Measurement postulate = von Neumann’s projection postulate?

[Aidyan]

TL;DR

I'm wondering if the "measurement postulate" and the "von Neumann’s projection postulate" refer to the same concept?

I find in the literature frequent reference to the "measurement postulate" and, sometimes, to the "von Neumann’s projection postulate". The difference, if any, seems to me subtle but I can't tell which. However, they are never mentioned both in the same context/paper, so I'm afraid that they may be two completely different postulates not to be confused. I don't get what the difference is. So, the question is if they are synonymous (in that case a simple "yes" answer is sufficient) or , if not, what distinguishes it?

 

[kith]

My impression is that "measurement postulate" is not a term with a well-defined meaning. If it is used to refer to the change of state during a textbook measurement, it is another name for the projection postulate, yes.

Sometimes, people distinguish between "von Neumann projection" and "Lüders projection" where the latter is used for projections on multidimensional subspaces in the presence of degeneracy but this is really just unimportant semantics.

 

[DarMM]

They are synonmous, just two different names for the same thing. You'll even see Von Neumann's measurement postulate.