Fig. 2: Qubit coherence time characterization.
From: Path toward manufacturable superconducting qubits with relaxation times exceeding 0.1 ms
a Qubit population (device C1) during typical decay time measurements. Line fits are shown for the qubit’s lifetime T1 = 59.6 ± 1.4. µs, and coherence times T2* = 63.8 ± 3.9 µs (Ramsey) and T2e = 59.3 ± 2.0 µs (spin-echo). b Fluctuation of the qubit’s energy relaxation time for a period of 11 h (device D1). Error bars represent the T1 SD from the line fit. c Qubit T1-statistics for several transmon devices, grouped for different process variations. Device names are shown on top. A violin plot is used to visualize the distributions and white dots indicate the mean value. Black bars mark the first and third quartile. Within the measurement uncertainty, no conclusive difference between etch processes and wafers resistivities is observed. d Inverse device quality factors (data is corrected for Purcell decay) as a function of MA surface participation ratio. Device types are shown on top. The gray area represents the 95% confidence bounds of the fit to the qubit data. Markers denote the mean Q-factor for each device. Error bars indicate the population’s SD (or the fit’s SD in case of single measurements). Upward and downward empty triangles depict wet and dry-etched RES devices, respectively. RES data reaffirms that both etch processes result in comparable device performance. Device details are presented in Supplementary Table 1.
