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arXiv · 1809.02999

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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Abstract

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.

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Jiyong Park, Jaehak Lee, Kyunghyun Baek, Se-Wan Ji, Hyunchul Nha. 2019-07-25. Faithful measure of Quantum non-Gaussianity via quantum relative entropy. https://doi.org/10.1103/physreva.100.012333

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