The Two-body Continuous Variable Entangled State One-dimensional Barrier Scattering

Continuous variable entangled states are the mainly resources of continuous variable quantum communication.The characteristic of continuous variable quantum information is that we can produce and manipulate the continuous variable state in high accuracy through linear optical devices;therefore,we can provide kinds of feasible manipulations for continuous variable quantum communication using relative perfect quantum optics means.As people study the continuous variable quantum communication more and more deeply, the work like teleportation of bipartite continuous variables,dense communication,the teleportation of multipartite continuous variables et al has been the focus in recent years. However,during the communication,there will be inevitable obstacles,then,what will the state be like would be the problem people have to face.This paper sets two kinds of continuous variable entangled states—two-mode squeezed vacuum state and entangled coherent state as examples,firstly take the simplest obstacle—barrier as beam splitter,and then discusses the changes of the continuous variable entangled state after barrier scattering.The mainly context includes two parts as following:Take the barrier as one beam splitter.We find that after the barrier scattering,the two-mode squeezed vacuum state entanglement will change like a similar parabola as the transmission coefficient,and also like a similar parabola as the incident squeezed factor;fidelity will increase as transmission coefficient increases,and decrease as the incident squeezed factor increases. After scattering,the entangled coherent state entanglement will change like a similar parabolic function as transmission coefficient,and increase linearly as incident entanglement increases; fidelity will rise as transmission coefficient increases,and go down as the module of the incident coherent state increases.Finally,we discuss under what circumstance the transmission coefficient would be bigger than 0.5,and we show that whether the entanglement can increase as transmission coefficient increases after scattering depends on the incident energy of the light,the height of the barrier and the width of the barrier.When the incident energy is bigger than the height of the barrier,the limitation on the width of the barrier can be relaxed a little,and when the incident energy approaches the height of the barrier or even smaller than it the limitation on the width of the barrier will be more and more sever.