When Independent Gaussian Models Break Down: Characterizing Regime-Dependent Modeling Failures in $ϕ^4$ Theory

Fuente: arXiv
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Main Authors: Bhat, Anish, Ide, Ryo, Zhao, Zihan
Format: Preprint
Published: 2026
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author Bhat, Anish
Ide, Ryo
Zhao, Zihan
author_facet Bhat, Anish
Ide, Ryo
Zhao, Zihan
contents In practical physical systems, modeling assumptions of Gaussianity and basis independence break down due to self-interactions. We study a specific instance of one-dimensional $ϕ^4$ theory on a lattice, analyzing how the interaction strength and system size jointly affect the marginal and joint distributions of frequency-based representation of the field (i.e., Fourier modes). We find that models relying on Gaussian and independent Fourier modes fail primarily from structured dependencies rather than marginal non-Gaussianity, since individual modes become approximately Gaussian despite mode coupling growing with size. Based on this, we identify three distinct regimes that delineate where traditional methods remain effective and where more expressive models are needed. Our results provide a computationally simple diagnostic to establish when Gaussian models are insufficient, and establish a concrete design criterion that future nonlinear models must satisfy.
format Preprint
id arxiv_https___arxiv_org_abs_2605_01145
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle When Independent Gaussian Models Break Down: Characterizing Regime-Dependent Modeling Failures in $ϕ^4$ Theory
Bhat, Anish
Ide, Ryo
Zhao, Zihan
Statistical Mechanics
High Energy Physics - Lattice
In practical physical systems, modeling assumptions of Gaussianity and basis independence break down due to self-interactions. We study a specific instance of one-dimensional $ϕ^4$ theory on a lattice, analyzing how the interaction strength and system size jointly affect the marginal and joint distributions of frequency-based representation of the field (i.e., Fourier modes). We find that models relying on Gaussian and independent Fourier modes fail primarily from structured dependencies rather than marginal non-Gaussianity, since individual modes become approximately Gaussian despite mode coupling growing with size. Based on this, we identify three distinct regimes that delineate where traditional methods remain effective and where more expressive models are needed. Our results provide a computationally simple diagnostic to establish when Gaussian models are insufficient, and establish a concrete design criterion that future nonlinear models must satisfy.
title When Independent Gaussian Models Break Down: Characterizing Regime-Dependent Modeling Failures in $ϕ^4$ Theory
topic Statistical Mechanics
High Energy Physics - Lattice
url https://arxiv.org/abs/2605.01145