Non-technical research description

I aim to make this discussion of my research broadly accessible. I have been publicly funded for most of my career, so I should explain to taxpayers the work they have made possible. I also hope to contribute to public understanding of science, an important issue in its own right. If you have any questions about my research, you are welcome to contact me.

My research focuses on theories of particle physics that involve strong interactions. The most familiar strongly interacting theory is quantum chromodynamics (QCD), the "color" theory of the strong nuclear force that binds quarks and gluons into composite particles such as protons. To understand why we say this interaction is "strong", imagine pulling apart two quarks: separating them by a femtometer (10-15 m) would require a force of roughly 10 tons to balance the attractive color force pulling the quarks together. That's strong.

Strongly interacting theories are very challenging to study because they cannot be treated by the standard analytical approach known as perturbation theory. This method treats interactions as minor corrections ("perturbations") to simpler systems, and can only be applied when interactions are weak in strength. In order to study strong dynamics from first principles, I perform numerical lattice field theory calculations. In this approach, space and time are replaced by a regular, finite lattice of discrete sites connected by links. The fields involved in the theory are likewise discretized, and defined on the lattice in such a way that we recover the original theory in continuous spacetime when the lattice is taken to be infinitely large, with its sites infinitesimally close together. The discretized theory involves "only" millions of degrees of freedom, which allows us to stochastically calculate observables through long-established numerical techniques known as Monte Carlo importance sampling. These techniques require large-scale supercomputing.

The great benefit of lattice calculations is that they provide non-perturbative means to study strongly interacting systems. Lattice field theory is currently the only method that can provide quantitatively reliable predictions for strongly interacting theories from first principles, and this will remain the case for the foreseeable future. A disadvantage of the approach is that it is extremely computationally intensive, and continues to push the bounds of high-performance computing.

My work in lattice field theory has addressed several different topics over the years, each of which is summarized on a separate page:

Last modified 6 September 2015

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