Figure 5

The comparison of the results of image pattern matching using different numbers of CNOT gates without amplification. The title of each subfigure is the target data in its situation, the x-coordinate represents the eight results with higher probability obtained by measurement in two cases respectively, ‘rest’ is the probability of remaining outcome and the y-coordinate is the corresponding value. Finally, the bar with the color watermelon red represents the output of the case with more gates, and the bar with the color grayish-blue represents that with fewer gates. Notably, here and in the following only the structure of \(U_{2}\) is optimized