Gaussian Equivalence for Self-Attention: Asymptotic Spectral Analysis of Attention Matrix

Fuente: arXiv
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Main Authors: Hayase, Tomohiro, Collins, Benoît, Karakida, Ryo
Format: Preprint
Published: 2025
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author Hayase, Tomohiro
Collins, Benoît
Karakida, Ryo
author_facet Hayase, Tomohiro
Collins, Benoît
Karakida, Ryo
contents Self-attention layers have become fundamental building blocks of modern deep neural networks, yet their theoretical understanding remains limited, particularly from the perspective of random matrix theory. In this work, we provide a rigorous analysis of the singular value spectrum of the attention matrix and establish the first Gaussian equivalence result for attention. In a natural regime where the inverse temperature remains of constant order, we show that the singular value distribution of the attention matrix is asymptotically characterized by a tractable linear model. We further demonstrate that the distribution of squared singular values deviates from the Marchenko-Pastur law, which has been believed in previous work. Our proof relies on two key ingredients: precise control of fluctuations in the normalization term and a refined linearization that leverages favorable Taylor expansions of the exponential. This analysis also identifies a threshold for linearization and elucidates why attention, despite not being an entrywise operation, admits a rigorous Gaussian equivalence in this regime.
format Preprint
id arxiv_https___arxiv_org_abs_2510_06685
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Gaussian Equivalence for Self-Attention: Asymptotic Spectral Analysis of Attention Matrix
Hayase, Tomohiro
Collins, Benoît
Karakida, Ryo
Machine Learning
Probability
Self-attention layers have become fundamental building blocks of modern deep neural networks, yet their theoretical understanding remains limited, particularly from the perspective of random matrix theory. In this work, we provide a rigorous analysis of the singular value spectrum of the attention matrix and establish the first Gaussian equivalence result for attention. In a natural regime where the inverse temperature remains of constant order, we show that the singular value distribution of the attention matrix is asymptotically characterized by a tractable linear model. We further demonstrate that the distribution of squared singular values deviates from the Marchenko-Pastur law, which has been believed in previous work. Our proof relies on two key ingredients: precise control of fluctuations in the normalization term and a refined linearization that leverages favorable Taylor expansions of the exponential. This analysis also identifies a threshold for linearization and elucidates why attention, despite not being an entrywise operation, admits a rigorous Gaussian equivalence in this regime.
title Gaussian Equivalence for Self-Attention: Asymptotic Spectral Analysis of Attention Matrix
topic Machine Learning
Probability
url https://arxiv.org/abs/2510.06685