How to observe and quantify quantum-discorded states
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 quantum discord and characterize a discorded state in an unentangled bipartite system. Our protocol is based on an electronic setup and relies on a characteristic of discord that can be extracted from repeated direct measurements of current correlations between subsystems. The proposed protocol opens a way of extending experimental studies of discord to many-body condensed matter systems.
Cite
@article{arxiv.1901.11514,
title = {How to observe and quantify quantum-discorded states},
author = {Matthew A. Hunt and Igor V. Lerner and Igor V. Yurkevich and Yuval Gefen},
journal= {arXiv preprint arXiv:1901.11514},
year = {2019}
}
Comments
5 pages, 5 figures, and Supplemental materials