Each checked pulse stage produces the source record for the next stage, so the computation is modeled as a chain of reviewed contracts. The final probabilities are exact only for the stated ideal stages and preserved normalization; laboratory runs add timing error, phase noise, gate infidelity, drift between stages, and sampling uncertainty in readout counts.
A computation is a sequence of checked physical stage contracts. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
One stage output feeds the next
The balanced state feeds a phase stage, and that output feeds the recombination stage.
balance→phase→recombine
Each stage reports the same conserved budget
The middle row shows why direct counts alone do not expose the phase; the final row shows recombination using it.