Quantum correlations in two-level atomic system over Herring-Flicker coupling (1807.01805v4)

Abstract: We study the thermal quantum correlations in tripartite atomic system under the existence of Herring-Flicker (HF) coupling among the atoms. We explore two topologically distinct configurations of three coupled two-level atoms, viz., loop and line, differing in their coupling pattern. Further, the systems having asymmetric arrangement of atoms are quantum mechanically correlated more strongly than systems having symmetric arrangements. The variable nature of HF coupling leads to the increase of both concurrence and discord from zero to a saturation value from where they decrease to zero as a function of inter-atomic distance. Further separation leads to both the quantities attaining another saturation value. This controlled correlations play an important role in the design of quantum data buses that can transfer quantum states to establish quantum communication. The systems coupled via HF coupling will be efficient for this task as they are maximally entangled in parametrically controlled manner. Thus, these systems will be propitious for various quantum protocols such as secure communication, quantum cryptography, quantum key distribution etc.