So I was recently modelling something that turned out to be basically Wigner's friend.
I saw there were some differences (in the Wiki page) in how it was modelled: Namely, that Wigner's friend somehow managed to perform a measurement without interacting with the system! (I mean if there was an interaction term in the Hamiltonian it would be much better. On the other hand, the interaction term would destroy the tensor product! The interaction term becomes important during the time of the measurement in the Heisenberg picture).
Does this point mute the calculations on the Wikipedia page?
