Influence of Frequency Detuning on Evolution of Quantum Field Entropy in Multimode Nondegenerate Multi-Photon Jaynes-Cummings Model
失谐量对多模场非简并多光子Jaynes-Cummings模型量子场熵演化的影响

The time evolution of the field quantum entropy in the system of a multi-mode coherent field interacting with a two-level atom through the non-degenerate multi-photon process is investigated using the Von Neumann reduced entropy, the analytical expression of the multimode field entropy including the frequency detuning is obtained. The numerical results for the three-mode field interacting with the atom are presented. The influence of the frequency detuning on the field quantum entropy is discussed. It is found that the frequency detuning has nearly no effect on the entanglement between the three-mode coherent field and the two-level atom when the field and the atom are near resonance, but the time evolution of the field quantum entropy is strongly dependent on the values of the frequency detuning when the field and the atom are far from resonance, especially when the frequency detuning is large enough, the field and the atom are nearly always in entangled states.