Fig. 2: Comparison of experimental results on the superconducting quantum processor with the ideal ones for the 2D diverging flow.

Density contours and streamlines are shown at (a) t = 0, (b) t = π/4, and (c) t = π/2. The flow is symmetric about y = 0 (upper panel: exact solution; lower panel: experimental measurement). The streamlines are color-coded by the momentum magnitude. d–f The x-averaged profiles for ρ, J_x, and J_y at t = 0, π/4, and π/2 (dashed lines: exact solution; triangles: experimental measurement with error bars denoting one standard deviation). The density and momentum are obtained with 10⁵ measurement shots, and the experiment is repeated for five times. g–i Scatter plots comparing ideal and experimental values for ρ, J_x, and J_y at t = 0, π/4, and π/2, along with the correlation coefficients (marked at the upper left). Data point density is color-coded by the kernel density estimation (KDE) from low (purple) to high (red) values.