My research is in elementary particle theory. Much of it uses the computational methods of lattice gauge theory and is done in collaboration with researchers at nine other institutions. This collaboration, known as MILC, tackles a wide range of problems in strong and weak interactions and high-temperature physics. Our lattice configurations, which take into account the effects of three flavors of light dynamical quarks, are freely available to researchers world-wide. MILC code is also available; it runs on a wide range of massively parallel computers as well as on individual workstations. Recent computations have been done, for example, at the National Center for Supercomputing Applications (NCSA), the Pittsburgh Supercomputing Center (PSC), the National Energy Research Scientific Computing Center (NERSC) , and the San Diego Supercomputing Center (SDSC) .

A key focus of my recent work has been analytic work on low energy effective theories of QCD, namely chiral perturbation theory . My calculations seek to bridge the gap between numerical lattice calculations and the real world of continuum particle physics. Building on work of Lee and Sharpe, graduate student Christopher Aubin and I have developed " staggered chiral perturbation theory," which adjusts the results of continuum chiral perturbation theory to take into account discretization errors introduced by staggered fermions on the lattice. Using staggered chiral perturbation theory allows the MILC collaboration to obtain precise results for various hadronic quantities. See, for example, an