Universality of the convergence rate for spectral radius of complex IID random matrices

Abstract

Let $X$ be an $n\times n$ matrix with independent and identically distributed entries $x_{ij} \stackrel{\text { d }}{=} n^{-1 / 2} x$ for some complex random variable $x$ of mean zero and variance one. Let $\{\sigma_i\}_{1\le i\le n}$ be the eigenvalues of $X$ and let $|\sigma_1|:=\max_{1\le i\le n}|\sigma_i|$ be the spectral radius. Set $Y_n=\sqrt{4 n \gamma_n}\left[|\sigma_1|-1-\sqrt{\frac{\gamma_n}{4 n}}\right],$ where $\gamma_{n}=\log{n}-2\log{\log{n}}-\log{2\pi}.$ As established in \cite{Cipolloni23Universality}, with specific moment-related conditions imposed on $x,$ the Gumbel distribution $\Lambda$ is identified as the universal weak limit of $Y_n.$ Subsequently, we extend this line of research and rigorously prove that the convergence rate, previously obtained for complex Ginibre ensembles in \cite{MaMeng25}, also possesses the property of universality. Precisely, one gets $$\sup_{x\in \mathbb{R}}|\mathbb{P}(Y_n \leq x)-e^{-e^{-x}}|=\frac{2\log\log n}{e\log n}(1+o(1))$$ and $$W_1\left(\mathcal{L}(Y_n), \Lambda\right)=\frac{2\log\log n}{\log n}(1+o(1))$$ for sufficiently large $n$, where $\mathcal{L}(Y_n)$ is the distribution of $Y_n$.