The interactions between electrons and nuclei provide the glue that holds all materials together, with the specifics of these interactions give rise to the vast array of different properties around us, ranging from metallic behaviour, to catalytic biomolecules or magnetic interactions. However, while it is now common to design large-scale engineering projects from buildings to planes with accurate computational simulation, it is curious that the techniques for microscopic simulations of the interactions of these most fundamental particles is still very much lacking. This is true to such an extent that many physical properties of materials cannot be predicted computationally from their underlying constituents with current techniques. This may not be such a problem if experiments could answer all questions about physical processes and mechanisms, but increasingly it is important to also use computational modelling as a complementary approach to guide experimental work and provide access to quantities and insight that is hard or impossible to probe by experimental means.
Research in my group concerns the development of novel computational methods to accurately simulate these many strongly interacting particles. The techniques draw on inspiration from approaches in both physics and chemistry to target specific classes of system, as well as development of efficient algorithms for their implementation. In contrast to the ubiquitous density functional theory, a key feature is that of systematic improvability – the desire for exact limits to the techniques that are guaranteed to reproduce the exact physics of the system. This limit can then theoretically be approached to improve the description of the system allowing for the correct physical processes to emerge naturally from the calculations. This is required for many systems where density functional theory simply cannot provide the accuracy for predictive results in the presence of strong quantum fluctuations.
Electronic Excitations, Strongly Correlated Systems, Embedded-Cluster Techniques, Quantum Monte Carl