The Generation And Application Of Hybrid Entanglement

Early in the research of quantum mechanics,the entanglement is considered to be a paradox.Quantum entanglement is of crucial importance for fundamental tests of quantum mechanics and implementations of quantum information processing.In recent years,quantum entanglements have been extensively explored.In particular,the study of quantum entanglement has involved the generation and application of discrete-variable quantum entanglement and continuous-variable quantum entanglement from bipartite to multipartite.Based on the knowledge about the advantages and disadvantages of discrete-variable quantum entanglement and continuous-variable quantum entanglement when used in the quantum information processes,a kind of hybrid entanglement is proposed.In 2014,a great number of scientific researchers were focused on two articles about the way to generate hybrid entanglement.As is known to all,building the quantum entanglement network needs hybrid entanglement with much more components.So,we began to learn the generation of duplex hybrid entanglement and multiplex hybrid entanglement.Using beam-splitter model as the main basis,we respectively using variable beam splitter and a series of beam splitters to generate the duplex hybrid entanglement and multiplex hybrid entanglement.In this paper,the fidelity between the final several divided hybrid entanglements and the primary hybrid entanglement are analyzed.This article focus on the generation and application of hybrid entanglement,the main works are as follows:(1)A system to manipulate duplex hybrid entanglement with linear optics in chapter two.This proposal manipulate duplex hybrid entanglement between single photon qubit and the cat states by adjusting the variable beam splitter.We calculate the final two sets of hybrid entanglement and primary hybrid entanglement,and then analyzes the fidelity versus with the size of the cat states and reflectivity of the variable beam splitters.This type of hybrid entanglement may provide some theory references for the generation of multiplex hybrid entanglement and the transmission of hybrid quantum information.(2)A system to generate multiplex hybrid entanglement with linear optics in chapter three.Based on the generation of duplex hybrid entanglement described in(1),we design a scheme to generate multiplex hybrid entanglement with a series of beam splitters.We calculate the fidelity between the final several pairs of hybrid entanglement and the primary hybrid entanglement,and then analyzes the fidelity versus with the size of the cat states and reflectivity of beam splitters.This kind of multiplex hybrid entanglement will be important resource for hybrid quantum information distribution and hybrid quantum information network.(3)A system of entanglement swapping with hybrid entanglement between single photon qubits and the cat states in chapter four.In this scheme,two copies of hybrid entangled states are prepared and the continuous-variable parts propagate through lossy media.We find that the entanglement swapping using hybrid states with small amplitudes offers larger entanglement than the discrete-variable entanglement swapping in the presence of large losses.Remarkably,this hybrid scheme still offers excellent robustness of entanglement to the detection inefficiency.Thus,the proposed scheme could be used for the practical quantum key distribution in hybrid optical states under photon losses.