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arXiv:1909.10534 · Physical Review Letters

Phase-Space Inequalities Beyond Negativities

Martin Bohmann, Elizabeth Agudelo

Published Mar 31, 2020• 37 citations
arXivHTMLPDF

Abstract

We derive a family of inequalities involving different phase-space distributions of a quantum state which have to be fulfilled by any classical state. The violation of these inequalities is a clear signature of nonclassicality. Our approach combines the characterization of nonclassical effects via negativities in phase-space distributions with inequality conditions usually being formulated for moments of physical observables. Importantly, the obtained criteria certify nonclassicality even when the involved phase-space distributions are non-negative. Moreover, we show how these inequalities are related to correlation measurements. The strength of the derived conditions is demonstrated by different examples, including squeezed states, lossy single-photon states, and even coherent states.

DOI
10.1103/physrevlett.124.133601

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