Dense Coding In A Three-Qubit Heisenberg Spin XXZ Chain

Quantum information is an interdisciplinary of quantum mechanics and information theory.As an the most prominent application of quantum mechanics.At the same time,the quantum information provide the tool to verify some quantum mechanics inference.The quantum information is information that use quantum state of micro particles are expressed.In the microscopic world the micro object has many characteristics that macroscopic quantum world cannot explain,these features focuses on quantum state properties,such as;superposition of quantum state,quantum entanglement,quantum states cannot be cloned,the wave-particle duality and phenomenon such as wave packet collapse that the result quantum object measurement.These strange phenomena comes from mutual interference between the micro object,the so-called quantum coherence features.Quantum information is based on the basic principle of quantum mechanics.Through various characteristics of quantum system(such as;quantum parallel,quantum entanglement and quantum cloning,etc.)the information is stored,coding,computation and transmission behavior such as theoretical system.Using quantum superpositions of microscopic particles and coherent characteristics can be achieved,the future computer high-speed parallel computing;Using micro particle entangled quantum states and cannot be cloned quantum mechanical properties can be achieved not crack,Secure communications.As a most fascinating freature of quantum mechanics,quanum entanglement attracts physicists attention.Wide work has been done from it`s definitions to applications and experiments.One of the most important works on entanglement is enatanglement dynamics which mainly refers to the time evolution of quantum enanglement.Work on quantum dynamics will be helpful to understad the dynamic behavior of quantum entanglement in quantum information,which provides us with exact application of quantum entanglement on quantum inforamtion.In reality the existence of decoherence leads to entanglement death and causes a change of entanglement.My elders studied the realization of quantum dense coding in JC model and two bits Heisenberg model respectively.This paper mainly research on the realize quantum dense coding in the thermal equilibrium state three bits Heisenberg model.Paper is divided into three chapters altogether.The first and second chapter presents the general situation of quantum information theory,and some basic knowledge about quantum entanglement.The third chapter mainly studies three bits Heisenberg XXZ model is used to implement quantum dense coding.Using quantum channel is three bits of Heisenberg XXZ spin chain in the thermal equilibrium state.By the expression of channel capacity analysis the influence of each parameters on the quantum dense coding,by using non-uniform magnetic field Heisenberg XXZ model to achieve three bits quantum dense coding theory.By numerical calculation have obtained that increase of model xy plane coupling constant J can effectively increase the channel capacity of dense coding.Not only that,but also J can effectively resist and the negative effect of the magnetic field,especially in ferromagnetic case the effect is more apparent.So,if you need to introduce additional magnetic field in the middle of the actual can reduce the negative effect of the magnetic field on the quantum dense coding through the parameter J.