Effects Of Hybrid Non-markovian Bath On The Quantum Correlation And Quantum Dense Coding Properties Of Heisenberg Spin Chain Mode

At the beginning of last century,quantum mechanics ushered in the development of instantaneous speed,and with the improving maturity of information technology,the field of quantum information has also finished unprecedented consequence.Due to the limitations of Moore’s theorem,scientists hope to realize the quantum computer composed of quantum solidstate system as soon as possible.At the same time,the coupling between the actual quantum system and the surrounding environment cannot be avoided,and under this coupling,the quantum system is difficult to maintain the existing quantum properties.In many physical systems such as solid-state systems,the bath around quantum systems has memory effect,which must be described by non-Markovian processes.Because the heat reservoir around an open quantum system always contains bosons and fermions at the same time,it is more practical to use hybrid non-Markovian bath to describe the heat reservoir of the system,rather than a single non-Markovian Bose bath or fermion bath.Using the quantum state diffusion method of hybrid non-Markovian bath,this is explores the effects of non-Markovian hybrid bath on quantum entanglement,quantum discord and quantum dense coding channel capacity in Heisenberg XYZ spin chain model.The main purpose is to explore whether the hybrid bath helps to improve quantum entanglement,quantum discord and channel capacity,and to verify the superiority of the hybrid nonMarkovian bath by comparing with the case of a single non-Markovian bath.This paper is divided into five chapters.In the first chapter,learning the purpose and significance of the research,the birth history of quantum information and other important issues.In Chapter 2,the basic knowledge theories such as hybrid non-Markovian bath and quantum state diffusion method of hybrid bath are introduced,and the concepts and measurement methods of concurrence and quantum discord,channel capacity and phase change points are introduced.In Chapter 3,using the hybrid non-Markovian quantum state diffusion method,the effects of hybrid bath on the dynamic evolution characteristics of quantum entanglement and quantum disharmony in Heisenberg spin chain model are studied,and compared with the evolution results in a single non-Markovian bath.The numerical simulation results show that the Heisenberg spin chain model coupled with hybrid nonMarkovian bath shows higher entanglement,better quantum discord state and longer relaxation time than a single non-Markovian bath.In Chapter 4,the effects of the coupling constants of quantum systems in different channels and spin chains on the dynamic evolution of hybrid bath and single bath on the capacity of quantum dense coding channel under different non-Markovian environmental parameters are studied.The results show that compared with a single bath,the system not only obtains a higher channel capacity value in the hybrid bath,but also has a significant decoherence delay.Before the channel capacity reaches the steady-state value,it maintains a non-Markovian oscillation for a long time,mean doing that increasing the environmental memory effect.