Quantum coherence in multipartite systems

Yao Yao, Xing Xiao, Li Ge, and C. P. Sun
Phys. Rev. A 92, 022112 – Published 12 August 2015

Abstract

Within the unified framework of exploiting the relative entropy as a distance measure of quantum correlations, we make explicit the hierarchical structure of quantum coherence, quantum discord, and quantum entanglement in multipartite systems. On this basis, we define a basis-independent measure of quantum coherence and prove that it is exactly equivalent to quantum discord. Furthermore, since the original relative entropy of coherence is a basis-dependent quantity, we investigate the local and nonlocal unitary creation of quantum coherence, focusing on the two-qubit unitary gates. Intriguingly, our results demonstrate that nonlocal unitary gates do not necessarily outperform the local unitary gates. Finally, the additivity relationship of quantum coherence in tripartite systems is discussed in detail, where the strong subadditivity of von Neumann entropy plays an essential role.

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  • Received 14 June 2015

DOI:https://doi.org/10.1103/PhysRevA.92.022112

©2015 American Physical Society

Authors & Affiliations

Yao Yao1,2,3,*, Xing Xiao3, Li Ge3, and C. P. Sun3,4,†

  • 1Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang Sichuan 621999, China
  • 2Microsystems and Terahertz Research Center, China Academy of Engineering Physics, Mianyang Sichuan 621999, China
  • 3Beijing Computational Science Research Center, Beijing, 100094, China
  • 4Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China

  • *yaoyao@csrc.ac.cn
  • cpsun@csrc.ac.cn

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Issue

Vol. 92, Iss. 2 — August 2015

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