Coherence-controlled stationary entanglement between two atoms embedded in a bad cavity injected with squeezed vacuum

Abstract

Abstract:We investigate the entanglement between two atoms in an overdamped cavity injected with squeezed vacuum when these two atoms are initially prepared in coherent states. It is shown that the stationary entanglement exhibits a strong dependence on the initial state of the two atoms when the spontaneous emission rate of each atom is equal to the collective spontaneous emission rate, corresponding to the case where the two atoms are close together. It is found that the stationary entanglement of two atoms increases with decreasing effective atomic cooperativity parameter. The squeezed vacuum can enhance the entanglement of two atoms when the atoms are initially in coherent states. Valuably, this provides us with a feasible way to manipulate and control the entanglement, by changing the relative phases and the amplitudes of the polarized atoms and by varying the effective atomic cooperativity parameter of the system, even though the cavity is a bad one. When the spontaneous emission rate of each atom is not equal to the collective spontaneous emission rate, the steady-state entanglement of two atoms always maintains the same value, as the amplitudes of the polarized atoms varies. Moreover, the larger the degree of two-photon correlation, the stronger the steady-state entanglement between the atoms. PACS

Population Dynamics of Excited Atoms in Dissipative Cavities

“…In other words, the atom will dissipate eventually its excitation energy into the lower state as the time tends to infinity. Therefore, how to trap the excited atom in dissipating environments is of great interest in researches of quantum many-body physics [15][16][17], quantum information processing [18] and quantum nonlinear optics [19]. In particular, the atomic spontaneous emission and the environment-induced dissipation inevitably lead to decoherence of quantum systems so that the population trapping of excited atoms is very fragile, which is undesirable in the above quantum physics researches.…”