The capstone keeps prepared, retained, leaked, coherent, and observed counts together. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
The retained shots also define phase visibility
Of the 80 retained shots, 48 remain coherent, giving coherent fraction 3/5.
48/80=53
The capstone ledger closes all stages
The final audit carries 52 zero reads, 28 one reads, and 20 leaked shots, so the open-system budget closes.