Normalization becomes easier to see when several exact rows square into closed budgets. 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 normalized pair is a full probability budget

The first row uses amplitudes 3/5 and 4/5. The diagram squares them into two probability bars that close at one.

925+1625=1\frac{9}{25}+\frac{16}{25}=1
Normalization row AThe first pair is checked as a complete state.left3/59/25right4/516/25

Three rows show which number changes

The scan repeats the same rule with two more exact pairs. Each row changes amplitudes, then checks the squared probabilities and the total.

ampsPLPRsum35,45925162511213,513144169251691513,1213251691441691\begin{array}{c|c|c|c}\text{amps}&P_L&P_R&\text{sum}\\\frac{3}{5},\frac{4}{5}&\frac{9}{25}&\frac{16}{25}&1\\\frac{12}{13},\frac{5}{13}&\frac{144}{169}&\frac{25}{169}&1\\\frac{5}{13},\frac{12}{13}&\frac{25}{169}&\frac{144}{169}&1\\\end{array}
Normalization three-row scanThe larger amplitude moves with the larger bar.left12/13144/169right5/1325/169

Swapping amplitudes swaps probabilities

The third row swaps the two amplitudes. Nothing else is hidden: the left and right probability bars swap because the squared amplitudes swap.

(513)2=25169,(1213)2=144169\left(\frac{5}{13}\right)^2=\frac{25}{169},\quad \left(\frac{12}{13}\right)^2=\frac{144}{169}
Swapped normalization rowThe probability bars follow the swapped amplitudes.left5/1325/169right12/13144/169