Fig. 2. GST (solid lines) and PAPA reconstruction (dashed-lines) N_σ vs. germ power L for each of the three experimental data sets.

N_σ quantifies the deviation from a Markovian qubit model. The goodness-of-fit parameter is provided by pyGSTi and ranges from single blackstar to five black stars, indicating how well the data fits the implicit model. Larger values of L correspond to increased sensitivity to gate error and to longer circuits.