中国物理B ›› 2022, Vol. 31 ›› Issue (3): 30306-030306.doi: 10.1088/1674-1056/ac1928
Cheng Xiang(向成)1,2, Shan-Shan Li(李珊珊)1,2, Sha-Sha Wen(文莎莎)1,2, and Shao-Hua Xiang(向少华)1,2,†
Cheng Xiang(向成)1,2, Shan-Shan Li(李珊珊)1,2, Sha-Sha Wen(文莎莎)1,2, and Shao-Hua Xiang(向少华)1,2,†
摘要: We propose three alternative measures for non-Gaussianity of quantum states: sine distance, Bures angle, and Bures distance, which are based on quantum fidelity introduced by Wang [Phys. Lett. A 373 58 (2008)]. Using them, we evaluate the non-Gaussianity of some relevant single-mode and two-mode non-Gaussian states and find a good consistency of the three examined measures. In addition, we show that such metrics can exactly quantify the degree of Gaussianity of even Schrödinger-cat-like states of small amplitudes that can not be measured by other known non-Gaussianity measures such as the Hilbert—Schmidt metric and the relative entropy metric. We make a comparative study between all existing non-Gaussianity measures according to the metric axioms and point out that the sine distance is the best candidate among them.
中图分类号: (Entanglement measures, witnesses, and other characterizations)