幅度损耗腔中V型原子与光场拉曼相互作用系统中的熵特性

推导了幅度损耗腔中Ⅴ型三能级原子与光场拉曼相互作用系统的密度算符，并由此研究了系统线性熵、光场线性熵和原子线性熵的特性．结果表明：损耗腔中系统和原子除初始时刻呈现纯态外，其它任何时刻均处于混合态，其混合程度经一段时间后保持不变，混合程度的高低与光场平均光子数有关且随其增加而升高，在td时刻，原子与光场完全退耦合，光场退回到初始纯态，但原子仍呈现混合态，当损耗系数增大时。原子和系统的线性熵趋于同一稳定值的速度加快，光场的平均光子数增大后，损耗系数对线性熵影响更为明显。

Entropy property of V-type atom interacting with a cavity-field through Raman process system in an amplitude damping cavity

The density operator was induced via V-type atom interacting with a cavity-field through Raman process system in an amplitude damping cavity, and the properties of linear entropies for atom-field system for atom and for field in the system were investigated. The results show that the linear entropy of the system and atom are larger than zero except the initial time in a dissipative cavity. The values remain a certain degree after some time and increase with the increase of mean photon number. At t_d, the atom is completely decoherent to the cavity. The field comes back to the initial pure state. But the atom is still in a mixed state. The larger the dissipation, the more rapid the linear entropies of the atom and system tend to the certain degree of mixture. And the larger the mean photon number, the more obvious the dissipation influence on the linear entropy.