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Von neumann, pointer state

  1. Feb 11, 2005 #1
    Could somebody please explain or give me a link to an explanation of the idea about measerument that von neumann put forward. That is that a system interacts with a pointer state associated with the measurering device with the hamiltonian

    H:=c * d(t) * A (X) * P

    where d(t) is diracs delta, (X) is the tensor product, A is an operator representing what we measure and P is a momentum operator acting on the pointer state.

    I have some understanding of this but I have failed to find a detailed explanation anywhere on the internet, just some notes that von neumann thought of it in 1932. I really would like to see some examples etc.
  2. jcsd
  3. Feb 11, 2005 #2


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    Did u try to look in his book...?I'm sure u won't find the book on the internet,only at the library.

  4. Feb 12, 2005 #3
    no I havent but I assume that its written in german ? von neumann sounds kind of german!
  5. Feb 12, 2005 #4
    Your right, my local library actually has a new edition of it, published in 96! thanks for the tip.
  6. Feb 12, 2005 #5


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    Johann (then John) von Neumann was a Hungarian-born American professor...

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