Dr Paddy Royall

"The buzz of achieving something can feel as though you’re on a wave. Taking things to the edge of what can be done – I find that enormously exciting."

Dr Paddy Royall is an experimental physicist whose research focuses on tackling key unsolved problems in everyday materials, from liquids to glass. After obtaining a degree in physics from Edinburgh University, Paddy took a year out of academia where a sailing trip followed by a stint as a modelling expert in London contributed to the realisation that science was his true calling.

He completed a PhD in Cambridge, then did a postdoc at the University of Utrecht in the Netherlands, before taking a fellowship at the University of Tokyo’s Institute of Industrial Science, and subsequently Bristol University, where he runs labs in Physics, Chemistry and the Centre for Nanoscience and Quantum Information (NSQI).

Paddy’s approach combines computer simulations with novel experiments where suspensions of micron-sized colloidal particles, whose Brownian motion leads them to obey statistical mechanics in the same way as atoms and molecules, are imaged in 3D at the single-particle level. This two-pronged approach is uniquely powerful for tackling a wide range of problems in condensed matter.

The big thing that led me into science was reading Stephen Hawking’s A Brief History of Time when I was 14; that was quite a moment. While studying physics at Edinburgh I was really inspired by some of the guys there. There was one particular scientist called Wilson Poon, who was about as old as I am now, and he’s now one of the real leaders in the field.

I remember going to see him one day just before my finals, I hadn’t even thought about a PhD at that time. I talked to him for about two or three hours and he talked about all the things we could do and that got me really excited. That’s what made me decide to do a PhD.

I had a year off in between where I went on a long sailing trip. Then I went to the city for a year, but within 30 minutes I realised that there were more exciting things than playing with extraordinarily large amounts of money. I thought working as a modeller would be interesting and challenging but it was neither.

Physics is about describing the world with numbers, so I thought it would be interesting to describe markets with numbers. I also thought the city would be quite lucrative; my plan had been to go there for about five years, retire, and live life on a boat. But I realised that I missed the physics.

I went back to science and got a post-doc in the Netherlands where I actually learned everything about liquid state theory. I then spent three years on a fellowship in Tokyo, which is where I was lucky enough to get my work into top journals; that was a very exciting time.

I then got the fellowship in Bristol in 2007 and have been here ever since, although I still spend a lot of time in Tokyo. I spend time all over the place – I work with people in many places – Australia, Japan, Italy, Germany and the US.

Liquid state theory is not for the faint hearted. I love liquids, they’re hard. Gases are easy, solids are easy, but liquids are hard. Very hard. An undergraduate physicist has a very good grounding in gases and solids; but as far as I’m concerned, they’re not remotely as difficult as liquids are.

Bristol has a strong background in liquids, dating back to at least to John Lennard-Jones in the 1920s and Charles Frank after the war. One of the questions that we work on is exploring what glass is – if you had a beaker that was full of glass, or it was full of water, you wouldn’t be able to tell the difference until you moved it because both glass and water are transparent.

Even with the most sophisticated ways of measuring the atomic arrangements in liquids and in glass, the structure looks the same in both.

What we’re interested in is trying to understand why you can have a liquid which moves, a glass which doesn’t move and yet the arrangement of atoms is apparently the same. Frank’s idea was that when you cooled down a very simple model of liquids, the atoms arrange into an icosahedron. But you can’t fit these five fold-symmetric objects together in 3D, in the same way you can’t fit pentagons together in 2D : five-fold symmetric objects don’t fill space.

Frank’s idea was that you’d cool down this simple liquid and it’d form these fivefold symmetric bodies and they would not fill space, that would mean that it would not be a crystal (usually when we cool things down they turn into a crystal). That was conjectured by him in 1952 and found experimentally by us in 2008 (see the Nature Materials paper referenced in the related links above).

My personal view on teaching is that it’s absolutely crucial. There’s a way that teaching makes you think which is actually essential to the way you do research; you don’t know something until you’ve had to teach it. Students ask questions that you can’t answer, so you have to know your material.

I’ve gained a huge amount from the teaching that I’ve done here because it’s made me go back and look at things that I thought I’d half-forgotten and that’s really important.

The scientific community here is great; people are very helpful and accessible. I think a lot of it comes down to culture. It’s very different to Japan where my experience was that every member of faculty has their own empire, which can be very isolating.

I much prefer interacting with people – two people can make something that is more than the sum of its parts sometimes. I get a lot out of that. There are many people throughout the University who I interact with and I think that’s very positive.

You have to work incredibly hard to succeed as a scientist. My field is quite small so if you can get to know people that’s quite good; I know many in the field. That’s productive when it comes to submitting papers and also in terms of keeping very high standards in your areas.

People are quite driven in science; they have personalities that are pretty unusual so you can sometimes get the situation where people don’t get on, and that can be difficult, but I suspect that’s the case wherever you work, I don’t imagine that’s specific to physics.

What might be particular to science is the fact that people can have deep disagreements of what theory is correct; people become very unhappy about this because they really care about their theory. If a lifetime’s worth of your work is about to be proved wrong, that’s not a comfortable feeling.

To an extent I’m okay because I’m an experimentalist so I don’t get mixed up in that but there are theories that are definitely wrong and people don’t necessarily react in a rational way to a challenge.

I’ve been working with a collaborator in Dusseldorf on a project that’s the absolute frontier of what’s being done in the field. It’s amazing; I love this kind of thing.

This originally came from one of my PhD students who began the collaboration after meeting at a conference. The idea is a clever development on some new ideas in statistical mechanics. It’s on the edge of what we could do. I find that enormously exciting.

Dr Paddy Royall, Royal Society University Research Fellow, School of Chemistry, School of Physics


Watch Paddy discuss what it means to be a scientist in the 21st century in our new film Can science save us?

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