My research interests are described briefly below. Many of these areas include longer treatments on separate pages.

Granular Physics

I study granular materials through the use of large-scale computer simulation. Sandia has developed a massively-parallel molecular dynamics code ideal for modeling granular materials. Using this code, I have looked in depth at many granular systems, from hopper flow to packings to gravity-driven chute flow. More information is available here.

Water on Surfaces

Sandia also has a massively parallel molecular dynamics code called LAMMPS ideal for modeling molecules of various types. We are using this code to model Micro-Electrical-Mechanical Systems (MEMS). Our specific interest is the effect of water on MEMS performance, specifically to gain an understanding of how water interacts with both the substrate (usually silicon oxide) and the molecules attached to that substrate.

Spin Glasses

My thesis project was on spin glasses, disordered magnetic materials that share many of the behaviors of glasses. We chose a very simple model of a spin glass, the 2D Edwards-Anderson model and studied it in detail. The first part of the project involved computing all the ground states of the model, a non-trivial undertaking because of the immense degeneracy of the ground state. We characterized perturbations of the system, examining both a quantum transverse field and a compressible lattice. More information is available here.

Combinatorial Optimization

Two short notes on matching problems that can be found here.