Faithful measure of quantum non-Gaussianity via quantum relative entropy

Jiyong Park, Jaehak Lee, Kyunghyun Baek, Se Wan Ji, Hyunchul Nha

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2 Citations (Scopus)


We introduce a measure of quantum non-Gaussianity (QNG) for those quantum states not accessible by a mixture of Gaussian states in terms of quantum relative entropy. Specifically, we employ a convex-roof extension using all possible mixed-state decompositions beyond the usual pure-state decompositions. We prove that this approach brings a QNG measure fulfilling the properties desired as a proper monotone under Gaussian channels and conditional Gaussian operations. As an illustration, we explicitly calculate QNG for the noisy single-photon states and demonstrate that QNG coincides with non-Gaussianity of the state itself when the single-photon fraction is sufficiently large.

Original languageEnglish
Article number012333
JournalPhysical Review A
Issue number1
Publication statusPublished - 23 Jul 2019


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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