The Research On Non-markovian,coherence And Entanglement Of Two Light-harvesting Models

As a part of physics,the main contents of quantum physics are the dynamic behavior of quantum systems and describe the characteristics of the real system.However,any real quantum system is not isolated.It must interact with the environment in which it is located.And the result will be inaccurate even false using a closed quantum system theory to describe a real quantum system.Thus,people were aware of the defects of closed quantum systems,and immediately focused their attention on the study of open quantum systems.According to whether to neglect the environmental memory effect and the interaction between the system and the environment,the dynamics of the evolution of the open quantum system includes Markov and nonMarkov.In the article,we mainly consider the non-Markov method,hierarchical equations of motion,HEOM,which is closer to the real situation to study quantum dissipative dynamics.With the development and utilization of quantum effects such as quantum parallelism,entanglement and quantum non-cloning,quantum information,a new subject,arises at the historic moment.However,due to the existence of the surrounding environment,the system is inevitable disturbed and the quantum information during transmission is largely destroyed.For example,quantum decoherence,quantum infidelity and quantum disentanglement can happen.This has become a major obstacle to quantum information processing.Therefore,it is the focus to seek to maintain and protect the coherence and entanglement of the system.In this paper,we mainly study the following two aspects: firstly,we study the nonMarkovian of a photosystem model.By calculating and comparing the evolution of seven definitions: trace distance,fidelity,quantum relative entropy,quantum fisher information,quantum entanglement,quantum mutual information and quantum discord,we conclude that they are equivalent in characterizing the non-Markovian of open quantum system.Secondly,we have presented a method which is based on the driving fields acted upon the system to protect the quantum coherence and entanglement in non-Markovian regime.By comparing the evolution of the coherence and entanglement of the system with or without an external driving field,we show that the application of the driving field can keep the coherence and entanglement of the open quantum system.