Fig. 4
Dispersion and decoherence. a The dispersion extracted from the transconductance data in Fig. 3a: The points are the frequencies extracted by applying a decaying sinusoidal fit to each cut in ε p. The background is the magnitude of the power spectral density of those same cuts, calculated using Welsh’s method. b The extracted values of the decay time from the sinusoidal fit: This value is actually a lower bound on phase decoherence time \(T_2^*\). The decay time increases rapidly at first and then begins to decrease. The longest value directly observed is 1.5 ns. The height of the lines in both a and b indicates the 1.5-σ standard errors derived from the numerically estimated covariance matrix
