Dynamical Properties Of A Coupled System Of Atom And Two Pseudomode Reservoirs And Quantum Zeno Effect

The interaction between the quantum system and the environment is an energetic research fields in quantum optics.How to adjust and control the environment,of the quantum system also attracts the attention of scientists.In this paper,different ext,ernal environments are modeled as various types of structure reservoir t,o study the interaction between various environments and different atomic systems.We place the atomic systems in the Lorentzian structure.reservoir or band-gap mode,and simulate different environments by different density functions of state for the structure reservoir.We study the unique properties of the atom decays in dif-ferent environments by changing the parameters of the structure reservoir.In this paper,the coupling of atom with two pseudomodes is discussed.It is found that in the case of strong coupling,the exchange of energy information between atom and reservoir is more significant.The effect of two Lorentzian structure reservoir on the atomic transition is greater than that of the single Lorentzian structure reservoir.When detecting photons emitted spontaneously by atoms in the reservoir,we find that as the detection time interval ? decreases the decay from the initial state of atom slows down gradually.When ??0,the atom are“frozen”in the initial state.This phenomenon shows that the continuous and frequent measurements change the decay-properties of the atom,and lead to the appearance ointeraction f quantum zeno effect.It should be emphasized that in the process of the between the atomic system and the band-gap mode,the state density function of the band-gap mode may become zero.At this point,the environment of the atom is an empty reservoir,so that the atom cannot emit spontaneously.In this way,the atom will remain in the initial state whether the external detection exist,s or not.We call this phenome.non population trapping rather than quantum zeno effect caused by measurement.For the case of three-level atom,the coupling with structure reservoir leads to the coherent,popula?tion trapping(CPT)when the two upper levers are degenerated.In order to further understand this phenc)omenon,we transform it into a new representation to find that the coupling between one transition channel of the atom and the structure reservoir is enhanced,while the other coupling is weakened which implies the phenomenon of decoupling and the occurrence of metastable state.The probability of the atom in the metastable state hardly changes with time.