Entanglement and quantum teleportation under superposed gravitational fields

The influence of gravitational field on entanglement of bipartite states is investigated based on the recent idea of superposition states of gravitational field. Different from earlier considerations, we study the case where the gravitational field cannot be separated unitarily from the bipartite system in the final stage of the interaction. When the different gravitational field states are orthogonal, entanglement cannot be generated for an initial product state. If the different gravitational field states are non-orthogonal, entanglement can be generated and the amount of generated entanglement depends on an overlap parameter between different gravitational field states. The influence of gravitational field on the transfer of the state through quantum teleportation is also studied, which might lead to an observable effect since the quantum teleportation can be performed using macroscopic object.