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Notational question, |1>

  1. Sep 5, 2010 #1
    What is meant when writing a "one-ket" like this |1> ?
  2. jcsd
  3. Sep 5, 2010 #2
    That usually means the principle quantum number is 1.
  4. Sep 5, 2010 #3


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    It depends on the system; for the one-dim. harmonic oscillator it means the first excited state |1> above the ground state |0>.
  5. Sep 5, 2010 #4
    Maybe I should have meantioned the whole context, I now realise that it means the eigenket coresponding to the eigenvalue 1 in my specific problem. Thanks anyway
  6. Sep 9, 2010 #5
    My understanding is that it is often an abstract way of referring to the n=1 basis vector. This is similar to what someone wrote above.

    The basis vectors must be implicitly defined, and then |n> refers to the nth basis vector. Unfortunately I am not clear on exactly where and how the |n> basis vectors are typically defined. I often see the notation |1> without it being clear what the ACTUAL eigenfunctions being referred to are. In that type of situation, I guess it is simply an abstraction; and index referring to a real function.
  7. Sep 11, 2010 #6


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    I think this explains it:

    (:uhh: ... is it because English is not my native language ... but "infinite-dimensional spaces" and "prepending bra" makes me think of something "completely different" ... :smile:)
    Last edited by a moderator: Apr 25, 2017
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