It is found that in the absence of dissipation and average photon number of the reservoir the linear entropies of the atom and the field varies with time periodically , going to zero at the disentanglement times , and the period is the same as that of bell function and the linear entropy of the total system is zero at any time . if the cavity dissipation and the average photon number of the reservoir is taken into account , the linear entropies of the atom and the field present local maxima and minima and the difference between them diminishes with time , tending to asymptotic values 結(jié)果表明,在忽略腔損耗和熱庫(kù)的平均光子數(shù)時(shí),原子和場(chǎng)的線性熵有周期性的變化,在沒有糾纏的時(shí)刻,值為0 ,此時(shí)的周期與bell函數(shù)相同,而系統(tǒng)的線性熵在任何時(shí)刻都為0 ;如果考慮到腔場(chǎng)的損耗和熱庫(kù)的平均光子數(shù),原子和場(chǎng)的線性熵有局部的最大值和最小值,它們之間的差距隨時(shí)間逐漸減小,趨向一個(gè)漸進(jìn)值。