11. Oct 7, 2012 #10

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    C^3 |2> = C C C |2> = C C |2> = C |2> = |2>

    Where is the difference?
     
  12. Oct 7, 2012 #11

    mfb

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    Oh sorry, I somehow read C |2> = 2 |2> in the first post. You are right.
    Ok, it might be the identity function (but we cannot be sure based on 2 examples only).
     
  13. Oct 7, 2012 #12

    Fredrik

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    The notation |1>|1>|1> doesn't make sense here.
     
  14. Oct 7, 2012 #13

    dextercioby

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    There's no such thing as the 3rd or any power of a vector.
     
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