Fig. 2: Two-qubit benchmarking using GST.

a Gate infidelity as a function of the Larmor frequency feedback rate and number of GST sequences per feedback cycle. Other routinely performed feedback protocols⁶⁵, like on the SET top gate voltage and spin resonance driving amplitude, remain unchanged throughout the manuscript. The star (⋆) indicates additional phase corrections based on the previous GST results. The green dashed line indicates the commonly considered 99% threshold. The inset is a zoom-in of the black-dashed box. b, c State preparation and measurement (SPAM) matrix, respectively. The insets show the respective theory matrix. d–f Error magnitude of error components for the XI, IX, and DCZ gates from GST with (coloured bars) and without (uncoloured bars) additional phase correction. The average gate fidelity is given above each plot for the phase corrected GST measurement. The on-target X gate fidelity F_X,Qi can be calculated from the relevant error components. Hamiltonian errors contribute to the fidelity in second order, while stochastic errors contribute in first order. Error bars represent the 95% confidence level.