Extended Data Fig. 8: Charge stability diagram for the few-electron regime.

Charge stability diagram for the few-electron regime of the samples in which qubit 1 and qubit 2 are measured. Smaller charge sensing maps are stitched together to obtain one large map. As pointed out in the main text, the Coulomb peaks become more irregular towards the single-electron regime, indicating dots forming under adjacent gates. Although we observe several spurious dots, the few-electron regime usually looks rather similar to this map. The approximate gate voltages at which qubit 1 and qubit 2 are measured are indicated.