Quantum transition probability
= Quantum transition probability
{title2=$P_{i\to f}(t)=|\langle f|U(t)|i\rangle|^2$}
For a prepared normalized <pure state> $|i\rangle$ and a final <projective measurement> onto the normalized state $|f\rangle$, <unitary time evolution> gives the displayed <probability>, by the <Born rule>. This depends on the preparation, final measurement, and <time-evolution operator>; it does not assume a classical <Markov chain> of transitions.