The Infinite-Dimensional Nature of Spectroscopy and Why Models Succeed, Fail, and Mislead

Fuente: arXiv
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Main Authors: Michelucci, Umberto, Venturini, Francesca
Format: Preprint
Published: 2026
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author Michelucci, Umberto
Venturini, Francesca
author_facet Michelucci, Umberto
Venturini, Francesca
contents Machine learning (ML) models have achieved strikingly high accuracies in spectroscopic classification tasks, often without a clear proof that those models used chemically meaningful features. Existing studies have linked these results to data preprocessing choices, noise sensitivity, and model complexity, but no unifying explanation is available so far. In this work, we show that these phenomena arise naturally from the intrinsic high dimensionality of spectral data. Using a theoretical analysis grounded in the Feldman-Hajek theorem and the concentration of measure, we show that even infinitesimal distributional differences, caused by noise, normalisation, or instrumental artefacts, may become perfectly separable in high-dimensional spaces. Through a series of specific experiments on synthetic and real fluorescence spectra, we illustrate how models can achieve near-perfect accuracy even when chemical distinctions are absent, and why feature-importance maps may highlight spectrally irrelevant regions. We provide a rigorous theoretical framework, confirm the effect experimentally, and conclude with practical recommendations for building and interpreting ML models in spectroscopy.
format Preprint
id arxiv_https___arxiv_org_abs_2604_04717
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Infinite-Dimensional Nature of Spectroscopy and Why Models Succeed, Fail, and Mislead
Michelucci, Umberto
Venturini, Francesca
Machine Learning
Materials Science
Artificial Intelligence
Machine learning (ML) models have achieved strikingly high accuracies in spectroscopic classification tasks, often without a clear proof that those models used chemically meaningful features. Existing studies have linked these results to data preprocessing choices, noise sensitivity, and model complexity, but no unifying explanation is available so far. In this work, we show that these phenomena arise naturally from the intrinsic high dimensionality of spectral data. Using a theoretical analysis grounded in the Feldman-Hajek theorem and the concentration of measure, we show that even infinitesimal distributional differences, caused by noise, normalisation, or instrumental artefacts, may become perfectly separable in high-dimensional spaces. Through a series of specific experiments on synthetic and real fluorescence spectra, we illustrate how models can achieve near-perfect accuracy even when chemical distinctions are absent, and why feature-importance maps may highlight spectrally irrelevant regions. We provide a rigorous theoretical framework, confirm the effect experimentally, and conclude with practical recommendations for building and interpreting ML models in spectroscopy.
title The Infinite-Dimensional Nature of Spectroscopy and Why Models Succeed, Fail, and Mislead
topic Machine Learning
Materials Science
Artificial Intelligence
url https://arxiv.org/abs/2604.04717