Master Thesis: Tunnelling in water clusters

In my first post I'll briefly talk about my first proper piece of research, my Master thesis. As part of my last year of Cambridge I spent 6 months doing a project in the theoretical chemistry group of Prof. Dr. Stuart Althorpe. Although I've done a few smaller research projects in previous summers, it is still quite different if one works on a topic for 6 months rather than just a few weeks. At the beginning it is much less clear what will be achieved and throughout it is quite difficult to keep everything ordered in your mind. From the little research I've done up to now, I'd say that staying on top of what you have tried and what has actually worked is quite crucial in order to not get lost in the ocean of possibilities. Most of the time what helped me was to go and talk to other members of the group about my work, trying to get ideas of the conversations. Luckily my group was very open about that and within just a few days I found myself taking part in passionate discussions.

What fascinated me most about the topic of quantum tunnelling were the mathematical and physical challenges. Firstly, we never really talked about tunnelling in lectures in a quantitative way, meaning that we never considered ways to actually calculate the resulting splittings in the spectra. So this project offered a good chance to gain a more thorough understanding of this quantum mechanical phenomenon. Next, the method to calculate the splittings uses the so-called Feynman path integral description of Quantum Mechanics and ever since my Physics friends talked about this over lunch, I was curious to find out more about it. This thesis provided an excellent opportunity to do so.

I will probably write a little bit more about ring-polymer instanton theory in a later post, but for now I will just provide the thesis itself. My first draft massively exceeded the allowed word limit, so I had to remove some details -- mostly from the theory section. This shorter version is the version I handed in and got my degree for. It can be found by clicking the link "Dissertation" in the table below. A proof-read extended version including everything from the first draft is given below as well.

Dissertation (extended version)