Measured qubit coherence times ({T}_{1},{T}_{2}^{* }) when the optical pulse was synchronized with each qubit preparation and readout pulse (empty circles) and for a free-running measurement sequence (filled circles) versus optical pulse repetition rate. Squares indicate the mean of the optical readout results in Fig. 3 . The decrease in T 1 and {T}_{2}^{* } was accurately modelled with theory (red and blue line with 3 σ confidence band), based on the measured thermal occupancy shown in c , the expected quasiparticle distribution and Purcell decay (red line). Data error bars show the two-sided 90% confidence interval of the mean according to a Student t distribution for five measurements (compare with Fig. 3 ).
