A detailed treatment of the entanglement dynamics of two distant but non-identical systems is presented. We study the entanglement evolution of two remote atoms interacting independently with a cavity field, as in the double Jaynes–Cummings model. The four-qubit pairwise concurrences are studied, allowing for asymmetric atom–cavity couplings and off-resonant interactions. Counter to intuition, imperfect matching can prove advantageous to entanglement creation and evolution. For two types of initial entanglement, corresponding to spin-correlated and anti-correlated Bell states Φ and Ψ, a full, periodic and directed transfer of entanglement into a specific qubit pair is possible, for resonant interactions, depending on the choice of relative couplings. Furthermore, entanglement transfer and sudden death (ESD) can be prevented using off-resonant interactions, although for some initial states, detunings will trigger an otherwise frozen entanglement, to allow a full entanglement transfer.
A scheme to generate shared tripartite entangled states, with two-trapped atoms in a cavity held by Alice (qubits
A1 and
A2) entangled to a single-trapped atom in a remote laboratory owned by Bob
(B), is proposed. The entanglement is generated through interaction of trapped atoms with two-mode squeezed light shared by the two cavities. The proposed scheme is an extension of the proposal of Son et al. [J. Mod. Opt. 49, 1739 (2002)], where the possibility of entangling two remote qubits using a bipartite continuous variable state was examined. While the global negativity detects the free entanglement of the three atom mixed state, the bound entanglement is detected by the negativity calculated from pure state decomposition of the state operator. The partial negativities calculated by selective partial transposition of the three atom mixed state detect the pairwise entanglement of qubit pairs
A1B,
A2B, and
A1A2. The entanglement of three atoms is found to be
W-like, no Greenberger-Horne-Zeilinger-like quantum correlations being generated.