The Universe is a beautiful and fascinating puzzle. I am lucky enough to get paid for trying to explain how it works, and to model it mathematically. I am a theoretical physicist lecturing and researching in the University of Leeds, Department of Applied Mathematics.
I study the ways in which microscopic particles interact collectively to generate the large-scale behaviour of flowing fluids. Physics is often misconceived as a purely “reductive” science in the sense of studying only the microscopic building-blocks of nature. In fact, finding the properties of elementary particles does not constitute a full understanding of the physical world, since matter is made of vast numbers of those particles and, surprisingly, its properties depend more on the statistics of large numbers of interactions, than on the details of the constituent particles. For instance, the elastic properties of rubber result from the large number of ways of tangling/untangling its thread-like polymer molecules, but are identical for rubbers made of entirely different chemical compounds. The same statistical principles govern clusters of proteins in the body and globular clusters of stars.
study of the collective properties of vast numbers of interacting
particles is known as statistical mechanics, and it is a large and
active research area worldwide. Statistical mechanics has had
enormous successes over the last century, in explaining and
predicting phenomena such as boiling and freezing,
liquid-crystallinity, magnetism, superconductivity; the list goes on.
However, in non-equilibrium situations, i.e. when the material in
question is flowing, the subject is still in its infancy, as it has
hitherto lacked the rigorous mathematical techniques that are
applicable at equilibrium. I have made progress in finding how the
statistics of large numbers of molecules in a flowing fluid may lead to
simple rules governing the rates at which the molecules undergo
various re-arrangements within the fluid.
All of the techniques that I am developing could help in the design of useful materials, from paints and cosmetics to engineering hydraulics. But, more importantly, the research will give us a better understanding of the world at a fundamental level; the potential applications of improved scientific knowledge are, of course, unpredictable and limitless.
Public Understanding of Science
As well as publishing in academic journals, I enjoy writing about all aspects of physics, and giving public talks about my work and other developments in theoretical physics and applied mathematics.
My blog articles for the Institute of Physics, on their physicsfocus site (listed here) cover my research, science and education policy, and more personal and whimsical views of physics and applied maths.
I try to convince the readers that they don’t need to be Albert Einstein to understand the answers. For instance I guess everyone has heard of “spacetime” and felt curious about what it really means, but most people assume that you need to be good at maths or have a degree in physics to have any chance of really knowing about it. I believe that no topic is too advanced to be explained in an entertaining way. So my articles are aimed at everyone. Curiosity is the only qualification that my readers need. The style is irreverent, but never at the expense of accuracy.
In a similar vein, I have written for BBC Sky At Night Magazine, where my series of feature articles, "The Big Questions", tackled the enduring questions about the universe. More details here.
My current lecture courses are:
MATH3424 Introduction to Entropy in the Physical World
MATH5452M Advanced Entropy in the Physical World
(For a full list, click here.)
Absence of dissipation in trajectory ensembles biased by currents