Fig. 5: Plot representing the energy error (from FCI) using different noise probabilities and VQE algorithms.

Plotted for H₂ (a), H₄ (at 1 Å) (b), LiH (c), and BeH₂ (d), using linear zero-noise extrapolation^31,32. Energy accuracies lower than chemical accuracy are highlighted by the yellow region. The crosses represent the intercepts of the curves with this region.