Quantum Correlations in Dimers

TL;DR

This paper compares geometric quantum discord, quantum discord, and measurement induced non-locality in a two-spin system, highlighting their differences and relevance for quantum correlations in quantum information processing.

Contribution

It provides a comparative analysis of different quantum correlation measures using a dimer system in NMR, clarifying their distinctions and applications.

Findings

Geometric quantum discord differs from quantum discord and measurement induced non-locality.

The study demonstrates how these measures behave in a two-spin NMR system.

Insights into quantum correlations relevant for quantum information processing.

Abstract

It has been proven that the quantum discord is a more general tool to capture non-classical correlation than quantum entanglement, because there is a non-zero quantum discord in several mixed states that could not be measured by quantum entanglement. But because of optimization part in formulating quantum discord, it is very difficult and nearly impossible to find quantum discord for some quantum states. So people proposed geometric quantum discord, which in a bipartite state could be describe as the distance of the states from the closest zero-discord state. To understand better geometric quantum discord, this paper is devoted to compare it with quantum discord and measurement induced non-locality that is in some sense dual to the geometric quantum discord. As studying the quantum correlation experimentally is one of the important thing in quantum information processing, so as our example for illustrating the difference of geometric quantum discord, quantum discord and measurement induced non-locality, our quantum system is a dimer (two spin-1/2 particles) in multiple quantum nuclear magnetic resonance.