Measurement of parametric correlations in spectra of resonating quartz blocks

Random matrix theory predicts parametric correlations for chaotic or disord ered systems which are as universal as their spectral counterparts. However , an experimental verification of parametric correlations is, in the vast m ajority of systems, a difficult task, because the motion of individual leve ls has to be followed as an external parameter is varied. We present the fi rst statistically highly significant result for a parametric correlator tha t uses solely experimental information. To this end, we measure the motion of acoustic resonances in quartz blocks as a function of its uniform temper ature. We find some deviation between theoretical prediction and experiment al results whose possible origin is discussed.