| Spontaneous emission is accompanied by the transition of atoms from the upper electron state to the lower electron state.And the large size of the three free spaces provides dense energy levels,which is very important for the effectiveness of Fermi's golden rule in calculating the emissivity.But spontaneous emission is not an inherent atomic property,on the contrary,it can be modified by adjusting the atomic radiation to the electromagnetic environment.This was first realized by Purcell,who pointed out that the spontaneous emission rate of atoms placed in the cavity can be increased when the cavity field resonates with the transition under consideration..It is also recognized that spontaneous emission can be replaced by periodic energy exchange between atoms and electromagnetic fields.This indicates the birth of CQED.We studying optomechanical cooling in highly unresolved sidebands and beyond Lamb-Dicke regions.The results show that when the detuning of the high excited state and the high frequency driving field is equal to that of the low excited state and the low frequency driving field,the noise spectrum has a single peak,and vice-versa.In the case of two peaks,we can change the coupling strength between quantum dots and cavity field to achieve the transformation of optomechanical cooling and heating,which is impossible in the case of single peak.At the same time,we study the evolution of the average phonon number with time,which is helpful to further study the optomechanical cooling.At the same time,we studying the Rabi oscillation of the V-type atom optomechanical,and give a general expression of the Rabi oscillation.By properly adjusting the atom cavity or phonon cavity coupling strength,we find that the Rabi oscillation is periodic or quasi periodic.The modulation period of Rabi oscillation and the number of oscillations in each period are given.The quantum decoherence effect of phonon field and cavity field is further studied and extended to the case of multimode cavity field. |
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