Extraction of spectral densities from lattice correlators: decoupling signal from noise

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Main Authors: Lupo, Alessandro, Tantalo, Nazario
Format: Preprint
Published: 2026
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author Lupo, Alessandro
Tantalo, Nazario
author_facet Lupo, Alessandro
Tantalo, Nazario
contents We expand the treatment of the problem of the extraction of smeared spectral densities from Euclidean correlators introduced in [Phys. Rev. D 99, 094508], providing an alternative which does not rely on the Backus-Gilbert regularization. This is possible due to the observation that the solution can be decomposed into a sum of terms, in the spirit of the singular value decomposition, where those with the largest contribution to the statistical noise happen to contribute the least to the central value of the smeared spectral density. The analysis of the systematics of the inverse problem is then shifted to finding the optimal truncation of such summation, so that the signal is saturated before the noise explodes. We scrutinise the performance and systematics of this approach either as a standalone procedure, or to complement the stability analysis required to extrapolate the unbiased result in the Backus-Gilbert regulated version of the solution.
format Preprint
id arxiv_https___arxiv_org_abs_2605_14652
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Extraction of spectral densities from lattice correlators: decoupling signal from noise
Lupo, Alessandro
Tantalo, Nazario
High Energy Physics - Lattice
We expand the treatment of the problem of the extraction of smeared spectral densities from Euclidean correlators introduced in [Phys. Rev. D 99, 094508], providing an alternative which does not rely on the Backus-Gilbert regularization. This is possible due to the observation that the solution can be decomposed into a sum of terms, in the spirit of the singular value decomposition, where those with the largest contribution to the statistical noise happen to contribute the least to the central value of the smeared spectral density. The analysis of the systematics of the inverse problem is then shifted to finding the optimal truncation of such summation, so that the signal is saturated before the noise explodes. We scrutinise the performance and systematics of this approach either as a standalone procedure, or to complement the stability analysis required to extrapolate the unbiased result in the Backus-Gilbert regulated version of the solution.
title Extraction of spectral densities from lattice correlators: decoupling signal from noise
topic High Energy Physics - Lattice
url https://arxiv.org/abs/2605.14652