Fig. 3: Comparison of the GST measured process matrices to the ideal and the PAPA reconstructions of the experimental data.
From: Bootstrapping quantum process tomography via a perturbative ansatz

The PAPA data points are the average trace distance of the three reduced processes from their corresponding GST characterizations. The ideal points are the average trace distance of the ideal gates to GST. The trace distances (Eq. (10)) for the PAPA reconstructions are lower for all 27 gates in the set.