Asymptotics of determinants with a rotation-invariant weight and discontinuities along circles

Christophe Charlier

Published 2021-09-08Version 1

We study the moment generating function of the disk counting statistics of a two-dimensional determinantal point process which generalizes the complex Ginibre point process. This moment generating function involves an $n \times n$ determinant whose weight is supported on the whole complex plane, is rotation-invariant, and has discontinuities along circles centered at $0$. These discontinuities can be thought of as a two-dimensional analogue of jump-type Fisher-Hartwig singularities. In this paper, we obtain large $n$ asymptotics for this determinant, up to and including the term of order $n^{-\smash{\frac{1}{2}}}$. We allow for any number of discontinuities in the bulk, one discontinuity at the edge, and any number of discontinuities bounded away from the bulk. As an application, we obtain the large $n$ asymptotics of all the cumulants of the disk counting function up to and including the term of order $n^{-\smash{\frac{1}{2}}}$, both in the bulk and at the edge. This improves on the best known results for the complex Ginibre point process, and for general values of our parameters these results are completely new. Our proof makes a novel use of the uniform asymptotics of the incomplete gamma function.