Coherence,Correlation And Quantum Non-Markovian Dynamics

Due to the wide range of existence and application, quantum non-Markovian dynamics has received the continuously development in recent years. Nowadays, people not only put forward several methods for the measure of non-Markovianity and also made some research on dynamical properties of non-Markovian processes. As everyone knows, the dynamical evolutions of open quantum systems relies on their environmental properties largely. However, there has been no special research work between the environmental coherence and the non-Markovian dynamics of open quantum systems. Because of the coherence maybe exist more or less in some realis-tic conditions, the roles of environmental coherence on the non-markovian dynamics of open quantum systems is still a problem worthy of investigating. Motivated by the above questions, in this paper, we construct a model which compose of one qubit system coupled to a single qubit environment to achieve an simple and accurate calculation. The main contents are arranged as following:In the first chapter, we mainly introduced some basic theories of the following three parts:quantum non-Markovian dynamics, quantum coherence and quantum correlation. The main background knowledge are recommended, including quan-tum non-Markovianity and its method of measurement, quantum entanglement and concurrence, quantum correlation and discord, quantum mutual information and so on.In the second chapter, through the adoption of the model of a qubit system coupled to another qubit environment, we have investigated the relationship be-tween environmental coherence to the non-Markovianity of the system dynamics. Both the measure based on the back-flow of information and the one based on the entanglement with an ancillary system, it has shown that although environmental coherence has no effect on the quantity of the non-Markovianity but can influence the optimal initial-state pair. Further, we studied the relation between the system-environment correlations and the information flow. It confirmed the conclusion that the information can be stored in either the reduced system, environment or the cor-relations. Finally, we have discussed the evolution of the environmental coherence over time and learned that it bounded by the sum of the initial coherence of the reduced system and the environment.In the third chapter, we have considered the influence of the environmental coherence to the evolution of the system entanglement both in the unilateral and the bilateral environment. We found that they have the same periodic entanglement swapping between the environment and system. In addition that the environmental coherence has nothing to do with the period of the entanglement evolution, but can change the speed of the entanglement evolution. Generally speaking, the evolution of entanglement in the bilateral environment decays more quickly than in the unilateral environment.The last chapter is the conclusion and overlook of the paper.