MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Physics, Harvard University, Cambridge, MA 02138, USA.
Science. 2022 Mar 4;375(6584):1006-1010. doi: 10.1126/science.abl7257. Epub 2022 Mar 3.
In this study, we achieved magnetic control of reactive scattering in an ultracold mixture of Na atoms and NaLi molecules. In most molecular collisions, particles react or are lost near short range with unity probability, leading to the so-called universal rate. By contrast, the Na + NaLi system was shown to have only ~4% loss probability in a fully spin-polarized state. By controlling the phase of the scattering wave function via a Feshbach resonance, we modified the loss rate by more than a factor of 100, from far below to far above the universal limit. The results are explained in analogy with an optical Fabry-Perot resonator by interference of reflections at short and long range. Our work demonstrates quantum control of chemistry by magnetic fields with the full dynamic range predicted by our models.
在这项研究中，我们实现了超冷钠原子和 NaLi 分子混合物中反应散射的磁控制。在大多数分子碰撞中，粒子在短程范围内以 100%的概率反应或损失，导致所谓的通用速率。相比之下，Na + NaLi 体系在完全极化状态下的损失概率仅约为 4%。通过控制散射波函数的相位，我们通过费什巴赫共振将损失率提高了 100 多倍，从远低于普遍极限提高到远高于普遍极限。结果通过短程和长程反射干涉，与光学法布里-珀罗谐振器类比进行解释。我们的工作证明了磁场对化学的量子控制，其动态范围与我们的模型所预测的完全一致。
