Faithful measure of quantum non-Gaussianity via quantum relative entropy Academic Article uri icon


  • 2019 American Physical Society. 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.

published proceedings


altmetric score

  • 0.75

author list (cited authors)

  • Park, J., Lee, J., Baek, K., Ji, S., & Nha, H.

citation count

  • 10

complete list of authors

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

publication date

  • July 2019