Sympathetic cooling of cold molecules

学生正在进行冷原子和分子的EPSRC认可的领域的实验研究。具体来说，他正在研究如何通过与激光冷却原子的冷得多的气体的热接触来实现分子气体到超冷状态的共振冷却。为了做到这一点，分子和原子气体必须被困在同一空间区域。不幸的是，两种气体之间这种接触的自然结果是发生化学反应或分子改变量子态，换句话说-化学发生。在这种情况下，化学是不希望的，因为它导致分子丢失。然而，令人感兴趣的研究问题是--化学物质是否可以被控制？该学生将致力于进一步开发一种名为移动陷阱塞曼减速器的机器，该机器可用于装载一种新型的磁阱，他也在开发原子和分子。这个陷阱的新奇之处在于它的磁场轮廓经过了调整，不仅允许两种气体的磁约束，而且还允许原子的激光冷却。它还被设计成可以通过光泵浦来操纵原子和分子的量子态。PW将研究如何使用磁场和光泵浦来关闭陷阱中的化学物质，以便使交感冷却不受阻碍地发生。

The student is conducting experimental research in the EPSRC-recognised area of Cold Atoms and Molecules. Specifically, he is researching how to achieve sympathetic cooling of a gas of molecules into the ultracold regime through thermal contact with a much colder gas of laser cooled atoms. In order to do this, both molecular and atomic gases must be trapped in the same region of space. Unfortunately, the natural outcome of such contact between the two gases is for a chemical reaction to take place or for the molecule to change quantum state, in other words - chemistry happens. Chemistry is undesirable in this context as it leads to the molecules being lost. However, the intriguing research question is - can the chemistry be controlled?The student will be working on the further development of a machine called a moving-trap Zeeman decelerator that can be used to load a novel magnetic trap, which he is also developing, with atoms and molecules. The novelty of the trap is that its magnetic-field profile has been tailored so as to allow, not only magnetic confinement of both gases, but the laser cooling of the atoms. It has also been designed such that the quantum state of the atoms and molecules can be manipulated by optical pumping. PW will research how to use the magnetic fields and the optical pumping to switch off the chemistry in the trap so as to allow sympathetic cooling to occur unhindered.