Working at the UK’s defence laboratory gives Gareth Brown the ability to apply his physics and mathematics knowledge to real-world applications – and not necessarily in the ways you might expect
They say that if you want to do a PhD, you need to be really, really interested in whatever you’re studying. This is undoubtedly true. I did my PhD in quantum field theory at the Institute for Particle Physics Phenomenology at Durham University, UK, and it was only there that I really came to understand Freeman Dyson’s maxim: "If you want to understand quantum mechanics, just do the math."
Initially, "doing the math" was a joy for me, because it meant I was finally getting to grips with topics I’d first encountered some 12 years earlier, while reading Stephen Hawking’s elating and frustrating bestseller A Brief History of Time. However, after several years of doing hard maths without gaining much additional physical insight, I felt drained and a bit disillusioned. This is one of the big problems with early-stage research careers: by the time you understand what you’re supposed to be doing, you realize that it’s either a bad idea or just plain impossible.
So after I passed my viva, these practical considerations and the seemingly limited opportunities within academia (combined with my newfound lack of drive) meant that I started to think more broadly about my career. Where could I apply mathematics and physics to solve real-world problems and get paid to do it?
It was Physics World that came to my rescue with an advertised vacancy for a "mathematical modeller" at the Defence Science and Technology Laboratory (Dstl). I knew little of this organization to start with but I quickly learned about its crucial role providing science and technology solutions and advice for the UK’s defence and security. I was also immediately taken by the tremendous scope of the organization: a workforce of around 3500 people with expertise in all technical disciplines, spread over four sites in the south and south-west of England.
When I joined I knew I would be working alongside software engineers, computer scientists, system engineers, biologists, chemists, psychologists, linguists, historians, technologists, statisticians and more. I also knew that the range of projects and technical work would be correspondingly diverse, and if in the future I wanted a change, I wouldn’t necessarily need to leave Dstl. Probably the greatest attraction was that the work of Dstl makes a tangible difference, solving real problems and helping the UK and its allies to be safer and more secure.
Cold atoms, hot science
During nearly nine years at Dstl, I have worked on many different projects, all requiring a strong grounding in physics and mathematics. Had I more space, then the topics I could eventually bore you with would include dispersion science, numerical weather prediction, detector modelling and performance, operational analysis, multi-sensor data fusion, signal processing to detect anomalies in large datasets, multi-modal biometrics and high-temperature materials science.
Right now I am the technical lead on Dstl’s Gravity Imaging project. This project is part of the UK’s £300m National Quantum Technology Programme, which is meant to help the UK translate world-leading research in quantum physics into new technology exploiting quantum science. By 2019 our group aims to demonstrate an array of gravity gradiometers that will be able to detect fluctuations in the Earth’s gravitational field at the "nano-g" scale – one billionth of the acceleration due to gravity. At that precision, it will be possible to map 100 m3 underground voids located 10 m beneath the Earth solely due to the reduced acceleration you would feel standing at the surface.
The way we intend to reach that sensitivity involves cooling rubidium atoms to around 100 μK above absolute zero and manipulating them to perform atom interferometry. This technique makes use of the de Broglie wavelength of the atoms: splitting each atom’s wave function into two trajectories and measuring the gravity-induced phase differences between those two paths. It’s exactly the same as in laser interferometry, except instead of photons in the arms of the interferometer, we have atoms; and instead of beam splitters and mirrors we use lasers tuned to specific electronic transitions to guide the wave function.
Essentially, Dstl is charged with being the interface between users of defence-related technologies (military, security services, police or even politicians) and providers from industry and academia. So, as the technical lead for the Gravity Imager project, I talk with military operators to understand the situations where being able to see through walls or image underground would be an advantage. I then use this information to build representative scenarios that can be modelled and used to define the performance characteristics required of gravity sensors. And, finally, I work with academia (in this case the University of Birmingham’s ultracold-atom research group) to help define project goals and understand where this technology could have the biggest impact for defence and security.
A typical day, week or even month is hard to describe, but some recent personal highlights include presenting my work on gravity imaging at conferences (you can watch my presentation at an IET signal-processing conference at http://ow.ly/4rHo3020r7H) and meeting with Vernon Gibson, chief scientific adviser at the Ministry of Defence, to discuss the future impact of quantum technology. As for the more mundane activities, I regularly talk to military personnel to understand their requirements; work with partners such as the University of Birmingham and the technology company e2v to understand technical risks; and review project progress and report achievements. I also build productive relationships with suppliers and international partners, as well as mentor colleagues and present and publish research.
So generally I split my time three ways. A third of it is spent meeting people at universities, in industry, in government, and internationally to develop research collaborations. Another third is doing independent research, reading technical papers, writing code (mostly Python) and making mathematics (mostly in Mathematica). The rest is your normal office stuff: having meetings, writing reports, phoning suppliers, making technical plans and last (but sadly not least) writing e-mails.
Developing and progressing
While all of the people I deal with – from military officers to technical experts – speak English, they rarely understand each other perfectly. Culture and background often influence the true meaning of a sentence, and our "acronym pools" are usually incompatible. This means that to progress at Dstl, being able to present information clearly and to empathize with the audience is really important.
But if that’s not a natural talent for you, don’t be put off. Dstl provides numerous training opportunities and support, and since joining I have learnt lots of new skills. I started out as an expert in particle physics, but I have enjoyed finding how a lot of that knowledge can be applied to other areas of science and technology; in particular, I am fascinated by how people in different fields of mathematical science often talk about essentially the same thing, but using very different language. Understanding other people’s motives and learning how best to communicate and present is a skill that has come on greatly since I was a PhD student. I have also learnt about project and people management, and have some insight into how government works.
You don’t join Dstl with a prescriptive pre-defined job and just plod along; there are always opportunities to do something different. Probably the best piece of advice I have for new starters at Dstl is to take control of your future. Don’t just let your manager tell you what you’re going to do next – tell them! Look around, speak to people and find opportunities to learn more about what other people at Dstl are doing. That’s what I did, and for me it has worked. I hope my future involves leading the development of quantum technologies to improve the UK’s defence, security and prosperity.
About the author
Gareth Brown is a principal scientist at Dstl
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