Extended Data Fig. 6: Coherence of qubit 2.
a, CPMG-curve for qubit 2 for n = 20. Fitting this curve, as described in the methods, gives \(T_{2,CPMG}=1.2\pm 0.2\) ms. b, Analogously to the case of qubit 1 (see main text), we demodulate and normalise the CPMG amplitude as a function of evolution time for different numbers of \(\pi\) pulses, giving the CPMG amplitude. c, The measured CPMG decay time as a function of the number of \(\pi\)-pulses. The orange line represents a fit through the data (excluding n = 1) following \(T_2^{{{\mathrm{CPMG}}}}\propto n^{(\gamma/(\gamma + 1))}\). We extract \(\gamma=1.51\pm0.15\). Performing a similar analysis as has been done for qubit 1 (see Supplementary Information, Fig. 16) gives unreliable results.
