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Auteurs principaux: Castaldo, Davide, Corni, Stefano
Format: Preprint
Publié: 2025
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Accès en ligne:https://arxiv.org/abs/2507.12438
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author Castaldo, Davide
Corni, Stefano
author_facet Castaldo, Davide
Corni, Stefano
contents Quantum phase estimation is the flagship algorithm for quantum simulation on fault-tolerant quantum computers. We demonstrate that an \emph{off-grid} compressed sensing protocol, combined with a state-of-the-art signal classification method, enables the simultaneous estimation of multiple eigenvalues of a unitary matrix using the Hadamard test while sampling only a few percent of the full autocorrelation function. Our numerical evidence indicates that the proposed algorithm achieves the Heisenberg limit in both strongly and weakly correlated regimes and requires very short evolution times to obtain an $ε$-accurate estimate of multiple eigenvalues at once. Additionally -- and of independent interest -- we develop a modified off-grid protocol that leverages prior knowledge of the underlying signal for faster and more accurate recovery. Finally, we argue that this algorithm may offer a potential quantum advantage by analyzing its resilience with respect to the quality of the initial input state.
format Preprint
id arxiv_https___arxiv_org_abs_2507_12438
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Heisenberg limited multiple eigenvalue estimation via off-the-grid compressed sensing
Castaldo, Davide
Corni, Stefano
Quantum Physics
Quantum phase estimation is the flagship algorithm for quantum simulation on fault-tolerant quantum computers. We demonstrate that an \emph{off-grid} compressed sensing protocol, combined with a state-of-the-art signal classification method, enables the simultaneous estimation of multiple eigenvalues of a unitary matrix using the Hadamard test while sampling only a few percent of the full autocorrelation function. Our numerical evidence indicates that the proposed algorithm achieves the Heisenberg limit in both strongly and weakly correlated regimes and requires very short evolution times to obtain an $ε$-accurate estimate of multiple eigenvalues at once. Additionally -- and of independent interest -- we develop a modified off-grid protocol that leverages prior knowledge of the underlying signal for faster and more accurate recovery. Finally, we argue that this algorithm may offer a potential quantum advantage by analyzing its resilience with respect to the quality of the initial input state.
title Heisenberg limited multiple eigenvalue estimation via off-the-grid compressed sensing
topic Quantum Physics
url https://arxiv.org/abs/2507.12438