Extended Data Fig. 6: Conductance spectra for ϕ_Δ between 0 and π.

In the main text, Fig. 3 shows measurements of conductance spectra at a three-site sweet spot, obtained at two B_z values corresponding to ϕ_Δ = 0 and ϕ_Δ = π. The ability to control the flux allows us to perform such measurements at any intermediate value of ϕ_Δ. a. RF-spectroscopy measurements of \({{\rm{S}}}_{21}^{{\rm{R}}}\) and corresponding numerical simulations, upon detuning V_QDL, for seven values of B_z corresponding to ϕ_Δ = 0 and ϕ_Δ = π. The experimental evolution corresponds well to the numerical simulation at each stage. Recent work on a three-site Kitaev chain with two separately grounded SCs²⁴ concludes that a small voltage difference between the SCs (on the order of μV) may give rise to rapid phase oscillations. Hence, it is assumed their (slow) measurements reflect an average over many periods of ϕ_Δ. b. Shows averaged RF-spectroscopy for 25 measurements in the same range as (a), and the corresponding numerically averaged simulation, finding good agreement with the reported behaviour in²⁴.