Nonlocality of two-qubit states of a nuclear spin-3/2

Classical and various quantum correlations have been studied in real spin-1/2 systems. The nonlocality measures provide a novel classification scheme for bipartite states, and nonlocality is a quantum resource quite different from entanglement. We first studied the temperature and field dependences of nonlocality measure in the two fictitious spins-1/2 system, which represents a nuclear spin-3/2 placed in magnetic and inhomogeneous electric fields and the relationship between nonlocality and entanglement and geometric discord. From the quantum information point of view, the states of a nuclear spin-3/2, fictitious spins-1/2, can be considered as two interacting qubits. The representation using these spins makes it possible to apply to the system under consideration well-developed methods for calculating correlation measures. It was shown that nonlocality can be without entanglement and discord which allows assuming that the quantum correlation is more general than the other. The state of every one of the interacting qubits created by the fictitious spins can be changed separately by external field variations. This is one of the advantages of fictitious spin systems over real spin ones.