Brief research career path

After a first degree in Physics and Theoretical Physics at Cambridge University in 1984, I started my research career as an elementary particle theorist working for a DPhil in quantum chromodynamics at Oxford University. I then took a job in the Theoretical Physics Division, at Harwell Laboratory (then part of the UK Atomic Energy Authority). Over eight years 1987-1995 the experience transmuted me into a condensed matter physicist. I made a return to the academic life with a part-time Royal Society Industrial Fellowship in the Materials Department at Oxford University 1993-1996, and then opted for academia full time when I took a job in the CMMP at the beginning of 1996 as Senior Research Fellow. I became a Reader in 2003 and a Professor in 2007.

The main thread which runs through my career is nucleation. This is the thermally activated process that allows condensation or freezing to take place. A successful description of it requires a knowledge of the behaviour of condensed matter at the level of small molecular clusters. I have studied the phenomenon of droplet nucleation from supersaturated vapours, the process of nucleation of crystalline diamond during thin film growth, the process of freezing of ice from water, the various phase transformations that take place in colloids; particles suspended in a liquid, and the changes in structure of biological molecules when stretched.  

In the late 1990s I derived the second nucleation theorem, a result that can be used to analyse experimental data for the rate of formation of droplets from supersaturated vapours, in order to extract the properties of small molecular clusters. I was able to obtain some first indications of the binding energies of clusters of organic molecules as small as six molecules in size. For this work, I received the Smoluchowski Award at the 1999 European Aerosol Conference, a prize for contributions to aerosol science.

I have also developed computer simulation methods to study the properties of molecular clusters. These are delicate structures requiring delicate simulation techniques. My fundamental area of interest is in understanding how to categorise a bound cluster. This is not an easy task in view of the fact that the clusters have short lifetimes before breaking apart. There are a number of ways to address the relative stability of a cluster, and I have tried several, including Monte Carlo, molecular dynamics, stochastic dynamics, phenomenological etc.

I broadened my activity to include nonequilibrium processes in areas other than nucleation. I am interested in stochastic thermodynamics and fluctuation relations and the understanding of entropy generation that this provides. I have developed these methods to include systems with velocity-like dynamical variables and I am interested in using the rate of entropy production as a means of characterising nonequilibrium steady states. I have coined the word 'obversibility' representing a test of irreversibility that differes from 'reversibiity'.

I have also extended my work on soft condensed matter to include biological applications, in particular on modelling the nuclear pore complex in the living cell.