von Neumann process 1
= von Neumann process 1
{c}
The projection step in the traditional measurement account. For outcome projectors $P_j$, the nonselective state is $\sum_jP_j\rho P_j$; conditional on outcome $j$ it is $P_j\rho P_j/\operatorname{Tr}(P_j\rho)$. Distinguishing these from the coherent state produced by <quantum premeasurement> avoids identifying a pure correlated projector with its dephased mixture.