Anomaly of the Nonergodicity Parameter and Crossover to White Noise in the Fast Relaxation Spectrum of a Simple Glass Former

We present quasielastic light scattering and dielectric spectra of the glass former $\alpha$-picoline. At high temperatures the evolution of the susceptibility minimum is well described by the mode coupling theory (MCT). Below the critical temperature $T_{\mathrm{c}}$ the simple scaling laws of MCT fail due to the appearance of the excess wing of the $\alpha$ process, which shows a universal evolution as a function of ${log}_{10}{\tau }_{\alpha }$. Taking this into account, however, we observe the predicted cusplike anomaly of the nonergodicity parameter as well as a crossover to “white noise.”