We’re rewarding the question askers & reputations are being recalculated! Read more.

Application of a unitary transformation $U$ on a state $|q\rangle$ really leads to a new state $U|q\rangle$. What you get after a measurement is a one particular outcome of $U|q\rangle$ state because the measurement leads to colapse of the state wave function. If you repeat measurement many times you will get probability distribution of possible outcomes of ...

Only top voted, non community-wiki answers of a minimum length are eligible