Physics Diary

A Year in Review

Hello everyone! Today’s post will be different than the usual string theory focused engagements. Normally I would be planning to write a new entry explaining a piece of computation, uploading a string note from one of my notebooks, or organising an essay on an important physics topic. However, I have been so busy with my research that there just has not been enough hours in the day to maintain a constant flow of posts. This should change soon, and I am happy that I already have a lot written and waiting to be edited. The real difficulty has to do with the fact that I don’t like clickbait articles and I have no interest in providing watered down popular guides. The goal is to contribute to making complex subjects like quantum gravity accessible without losing conceptual and technical detail, given that accessibility here also implies an engaged reader wanting to study and understand the subject at hand. The thing about string theory is that it demands one’s full attention. If I am to maintain a research and general string theory blog I would prefer that every entry, whether based on textbook content or frontier research questions, is reasonably substantial and certainly thorough so that it may be beneficial to the reader. I’ve had some great feedback on my articles and notes so far, which I have found both affirming and motivating. I’ve also received some nice feedback about the odd personal post. Slowly over time the process of sharing more personal updates and keeping a personal physics diary is something with which I have become more comfortable. I thought that in this post it might be nice at the turn of the calendar to write about the last year – a year in review of sorts.

It is actually fitting that I would write such a post on this of all days. It so happens that this morning I received a formal PhD offer! Moving on to a PhD is a reality to which I have been orientating myself for some time. But no matter how many times I have thought about it and have tried to prepare for it, especially in terms of my current research focus, when I received my offer this morning it still felt as though everything was happen very quickly. Objectively, I suppose a lot has happened at a relatively rapid pace. Just last year I was an undergraduate being academically accelerated to a full-time research year. I am now only a few months into that research year, planning my MRes dissertation and celebrating the fact that I have been formally offered a PhD position in quantum gravity.

In the time between first arriving at the University of Nottingham for the start of the 2018/19 academic year and the present, I couldn’t possibly list all of the things that I have studied. It has been intense. It started with a complete and comprehensive review of string theory, rederiving the whole of bosonic string theory for my own notes before moving on to superstring theory. In just that time I also taught myself conformal field theory, I had to brush up on quantum field theory, and I had to learn an assortment of important tools ranging from BRST quantisation and the Faddeev–Popov approach to computing string scattering amplitudes, learning about string compactifications, and then trying to cram everything I could about orbifolds and D-branes. Then, as we pushed further into 2019 I moved to superstrings and string geometry while also learning long lists of other physical concepts and mathematical tools in addition to continually working to sharpen my existing knowledge. But what stands out the most about the last year is the Swampland – in fact, I think for me it was the year of the Swampland. It is an absolutely fascinating space of research and I very much enjoyed my time in Spain attending a PhD summer school reviewing things like the Distance and Weak Gravity Conjectures. What also stands out from that first arrival at university to the present time is learning Calabi-Yau manifolds and related geometry; pure spinors, which I started studies while at the summer school in Spain; and then last autumn having to catch up on advanced gravity theory and the braneworld formalism. And now here we are with all of this stuff and more as I work to learn non-commutative geometry and contemplate the nuances of string de Sitter solutions.

Although this really only scratches the surface of an entire year, these descriptions provide some sense of range. I am by no means an expert in any of it, to be frank. Going back to some old calculations I often need to remind myself of certain first principle definitions, like when recently uploading my CFT notes. Typically, it seems like a day is equivalent to a week, as there is just so much to learn. Of the material covered so far and of all the concepts, tools, and theorems studied I can say that one thing I’ve learned is that, in terms of a definitive and coherent theme to research in string / M-theory, in this field every day there seems a new mountain that needs to be climbed. A few days ago it was more to do with gauge-gravity duality and matrix models, which I am learning. Today, it is ‘axilaton’ models. No matter how many mountains one seems to climb, the nature of frontier physics research seems to guarantee tomorrow there will be many new summits.

The last year has also been a momentous one for me personally. Having Asperger’s (Autism Spectrum Condition), which has been described clinically as severe, I experience many challenges in basic day to day life. This also includes assistance with functioning and needs. Now being a formal member of university also presents many additional challenges. What I can that also stands out about 2019 is that I am also ever so grateful to be at a school with tremendous support staff. Being able to participate in a formal academic institution, thanks to the support I receive, has opened up so many new opportunities that would otherwise not have been possible. It has probably been one of my greatest years. Growing up with little support, perhaps this story will serve as an example of how important proper support is for people like myself – or anyone for that matter – to succeed. It reminds me that in the future I would like to write more about living with Asperger’s. It is something I have tried to write about in the past, however successfully or unsuccessfully. But I think the message is also more general – everyone needs support to be themselves, to pursue their interests, and ultimately to self-actualised in a healthy and positive way.

Thinking about the future is something I find difficult. In moving from the past to the present, I’m not quite sure how to project forward in time. What I know for certain is that the next year should be a productive one, given the current trajectory. At present I am planning my MRes dissertation and thinking about possible PhD projects, with the troubles of string de Sitter vacua very much an interest. As I have written before, non-perturbative theory seems to be my point of entry into string research, instead of computing scattering amplitudes or focusing on SCFTs for example. I am thankful to be working under my brilliant professor, Tony Padilla, who is encouraging in this regard and also with my other interests, such as for instance exploring non-geometric backgrounds and matrix models. Every discussion we have is a stimulating, and I enjoy going to his office every week with new ideas to share. Non-geometry will be a lasting topic. One motivation for it, of course, has to do with the no-go theorems for supergravity, which, in turn, relates to questions about the sigma-model prescription that gives geometric vacua. Moreover, there are a number of suggestions in string / M-theory that a perturbative string vacua will not be geometric in the typical sense. Instead, it will be non-geometric. What this means, and to explore some of the mathematical/physical intuition as to why we might think about non-geometric vacua, I think this would make for a terrific future post. Additionally, if a further consequence of strings is that geometry and gravity may even be emergent concepts, and that there is some hint at possibly the idea of non-commutative (non-associative) theory of gravity, then I think another principle of direction is to try and investigate how these are related. We could also ask about how non-perturbative vacua and non-geometric vacua are related, if in fact a formal relation may be defined.

These sorts of topics and questions I suspect will define much of my research year in 2020. But, then again, with each new mountain there sometimes also appears an exotic new valley waiting to be explored. I think I shall take it day by day.