English

Outlier eigenvalues for full rank deformed single ring random matrices

Probability 2025-04-30 v2 Operator Algebras

Abstract

Let AnA_n be an n×nn \times n deterministic matrix and Σn\Sigma_n be a deterministic non-negative matrix such that AnA_n and Σn\Sigma_n converge in *-moments to operators aa and Σ\Sigma respectively in some WW^*-probability space. We consider the full rank deformed model An+UnΣnVn,A_n + U_n \Sigma_n V_n, where UnU_n and VnV_n are independent Haar-distributed random unitary matrices. In this paper, we investigate the eigenvalues of An+UnΣnVnA_n + U_n\Sigma_n V_n in two domains that are outside the support of the Brown measure of a+uΣa +u \Sigma. We give a sufficient condition to guarantee that outliers are stable in one domain, and we also prove that there are no outliers in the other domain. When AnA_n has a bounded rank, the first domain is exactly the one outside the outer boundary of the single ring, and the second domain is the inner disk of the single ring. Our results generalize the results of Benaych-Georges and Rochet (Probab. Theory Relat. Fields, 2016).

Keywords

Cite

@article{arxiv.2502.10796,
  title  = {Outlier eigenvalues for full rank deformed single ring random matrices},
  author = {Ching-Wei Ho and Zhi Yin and Ping Zhong},
  journal= {arXiv preprint arXiv:2502.10796},
  year   = {2025}
}
R2 v1 2026-06-28T21:45:28.564Z