Research On Spontaneous Emission And Slow Light Mechamsim In Non-markovian Reservoir

The characteristics of atomic spontaneous emission have great application value in the fields of quantum information and quantum computation,optical information storage,optical communication,therefore,the study of atomic spontaneous emission behavior has attracted much attention.The spontaneous emission of an atom is a process in which an atom at a high energy level spontaneously transitions to a low energy level and emits a photon without any external disturbance.However,it is found that the spontaneous emission of an atom is not only determined by its energy level structure,but also closely related to its environment.Since the spontaneous emission characteristics of atoms placed in the photonic crystals reservoir have been deeply studied,researchers can make predictive assumptions about new physical phenomena.In this paper,we study the spontaneous emission behavior of the three-level and four-level atoms in the photonic crystal reservoir by using the photonic crystal,a special non-Markovian reservoir,as the background environment.The details are as follows:We first introduce the photonic crystal,a special non-Markovian reservoir,and describe the research status of atomic spontaneous emission in photonic crystal and the influence of photonic crystal on slow light behavior.Some basic theories for studying atomic spontaneous emission in photonic crystals are introduced,such as the description of three basic scenes of quantum systems,the concepts of Markovian reservoir and non-Markovian reservoir,Delayed Green's function and Laplace transform and its inverse transformation.Then,based on the specific mode density of the two-band edge mode,the spontaneous emission behavior of a three-level ? type atom in a photonic crystal is studied,in which the atom transitions to a discrete reservoir and the same photonic band gap reservoir,and the spontaneous emission is coupled with it,on the basis of the same conditions,the slow light mechanism and its law of the three level ? type atom are explored.Finally,the atomic decay characteristics of four-level atoms in photonic crystals are studied when they are transferred to a discrete reservoir and coupled to the same photonic band gap reservoir,at the same time,the atomic spontaneous decay characteristics based on different mode densities are studied.It is widely found that the interaction between atom and photonic band gap reservoir determines whether the upper energy level is split,whether the spontaneous emission spectrum is non-Lorentzian line shape and whether there are dark lines in the spontaneous emission spectrum.