Equivalent relation between quantum entanglement and steering in two-fermion spin systems under static magnetic fields

Abstract Quantum entanglement and steering are both fundamental concepts for describing quantum correlations, with steerable states forming a strict subset of entangled states. In general two-qubit systems, the relation between entanglement and steering can be characterized by an inequality, referred to as the constraint relation. In this work, we investigate a two-fermion spin system to explore the influence of static magnetic fields on quantum entanglement and steering. Our results demonstrate that entanglement and steering are equivalent in this system. The finding provides new perspectives for understanding quantum correlations in two-fermion spin systems. Furthermore, we examine the dynamic behavior of entanglement, showing that the maximum entanglement of this system affected by both external and internal factors.