Geometric quantum discord and coherence in a dipolar interacting magnetic system

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 interaction, on the quantum discord and coherence of a dinuclear spin-1/2 system. The analytical expressions for the quantum discord, based on Schatten 1-norm, and the $l_1$ {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 axial quantum coherence hides the crossover regarding the measured basis. Moreover, global coherence was expressed in terms of the co-latitude and longitude angles of the Bloch sphere representation. Through this result, the average quantum coherence is numerically measured in order to obtain a basis-independent perspective for the $l_1$ quantum coherence. The results show that the average measurement revealed the signature of the energy-level crossover obtained in the measurement of quantum discord, being wholly stored within the correlations of the system, even in the absence of entanglement.

Suppressing the degeneration of quantum resources through coupling auxiliary qubits

“…Recently, the QC has been used to reveal the nonclassical characteristics of various systems. Involving superinductors [36], two-level molecular system [37], polariton condensates [38], critical unstable two-level systems [39], quantum dot systems [40], cavity magnomechanical systems [41], quantum batteries [42], neutrino [43], linear systems of equations [44], dipolar interacting magnetic system [45], Heisenberg model [46], noninertial frame [47], and spacetime expansion [48]. Besides, reservoir system is significant for quantum information [49], and the transformation between coherence and entanglement of reservoir system was revealed by Hu et al [50].…”