A Paley-Wiener Type Theorem for Singular Measures on $\mathbb{T}$

Abstract

For a fixed singular Borel probability measure $\mu$ on $\mathbb{T}$, we give several characterizations of when an entire function is the Fourier transform of some $f\in L^2(\mu )$. The first characterization is given in terms of criteria for sampling functions of the form $\hat{f}$ when $f\in L^2(\mu )$. The second characterization is given in terms of criteria for interpolation of bounded sequences on ${\mathbb{N}}_0$ by $\hat{f}$. Both characterizations use the construction of Fourier series for $f\in L^2(\mu )$ demonstrated in Herr and Weber via the Kaczmarz algorithm and classical results concerning the Cauchy transform of $\mu$.