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Quantum 2.0 Conference and Exhibition

Experimentally verifiable criteria of non-Gaussian coherences

Ambroise Boyer, Beate E. Asenbeck, Lukáš Lachman, Priyanka Giri, Albane Lapras, Alban Urvoy, Radim Filip, Julien Laurat

Published Jan 1, 2025• 0 citations
Publisher

Abstract

We introduce a hierarchical framework using absolute, relative, and qubit-specific thresholds assessing non-Gaussianity and non-classicality in local coherences. We generate high purity superpositions of 1- and 2-photons with vacuum that surpass the specified criteria.
DOI
10.1364/quantum.2025.qm3b.8

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The algebraic quantification of nonclassicality, which naturally arises from the quantum superposition principle, is related to properties of regular nonclassicality quasiprobabilities. The latter are obtained by non-Gaussian filtering of the Glauber-Sudarshan PPP function. They yield lower bounds for the degree of nonclassicality. We also derive bounds for convex combinations of Gaussian states for certifying quantum non-Gaussianity directly from the experimentally accessible nonclassicality quasiprobabilities. Other quantum-state representations, such as sss-parametrized quasiprobabilities, insufficiently indicate or even fail to directly uncover detailed information on the properties of quantum states. As an example, our approach is applied to multi-photon-added squeezed vacuum states.