Fernando Galve \emph{et al.} [Phys.Rev.Lett.110,010501(2013)] introduced discording power for a two-qubit unitary gate to evaluate its capability to produce quantum discord, and found that a π/8 gate has maximal discording power. This work analyzes the entangling power of a two-qubit unitary gate, which reflects its ability to generate quantum entanglement in another way. Based on the renowned Cartan decomposition of two-qubit unitary gates, we show that the magic power of the π/8 gate produces maximal entanglement for a general value of purities for two-qubit states.
Cite
@article{arxiv.1306.1443,
title = {Universal Optimal Gates Regarding Quantum Entanglement and Discord Generating},
author = {Zhe Guan and Huan He and Yong-Jian Han and Chuan-Feng Li and Guang-Can Guo},
journal= {arXiv preprint arXiv:1306.1443},
year = {2013}
}