Coherent sequences of matrix spectra

Abstract

We attach sequences of matrix spectra to sequences of rational numbers and study them with numerical experiments. The initial segments of the spectrum sequences associated to each of several rational sequences appear to exhibit geometric regularities. Identities originating in the theory of symmetric functions express members of arithmetic sequences $\{h_n{\}}_{n\ge 0}(h_0=1)$ as $h_n=|J_{h,n}|/n!$ for particular matrices $J_{h,n}$, where $|\cdot |$ is the determinant. In this setting we studied numerically sequences $\{a(n){\}}_{n\ge 1}$ obtained from the Fourier expansions of cusp forms. Within the range of our observations, the sequences of spectra of certain "treated" matrices $\{J_{a,n}^{(c)}{\}}_{n=1,2,3,...}$ exhibit coherent behavior, meaning that the plots of the minimum moduli among the eigenvalues of the $J_{a,n}^{(c)}$ appear to oscillate or to form approximately straight lines of non-negative slope once $n$ is large enough.

22 figures, 10 tables