Geometrical Quantum Discord in the Coupled Cavities System with Tetrahedral Structure

In this paper we consider the situation that four identical two-level atoms are separately trapped in four single-mode optical cavities, which are placed at the vertices of a tetrahedron and coupled by six fibers. Each atom resonantly interacts with cavity via a one-photon hopping. The evolution of the state vector of the system is given by solving the schrödinger equation when the total excitation number of the system equals one. The geometrical quantum discords between atoms and between cavities are investigated. The effects of cavity-fiber coupling coefficient on the geometrical quantum discords between atoms and between cavities are discussed. The results obtained using the numerical method indicate that the geometrical quantum discords between atoms and between cavities are all weakened with increase of cavity-fiber coupling coefficient.