Journal of Henan Normal University
Entropy Properties of Atom-Field System with Raman Coupling In a Cavity
Lai Zhen-jiang
Abstract
Using the method of super-operator that describes the dissipative effects,the study has obtained exact solution of the master equation that represents a Raman interaction between three-level atoms and cavity-field.The linear entropy of the system,along with atoms and cavity-field in the system is formulated.The influences of the Stark shift between two atomic levels,intensity of the cavity-field and the dissipative coefficient of the cavity on the linear entropy are discussed.It is found that the more intense the cavity-field,the longer the persistent time of the exchange of entropy between the cavity field and atoms.Because the cavity field leaks,the cavity dissipation blocks entropy exchange between the subsystems;to make the entropy of the system and subsystem increase irreversibly and reduce the amount of the coherent information,and so that it is finally to zero.When the Stark shifts between the atomic levels changes and the cavity dissipation coefficient remain has unchanged,the coupling between atom and cavity field enhances,the entropy exchange of the system speed up and the steady-state values become smaller.When the dissipation of the cavity is absent,the entropy of the light field and the atoms follow the same evolutionary regularity and reversible,show saturated and retreat saturated natures corresponding to the collapse and restoration of the atomic levels,respectively.Along with the increase of atomic number in saturated and retreat saturated time the entropy evolution characteristics is becoming more and more complicated.