Fig. 4: Measured and simulated power spectral densities of the complex conductivity.
From: Recombination of localized quasiparticles in disordered superconductors
Different colors are for different bath temperatures, as indicated by the colorbar. Other noise sources, such as amplifier noise and 1/f-noise have been subtracted from the measured spectra in (a) and (b), as explained in the Supplementary Section 4. The dashed black line in (b) is an example fit using Equation (5). c, d Calculated power spectral densities for quasiparticle fluctuations at the same bath temperatures as the measurements. The quasiparticle fluctuation spectra are calculated with the framework described in ref. 28, including the localized quasiparticle dynamics described in ref. 16. The quasiparticle density fluctuations are analytically converted to σ2/∣σ∣-fluctuations. For details on the model and calculations, see Supplementary Section 6.
