Geometric quantum discord and coherence in a dipolar interacting magnetic system

TL;DR

This paper investigates how magnetic anisotropies in dipolar spin systems influence quantum discord and coherence, revealing that quantum discord clearly signals level-crossing while coherence depends on measurement basis.

Contribution

It provides analytical formulas for quantum discord and coherence in dipolar spin systems and analyzes their behavior across quantum level-crossings.

Findings

Quantum discord signals quantum level-crossing clearly.

Quantum coherence depends on the measurement basis.

Global quantum coherence resides in system correlations.

Abstract

The study of low-dimensional metal complexes has revealed fascinating characteristics regarding the ground-state crossover shown by spin-gaped systems. In this context, this work explores the effect of the quantum-level crossing, induced by the magnetic anisotropies of dipolar interacting systems, on the quantum discord and coherence of the system. The analytical expressions for the quantum discord, based on Schatten 1-norm, and the $l_1$ trace-norm quantum coherence for dinuclear spin-1/2 systems, are provided in terms of the magnetic anisotropies. The results show that, while the quantum discord has a clear signature of the quantum level-crossing, the basis dependence of the quantum coherence hides the crossover regarding the measured basis. In addition, the global quantum coherence is wholly stored within the correlations of the system, regardless of its reference basis.