Christoffel functions of measures on the real line with divergent logarithmic integral

Abstract

Let $\sigma$ be a Poisson-finite measure on the real line. If its logarithmic integral diverges, then the functions from the classical Hardy space $H^2$ with compactly supported Fourier transform are dense in $L^2(\mathbb{R}, \sigma)$. We give a quantitative version of this result, adapting the ideas from the 2020 paper by Borichev, Kononova and Sodin, where a similar question was studied in the setting of polynomial approximation.