High success standard quantum teleportation using entangled coherent state and two-level atoms in cavities

We propose here a new idea for quantum teleportation of superposed coherent state which circumvents the problem of performing non-unitary Z= | α⟩ ⟨ α| - | - α⟩ ⟨ - α| operation on coherent state qubit. The receiver only requires to perform either no unitary operation or a π phase shift in order to recreate the information state. We use entangled resource ∼|α,α2⟩-|-α,-α2⟩ in contrast with the usual ∼ | α, α⟩ - | - α, - α⟩ -(both states unnormalized). Bob receives state which is then superposition of the states |±α2⟩. Bob mixes these with even or odd coherent states involving superposition of states |±α2⟩ to obtain a two-mode state which is one of ∼ | I, 0 ⟩ ± | 0 , I⟩ , | I⟩ being the information state. Bob then obtains the teleported information by using the interaction of one of these modes in two cavities with resonant two-level atoms. This scheme results in average fidelity of ≃ 0.95 for | α| ≃ 10 , which increases with | α| and tends to 1 asymptotically, varying as 1-π216|α|2+π2(π2+8)256|α|4 for large values of | α| .