Sympathetic cooling of cold molecules

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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.