Schematic illustrations for the simulations of QST. (a) QST of an unknown state (the black boxes) by measurements M i with results m _i that are processed into a classical computer to yield the information [ ψ ] of the unknown state. (b) Quantum simulation of QST by starting from samples of the state ∣ ψ 〉 . (c) Classical digital simulation of QST with many copies of [ ψ ] and the information for each measurement [ M i ] . (d) SAC simulation of QST with fixed-basis states ∣ ψ 〉 i and classical measurements M i of position and momentum.