From one of the postulates we know we can represent any system with a state space. I am considering, that if I do this I will sensibly assign different vectors to different entities of my system. But now how do I find these measurement operators?$$M_{m}$$ which are used to measure the system and the outcome is $m$.

  • $\begingroup$ what situation are you think about exactly? On what kind of system (a qubit? a finite-dimensional system? something else?)? Generally speaking, any Hermitian operator (observable) represents a valid measurement. Or more generally, you can take any set of positive operators summing to the identity (a POVM) as a measurement. These are all valid, which one you want to use depends on what you are trying to do $\endgroup$
    – glS
    Commented Feb 16, 2021 at 9:29
  • $\begingroup$ @glS.: Be it any system. I am curious how do people usually find these matrices? $\endgroup$
    – user27286
    Commented Feb 16, 2021 at 12:53


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