Fisher information approximation of random orthogonal matrices by Gaussian matrices

Fuente: arXiv
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Main Authors: Chen, Yutong, Ma, Yutao, Xie, Shuhong, Yao, Zhuoya
Format: Preprint
Published: 2025
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author Chen, Yutong
Ma, Yutao
Xie, Shuhong
Yao, Zhuoya
author_facet Chen, Yutong
Ma, Yutao
Xie, Shuhong
Yao, Zhuoya
contents Let $Γ_n$ be an $n\times n$ Haar-invariant orthogonal matrix. Let ${ Z}_n$ be the $p\times q$ upper-left submatrix of $Γ_n$ and ${G}_n$ be a $p\times q$ matrix whose $pq$ entries are independent standard normals, where $p$ and $q$ are two positive integers. Let $\mathcal{L}(\sqrt{n} {Z}_n)$ and $\mathcal{L}({G}_n)$ be their joint distribution, respectively. Consider the Fisher information $I(\mathcal{L}(\sqrt{n} { Z}_n)|\mathcal{L}(G_n))$ between the distributions of $\sqrt{n} {Z}_n$ and ${ G}_n.$ In this paper, we conclude that $$I(\mathcal{L}(\sqrt{n} {Z}_n)|\mathcal{L}(G_n))\longrightarrow 0 $$ as $n\to\infty$ if $pq=o(n)$ and it does not tend to zero if $c=\lim\limits_{n\to\infty}\frac{pq}{n}\in(0, +\infty).$ Precisely, we obtain that $$I(\mathcal{L}(\sqrt{n} {Z}_n)|\mathcal{L}(G_n))=\frac{p^2q(q+1)}{4n^2}(1+o(1))$$ when $p=o(n).$
format Preprint
id arxiv_https___arxiv_org_abs_2504_10887
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fisher information approximation of random orthogonal matrices by Gaussian matrices
Chen, Yutong
Ma, Yutao
Xie, Shuhong
Yao, Zhuoya
Probability
60B20, 62B10, 62E17, 15B52
Let $Γ_n$ be an $n\times n$ Haar-invariant orthogonal matrix. Let ${ Z}_n$ be the $p\times q$ upper-left submatrix of $Γ_n$ and ${G}_n$ be a $p\times q$ matrix whose $pq$ entries are independent standard normals, where $p$ and $q$ are two positive integers. Let $\mathcal{L}(\sqrt{n} {Z}_n)$ and $\mathcal{L}({G}_n)$ be their joint distribution, respectively. Consider the Fisher information $I(\mathcal{L}(\sqrt{n} { Z}_n)|\mathcal{L}(G_n))$ between the distributions of $\sqrt{n} {Z}_n$ and ${ G}_n.$ In this paper, we conclude that $$I(\mathcal{L}(\sqrt{n} {Z}_n)|\mathcal{L}(G_n))\longrightarrow 0 $$ as $n\to\infty$ if $pq=o(n)$ and it does not tend to zero if $c=\lim\limits_{n\to\infty}\frac{pq}{n}\in(0, +\infty).$ Precisely, we obtain that $$I(\mathcal{L}(\sqrt{n} {Z}_n)|\mathcal{L}(G_n))=\frac{p^2q(q+1)}{4n^2}(1+o(1))$$ when $p=o(n).$
title Fisher information approximation of random orthogonal matrices by Gaussian matrices
topic Probability
60B20, 62B10, 62E17, 15B52
url https://arxiv.org/abs/2504.10887