Extended Data Fig. 2: Quantum dot characterisations.

Results presented in the main text are obtained using a single orbital in each QD. Characterisation measurements of each QD is shown here. Left, middle and right columns pertain to the left, middle and right QD respectively. a-c. Coulomb diamonds measured at B_x = 0 mT. To achieve strong interdot coupling, barriers between QD and neighbouring regions are kept relatively open, such that a finite current can be observed within each Coulomb diamond. The outline roughly indicates the charging energies to be > 1 mV. d-f. RF-Spectroscopy of each QD in the same regime as (a-c), for a smaller range of applied voltage biases. In this strong coupling regime, so-called Yu-Shiba-Rusinov states form at sub-SC gap energy scales whose energies are non-linearly dependent on the plunger gate voltages⁵⁷. g-i. Spectroscopy as a function of magnetic field B_x applied along the 1-D channel, with each plunger gate set close to the zero field charge degeneracy point based on (d-f). The slope of the splitting sub-gap states provides an estimate of the g-factors for these parameters to be 18.4, 14.8 and 13.7 respectively. j-m. Examples of QD-ABS charge stability diagrams, used to calibrate the interdot interactions following the procedure detailed in^34,36. The discrepancies in the plunger gate voltages used for each orbital between (a-c) and (j-m) arise due to gate-jumps and cross-talk between neighbouring barrier gates.