Hunt, Matthew A., Lerner, Igor V., Yurkevich, Igor V. and Gefen, Yuval (2019). How to observe and quantify quantum-discord states via correlations. Physical Review A, 100 (2),
Abstract
Quantum correlations between parts of a composite system most clearly reveal themselves through entanglement. Designing, maintaining, and controlling entangled systems is very demanding, which raises the stakes for understanding the efficacy of entanglement-free, yet quantum correlations, exemplified by quantum discord. Discord is defined via conditional mutual entropies of parts of a composite system and its direct measurement is hardly possible even via full tomographic characterization of the system state. Here we design a simple protocol to detect and quantify quantum discord in an unentangled bipartite system. Our protocol relies on a characteristic of discord that can be extracted from repeated direct measurements of certain correlations between subsystems of the bipartite system. The proposed protocol opens a way of extending experimental studies of discord to electronic systems, but can also be implemented in quantum-optical systems.
| Publication DOI: | https://doi.org/10.1103/PhysRevA.100.022321 |
|---|---|
| Divisions: | College of Engineering & Physical Sciences Aston University (General) |
| Funding Information: | This work was supported by the Leverhulme Trust Grants No. RPG-2016-044 (I.V.Y.), No. VP1-2015-005 (I.V.Y., Y.G.), the Italia-Israel project QUANTRA (Y.G.), and the DFG within the network CRC TR 183, C01 (Y.G.). The authors (I.V.L., I.V.Y., and Y.G.) are grateful for the hospitality extended to them at the final stage of this work at the Center for Theoretical Physics of Complex Systems, Daejeon, South Korea. APPENDIX A: |
| Additional Information: | © 2019 The American Physical Society |
| Uncontrolled Keywords: | Atomic and Molecular Physics, and Optics |
| Publication ISSN: | 1094-1622 |
| Last Modified: | 20 Feb 2026 11:01 |
| Date Deposited: | 02 Sep 2019 08:14 |
| Full Text Link: |
https://arxiv.o ... /abs/1901.11514 |
| Related URLs: |
https://www.sco ... ons/85070861882
(Scopus URL) https://journal ... RevA.100.022321 (Publisher URL) |
PURE Output Type: | Article |
| Published Date: | 2019-08-16 |
| Accepted Date: | 2019-01-27 |
| Authors: |
Hunt, Matthew A.
Lerner, Igor V. Yurkevich, Igor V. ( 
0000-0003-1447-8913)
Gefen, Yuval |