【作者】 董超；

【导师】 谢芳森；

【作者基本信息】 江西师范大学 ， 光学， 2004， 硕士

【摘要】 首先，本文研究了相位损耗腔中大失谐下两个全同二能级原子与相干态场相互作用系统中场熵的演化特性。讨论了不同原子初始状态、光场平均光子数以及衰变常数对光场线性熵，原子线性熵和光场-原子系统线性熵的影响。结果表明，光场线性熵和原子线性熵较强地依赖于原子的初始状态，但系统的线性熵与原子的初始状态无关。当原子初始处于基态或激发态时，原子始终呈现纯态，而光场和原子-光场系统除在初始时刻对应着纯态外，在其它任何时刻均呈混合态。经一段时间以后，趋于一稳定值，到达稳定值的时间随衰变常数和初始平均光子数的增加而缩短。当原子初始处于基态与激发态的等概率相干叠加态时，系统的线性熵随时间的演化规律不变，光场线性熵随时间作振荡幅度减小的振荡，随时间的延长，该振荡消失，趋于与系统线性熵相同的稳定值。其振荡的时间随初始平均光子数的增加和衰变常数的增大而缩短。随着初始平均光子数的增加，光场的线性熵和系统的线性熵也随之而增大。原子线性熵随时间演化具有准周期性，并趋于一稳定值。随着光子数的增加，原子线性熵随时间的演化频率也随之而增大、振荡的幅度随之减小，原子线性熵与衰变常数无关。 其次，本文还研究了双模压缩真空场与∧型三能级原子非共振相互作用系统中场模失谐量δ和光场的初始压缩因子r对光场压缩影响。结果表明：光场呈现出较规则的压缩现象，压缩程度与r、δ明显相关。当r从零逐渐增大时，光场的压缩程度将经历一个由浅变深然后又由深变浅以至最终消失的过程：较小的场模失谐量对光场的压缩没有明显的影响，而较大的场模失谐量将加深光场的压缩程度。更多还原

【Abstract】 By the quantum theory, we present the evolution of linear entropy in the phase-exhausting chamber, where two identical photons in the 2-level system interact with the coherent field under the condition of large disarrangement. We discuss the effect of different initial atomic status, the mean photon number and the decay constant on the photon linear entropy (PLE), the atom linear entropy (ALE) and the system photon-atom linear entropy (PALE). The results show that when the atom initially stays either in ground state or in the excited state the evolutions of the PLE and ALE are identical, but the PALE maintains zero. Besides, when the atom initially locates in the coherent state in which the probability of the ground state and excited one is equal, there are two points we want to mention. One is that when the mean photon number increases, the PALE evolution versus time is the same as the PLE and ALE ones. The other is that at the temperature of given value, the ALE is invariable while the time for PALE and PLE to reach the stable value shortens as the decay constant X increases.We also discuss the effect of Sand the initial compression factor r of optical field on the optical field compress. Here Sis the disarrangement value of the field variable pattern in the system, in which the non-resonant interaction takes place between double mode compression vacuum field and the A-form 3-level atom. The results shows that the optical field constricts regularly and the degree of the constriction strongly depends on the r and δ.更多还原