Control Of Entanglement And Population For Open ?-type Atoms

The study of open quantum systems is one of the most challenging topics in quantum informatics.Due to the complexity of open quantum systems,some approximations are often used in the dynamics of open quantum system.However,the study of quantum non-Markov processes very requires the exact analytical solution of dynamics,because any approximation may erase the non-Markovian properties of dynamics.The content of this paper includes: Firstly,we introduce the research methods and research progress of open quantum systems.Then we introduce the concept of entanglement and three classifications of open quantum dynamics,and introduce the concept of population transfer.Finally,we study the control of entanglement and population for open ?-type atoms.we calculate the exact analytical solution of the dissipative ?-type atomic dynamics in a zerotemperature Lorentz environment.On this basis,two aspects are studied: on the one hand,we study the evolution of entanglement for the two kinds of situations of unilateral environment and bilateral environment.For the Werner-like state of the initial state,it is found that the adjustability of the environmental spectral frequency and the relative decauing rate to the stable entanglement of the atom is very small.On the other hand,we study the control of the population.It is found that by adjusting the relative decauing rate and the environmental spectrum frequency,the stable population of the ?-type atom at two lower levels can be effectively adjusted.