A REANALYSIS OF EXPERIMENTAL HIGH-FREQUENCY SPECTRA USING PERIODIC ORBIT THEORY

The data, obtained [R. L. Weaver, J. Acoust. Soc. Am. 85, 1001 (1989)] on high eigenfrequencies of small aluminum blocks, is reanalyzed usin g improved fitting procedures. If the results are quantitatively diffe rent from those published previously, they do not significantly modify the main conclusion that fluctuations of the spectrum on a small scal e (involving a few mean eigenfrequency spacings) are well described by the model of Gaussian orthogonal ensemble (GOE) of random matrices. I n addition, it is shown that, on a larger scale, the spectrum is corre lated due to the existence of periodic classical ray trajectories. In other words, the large scale oscillations of the spectrum yield inform ation on the size and shape of the aluminum blocks.