Diagonal quantum discord
Name
Liu_2019_J._Phys._A _Math._Theor._52_135301.pdf
Description
Published version
Size
1.81 MB
Format
Adobe PDF
Checksum (MD5)
4402106596b141e832d56b724c518e74
Author(s)
Liu, Zi-Wen
Takagi, Ryuji
Lloyd, Seth
Date Issued
February 2019
Journal
Journal of Physics A: Mathematical and Theoretical
Publisher
IOP Publishing
Citation
Liu, Zi-Wen et al., "Diagonal quantum discord." Journal of Physics A: Mathematical and Theoretical 52, 13 (March 2019): no. 135301 doi. 10.1088/1751-8121/ab0774 ©2019 Authors
Version
Final published version
Abstract
Quantum discord measures quantum correlation by comparing the quantum mutual information with the maximal amount of mutual information accessible to a quantum measurement. This paper analyzes the properties of diagonal discord, a simplified version of discord that compares quantum mutual information with the mutual information revealed by a measurement that correspond to the eigenstates of the local density matrices. In contrast to the optimized discord, diagonal discord is easily computable; it also finds connections to thermodynamics and resource theory. Here we further show that, for the generic case of non-degenerate local density matrices, diagonal discord exhibits desirable properties as a preferable discord measure. We employ the theory of resource destroying maps (Liu Z-W et al 2017 Phys. Rev. Lett. 118 060502) to prove that diagonal discord is monotonically nonincreasing under the operation of local discord nongenerating qudit channels, d > 2, and provide numerical evidence that such monotonicity holds for qubit channels as well. We also show that it is continuous, and derive a Fannes-like continuity bound. Our results hold for a variety of simple discord measures generalized from diagonal discord. ©2019 IOP Publishing Ltd.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/1751-8121/AB0774
