Extended Data Figure 2: Average density profile in the system.

a, The average single-particle density map for a sample at half-filling shows a central region of uniform density, surrounded by a doughnut-shaped ring of low density. The dotted white circle indicates our system size, excluding edge effects. b, The azimuthal average of the single-particle density n_s shown in a, for the system and for the inner edge of the doughnut where the density drops off to the reservoir density. The vertical dotted lines denote the boundary of the system. c, Azimuthal average of the single-particle density n_s for three values of the hole doping δ used in the experiment, indicating uniformity of atom number across our system to within 4%. The horizontal lines are at the system-wide average densities. Error bars in c are one standard deviation of the sample mean. The figure is based on 2,105 experimental realizations.