Fig. 2
From: Characterizing large-scale quantum computers via cycle benchmarking
Experimental evidence demonstrating rapid convergence under finite sample size with favorable constant factors. a Mean fidelity estimates from 30 randomly sampled subsets of Pauli matrices as a function of the size \(K\) of the subset. The error bars illustrate the standard deviation of the 30 samples, that is, the standard error of the mean. The green line describes the mean fidelity \(F=97.25(8)\)% calculated from the complete data set. b The standard deviation of the fidelity from plot a against \(K\) including a bound due to finite sampling of Pauli channels \({\sigma }_{{\rm{Pauli}}}=0.0275(8)/\sqrt{K}\) in orange, a fit of the standard deviation \(\sigma =0.0127(2)/\sqrt{K}\) in green, and a fit of the expected projection noise \({\sigma }_{{\rm{lower}}}=0.00375(1)\sqrt{K}\) in red (see Supplementary Note 5).
