A gas of ultracold polar molecules at high phase-space density

超冷极性分子在物理学和物理化学中有着广泛的新应用。它们可以用来测试基础物理，研究超冷化学，研究偶极量子气体，处理量子信息，以及模拟强相互作用的多体量子系统的行为。所有这些应用都需要高相空间密度的分子气体-这意味着非常低的温度和足够高的密度。最近，激光冷却已被应用于分子，在微开尔文温度下产生捕获的分子样品。然而，相空间密度仍然低于许多应用所需的数量级。本项目的目标是提高相空间密度，目标是分子的量子简并气体。首先，将探索压缩气体的方法，以增加其密度。然后，分子将与超冷原子共同捕获，并将探索增强弹性碰撞同时抑制非弹性和反应性碰撞的方法。在碰撞得到控制的情况下，原子的蒸发冷却以及原子和分子之间的共振冷却将提高相空间密度。

Ultracold polar molecules are needed for a wide range of new applications in physics and physical chemistry. They can be used to test fundamental physics, to study ultracold chemistry, to investigate dipolar quantum gases, to process quantum information, and to simulate the behaviour of strongly-interacting many-body quantum systems. All these applications require molecular gases at high phase-space density - meaning very low temperature and sufficiently high density. Recently, laser cooling has been applied to molecules, producing trapped samples of molecules at micro-kelvin temperatures. However, the phase-space density remains orders of magnitude below that needed for many applications. The goal of this project is to increase the phase-space density, aiming for a quantum degenerate gas of molecules. First, a method to compress the gas will be explored, in order to increase its density. Then, the molecules will be co-trapped with ultracold atoms, and methods will be explored to enhance elastic collisions while inhibiting inelastic and reactive collisions. With the collisions under control, evaporative cooling of the atoms, together with sympathetic cooling between atoms and molecules, will drive up the phase-space density.