利用量子信息论和数值计算方法, 对Pólya场态与玻色-爱因斯坦凝聚原子相互作用系统的量子态保真度演化问题进行了研究。讨论了玻色-爱因斯坦凝聚原子间的相互作用强度、Pólya场态概率参数和分布参数, 以及这些物理参数如何影响量子态保真度随时间的演化。研究结果表明: 上述三种物理参量均可调制信号传输中的量子态保真度, 其中光场概率参数η对量子态保真度的变化影响最大, 当 η=0.01时, 量子信息保真度的值非常接近信息理想传输的情形; 另一方面, 凝聚原子间的耦合强度越大, 量子态保真度呈现出的周期性振荡也越强, 但量子态保真度的取值范围不变。

We investigate the dynamics of a system that consists of ultra-cold three-level atoms interacting with radiation fields. We derive the analytical expressions for the population dynamics of the system, particularly, in the presence and absence of nonlinear collisions by considering the rotating wave approximation (RWA). We also reanalyze the dynamics of the system beyond RWA and obtain the state vector of the system to study and compare the time behavior of population inversion. Our results show that the system undergoes two pure quantum phenomena, i.e., the collapse–revival and macroscopic quantum self-trapping due to nonlinear collisional interactions. The occurrence of such phenomena strongly depends on the number of atoms in the system and also the ratio of interaction strengths in the considered system. Finally, we show that the result of the perturbed time evolution operator up to the second-order is in agreement with the numerical solution of the Schrödinger equation. The results presented in the paper may be useful for the design of devices that produce a coherent beam of bosonic atoms known as an atom laser.