Unitary equivalence to a truncated Toeplitz operator: analytic symbols

Unlike Toeplitz operators on \(H^2\), truncated Toeplitz operators do not have a natural matricial characterization. Consequently, these operators are difficult to study numerically. In this note we provide criteria for a matrix with distinct eigenvalues to be unitarily equivalent to a truncated Toeplitz operator having an analytic symbol. This test is constructive and we illustrate it with several examples. As a byproduct, we also prove that every complex symmetric operator on a Hilbert space of dimension \(\leq 3\) is unitarily equivalent to a direct sum of truncated Toeplitz operators.