The decay of quantum correlations between quantum dot spin qubits and the characteristics of its magnetic-field dependence

We address the question of the role of quantum correlations beyond entanglement in the context of quantum magnetometry. We study the evolution of the rescaled variant of the geometric quantum discord of two electron-spin qubits interacting with an environment of nuclear spins via the hyperfine interaction. We have found that quantum correlations display a strong magnetic-field sensitivity which can be utilized for decoherence-driven measurements of the external magnetic field. The discord-based measurement is sensitive to a wider range of magnetic-field values than the entanglement-based measurement, including very small fields which are inaccessible via entanglement.