Various Quantum Correlation Evolution Characteristics Of The Open Quantum System In The Non-Markov Environment

With the gradual deepening of quantum information science research,the quantum information theory has reached a new height.As an emerging discipline-quantum information science,which not only demonstrates the broad prospect of quantum theory,and pointed out the direction for modern information science.Quantum entanglement as a core resources in quantum information processing,has shown an inestimable advantage in the field of quantum communication and quantum computing.However,in the real life environment,the external environment will affect the quantum system more or less.When the interacts with the system and environment,decoherence may occur,and the entangled resources of the quantum system are destroyed.Therefore,the singular characteristics of the dynamics of quantum open systems are inevitable research directions.According to the different properties of the environment when the system interacts with the environment,the dynamic evolution of the quantum open system can be divided into two basic processes:Markov and non-Markov.When the open quantum system is strongly coupled with its environment,the decoherence or relaxation time scale of the system are equivalent,and the environmental correlation time is even greater than the system's association time.At this time,the system is affected by the environmental memory effect,and the impact of the environment cannot be ignored,especially in solid-state systems with advantages such as easy embedding and scalability.The quantum state diffusion(QSD)method,as a method of numerically processing a random pure state,can not only be used to accurately study the singular properties brought about by non-Markov processes and can greatly improve the computational efficiency.The characteristics of quantum open system dynamics is the common problem in many research fields of quantum mechanics,so the singularity of the memory effect of the research environment is of great significance.The paper is divided into four chapters.In the first chapter,we introduce the research background of quantum information theory and the basic research content of open quantum system dynamics.In the second chapter,we present the description method of quantum open system dynamics: Quantum state diffusion method,and give a variety of quantum correlation measurement methods.In the third chapters,the quantum state diffusion method is mainly used to study the dynamics of the geometric quantum discord evolution in non-Markov environment in Heisenberg XX and XXZ spin models.The results show that the memory correlation time is shortened,the more obvious the memory effect is,which makes the geometric quantum discord increase and maintains the ideal value for along time.For the selection of different initial states,the geometric quantum discord with time as the coupling constants in different directions change.In the fourth chapter,the effects of environmental non-Markov properties on the evolution of each quantum correlation over time in a two-bit Heisenberg XXZ model at finite temperature are studied.The results show that the time-dependent evolution of various quantum correlations is highly dependent on temperature when the environment is non-Markovian.Especially,the laws of quantum entanglement and quantum discord change with time at lower temperature are ideal.