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.
I have been President of the UK Aerosol Society, 2006-9, and a member of the board of the European Aerosol Assembly and the International Aerosol Research Assembly. I have acted as External Examiner to the undergraduate teaching programmes at the Department of Physics, University of Mauritius and Department of Physics, Royal Holloway University of London.