Statistical, active, and soft matter physics
We are developing theories and powerful Monte Carlo methods for studying the behaviour of active matter and the interfacial structure of complex such as colloids and knotted macromolecules.
The behaviour of liquids at an interface is an important physical problem with wide-ranging fundamental and practical implications. For example, the behaviour of a liquid squeezed between two surfaces determines how good that liquid can act as a lubricant. Likewise having a surface which repels water, called hydrophobicity, is crucial for reducing drag on ship hulls and also underpins Teflon coating on non-stick cooking pans.
To understand and engineer this behaviour requires a detailed understanding of the nature of the interactions between particles within the bulk of the liquid and interactions they have with any interfaces confining them. Much of our research involves applying state-of-the-art Monte Carlo simulation methods to explore the fascinating physics that occurs in complex fluids like colloids, such as self-assembly and their unusual phase behaviour. An appealing aspect of colloidal physics is that simple models often correspond quite closely to real systems, and this allows us to collaborate meaningfully with experimentalists.
Another novel statistical physics problem we are researching is active particles. These are particles that have a capability to drive themselves through a fluid. Examples in nature would include bacteria, but many synthetic active particles have been created that use optical fields to propel themselves. When there are many active particles, they interact with each other often resulting in interesting phenomena like collective flocking motion and phase transitions. Our work models both the physics driving active matter and their emergent behaviour.