Entanglement and quantum teleportation in a nonlinear spin channel

The ground state and thermal entanglement of a two-qubit spin system in the presence of the nonlinear coupling interaction is investigated. It is found that the nonlinear coupling interaction can excite and enhance the entanglement both for ferromagnetic chain and anti-ferromagnetic ones even at the higher temperature. The entanglement teleportation via the quantum channel constructed by this system is also discussed, and the influence of the nonlinear coupling interaction on the fidelity of the teleportation is studied. The results show that both the entanglement of the output state and the fidelity can be increased by inducing a proper nonlinear coupling interaction.