Measuring non-Gaussianity with Correlation

Fuente: arXiv
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Main Authors: Hahn, Oliver, Takagi, Ryuji
Format: Preprint
Published: 2025
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author Hahn, Oliver
Takagi, Ryuji
author_facet Hahn, Oliver
Takagi, Ryuji
contents Quantum non-Gaussianity is a key resource for quantum advantage in continuous-variable systems. We introduce a general framework to quantify non-Gaussianity based on correlation generation: two copies of a state become correlated at a $50{:}50$ beam splitter if and only if the state is non-Gaussian, with correlations reducing to entanglement in the pure-state case. This connection enables operational measures of non-Gaussianity, defined through correlation quantifiers such as Rényi-$α$ entropy for pure states and Rényi-$α$ mutual information for mixed states. We prove that all such measures are monotonic under Gaussian channels. Building on this framework, we propose a sample-efficient experimental protocol to estimate non-Gaussianity using standard optical components, even in the state agnostic setting. Finally, we establish a lower bound on the sample complexity of estimating Wigner negativity, allowing a direct comparison with our protocol. Our results provide both a unifying theoretical framework for non-Gaussianity and a practical route toward its experimental quantification.
format Preprint
id arxiv_https___arxiv_org_abs_2508_19890
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Measuring non-Gaussianity with Correlation
Hahn, Oliver
Takagi, Ryuji
Quantum Physics
Quantum non-Gaussianity is a key resource for quantum advantage in continuous-variable systems. We introduce a general framework to quantify non-Gaussianity based on correlation generation: two copies of a state become correlated at a $50{:}50$ beam splitter if and only if the state is non-Gaussian, with correlations reducing to entanglement in the pure-state case. This connection enables operational measures of non-Gaussianity, defined through correlation quantifiers such as Rényi-$α$ entropy for pure states and Rényi-$α$ mutual information for mixed states. We prove that all such measures are monotonic under Gaussian channels. Building on this framework, we propose a sample-efficient experimental protocol to estimate non-Gaussianity using standard optical components, even in the state agnostic setting. Finally, we establish a lower bound on the sample complexity of estimating Wigner negativity, allowing a direct comparison with our protocol. Our results provide both a unifying theoretical framework for non-Gaussianity and a practical route toward its experimental quantification.
title Measuring non-Gaussianity with Correlation
topic Quantum Physics
url https://arxiv.org/abs/2508.19890