Enhancing entanglement of entangled coherent states by single-mode coherent superposition of photon subtraction and addition

Abstract

We introduce a new entangled quantum state generated by applying single-mode coherent superposition of photon subtraction and addition (a†cosθ+asinθ)m to the entangled coherent state |Ψ±α,0〉, and then investigate the entanglement properties affected by coherent superposition operation. It is shown that this operation can be applied to enhance the entanglement of the state |Ψ+α,0〉. In addition, the effects of the coherent operation is better to improve the entanglement than that of the creation operation (a†m) for |Ψ+α,0〉 in a small-amplitude regime and for |Ψ−α,0〉 in any regime.