Lithium-rubidium gas mixtures and molecules

在过去的二十年里，世界各地的许多研究小组已经生产和研究了元素超冷原子气体，即温度仅比绝对零度高百万分之一或十亿分之一的气体，由元素周期表上单一元素的原子组成。这些超冷气体实验的应用主要是科学的，探索与量子力学和多体系统物理相关的基本现象，但也越来越多的技术实用，例如努力开发测量加速度，旋转，力和电磁场的传感器，精度非常高。这个项目将通过研究由两种不同元素的原子组成的量子气体来扩展这项工作。在同一个实验中，两种气体的结合使得研究更广泛的量子现象成为可能。此外，这种结合可以产生超冷的分子气体，这种气体是由双元素原子气体中的两个原子结合在一起形成的。分子对外部场和彼此之间的反应不同于原子。相应地，由分子气体组成的量子力学系统将表现出不同于原子气体的量子现象，也可以服务于不同类型的传感器，而不是原子。更具体地说，这个项目关注的是由锂原子和铷原子组成的气体。本文将利用一种双元超冷原子气体，研究允许自旋自由度动态演化的超冷气体的磁化顺序和动力学。这两种元素的质量差别很大，这将使在周期光势内研究重原子和轻原子之间的相互作用成为可能。最后，研究了锂和铷的光结合形成异核分子。该项目旨在实现单位点分辨率和控制被困在光学晶格中的原子的光缔合和光离解。

In the last two decades, numerous research groups worldwide have produced and studied elemental ultracold atomic gases, i.e. gases at temperatures just a millionth or billionth above absolve zero and composed of atoms from a single element on the periodic table. The applications of these ultracold gas experiments have been mostly scientific, exploring basic phenomena associated with quantum mechanics and the physics of many-body systems, but also increasingly of technological utility, such as efforts to develop sensors that measure acceleration, rotation, forces, and electromagnetic fields with very high precision. This project will expand on this work by studying quantum gases composed of atoms of two different elements. The combination of the two gases in the same experiment allows for studies of a wider range of quantum phenomena. Moreover, the combination enables the creation of ultracold gases of molecules, which are formed by binding together two atoms from the two-element atomic gas. Molecules respond differently than atoms to external fields and to each other. Correspondingly, quantum mechanical systems composed of molecular gases will display different quantum phenomena than atomic gases, and can also serve for different types of sensors than do atoms.More specifically, this project focuses on gases composed of both lithium and rubidium atoms. A two-element ultracold atomic gas will be used to study magnetization order and dynamics in ultracold gases for which the spin degree of freedom is allowed to evolve dynamically. The largely different masses of the two elements will allow for studies of interactions between heavy and light atoms within periodic optical potentials. Finally, the photoassociation of lithium and rubidium into heteronuclear molecules will be investigated. The project aims to achieve single-site resolution and control over photoassociation and photodissociation of atoms trapped within optical lattices.