English

Large deviation principle for the largest eigenvalue of random matrices with a variance profile

Probability 2024-03-25 v2

Abstract

We establish large deviation principles for the largest eigenvalue of large random matrices with variance profiles. For NNN \in \mathbb N, we consider random N×NN \times N symmetric matrices HNH^N which are such that HijN=1NXi,jNH_{ij}^{N}=\frac{1}{\sqrt{N}}X_{i,j}^{N} for 1i,jN1 \leq i,j \leq N, where the Xi,jNX_{i,j}^{N} for 1ijN1 \leq i \leq j \leq N are independent and centered. We then denote Σi,jN=Var(Xi,jN)(1+1i=j)1\Sigma_{i,j} ^N = \text{Var} (X_{i,j}^{N}) ( 1 + \textbf{1}_{ i =j})^{-1} the variance profile of HNH^N. Our large deviation principle is then stated under the assumption that the ΣN\Sigma^N converge in a certain sense toward a real continuous function σ\sigma of [0,1]2[0,1]^2 and that the entries of HNH^N are sharp sub-Gaussian. Our rate function is expressed in terms of the solution of a Dyson equation involving σ\sigma. This result is a generalization of a previous work by the third author and is new even in the case of Gaussian entries.

Keywords

Cite

@article{arxiv.2403.05413,
  title  = {Large deviation principle for the largest eigenvalue of random matrices with a variance profile},
  author = {Raphaël Ducatez and Alice Guionnet and Jonathan Husson},
  journal= {arXiv preprint arXiv:2403.05413},
  year   = {2024}
}
R2 v1 2026-06-28T15:13:45.807Z