Von Neumann's measurement model with delta function coupling

[trosten]

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.

 

[dextercioby]

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

Daniel.

 

[trosten]

no I haven't but I assume that its written in german ? von neumann sounds kind of german!

 

[trosten]

Your right, my local library actually has a new edition of it, published in 96! thanks for the tip.

 

[dextercioby]

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

Daniel.