Hard edge asymptotics of correlation functions between singular values and eigenvalues
Abstract
Any square complex matrix of size can be partially characterized by its eigenvalues and/or singular values. While no one-to-one correspondence exists between those two kinds of values on a deterministic level, for random complex matrices drawn from a bi-unitarily invariant ensemble, a bijection exists between the underlying singular value ensemble and the corresponding eigenvalue ensemble. This enabled the recent finding of an explicit formula for the joint probability density between eigenvalue and singular values, coined -point function. We derive here the large asymptotic of the -point function around the origin (hard edge) for a large subclass of bi-unitarily invariant ensembles called polynomial ensembles and its subclass P\'olya ensembles. This latter subclass contains all Meijer-G ensembles and, in particular, Muttalib-Borodin ensembles and the classical Wishart-Laguerre (complex Ginibre), Jacobi (truncated unitary), Cauchy-Lorentz ensembles. We show that the latter three ensembles share the same asymptotic of the -point function around the origin. In the case of Jacobi ensembles, there exists another hard edge for the singular values, namely the upper edge of their support, which corresponds to a soft edge for the eigenvalue (soft-hard edge). We give the explicit large asymptotic of the -point function around this soft-hard edge.
Keywords
Cite
@article{arxiv.2501.15765,
title = {Hard edge asymptotics of correlation functions between singular values and eigenvalues},
author = {Matthias Allard},
journal= {arXiv preprint arXiv:2501.15765},
year = {2025}
}
Comments
Results remain unchanged. This version includes minor revisions, corrections, and additional comments compared to the published version. 44 pages, 1 figure, 1 appendix