I've been thinking about this and the best I can come up with is the same as smanek's answer. It's not a form of computation; I'd say it's a physical concept ra

I've been thinking about this and the best I can come up with is the same as smanek's answer. It's not a form of computation; I'd say it's a physical concept rather than a mathematical one. Retrieving information about a quantum system's state changes that that state. Moreover, it is impossible to have a complete set of information about the system's state.