提出了利用Efimov共振辅助的受激拉曼绝热通道(ER-STIRAP)过程实施超冷原子向异核四聚物分子A3B转化的理论方案,得到了转化过程中中间态分别为同核Efimov三聚物A_3和异核Efimov三聚物A_2B两种途径下系统的暗态解,证实了ER-STIRAP技术对超冷异核四聚物分子A_3B合成的可行性和有效性.研究了外场参数,包括缔合光脉冲的强度、脉宽、磁耦合强度及其失谐量等对A_3B形成的影响.对两种不同中间态的转化途径进行比较发现,与中间态为异核Efimov三聚物A_2B的途径相比,经历中间态为同核Efimov三聚物A_3的途径时系统实现最终四聚物分子A_3B的产率更高.另外,还讨论了系统内禀的非线性和中间态的自发辐射损失对异核四聚物分子合成的影响.
We present a theoretical scheme for conversion from ultracold atoms to heteronuclear tetrameric molecule A_3B via Efimov resonace-assisted stimulated Raman adiabatic passage(ER-STIRAP).The dark state solutions of the system are obtianed for two different pathways.For the first pathway,the intermediate state is populated by homonuclear Efimov trimer A_3 and the second one by heteronuclear Efimov trimer A_2B.The feasibility and the effectiveness of the scheme are also verified.Meanwhile,we investigate the effects of external field parameters,including the intensity of associated laser pulses,its width,magnetic coupling strength and its detuning,on the fomation of heteronuclear tetrameric molecules.By comparison,it is found that the ultimate yield of the tetrameric molecules for the second pathway is less than ones for the first pathway.In addition,the effects of the intrinsic nolinearity of the system and the spontaneous decay in the intermediate state on the tetramer formation are discussed.