Fig. 4: Frequency and power dependence of conductance replicas.
From: Microwave-induced conductance replicas in hybrid Josephson junctions without Floquet—Andreev states
a Linecuts of conductance from Fig. 2, after subtraction of a slowly varying background. Traces are successively offset by 0.05G0. Dashed lines mark the expected peak positions. Linecuts are taken at P = 1.5, 4.5, 4, and 4.5 dBm, respectively. b Spacing of conductance replicas measured at finite (circles) and close to zero (squares) bias. Dashed and dotted lines represent the equations ΔVSD = hf/e and ΔVSD = hf/2e, respectively. Filled and empty grey markers refer to additional data collected on the same device and on a second device, respectively (see Supplementary Notes 8 and 9). c Conductance at a top-gate voltage VTG = − 1.4 V, as a function of microwave (MW) source power for irradiation frequency f2 = 7.20 GHz. Blue lines indicate a MW coupling strength of α0 = 3.0, identical to Fig. 2c, h. Yellow lines indicate a coupling strength α0 = 2.25, reduced by 25% with respect to Fig. 2c, h. Blue (yellow) lines show the expectation for photon assisted tunnelling (Floquet–Andreev states). d Conductance of the first seven replicas in Fig. 2i, taken at constant bias VSD (circles), alongside the simulated conductance from a photon assisted tunnelling model (lines, see Supplementary Figs. 3–5). Inset shows the sum S of conductance features in Fig. 2i over positive (blue) and negative (grey) bias. Data is shown for the range of powers where all conductance replicas are within the measured bias range.
