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Main Authors: Rácz, Éva, Ruppert, László, Filip, Radim
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.20492
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author Rácz, Éva
Ruppert, László
Filip, Radim
author_facet Rácz, Éva
Ruppert, László
Filip, Radim
contents Direct measurement of quantum non-Gaussianity requires some variant of a discrete photon-resolving detection, which is feasible only for low mean photon numbers. For a large mean photon number, intensity detection by linear photodiodes provides a continuous signal; therefore, the Fock probabilities of the unknown input state are not directly available. On the other hand, intensity moments can be measured directly, and photon-number moments can be estimated. Therefore, we derive and analyze a quantum non-Gaussianity witness based solely on the photon number mean and variance (or alternatively, the second-order correlation $g^{(2)}$) of an unknown state. Due to the simplicity of the used photon-number moments, the measurement results are easy to correct for losses and additive noise. We provide examples of simple amplification-based measurement schemes where our witness can be applied directly, thereby opening pathways to proof-of-principle tests and applications.
format Preprint
id arxiv_https___arxiv_org_abs_2509_20492
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Witnessing quantum non-Gaussianity from intensity moments
Rácz, Éva
Ruppert, László
Filip, Radim
Quantum Physics
Direct measurement of quantum non-Gaussianity requires some variant of a discrete photon-resolving detection, which is feasible only for low mean photon numbers. For a large mean photon number, intensity detection by linear photodiodes provides a continuous signal; therefore, the Fock probabilities of the unknown input state are not directly available. On the other hand, intensity moments can be measured directly, and photon-number moments can be estimated. Therefore, we derive and analyze a quantum non-Gaussianity witness based solely on the photon number mean and variance (or alternatively, the second-order correlation $g^{(2)}$) of an unknown state. Due to the simplicity of the used photon-number moments, the measurement results are easy to correct for losses and additive noise. We provide examples of simple amplification-based measurement schemes where our witness can be applied directly, thereby opening pathways to proof-of-principle tests and applications.
title Witnessing quantum non-Gaussianity from intensity moments
topic Quantum Physics
url https://arxiv.org/abs/2509.20492