The Preparation And Distribution Of Quantum States Based On The Nonlinearity Of Kerr Media

Since the quantum information developed,in the process of people's continuous efforts to explore,so many new research topics gradually appear in various fields.As one of the two important resources in quantum information,quantum entanglement plays a decisive role in quantum information and becomes one of the frontier research topics in the field of quantum information.With the emergence of these topics,many difficulties have been encountered in many studies,such as the preparation of multi particle entangled states,distribution of quantum states in noisy channels and lossy channels,and so forth.Based on the nonlinear Kerr medium,a scheme for preparing three-photon polarization-entangled perfect W states is proposed.Considering the effects of collective noise.In this paper,a scheme for distributing multi-photon entangled states is proposed.There are four chapters in this paper.The first chapter mainly introduces the birth of quantum information and the development process of quantum information.The second chapter gives some preliminary knowledge related to the research content,such as quantum bits,transformation of the single bit quantum state,the definition of entangled states,nonlinear cross-Kerr effect and quantum measurement and so on.The main content of the third chapter is the preparation of three-photon polarization-entangled perpect W States,which is divided into several parts to describe,respectively the introduction of perfect W state,the spatial entanglement process of three photons,the polarization entanglement process of two photons,channel combination process and the analysis of fidelity.In the fourth chapter,by using other degrees of freedom,we present a fault-tolerant distribution of multi-photon polarization-entangled states via collective noise channel.Finally,the summary of this paper are given.