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

TL;DR

This paper derives precise large $n$ asymptotics for determinants with rotation-invariant weights and discontinuities along circles, extending results for the complex Ginibre process and analyzing cumulants of disk counting statistics.

Contribution

It provides the first detailed asymptotic analysis of such determinants with multiple discontinuities, including at the bulk and edge, using novel asymptotics of the incomplete gamma function.

Findings

Asymptotics of determinants with discontinuities along circles obtained.

Large $n$ asymptotics of cumulants of disk counting function derived.

Results extend and improve upon known results for the complex Ginibre process.

Abstract

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 finite number of discontinuities in the bulk, one discontinuity at the edge, and any finite 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.